FOUNDATIONS Flashcards

Question

What is the Golgi Apparatus?

Answer 1

Flattened, membrane bound cisternae

Answer 2

Transport vesicles arrive from SER; Golgi modifies and packages them - eg: adds sugars, cleaves some proteins

Answer 3

- Oblong, cylindrical organelles - Power generators of the cell (generate ATP via oxidative phosphorylation and involved in the synthesis of certain lipids and proteins)

Answer 4

- Inner membrane: extensively folded to form cristae, which act to increase SA - Contain their own DNA and system for protein production

Answer 5

- Specialised membrane structures which link individual cells together into a functional unit - prominent in epithelia - 3 types

Answer 6

- link cells to form diffusion barrier - also known as 'tight junctions' or 'zonula occludens'

Answer 7

Provides mechanical strength - Adherent junctions: create network of interconnected cells via actin, ties cell together, important in tissue exposed to abrasive forces - also termed 'zonula adherens' - Desmosomes: Links submembrane intermediate filaments of adjacent cells

Answer 8

- allow movement of molecules between cells - Each junction is a circular patch studded with pores produced by connexon proteins found in epithelia

Answer 9

Close association of several types of junctions found in certain epithelial tissues - eg: ZO: zonula occludens or tight junction, ZA: zonula adherens

Answer 10

- Endo: material from the extracellular space can be incorporated into the cell. Membrane invaginates (turns inside out), fuses, and newly made endocytic vesicle buds into cell. (Exo: opposite) - Phago: bacteria binds to cell surface, cell engulfs it to form phagosome, binds with lysosome containing digestive enzymes

Answer 11

Period of time between the birth of a cell and its own division to produce 2 daughter cells

Answer 12

Cells that continue to divide regularly in definite intervals

Answer 13

Mitosis and Interphase

Answer 14

G1, S phase, G2

Answer 15

Proteins whose concentration increases and decreases throughout the cycle (Cyclins A,B,E)

Answer 16

Cyclin-dependent kinases (CDKs) - act in conjunction with cyclins

Answer 17

Interval between the end of mitosis and beginning of next - Cell is either resting or performing its specialised work not in mitosis

Answer 18

DNA replication - promoted by cyclin A and CDKs - Begins 8hrs after mitosis... 7 to 8 hours to complete

Answer 19

When the double-stranded DNA unwinds, each single strand serves as a template for creating a new matching strand.

Answer 20

Condition with defective DNA repair due to a deficiency in the "nicking endonuclease" enzyme.

Answer 21

UV irradiation

Answer 22

- dry keratosis hyperpigmentation - skin atrophy - increased UV sensitivity - potential for corneal ulcers.

Answer 23

Risk of developing squamous cell carcinoma of the skin.

Answer 24

Homologous strand exchange directed by the RAD51 protein.

Answer 25

Hereditary breast cancer suppressors

Answer 26

Mutations in the hMSH2 gene, which is responsible for mismatch repair.

Answer 27

Chromosome 2.

Answer 28

Gap between end of mitosis and beginning of S phase - Growth phase - initiate another cycle - controlled by cyclin E and CDKs - longest phase

Answer 29

DNA damage results in apoptosis or G0

Answer 30

Contain cells that retain capacity for division and in process of differentiation but are no longer dividing - growth factors can stimulate quiescent cells to leave G0 and re-enter the cell cycle

Answer 31

Gap between the end of S phase and beginning of mitosis - Cell must duplicate organelles - controlled by cyclin B and CDKs - 2-4 hours to complete

Answer 32

Distribution of identical copies of the parent cell genome to the two daughter cells

Answer 33

- Prophase - Metaphase - Anaphase - Telophase

Answer 34

- Nuclear membrane disintergrates, chromosomes condense - Centrosomes migrate to opposite sides

Answer 35

- Nuclear membrane and nucleolus disappear. - Chromosomes are entangled in a meshwork of continuous microtubules.

Answer 36

- Chromosomes align at metaphase plate and attach to spindle fibres - Colchicine arrests cell division preventing formation of microtubules of the spindle

Answer 37

- Spindle fibres contract, each pair of newly formed chromosomes separates and migrates to the opposite pole of spindle. 2 identical and complete chromosomes are formed.

Answer 38

Chromosomes fail to migrate properly in Ana: one daughter cell receives extra chromosomes and the other is deficient

Answer 39

2 daughter cells of unequal length due to centromere splitting transversely instead of longitudinally

Answer 40

New nuclear membrane and nucleolus appears

Answer 41

Cytoplasm divides and two complete cells are formed Cytokinesis: cleavage furrow develops around the equator region and daughter cells separate

Answer 42

- Enter the cell cycle again - Enter the G0 phase

Answer 43

- Epithelium - Connective tissue - Muscle tissue - Nervous tissue

Answer 44

- covers body surfaces - lines hollow organs - forms glands

Answer 45

Through their cytoskeleton

Answer 46

- thin layer of specialised extracellular material that separates the basal surface of epithelial cells from underlying tissue and provides support - non-vascular: lacks blood vessels

Answer 47

- Apical side: facing lumen or external environ - Basal side: attaching to basement membrane.

Answer 48

- Mechanical barrier (e.g., skin) - - Chemical barrier (e.g., lining of the stomach), - Facilitates diffusion, - Absorption/secretion, Containment (e.g., urinary bladder lining)

Answer 49

1. No. layers of cell 2. Cell Shape 3. Cell/Tissue Surface 4. Presence of any specialised cell types

Answer 50

Multiple layers but all cells make contact with basal lamina

Answer 51

Tall and thin

Answer 52

Finger-like projections at apical end of cells that increase SA and aid in absorption - found in digestive system

Answer 53

These tissues contain a tough, protective protein called 'keratin', often found in the skin, hair, and nails

Answer 54

Goblet Cells

Answer 55

Lack ducts and release their products, eg: hormones, directly into bloodstream - distributed throughout body via vascular system.

Answer 56

Exocrine glands secrete their products onto a surface directly through a duct

Answer 57

Loose and dense CT - tissues and tendons

Answer 58

Aligned in parallel fashion - eg: tendons

Answer 59

Run in many directions - eg: ligaments.

Answer 60

Dense: densely packed bundles of collagen fibres Loose: loosely packed fibres separated by ground substance

Answer 61

- Type of hard CT - strong, flexible, compressible, and semi-rigid tissue that is avascular (lacks blood vessels)

Answer 62

- Hyaline, Elastic, and Fibrocartilage

Answer 63

Glassy appearance - most common type, found in every joint

Answer 64

Contains thin elastic fibres that provide elasticity

Answer 65

Contains more collagen, making it tougher and gives additional strength to other parts - eg: intervertebral discs.

Answer 66

- Cortical: dense outer shell with no cavities - Spongy/Trabecular bone: with numerous interconnecting cavities

Answer 67

Characteristic structures of mature bone formed during bone remodeling

Answer 68

- Osteocytes (bone cells) - Osteoclasts (bone-resorbing cells) - Osteoblasts (bone-forming cells)

Answer 69

- Organic matrix (collagen and glycoproteins) - Inorganic matrix (calcium and minerals)

Answer 70

- Metabolically active cells responsible for synthesising and turning over a large volume of ECM

Answer 71

- specialised to generate force by contraction - achieved through movement of actin fibres over myosin fibres.

Answer 72

- Smooth - Cardiac - Skeletal

Answer 73

- Involuntary, non-striated

Answer 74

- Involuntary, striated, single nucleus at centre of fibre, intercalated discs: contains intracellular junctions for stability

Answer 75

Voluntary, striated, multinucleated with peripheral nuclei (no nucleus at centre)

Answer 76

Neurons and their supporting gila cells

Answer 77

- CNS: the meninges - PNS: the perineurium

Answer 78

Allows for rapid communication between different parts of the body, facilitating the transmission of electrical signals/info

Answer 79

- most common type - multiple dendrites, one axon.

Answer 80

one dendrite, one axon.

Answer 81

Single process that divides into a peripheral and central branch

Answer 82

Responsible for immune surveillance

Answer 83

Provide support and are involved in ion transport

Answer 84

Produce myelin which insulates and speeds up nerve cell conduction

Answer 85

Produce myelin and provide support to axons.

Answer 86

arteries → arterioles → capillaries → venules → veins

Answer 87

arteries, veins, and capillaries

Answer 88

Consists of single layer of squamous epithelial cells (endothelium) supported by a basal lamina and a thin layer of CT - separated from the t.media by internal elastic membrane

Answer 89

- Composed of smooth muscle cells - separated from the t.adventitia by external elastic membrane

Answer 90

- Composed of supporting CT

Answer 91

- Elastic arteries contain multiple sheets of elastic fibres in their t.media, providing elastic recoil to handle high-pressure blood.

Answer 92

Responsible for delivering nutrients and oxygen to the walls of arteries/ veins while removing waste products

Answer 93

- only 1/2 layers of smooth muscle in their t.media - minimal adventitia

Answer 94

Consist of endothelial cells and basal lamina

Answer 95

- Continuous: (no pores, found in muscle, nerve, skin) - Fenestrated (small pores, found in kidney) - Discontinuous (large gaps, found in liver)

Answer 96

-In epithelial cells resting on the basement membrane - Epidermis of skin, hair, nails - Cornea of eye - Hyaline cartilage

Answer 97

- Meta arterioles (branches of small arterioles, pre-capillary) - Pre-capillary sphincters (control flow to the meta arterioles and capillaries), - Thoroughfare channels (allow flow when pre-capillary sphincters are closed, saving material and heat) - Capillaries (material exchange occurs).

Answer 98

large vein → medium vein → small vein → venule

Answer 99

Consist of endothelium and a thin layer of CT

Answer 100

- Venules: intermittent smooth muscle in t.media - Postcapillary venules: no significant smooth muscle layer

Answer 101

T.intima, a thin continuous t.media, t. adventitia

Answer 102

Has a thick t.adventitia that incorporates bundles of oriented smooth muscle

Answer 103

Transports lymph to lymph nodes for immunological surveillance

Answer 104

- Tissue pressure - Muscle contraction - Presence of valves in the lymphatic vessels

Answer 105

6L - separated by spinning in a centrifuge

Answer 106

- Top: Plasma - Middle: WBCs - Bottom: Erythrocytes (RBCs)

Answer 107

When blood clots are removed after the clotting factors have been taken out

Answer 108

Plasma contains clotting factors, while Serum does not.

Answer 109

- Water (about 90%) - plasma is worth 55% - it carries various proteins (albumin, immunoglobulins, clotting factors)

Answer 110

- Hydrostatic pressure: forces plasma components into cells - Osmotic pressure: draws water out of capillaries due to low water concentration on the venous side

Answer 111

45% - Erythrocytes (red blood cells) that are biconcave discs with no nucleus - stain red (haemogloblin)

Answer 112

- role in hemostasis (prevention of blood loss)

Answer 113

- white blood cells with granules in their cytoplasm neutrophils, eosinophils, and basophil

Answer 114

Single, multi-lobed nucleus -make up 40-75% of WBCs -Function as phagocytes when activated

Answer 115

- have acidic granules that stain pink, bi-lobed nucleus, and make up 5% of WBCs. - Granules contain hydrolytic enzymes involved in inflammation.

Answer 116

- Bi-lobed or S-shaped nucleus, basic granules that stain purple/blue (different from eosinophils), and make up 5% of WBCs. - Serve as effector cells in allergic reactions

Answer 117

- WBCs without granules in their cytoplasm Monocytes and Lymphocytes

Answer 118

- Large kidney bean-shaped nucleus, make up 1-5% of WBCs - Serve as precursors of tissue macrophages, functioning as phagocytes.

Answer 119

- Small spherical nucleus and basophilic (blue) cytoplasm. Make up 20-50% of WBCs and can differentiate into B cells, which give rise to antibody-secreting plasma cells, and T cells, which have various defensive functions

Answer 120

= development of blood cells - earliest blood cell development occurs about 3 weeks into gestation

Answer 121

- Development occurs in the second trimester within bone marrow - B.M responsible for producing blood cells

Answer 122

+ charge Mass of + 1

Answer 123

- charge Mass: negligible (too small)

Answer 124

No charge Mass of 1

Answer 125

Covalent bonds

Answer 126

Ionic bond

Answer 127

Hydrogen bond

Answer 128

Hydrophobic interaction

Answer 129

Interaction of electrons of non-polar substances

Answer 130

The attractive force that an atomic nucleus exerts on electrons within a bond

Answer 131

(De)Phosphorylation

Answer 132

Acylation: - stable and useful for joining molecules

Answer 133

Involves the addition of a carboxyl group - occurs at end of a molecule, often at its reactive centre.

Answer 134

Esterification - water is released

Answer 135

Water is removed - molecules polymerise, forming larger compounds

Answer 136

Water is added - molecules depolymerise/break down into smaller components

Answer 137

Involve transfer of electrons from one molecule to another - O: loss - R: gain Redox pairs: one molecule is oxidised while another reduced

Answer 138

Molecule's structure and electronegativity differences

Answer 139

Carbs with SINGLE ring structure

Answer 140

Carbs with DOUBLE ring structure

Answer 141

Long chains of monosaccharides - serve as storage carbs - eg: Glycogen- rapid metabolism of glucose.

Answer 142

Energy is neither created nor destroyed (conserved)

Answer 143

-Enthalpy: heat content - Entropy: randomness/disorder - affects free energy of system + determines whether a reaction is spontaneous or requires energy

Answer 144

Energy transformations aren't 100% efficient - some energy loss in form of heat

Answer 145

𝝙G = Energy of Products (𝝙H) – Energy of Reactants (T 𝝙S)

Answer 146

Reaction is in state of equilibrium readily reversible (proceed in forward or reverse direction)

Answer 147

- Negative ΔG - Energy of products < Energy of reactants - occur spontaneously + release energy used for cellular processes

Answer 148

- Positive ΔG - Energy of products > Energy of reactants - cannot occur spontaneously + require energy input to proceed

Answer 149

All biochemical reactions occurring within body

Answer 150

Breaking down complex molecules into simpler ones, releasing energy (exer.and oxidative)

Answer 151

Synthesis of complex molecules from simpler ones + requires energy input (ender. and reductive).

Answer 152

Electrons are shared unequally, enabling it to act as a universal solvent.

Answer 153

Non-polar substances aggregate in aq.solutions and exclude water molecules, leading to formation of structures like micelles, lipid bilayers, 'oil slicks.'

Answer 154

Act as selective and controllable barriers to outside world

Answer 155

- Polar hydrophilic head and Non-polar hydrophobic tail - form micelles and lipid bilayer of CMs

Answer 156

⍺-carbon bonded to: - Amino group (-NH2) - Carboxyl group (-COOH) - A hydrogen (-H) - A side chain (-R)

Answer 157

Uneven distribution of electrons: partial positive and negative charges, making them hydrophilic (water-attracting)

Answer 158

- Non-polar, Hydrophobic - Polar, Hydrophilic - Acidic - Basic

Answer 159

Even distribution of electrons: no significant partial charges, making them hydrophobic (water-repelling)

Answer 160

Formed by endergonic process, joining amino acids through condensation reaction - strong, rigid, crucial for protein folding

Answer 161

Yes: - N-terminus (left/amino end) - C-terminus (right/carboxyl end).

Answer 162

-partial double bond - planar in structure

Answer 163

Proton acceptors

Answer 164

- Proton (H+) donor - Strength depends on how readily it donates a proton to base, which is measured by acid dissociation constant (Ka)

Answer 165

Measurement of number of protons (H+) in solution - Formula: pH = -log10[H+].

Answer 166

Connects Ka (acid dissociation constant) of weak acid with pH of solution containing this acid - expressed as: pH = pKa + log[A]/[HA]

Answer 167

Solutions used to control pH of reaction mixture - At pKa value, buffers resist change in pH when moderate amounts of acid/base added, as long as the conc of acid is equal to the conc of conjugate base.

Answer 168

TRUE - Haemoglobin in blood

Answer 169

Molecules with no charged side groups but have separate positively/negatively charged ions

Answer 170

Change in ionisation leading to changes in structure/ function

Answer 171

Between Alpha carbon and amino group Alpha carbon and carboxyl group

Answer 172

Sequence of amino acid residues in polypeptide chain

Answer 173

Localised conformations of the polypeptide backbone that are held together by hydrogen bonds

Answer 174

- Alpha helix - Beta sheets (strands and sheets) - Triple helix

Answer 175

Polypeptide chain where the CO group of one amino acid forms hydrogen bonds with the NH group of another amino acid located 4 residues away

Answer 176

- (anti)/parallel and turns between strands - form zigzag beta-pleated sheets.

Answer 177

Component of proteins in bone and tissue - most abundant in vertebrates and forms water-insoluble fibres - eg: Tropocollagen

Answer 178

Influences strength of CT

Answer 179

Undergoes covalent crosslinking as age increases - weaken tissues

Answer 180

Bleeding gums, Skin discolouration (Scurvy)

Answer 181

3D arrangement of entire polypeptide chain

Answer 182

- Covalent disulfide bonds - Electrostatic interactions (salt bridges) - Hydrophobic interactions - Hydrogen bonds (in backbone and side chains)

Answer 183

Keratin found in hair and wool: mechanically strong structures with parallel polypeptide chains aligned along a single axis - insoluble in water

Answer 184

Haemoglobin: - spherical shape - soluble in water/salt solutions

Answer 185

Spatial arrangement of polypeptide chains in a protein with multiple subunits.

Answer 186

Hemoglobin - 4 subunits : 2 ⍺ and 2 β chains. Each subunit contains 1 haem group, binds to oxygen - changes affinity of other subunits for oxygen.

Answer 187

Tropocollagen - structural unit of a collagen fiber - formed by 3 helical chains twisted around each other to create a right-handed superhelix - contains interchain hydrogen bonds and intermolecular covalent bonds.

Answer 188

Fold spontaneously but can be slow and proteins may fold incorrectly before completely synthesised or associate with other proteins before folding properly: lead to conditions like Alzheimer's, Parkinson's, OCD

Answer 189

- Heat: increases vibrations in proteins - pH extremes: disrupt electrostatic interactions - Detergents and urea: disrupt hydrophobic interactions - Thiol agents and reducing agents: disrupt disulfide bonds

Answer 190

Maintenance of steady states within our bodies coordinated by physiological mechanisms.

Answer 191

- Intrinsic: controls inside organ - Extrinsic: mechanisms initiated outside an organ, accomplished by nervous and endocrine systems

Answer 192

- Feedforward: responses made in anticipation of change - Feedback: after change detected

Answer 193

Sensor, Control center, Effector - promote stability

Answer 194

Oppose initial change in controlled variable, maintain stability and keep physiological conditions within narrow range

Answer 195

Amplify an initial change in a controlled variable - leading to rapid and dramatic physiological responses

Answer 196

- Mean Arterial Blood Pressure - Core Body Temperature - Blood Glucose - Blood Gases (arterial PO2 and PCO2) - Blood H+ concentration (pH)

Answer 197

Sensor → Control centre → Effector

Answer 198

- Electric current heats cathode - Electrons emitted + strike the anode - X-rays exit through a window, penetrate patient, and scatter - Denser tissues allow fewer X-rays to pass through, forming the image

Answer 199

- Reveals structures surrounded by bone - Highlights abnormalities that damage white bone, eg: cancer

Answer 200

- Radiation (health risks) - Abnormality must be different density to surrounding tissue in order to be visible

Answer 201

Mature haploid male/female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote

Answer 202

Factor that can cause abnormalities in a developing fetus

Answer 203

Cause mutations in genetic material

Answer 204

Conceptus/Embryo

Answer 205

EMBRYONIC PERIOD

Answer 206

Foetal period

Answer 207

- Gametogenesis - Fertilisation - Cleavage - Gastrulation - Formation of Body Plan - Organogenesis

Answer 208

- Formation of gametes: Spermatogenesis: formation of male gametes Oogenesis: formation of female gametes - Primary oocytes begin meiosis by weeks 28-30 but arrest in prophase until puberty

Answer 209

- Tough protective protein coat around oocyte

Answer 210

Fusion of sperm and oocyte to form zygote - in ampulla of uterine tube

Answer 211

Rapid mitotic cell division process, with no increase in size, resulting in small cells (Blastomeres)

Answer 212

Zygote → Morula → Blastocyst

Answer 213

Formation of germ layers (body axis): - Ectoderm (outer) - skin, nervous tissue - Mesoderm (middle) - muscle tissue, organs - Endoderm (inner) - GI lining tract

Answer 214

Folding of embryo, leading to creation of 3D human shape

Answer 215

Structural arrangement where GI tube develops within embryo, forming the basis for digestive system

Answer 216

Formation of organs

Answer 217

- Significant growth and weight gain, -- Maturation of tissues and bone development - Establishment of connections in CNS

Answer 218

- Cell division: increase no. cells - Differentiation: specialisation - Cell attachment: formation of tissues - Apoptosis: programmed cell death - Induction: ability of one cell to cause another to differentiate - Cell migration: movement from one location to another

Answer 219

- Axis formation/Polarity - Folding/Rotation

Answer 220

Genetic, Epigenetic (environ.)

Answer 221

Downsyndrome: - caused by nondisjunction (failure of chromosomes to separate)

Answer 222

Acrosomal enzymes are released from sperm head - sperm digests its way into egg

Answer 223

Sperm binds to Zona Pellucida glycoprotein (ZP3)

Answer 224

Egg and sperm plasma membranes fuse - sperm content enters egg

Answer 225

Sperm entry triggers completion of Meiosis 2 in egg and the release of cortical granules by the oocyte - makes zona pellucida impenetrable to other sperm

Answer 226

Totipotent - potential to develop into any cell type

Answer 227

2/more genetically different sets of cells in body - due to mitotic dysfunction

Answer 228

- Where cells are confined within ZP causing embryo to change shape - occurs during transition from morula to blastocyst

Answer 229

Fluid enters through ZP, contributing to transformation of Mor. into Blas. and facilitating the formation of gap junctions among outer cells

Answer 230

Morula (zygote divided into 16+ cells) and then Blastocyst (200-300 cells) - Cells maximise space, closer contact with each other, form cell junctions

Answer 231

Blastocyst expands until it bursts through ZP

Answer 232

Aids fertility by maintaining thickness of endometrial wall

Answer 233

- Outer cell mass (Trophoblast): allows embryo to interact directly with endometrial lining of uterus for implantation and forms placenta - Inner cell mass (Embryoblast): responsible for formation of embryo

Answer 234

By Day 6 - after fertilisation

Answer 235

When the fertilised egg attaches and embeds itself into the lining of the uterus

Answer 236

When implantation occurs outside uterus

Answer 237

Placenta lies low in uterus and partially/completely covers cervix

Answer 238

- Trophoblast divides into cytotrophoblast (individual cells) and syncytioblast (single multinucleated cell which produces hCG) - Embryo organises into epiblast (dorsal surface) and hypoblast (ventral surface) - Amniotic cavity begins to form

Answer 239

- Formation of 2 cavities: - amniotic cavity (epiblast) - primitive yolk sac (hypoblast) - Implantation complete, closure by fibrin coagulum - Vacuoles in syncytiotophoblastand unite to form lacunae

Answer 240

-Uteroplacental circulation established - maternal blood flows into lucunae to diffuse to embryoblast - Extraembryonic mesoderm (outside) develops then degenerates, - forming chorionic cavity

Answer 241

- Further development of chorionic cavity - Presence of connecting stalk (later umbilical cord) - Second wave of hypoblast cells migrate to form definitive yolk sac

Answer 242

Primitive Streak - appears in midline at caudal end of epiblast - Cranial end of PS = Primitive Pit and Node

Answer 243

Measures heart rate - 60-100 beats per minute

Answer 244

Around 120/80 mmHg, with a range of 70-105 mmHg

Answer 245

12-20 breaths per minute

Answer 246

Equal to or greater than 96%

Answer 247

37.8 degrees Celsius

Answer 248

"A" representing conscious

Answer 249

Less than 2 seconds

Answer 250

- Increased temp = faster metabolism - Decreased temp = slower metabolism

Answer 251

Menstrual cycle, activity, exercise, emotions

Answer 252

Maintaining normal body temp within narrow range despite environ changes - essential for optimum cellular metabolism and function

Answer 253

Protein denaturation, Nerve malfunction, Death

Answer 254

Used for indirect estimate of core body temp

Answer 255

Infrared tympanic thermometers, Infrared forehead thermometers, Forehead strips

Answer 256

Less accurate estimates of body temp

Answer 257

Ear drum (tympanic)

Answer 258

Between 36°C and 37°C

Answer 259

38°C or higher

Answer 260

40°C or higher

Answer 261

Below 35°C

Answer 262

Includes Basal Metabolic Rate (BMR), the basic level of heat production, which can increase due to hormones like adrenaline and noradrenaline - Muscle activity, such as shivering, generates heat

Answer 263

- Radiation (emission of heat energy as electromagnetic waves) - Conduction (transfer of heat between objects in contact, moving from warmer to cooler objects) - Convection (movement of air carrying heat)

Answer 264

Accounts for half of body's heat loss

Answer 265

Temp gradients and Thermal conductivity - combines with Convection

Answer 266

When air next to the skin is warmed by conduction, causing warmed air to rise due to its lower density while cooler air moves in next to the skin

Answer 267

- Passive: where water passively diffuses from the skin and respiratory linings - Active: involves sweating controlled by the sympathetic nervous system (SNS).

Answer 268

- Sensor detection Central and Peripheral thermoreceptors

Answer 269

- Skeletal muscles, Skin arterioles, Sweat glands trigger responses to restore the temp variable to normal

Answer 270

Sweat Glands: SWEATING - Skin arterioles: VASODILATE - Skeletal muscles: DECREASED MUSCLE TONE

Answer 271

Sends signal to hypothalamus

Answer 272

2 centres: - Posterior center activated by COLD - Anterior center activated by WARMTH

Answer 273

- Skin arterioles: VASOCONSTRICT - Skeletal muscles: SHIVERING, INCREASED MUSCLE TONE

Answer 274

Macrophages release endogenous pyrogen

Answer 275

Hypothalamus to release prostaglandins

Answer 276

If the release of pyrogen is reduced or stopped

Answer 277

Hypothalamus initiates mechanisms to heat the body, including shivering and vasoconstriction

Answer 278

Prostaglandins "reset" the thermostat to a higher temp

Answer 279

Genetic information

Answer 280

- consists of sugar-phosphate backbone (deoxyribose) - base pairings are adenine (A) with thymine (T) and cytosine (C) with guanine (G)

Answer 281

5'→3' direction - Antiparallel structure

Answer 282

DNA strands are associated with Histones and wound into chromosomes within the cell nucleus

Answer 283

G1, S, G2, and M phases - DNA synthesis occurs during S phase

Answer 284

- 1 diploid parent cell giving rise to 2 identical diploid daughter cells. Mutations acquired are somatic (not inherited) - every cell can acquire them

Answer 285

- 1 diploid parent cell produces 4 haploid daughter cells - Key feature: crossing over (P1), where genes segregate independently, even if they are on same chromosome. Meiosis crucial for gamete formation.

Answer 286

- Flow of genetic information from DNA to RNA to protein - affected by: transcription rate, splicing and polypeptide processing, and mRNA half-life

Answer 287

- Single-stranded - Ribose sugar backbone - uses Uracil (U) instead of Thmine (T) in its base pairs.

Answer 288

Change in DNA sequence

Answer 289

Any heritable change in DNA sequence

Answer 290

Changes in the: - Promoter sequence (initiates gene expression) - Exon sequence (contains coding info for protein synthesis)

Answer 291

Variant that doesn't cause disease on its own - PF greater than 1%

Answer 292

Genetic variations that involve single nucleotide changes. - prone to disease, often by altering transcription, such as modifying promoter region

Answer 293

Variations that involve extra/missing stretches of DNA, such as deletions/duplications

Answer 294

Base and 5-carbon sugar

Answer 295

Nucleoside and Phosphate group

Answer 296

Adenine and Guanine

Answer 297

DNA: A,C,G, T RNA: A,C,G, U

Answer 298

Phosphodiester bonds form between the 3' hydroxyl group and the 5' triphosphate, linking nucleotides together

Answer 299

- Anti-parallel double helix structure, with one strand running from 5' to 3' and other from 3' to 5' - Sugar-phosphate backbone and base pairs on inside, held together by hydrogen bonds

Answer 300

DNA Primer

Answer 301

DNA Helicase

Answer 302

Replication Fork - consists of leading and lagging strands

Answer 303

5'→3' direction - DNA polymerase catalyses this synthesis

Answer 304

Synthesized in Okazaki fragments - joined together by DNA ligase

Answer 305

Starts simultaneously at several points in genome - speeds up replication process and is bidirectional.

Answer 306

Combines with proteins to form ribosomes (protein synthesis)

Answer 307

Carries amino acids to be incorporated into proteins during Translation

Answer 308

Carries genetic information from DNA to ribosomes for p.synthesis

Answer 309

Multi-subunit complexes responsible for making RNA - Pol I, Pol II, Pol III

Answer 310

At (-25) introduces a kink into DNA, determining start and direction of transcrip. - TBP binds to TATA box, facilitating binding of other transcrip. factors and RNA poly.

Answer 311

1st general transcrip. factor to bind to promoter - binds to TATA box through TBP - required for all Pol II transcribed genes

Answer 312

Specific promoter at position (0)

Answer 313

Begins at nucleotide +1 - Transcription Start Site

Answer 314

Catalyses unwinding of DNA during transcrip, leading to DNA chain separation

Answer 315

Selection of 1st nucleotide of growing RNA - requires additional general transcrip. factors

Answer 316

Addition of further nucleotides to RNA chain in 5'→3' direction

Answer 317

Release of finished mRNA molecule

Answer 318

Removes introns (non-coding regions) from premature mRNA to create mature mRNA containing only exons (coding regions)

Answer 319

Poly-adenosine tail - aka: poly-A tail

Answer 320

Formation of an initiation complex - provided by GTP (guanosine triphosphate)

Answer 321

Anticodons of tRNA form base pairs with codons on mRNA. Aminoacyl-tRNA synthetases catalyse covalent attachment of amino acids to their corresponding tRNA molecules

Answer 322

- occurs when the A site encounters a stop codon. Termination protein binds to codon, causing ribosome to dissociate - change in peptidyl transferase activity, resulting in release of protein from the last tRNA to which it was attached

Answer 323

- Glycosylation - Disulphide bods (ER) - Folding/assembly of multi-subunit proteins (ER) - Specific proteolytic cleavage (ER, Golgi, secretory vesicles)

Answer 324

Peptidyl transferase catalyses peptide bond formation between amino acids in P and A sites - EF-2 (Elongation Factor-2) moves ribosome along mRNA

Answer 325

- P (peptidyl site) - A (acceptor site) - E (exit site) In translation: PAE

Answer 326

In cytosol - produce proteins for the cytosol, nucleus, mitochondria - are synthesised post-translationally (produced in cytosol then translocated (after translation))

Answer 327

On Rough Endoplasmic Reticulum (ER) - produce proteins for plasma membrane, ER, Golgi, secretion - are synthesised co-translationally, with translocation occurring concurrently with translation.

Answer 328

- Translocation: movement of materials within a cell/organism - Translation: protein synthesis in which amino acids are assembled into a protein based on the info provided by messenger RNA (mRNA)

Answer 329

Change in a single base in DNA sequence

Answer 330

Change in amino acid sequence

Answer 331

Creates new termination codon (stop codon) in DNA sequence, terminating protein synthesis

Answer 332

No change of amino acid sequence even though base in DNA altered

Answer 333

Addition/deletion of 1 or 2 bases which changes reading frame of translation, potentially altering entire amino acid sequence

Answer 334

- Genetic changes that affect larger portions of genome, including: Deletions (loss of genetic material), Duplications (extra copies of genetic material), Inversions (reversal of genetic material), Dislocations (translocation of genetic material to a different chromosome)

Answer 335

- Degenerate (multiple codons can code for the same amino acid) - Unambiguous (each codon codes for a specific amino acid) - Near-universal (it's shared by most living organisms)

Answer 336

The ability of an enzyme to select a specific substrate from a range of chemically similar compounds

Answer 337

Speed up rate of reaction by binding to and stabilising transition state, reducing activation energy, and providing alternative reaction pathway

Answer 338

Can convert many substrate molecules into products per second - making them efficient catalysts for chemical reactions

Answer 339

Kinase enzymes

Answer 340

Required for enzymatic activity and can be metal ions. - essential for enzyme function - metals (e.g. magnesium, copper) or organic compounds (e.g. heme, sugars, proteins)

Answer 341

Organic molecules, such as vitamins, required for enzymatic activity - transiently associate with the enzyme, change charge or structure during the reaction, but are regenerated for further use

Answer 342

Tightly bound coenzymes that remain closely associated with enzyme

Answer 343

- Apoenzyme: enzyme without cofactor - Holoenzyme: enzyme with cofactor

Answer 344

Active site - contains amino acids for catalytic activity and specific interactions

Answer 345

Active site of unbound enzyme is complementary in shape to substrate, allowing them to fit together

Answer 346

- Chymotrypsin: has hydrophobic pocket that binds aromatic amino acids - Trypsin: has negatively charged Asp that interacts with positively charged Lys or Arg. - Elastase: has active site partially blocked, allowing only amino acids with small/no side chains to bind

Answer 347

Binding of substrate induces conformational change in enzyme, resulting in complementary fit between enzyme and substrate

Answer 348

Each enzyme has an optimum temperature and pH, and activity decreases on either side of this optimum - extreme temperature/pH alter enzyme's active site and reduce its function

Answer 349

Enzymes that catalyse the same reaction but have different properties and structures

Answer 350

- Synthesised during different stages of fetal and embryonic development - Being present in different tissues - Located in different cellular locations

Answer 351

Lactate Dehydrogenase (LDH) has tissue-specific isoforms, such as H (heart) that promotes aerobic metabolism, M (muscle) that promotes anaerobic metabolism. LDH found in blood is associated with hypoxia

Answer 352

Activity can be activated/inactivated through addition/removal of phosphate groups by kinases and phosphatases

Answer 353

Inactive precursors of enzymes - transformed into active enzymes by cleavage of covalent bonds

Answer 354

- In pancreas: Trypsinogen and Chymotrypsinogen are inactive precursors formed - In small intestine: Enteropeptidase cleaves Trypsinogen to form active Trypsin, which cleaves Chymotrypsinogen to form active Chymotrypsin

Answer 355

The rate and mechanism of enzyme-catalysed reactions: V = V max [S] / KM + [S]

Answer 356

Solute (substrate) concentration

Answer 357

Initial velocity (rate) of an enzyme-catalysed reaction

Answer 358

Max. rate of reaction when all enzyme active sites are saturated with substrate - represents enzyme's maximal catalytic capacity

Answer 359

Substrate conc that results in half max velocity (0.5 * VMAX) - reflects enzyme's affinity for substrate

Answer 360

Enzyme requires low substrate conc to work at half max velocity - indicating high affinity for substrate

Answer 361

Enzyme requires high substrate conc to work at half max velocity - indicating low affinity for substrate

Answer 362

Км = k _1 + K2 / k1

Answer 363

Rate of enzyme dissociation from substrate, which is Backward rate of reaction

Answer 364

Forward rate at which enzyme converts substrate into product

Answer 365

Forward rate at which enzyme associates with substrate

Answer 366

Where line intersects Y-axis - represents max rate of enzyme-catalysed reaction

Answer 367

Where line intersects X-axis - represents substrate conc at which reaction rate is half of VMAX

Answer 368

Large change in reaction rate (V) - indicating high sensitivity to substrate changes

Answer 369

Little effect on reaction rate

Answer 370

Molecule binds to active site of enzyme, competing with substrate for binding

Answer 371

- VMAX same - Km (Michaelis constant) changes

Answer 372

Molecule binds to allosteric site on enzyme, not active site

Answer 373

- VMAX changes - Km same

Answer 374

Where end product of metabolic pathway inhibits an earlier enzyme in pathway through allosteric control

Answer 375

Substrate that remains covalently bound to enzyme's active site - enzyme permanently inactive

Answer 376

Formation/breakage of covalent bonds within enzyme complex

Answer 377

Involves inhibition of rate-limiting enzymes by end products - results in sigmoidal curve. Eg: binding oxygen to haemoglobin

Answer 378

Any heritable change in human genome causing genetic disorder

Answer 379

Variations in human genome with population frequency >1% - don't cause disease on their own but may predispose to common diseases

Answer 380

Likelihood of having a disease if you have gene mutation

Answer 381

Variation in phenotype (observable traits) if you have a disease

Answer 382

Require just one mutation to cause disease - high penetrance - small environmental contribution

Answer 383

Multiple polymorphisms collectively contribute to the risk of disease - penetrance for any one mutation is low

Answer 384

- Stops transcription - Causes abnormal splicing

Answer 385

- Stops transcription - Causes abnormal splicing

Answer 386

- Leads to a short/absent protein - mRNA decay

Answer 387

Results in a different or non-functioning protein

Answer 388

Complete change to the amino acid sequence after the mutation site

Answer 389

- "In frame": insertion/deletion of a multiple of 3 bases - "Out of frame": results in frameshift mutation

Answer 390

- G: genomic build - C: describes effect on mRNA sequence (e.g: c.125[C>G]) - P: indicates effect on peptide sequence (e.g., p.Pro172Arg) - >: signifies substitution of bases - Ins/Del: insertion/deletion mutations (e.g., c.76insG) - c.267+2: indicates substitution within intron

Answer 391

c.267G>A represents a substitution. c.267delG signifies a deletion. c.267InsA denotes an insertion of an A. c.267+2T>A describes a substitution within an intron.

Answer 392

Rearrangement of chromosomes

Answer 393

Fusion of 2 acrocentric chromosomes stuck end to end

Answer 394

Exchange of genetic material between 2 non-homologous chromosomes

Answer 395

all chromosomal material is present - doesn't result in visible phenotype, but risk of malsegregation during pregnancy

Answer 396

Extra/missing chromosomal material, involving 1 or 3 copies of genes - major developmental problems/miscarriages

Answer 397

Presence of abnormal number of chromosomes, either with extras or missing ones - X chromosome aneuploidy better tolerated due to X chromosome inactivation

Answer 398

Missing/duplicated genetic material

Answer 399

Identify certain genetic conditions

Answer 400

Down's syndrome

Answer 401

Turner syndrome

Answer 402

+18: Edwards syndrome +14: Miscarriage

Answer 403

Klinefelter syndrome

Answer 404

Amplifies small piece of human genome from patient, allowing detection of mutations in that specific region

Answer 405

Find missing/duplicated pieces of chromosomes and polymorphisms - first-line chromosome test and examines 3 million base pairs. However, doesn't detect balanced rearrangements

Answer 406

Fluorescence in Situ Hybridisation - identify evidence of translocations/deletions by using fluorescent probes to stain pieces of chromosomes

Answer 407

- Whole Exome sequencing: focuses on sequencing all exons (protein-coding regions) - Whole Genome sequencing: both exons and introns

Answer 408

Identify polymorphism variants by removing those unlikely to be disease-causing

Answer 409

Presence of 2 genetically distinct populations of cells, resulting from post-zygotic mutation

Answer 410

Mosaic Down syndrome - some cells have 46 chromosomes, while others have 47 chromosomes

Answer 411

NO - affect portion of body

Answer 412

Activate oncogene/delete tumor suppressor gene

Answer 413

High penetrance, monogenic diseases that follow Mendel's laws of inheritance - autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, mitochondrial, Y-linked

Answer 414

Conditions related to methylation, imprinting, mitochondrial mutations, mosaicism

Answer 415

1 faulty gene - all generations in family affected - 50% chance of passing the mutated gene to each child if one parent is a carrier

Answer 416

2 faulty genes - all generations in family affected - 25% chance of passing the mutated gene to each child if both parents carriers

Answer 417

Random X inactivation - where half of cells will have faulty gene

Answer 418

Gene fault located on X chromosome - X-linked Recessive: females with one pathogenic allele and one normal allele don't show major clinical features, but males with a single faulty allele are fully affected

Answer 419

Transmitted maternally, in ovum - Mutations in mitochondrial genome are only present in some mitochondria, and proportion varies between cells within an individual

Answer 420

Complex interplay of multiple genes and environ. factors

Answer 421

25% each: - unaffected or affected son, unaffected or carrier daughter

Answer 422

- All daughters will be carriers - All his sons will be unaffected (no male-male transmission)

Answer 423

Tailoring medical interventions to genetic makeup

Answer 424

- Plasma membrane - Cell wall - Nucleoid - Ribosomes - Cytoplasm with lipid bilayer

Answer 425

Essential for energy generation, maintaining positive charge - Target because: electrons released from high-energy compounds in cytoplasm pass through series of electron acceptors at membrane, disrupting bacterial energy production

Answer 426

- contains DNA and associated proteins Unlike eukaryotic cells, no nuclear membrane, histones, or nucleus exist. Chromosomes in prokaryotes are single, circular molecules and are organised by Gyrases. Ribosomes in prokaryotes are distinct from eukaryotes and susceptible to interference from drugs that don't affect eukaryotic ribosomes

Answer 427

Provides protection to bacterial cells

Answer 428

- Multi-layered peptidoglycan layer, contain second polymer - Resistant to osmotic pressure - STAIN PURPLE

Answer 429

- Thinner peptidoglycan layer - Decorated with inner and outer membranes - STAIN PINK

Answer 430

Key component of endotoxin found in outer membrane of Gram-negative bacteria - acts as antigen and bacterial toxin - roles in antibiotic uptake, inflammation

Answer 431

- Flagella: hair-like structures found in Gram-negative bacteria - Fimbriae (or pili): found in Gram-positive bacteria

Answer 432

Allow horizontal gene transfer (HGT) and facilitate the transfer of plasmids between prokaryotes - inject toxins into host cells and other bacteria

Answer 433

Electrons are released from high-energy compounds in cytoplasm

Answer 434

Electrons passed through series of electron acceptors after reaching the cell membrane

Answer 435

Protons outside membrane create positive charge and a proton gradient, which is used by ATP synthase for ATP synthesis

Answer 436

- Food availability - Temperature - pH

Answer 437

- Thermophiles: thrive in HIGH temp - Mesophiles: thrive at BODY temp - Psycrophiles: thrive in LOW temp Fever: response to infection, raises temp above mesophiles

Answer 438

Affecting acidity/alkalinity of environ

Answer 439

Provided by a 0.85% NaCl (salt) solution

Answer 440

- Aerobes: won't survive in anaerobic conditions - Micro-aerophiles: require little free oxygen - Facultative anaerobes: can grow with/without oxygen - Obligate anaerobes: only grow in anaerobic conditions - Caponphilic: require CO2

Answer 441

Colonies of bacteria that adhere together and to environ surfaces. - Bacteria inside biofilm more resistant to antimicrobial agents

Answer 442

Capsule - made of polysaccharides

Answer 443

Spherical bacterial shapes Examples: - Staphylococcus (forming clumps) - Streptococcus (arranged in chains)

Answer 444

Rod-shaped bacteria - Gram-positive bacilli appear in chains

Answer 445

- Spirillum (rigid spirals) - Spirochaete (flexible spirals)

Answer 446

Curved rod shape - Gram-negative

Answer 447

Spindle-shaped appearance

Answer 448

Inert structures highly resistant to physical/chemical damage. They are inactive but can persist in environ. and later initiate infections. - associated with Gram-positive organisms

Answer 449

Germination → binary fission → sporulation → cell lysis → spore secretion

Answer 450

Distinguish bacteria based on cell wall structure

Answer 451

Bacteria may have a resistant cell wall that doesn't take up the stain - Eg: Mycobacterium tuberculosis (TB) and Treponema pallidum ( spirochaete organism causing syphilis), don't stain well

Answer 452

- Aerobes - Anaerobes

Answer 453

Grow in presence of oxygen

Answer 454

- Gram-Negative bacteria part of G-Negative bacterial cell wall

Answer 455

Produced by Gram-Positive bacteria. Generated inside bacterial cell and then exported from it

Answer 456

- Growth in differential media - Obtain single colony - Pass to automated biochemical processing

Answer 457

Component of the Holoenzyme, serves as a molecular clock and a fingerprint of species for bacterial identification

Answer 458

Size, colour, mucoid appearance, and odour - For Streptococcus spp, haemolytic characteristics (alpha, beta, gamma) can aid in identification.

Answer 459

Collection of all microbes, such as bacteria, fungi, viruses, and their genes, that naturally live on our bodies and inside us

Answer 460

Harmful organism that can cause disease in a host

Answer 461

Organism part of the normal flora - mutualistic relationship, where both host and organism benefit - Endogenous relationship (naturally occurring)

Answer 462

Ability to cause disease/infect host

Answer 463

Severity of disease in host

Answer 464

Differentiate between Staphylococcus aureus and coagulase-negative Staphylococcus species

Answer 465

If Coagulase Test is positive (coagulase is present), indicates Staph. Aureus, appears GOLDEN

Answer 466

Causes problems in immunocompromised patients

Answer 467

Grows in culture by accident

Answer 468

Organism is not Staph. aureus but another Staphylococcus species, including Staphylococcus epidermis

Answer 469

PARTIAL haemolysis, resulting in GREENing of colonies. - associated with Streptococcus pneumoniae + viridans

Answer 470

Used to differentiate between Streptococci

Answer 471

NO haemolysis - associated with Enterococcus

Answer 472

COMPLETE haemolysis - YELLOW - associated with Group A (pyogenes) and B Strep

Answer 473

Caused by enzymes that denature haemoglobin inside RBCs

Answer 474

Caused by enzymes that lyse (rupture) cell wall of RBCs

Answer 475

Neisseria meningitidis

Answer 476

Gut commensal coliforms

Answer 477

Gram-negative bacilli - cause serious infections if they enter normally sterile sites, such as UTIs

Answer 478

Gentamicin

Answer 479

Endotoxin (LPS)

Answer 480

Based on O antigens (cell wall LPS) and H antigens (flagella)

Answer 481

Host response to immune infection, and can lead to small blood vessels becoming leaky, decreased blood volume, poor tissue perfusion, increased blood clotting, and increased risk of hemorrhage

Answer 482

Endotoxin is released from Gram-negative cell wall when bacteria die, contributing to sepsis

Answer 483

1. Antigen/LPS interacts with macrophages 2. Macrophages release cytokines into the bloodstream 3. Cytokines travel to anterior hypothalamus 4. Prostaglandin E is released, increasing the body's thermal set point 5. The body perceives it as cold and starts to shiver 6. Fever occurs

Answer 484

Identified by Haemolysis (rupture/destruction of RBCs) - Group A Streptococcus (GAS): Scarlet fever, Impetigo - Streptococcus pneumoniae: causes pneumonia

Answer 485

Enterococci: Enterococcus faecalis, Enterococcus faecium

Answer 486

Nosocomial (hospital-acquired) pathogen associated with foreign devices like catheters - coagulase-negative

Answer 487

Most common cause of skin, soft tissue, and wound infections. - Coagulase-positive, appears golden in colour, and associated with both nosocomial and community-acquired infections - Lead to sepsis and has a characteristic clump-forming appearance, resembling grapes

Answer 488

Associated with enteric infections and is part of normal bowel flora. It can cause problems when it enters normally sterile areas

Answer 489

Gram-positive anaerobic bacillus that is part of normal bowel flora - produces exotoxins that can cause severe tissue damage. Clostridium difficile, a species of Clostridioides, is responsible for antibiotic-associated diarrhoea, especially in the elderly. It proliferates in the absence of normal flora.

Answer 490

Inhaled pneumococci of the species Streptococcus pneumoniae

Answer 491

Can be DNA or RNA, single or double-stranded, linear or circular - carries genetic information of virus

Answer 492

Protects the viral genome from the environ and helps deliver the genome into host cell

Answer 493

Lipid bilayer that contains viral proteins - present only in some viruses

Answer 494

Structure consisting of repeated subunits that make up equilateral triangles, arranged in a symmetrical fashion

Answer 495

Virus is made up of a single repeated unit, typically forming a spiral or helical shap

Answer 496

- Spike (S) - Membrane (M) - Envelope (E) - Nucleocapsid (N)

Answer 497

- Neural spread (e.g. herpes simplex virus) - Hematogenous spread (e.g., through the blood, as seen in HIV).

Answer 498

1. Viral replication: involves gene expression and gene replication 2. Attachment: virus interacts with specific receptors on target cell 3. Entry: virus enters cell, often through endocytosis For respiratory viruses, entry can occur through inhalation or touch 4. Uncoating: viral nucleic acid is released from the capsid 5. Nucleic acid and protein synthesis: host ribosomes are used, along with host polymerases, to produce new viral proteins 6. Assembly: nucleic acids and proteins are packaged together to form new viral particles 7. Release: virus can be released through either budding, where it exits the cell with an envelope derived from the host cell membrane (non-lethal to the cell), or lysis, where the virus accumulates until the cell bursts, leading to cell death.

Answer 499

Cell lysis, cell-cell fusion (sharing cytoplasm), inhibition of host cell transcription and translation (altering cellular function)

Answer 500

Viruses initally be asymptomatic, allowing for easy spread to other hosts - become quiescent with no active replication and reactivate after a period of latency. Some viruses may remain continually active, leading to chronic infections

Answer 501

PCR, Antigen test - Host response and serology assessed using antibody tests

Answer 502

Defense mechanism present from birth, providing rapid response Includes: physical barriers (epithelium, cilia), chemical barriers (lysozyme, low pH)

Answer 503

- Targeting antiviral agents, such as reverse transcriptase inhibitors in the case of HIV - Vaccination

Answer 504

Provides protection from pathogens while minimising the risk of rejecting donor tissue

Answer 505

- Immunisation - Anti-inflammatory and immunosuppressive drugs - Cancer immunotherapy (CAR T-cell therapy)

Answer 506

Induced by presence of foreign materials and generates a unique response to each pathogen - exhibits slower response

Answer 507

- Traps bacteria and contains lysozymes and defensins, which directly combat invading pathogens - lines body cavities exposed to external environ, such the resp, GI, and urogenital tracts - IgA Role

Answer 508

Compete with pathogens for resources and produce fatty acids and bactericidins, inhibit pathogens

Answer 509

Molecules found on surface of pathogens like bacteria, viruses, and fungi that trigger innate immune response. - recognised by Pattern Recognition Receptors (PRRs) on immune cells, leading to immune response to combat the invading pathogens

Answer 510

They signal neighbouring cells to destroy viral RNA, reduce protein synthesis, undergo apoptosis - activate immune cells like NK cells

Answer 511

Process by which intact particles, such as bacteria, are internalised whole by macrophages

Answer 512

1. PRRs on macrophages bind to PAMPs on pathogen, signalling formation of phagocytic cup 2. Cup extends around pathogen and pinches off, creating phagosome 3. Phagosome fuses with a lysosome, forming a phagolysosome 4. Pathogen is killed, and its contents are degraded 5. Debris is released into extracellular fluid 6. Pathogen-derived peptides are presented on special cell surface receptors like MHC-II 7. Pro-inflammatory mediators, such as TNF-α, are released, leading to acute inflammation

Answer 513

Coating of pathogens by soluble factors (opsonins) to enhance phagocytosis - IgG, C3b

Answer 514

Physical barrier - tightly packed, highly keratinised cells - Low pH (5.5), low oxygen tension, - contains sebaceous glands that produce hydrophobic oils, lysozymes, ammonia to deter pathogens

Answer 515

- Phagolysosomal mechanism: where immune cells engulf and digest invading pathogens within specialised compartments (phagolysosomes) - ROS-dependent mechanism: use reactive oxygen species (ROS) to attack and destroy pathogens, which helps in the immune response against infections

Answer 516

- Deal with pathogens that are too large for phagocytosis - Initiate response when endotoxin damages mast cell

Answer 517

- Degranulation: involves the release of pre-formed pro-inflammatory substances, such as histamine - Gene expression: leads to production of new pro-inflammatory substances like leukotrienes and prostaglandins

Answer 518

- Vasodilation of small blood vessels - Increased blood flow - Cell accumulation - Increased cell metabolism

Answer 519

- No inflammatory mediators - Normal vasculature - Circulating neutrophils

Answer 520

- Swelling - Pain - Heat - Redness - Joint immobility

Answer 521

- Change in vascular permeability - Recruitment and activation of neutrophils (transendothelial migration) - Bacteria produce chemicals that attract neutrophils to site of infection

Answer 522

1. Loss of intravascular fluid in the presence of inflammation causes slower blood flow, allowing neutrophils to undergo margination 2. Neutrophils travel close to endothelial cells instead of the centre of vessel 3. Neutrophils encounter and bind to adhesion molecules expressed by endothelial cells (e.g. Selectins, ICAM-1) 4. Neutrophils migrate across endothelium via diapedesis 5. Once in tissues, neutrophils travel to exact site of injury via chemotaxis 6. Neutrophils activated by PAMPs and pro-inflammatory mediators such as TNF⍺

Answer 523

1. Phagocytosis: utilises phagolysosomal killing similar to macrophages by producing ROS 2. Degranulation: involves release of anti-bacterial granules into Extracellular matrix (ECM) 3. NETs (Neutrophil Extracellular Traps): release a net-like structure that traps pathogens, leading to phagocytosis

Answer 524

- Receptor-mediated Endocytosis: molecules bound to membrane receptors are internalised - crucial for generating adaptive immunity - Pinocytosis: ingestion of fluid from surrounding cells - Phagocytosis: process in which bacteria are engulfed by cell surface

Answer 525

- Contain granule: release histamine - act as effector cells in allergic reactions

Answer 526

- Kill infected/abnormal cancer cells - Lymphocytes involved the rejection of tumors and virally infected cells - Respond to levels of MHC class I - Kill targets by degranulation, releasing perforin - Produce Interferon-gamma (IFN𝛾)

Answer 527

Associated with allergic reactions

Answer 528

- Boosted by antibodies - The complement system, particularly the classical pathway activated by IgM and IgG, plays role - TNF-alpha initiates inflammation - Dendritic cells capture antigens and deliver them to lymph nodes

Answer 529

- Use surface molecules such as PAMPs (pathogen-associated molecular patterns) - Contain components from bacterial and fungal walls - For intracellular pathogens like viruses, PAMPs can be RNA or DNA

Answer 530

- Phagocytise dead cells and invading pathogens - Distinguish between self-cells and pathogens based on their cell surface characteristics - DON'T distinguish between different types of pathogens

Answer 531

- Macrophages - Neutrophils - Eosinophils - Basophils - Mast cells

Answer 532

Pathogen-Associated Molecular Patterns - recognised by Pattern Recognition Receptors (PRRs) - specific molecular patterns on pathogens that PRRs detect

Answer 533

Receptors on immune cells that can activate when there are few pathogens present - bind to PAMPs, allowing phagocytes to ingest pathogens

Answer 534

When there's a high number of pathogens - stimulate release of cytokines

Answer 535

Small secreted proteins that act as messengers, allowing communication between cells in immune response

Answer 536

- Involved in the cell-mediated immune response - Recognises antigens presented by MHC class II molecules - Expresses CD4 - also CD3, TCR & CD28 - Major source of IL-2 - Mediates acute and chronic organ rejection

Answer 537

- Involved in the cell-mediated immune response - Recognises antigens presented by MHC class I molecules - Induce apoptosis in virally infected and tumour cells - Expresses CD8 - also CD3, TCR - Mediates acute and chronic organ rejection

Answer 538

- Major cell of the humoral immune response - Act as antigen-presenting cells - Mediate hyperacute organ rejection

Answer 539

- Differentiated from B cells - Produces large amounts of antibody specific to a particular antigen

Answer 540

Generates proteins that sustain vasodilation and other physical inflammatory effects

Answer 541

Forms a protective protein mesh over sites of injury

Answer 542

Opposition to the Coagulation system - counterbalancing clotting and generating other inflammatory mediators

Answer 543

Activated in response to inflammation and creates cascade of chem.reactions that promote: - Opsonisation of pathogens - Direct pathogen killing - Acute inflammation - Leukocyte recruitment

Answer 544

1. Mannose-Binding Lectin (MBL) pathway 2. Alternative pathway 3. Classical pathway

Answer 545

IgG or IgM antibodies bind to antigens, leading to cleavage of C3 into active C3a and C3b

Answer 546

C3b can cleave C5, resulting in formation of C5a and C5b, leading to production of Membrane Attack Complex (MAC) - C3b also amplifies the reaction via alternative pathway

Answer 547

Inserts into cell walls and destroys cell by letting salt and water in

Answer 548

Produced by the liver that have their plasma concentrations increase or decrease in response to inflammation

Answer 549

- C3b: promotes opsonization and enhances phagocytosis - C3a and C5a: responsible for acute inflammation

Answer 550

- C-reactive protein - acute phase protein that activates complement via classical pathway - rapidly increases during inflammation and has a short half-life, decreasing rapidly once inflammation resolves

Answer 551

Activates the complement system via the MBL pathway in response to inflammation

Answer 552

Act as a bridge between innate and acquired immune systems - capture antigens, deliver them to lymph nodes, and present these antigens to T cells (antigen-presenting cells)

Answer 553

In Bone Marrow - responsible for the humoral immune response - antigen-presenting cells and produce antibodies that attack pathogens in the blood and lymph

Answer 554

Lymph and lymphocytes leave lymph nodes, enter medullary sinus, flow through efferent lymphatic vessels, and re-enter bloodstream via lymphatic ducts at subclavian vein

Answer 555

- Basophils - Eosinophils - Neutrophils - Mast cells - NK cells

Answer 556

- B cells (produce antibodies) - T cells (TH and Tc cells)

Answer 557

- Antigen exposure - "Helping" signals

Answer 558

Plasma cells

Answer 559

Low-affinity antigen-specific IgM antibodies are secreted by short-lived plasma cells. These later undergo somatic hypermutation to become high-affinity IgG antibodies. B cells mutate and secrete improved antibodies, switching from low to high-affinity antibody production. This leads to differentiation of long-lived plasma cells and long-lived memory B cells (Bm)

Answer 560

- Naturally acquired passive immunity through IgG (placenta) and IgA (milk) - Artificially acquired passive immunity through interventions like antivenom

Answer 561

- Naturally acquired active immunity through actual infection by a pathogen - Artificially acquired active immunity through vaccines and booster shots involving exposure to weakened/dead pathogens

Answer 562

- Membrane-bound antibodies on B cells bind to target antigen (IgM or IgD) in B cell zone of lymph nodes - B cells require for activation: antigen and helper signals from T helper (TH) cells, PRR and PAMPs, or multiple antigens - Once activated, proliferate and become plasma cells (producing antibodies) or memory B cells, often in germinal centres - High-affinity antibodies are generated, starting with IgM (produced by plasma cells) and transitioning to IgG (produced by B cells responding to specific antigens), assisted by TH cells

Answer 563

Peptide antigens

Answer 564

Activate B cells and stimulate production of memory B cells - can differentiate into Th1, Th2, Tfh, and regulatory T cells

Answer 565

Kill virally infected body cells

Answer 566

Lymphocyte suppression

Answer 567

Protective immunity against invading pathogens - role in adaptive immune response

Answer 568

aka: HLA (Human Leucocyte Antigens) - display peptide antigens to T cells - T cells can only recognise peptide antigens presented to their T cell receptor (TCR) by MHC molecules

Answer 569

On all nucleated cells - present peptide antigens to CD8+ Killer T cells

Answer 570

- Only on professional Antigen Presenting Cells (APCs), including dendritic cells, macrophages, B cells - Present peptide antigens to CD4+ Helper T cells

Answer 571

In Secondary lymphoid tissues: such as lymph nodes, spleen, mucosa-associated lymphoid tissue (MALT)

Answer 572

Constantly re-circulate between the blood, secondary lymphoid tissues, and lymphatic vessels

Answer 573

Dendritic cells recognise and phagocytose antigenic debris

Answer 574

Mature and increase the expression of stimulatory molecules on their surface

Answer 575

Dendritic cells phagocytose pathogenic antigens, break them down into short peptides, and load them onto MHC II molecules

Answer 576

Transported to cell surface of dendritic cells

Answer 577

Migrate into lymph nodes via the afferent lymphatic vessels

Answer 578

Co-stimulatory molecules

Answer 579

CD4+ T cells differentiate into T helper cells, which include effector TH cells

Answer 580

- Memory T cells - Effector T cells

Answer 581

Release IL-2 - enhances growth and function of both T and B cells

Answer 582

Activate macrophages to be more efficient, which includes activation of NADPH oxidase genes to produce reactive oxygen species (ROS)

Answer 583

Activate B cells in germinal centre

Answer 584

CD8+ T cells differentiate into Cytotoxic T lymphocytes (CTLs)

Answer 585

Bind to infected cells and induce apoptosis - use granules containing perforin, granzymes, and granulysin to trigger apoptosis

Answer 586

Migrate out of lymph nodes and enter site of infection via transendothelial migration to kill infected host cells and stop further inflammation - Involved in killing cancer cells

Answer 587

B and T lymphocytes, each with its own antigen receptor

Answer 588

Getting rid of lymphocytes with self-reactive antigens to ensure self-tolerance and prevent autoimmune reactions

Answer 589

Monomer * Enhance phagocytosis of bacteria and viruses * Fixes complement and passes to fetal circulation * Most abundant isotype in blood serum

Answer 590

Monomer/Dimer * Found in breast milk, secretions of digestive, respiratory and urogenital tracts/systems * Provides localised protection on mucous membranes * Most commonly produced immunoglobulin (but blood serum concentrations lower than IgG) * Transported across interior of the cell via transcytosis

Answer 591

Pentamer * First immunoglobulin to be secreted in response to infection * Fixes complement but doesn't pass to fetal circulation (result in haemolysis) * Anti-A, B blood antibodies

Answer 592

Monomer * Role in immune system largely unknown * Involved in activation of B cells

Answer 593

Monomer * Mediates Type 1 hypersensitivity reactions * Synthesised by plasma cells * Binds to Fc receptors found on surface of mast cells and basophils * Provides immunity to parasites such as helminths * Least abundant isotype in blood serum

Answer 594

Immune response that results in bystander damage to the self

Answer 595

IgE-mediated antibody response - Onset: seconds - production of IgE antibodies upon initial allergen exposure, bind to mast cells + cause degranulation upon re-exposure to allergen - Conditions: Anaphylaxis, Atopy (e.g. asthma, eczema, hayfever)

Answer 596

IgG or IgM binds to antigen on cell surface → complement system activation - Onset: seconds/hours - Conditions: Goodpasture’s syndrome, Rheumatic fever

Answer 597

- Antibody binds to excess soluble antigen producing small immune complexes, trapped in small blood vessels, joints and glomeruli → activate complement → attracts inflammatory cells - Onset: hours - Conditions: Systemic lupus erythematosus, Post-streptococcal glomerulonephritis, Extrinsic allergic alveolitis

Answer 598

T cell mediated: release of inflammatory cytokines and cell-mediated cytotoxicity - Onset: days - Conditions: Tb, Allergic contact dermatitis, Guillain Barre syndrome

Answer 599

Presence of immune responses against self-tissues/cells

Answer 600

- IPEX syndrome: results from X-linked mutation in the FOXP3 gene, involved in TREG (regulatory T cell) development - Certain HLA (Human Leucocyte Antigen) alleles, which encode for MHC (Major Histocompatibility Complex) cells and are associated with an increased predisposition to autoimmune diseases - Autoimmune diseases are more common in females - influenced by hormonal factors

Answer 601

- Central tolerance: deletion of self-reactive lymphocytes in primary lymphoid tissues, such as thymus and bone marrow - Peripheral tolerance: inactivates self-reactive lymphocytes in peripheral tissues, such as lymph nodes, spleen, tonsils, which may escape central tolerance. TREG cells are involved

Answer 602

- Infections that can lead to cross-reactivity (molecular mimicry), where immune response against pathogens may inadvertently target self-antigens - Alteration of self-antigens due to processes like the conjugation of self-antigens with products of drug or chemical metabolism - The role of super-antigens produced by certain bacteria, which can reactivate autoreactive T cells that have been inactivated by TREG cells - Antigen sequestration: occurs when antigens in tissues that don't normally communicate with the bloodstream or lymphatics (e.g: eye or brain) are exposed due to trauma, leading to an autoimmune reaction

Answer 603

Serving as physical barrier between host and external environ. - consists of single layer of cells and layer of mucus

Answer 604

Through secretion of cytokines and antimicrobial peptides, including human defensins, trefoil factors, cathelicidin, REGIIIγ, MUC proteins

Answer 605

Lgr5+ stem cells located at base of the crypts - As these cells proliferate and differentiate, they move up crypt - Cell shedding occurs at tip of crypt, maintaining tight control over the barrier through signaling molecules

Answer 606

Immune cells are present in the lamina propria and specialised cell types, including intra-epithelial T cells - Self tolerance: development of non-responsiveness to self-antigens, preventing immune system from attacking body's own tissues - Exogenous tolerance: development of non-responsiveness to many newly encountered environmental antigens, such as food and microbes

Answer 607

They sense and respond to microbes They express Pattern Recognition Receptors (PRRs), stimulate the secretion of antimicrobial peptides (AMPs), cytokine responses, and regulation of tight junction proteins (TJP), impacting gut permeability - influence microbial diversity in gut - IECs produce mucins, which serve as energy source for gut microbes

Answer 608

Drugs used to treat/prevent infections caused by microorganisms

Answer 609

Inhibit bacteria growth

Answer 610

Kill bacteria

Answer 611

- Cidial - Long half life - Appropriate tissue distribution - No adverse drug interactions/side effects - Oral & parenteral preparations

Answer 612

Administered: intravenously (IV) or, rare cases, intramuscularly (IM) - Excreted through: urine, liver, biliary tract, and can be excreted into faeces

Answer 613

- Bacterial cell walls (inhibiting peptidoglycan synthesis) - Ribosomes (affecting protein synthesis)

Answer 614

- Penicillins - Glycopeptides - Cephalosporins - Aminoglycosides - Nitromidazoles - Quinolones

Answer 615

- Macrolides - Tetracyclines

Answer 616

Penicillins, Cephalosporins, Glycopeptides

Answer 617

Eg: Flucloxacillin, Amoxicillin, Co-amoxiclav - β-lactam antibiotics: targeting Penicillin Binding Proteins (PBPs) in bacteria

Answer 618

- Safe in pregnancy - Few side effects - Range from narrow to broad spectrum

Answer 619

- Patients can be hypersensitive (allergic) and allergy to one penicillin potentially means allergy to all penicillins - Rapidly excreted via kidneys and resistance can develop

Answer 620

Flucloxacillin (IV, Oral)

Answer 621

1. Amoxicillin (IV, Oral) 2. Co-Amoxiclav (IV, Oral) 3. Tazocin (IV only)

Answer 622

Temocillin (IV only)

Answer 623

- Benzylpenicillin - Phenoxymethyl penicillin - Benzathine penicillin

Answer 624

- Safe, well tolerated antibiotic - Well absorbed when given orally - Low binding to plasma proteins & good tissue distribution - Effectiveness challenged by spread of beta lactamases (enzyme that destroys beta-lactam ring)

Answer 625

Combination of Amoxicillin and Clavulanic acid - CA: beta-lactamase inhibitor, NO antibiotic properties of its own

Answer 626

- IV and Oral - Narrow spectrum antibiotic - Prescribed for Staph and Strep - For skin and soft tissue infections, wound infections, cellulitis

Answer 627

- IV antibiotic with a Gram-Negative spectrum - Beta-lactamase-resistant penicillin and used for coliform infections - Active against ESBL (Extended Spectrum Beta-Lactamase) producing organisms

Answer 628

Eg: Cefaclor, Cefadroxil, Cefalexin - Inhibit cell wall synthesis & bactericidal - Excreted via kidneys and urine - More resistant to β-lactamases - Few side effects, reduced allergy, safe in pregnancy Broad-spectrum antibiotics: - kill normal gut bacteria - allow overgrowth of Clostridium difficile - Hospitals avoid use

Answer 629

Eg: Vancomycin (IV), Teicoplanin (IV) - Inhibits cell wall synthesis through different mechanisms - Bactericidal - Side effects: vancomycin damages kidneys, causes ‘red man syndrome’ (allergy) - Excreted via kidneys and urine - NO activity against Gram-Negative organisms

Answer 630

- Erthyromycin - Doxycylin - Gentimicin (most prescribed)

Answer 631

Antibiotics' ability to inhibit protein synthesis by attaching to bacterial ribosomes while structurally differing from mammalian ribosomes - allows antibiotics to target bacterial cells without harming human cells

Answer 632

Bacteriostatic - Exemption: aminoglycosides are bactericidal meaning they directly kill bacteria by binding to ribosomes in a way that is lethal wa

Answer 633

- Aminoglycoslides - Tetracylines - Macrolides

Answer 634

Eg: Gentamicin - Treat severe, life-threatening infections caused by Gram-Negative aerobic organisms - Administered IV and have irreversible binding to 30s ribosome, making them bactericidal

Answer 635

Eg: Erythromycin - safe in pregnancy - Excreted via liver, biliary tract, and into gut - Bacteriostatic - useful when infections hide from host immune system - Lipophilic: easily pass through cell membranes

Answer 636

Eg: Doxycycline - Inhibit protein synthesis: bind to 30s subunit of ribosome, prevent attachment of tRNA - Useful against: intracellular bacteria, atypical bacteria - Side effects: destruction of normal intestinal flora, staining of bone/teeth in children under 12

Answer 637

2nd-line treatment against serious Staphylococcal and Streptococcal infections, especially in patients with penicillin allergies - Active against "true" anaerobes

Answer 638

Used for topical treatment of eye infections

Answer 639

Via liver and biliary system

Answer 640

- Fluroquinolones - Metronidazoles - Trimethoprim - Rifampicin - Rifampin

Answer 641

Exhibit both Gram-Negative and Gram-Positive activity, making them effective against wide range of bacteria

Answer 642

By targeting metabolic pathways that are absent in humans - specifically bind to the A subunit of DNA gyrase, preventing supercoiling of bacterial DNA

Answer 643

Eg: Ciprofloxacin - Bind to the A subunit of DNA gyrase, preventing supercoiling of DNA, indirectly inhibits DNA synthesis - Gram-Negative & Gram-Positive activity

Answer 644

- Urinary tract infections (UTIs) - Bone infections - Community-acquired pneumonia

Answer 645

Restricted to reduce risk of Clostridium difficile (C. difficile) infections, especially in elderly patients

Answer 646

Eg: Metronidazole - breaks strands of bacterial DNA, making it effective against anaerobic bacteria and some protozoa

Answer 647

Yes - interacts with alcohol and should be avoided when consuming alcoholic beverages

Answer 648

Treatment of urinary tract infections (UTIs), especially those caused by bacteria like E. coli

Answer 649

Inhibits bacterial folic acid synthesis, making it effective against both gram-negative and gram-positive bacteria

Answer 650

- Nausea, Vomiting, Diarrhea - Gentamicin: renal and VII nerve damage - Ciprofloxacin: cause tendonitis and avoided in pregnant/breastfeeding women

Answer 651

- Empiric prescribing: prescribing antibiotics without lab identification, based on the likely pathogen - Targeted prescribing: prescribing antibiotics based on lab identification of pathogen.

Answer 652

- Cephalosporins - Co-amoxiclav - Ciprofloxacin - Clindamycin

Answer 653

Class of cellular macromolecules that are concerned specifically with chemical signalling

Answer 654

Study of how the function of tissues/ organs is modified by chemical substances

Answer 655

Ability of a drug to distinguish between different molecular targets within body

Answer 656

Substance bound to protein

Answer 657

What the body does to a drug

Answer 658

What a drug does to the body

Answer 659

Ensures that a drug acts selectively on a specific receptor/binding site - This specificity reduces the likelihood of side effects since the drug only interacts with its intended target, not activating other receptors - NO DRUG IS 100% SPECIFIC

Answer 660

Drug that binds to receptor to produce cellular response - Temporarily activate receptors by producing conformational change - Possess affinity and efficacy

Answer 661

Drug that reduces/inhibits the actions of agonist by binding to same receptor - Possess affinity but lack efficacy

Answer 662

How strongly medication binds to its receptor - higher affinity = higher potency

Answer 663

P: amount of drug required to produce a desired effect E: max. response achievable from drug

Answer 664

When equilibrium is reached, the rate at which ligand-receptor complexes form is equal to the rate at which they dissociate, and this equilibrium is concentration-dependent

Answer 665

Measure of the concentration of ligand required to occupy half of the available receptors - Lower Ka indicates a higher affinity of the ligand for the receptor

Answer 666

Conc of drug where 50% of max effect (response) is achieved - Smaller EC50 indicates: less medication is needed to reach halfway to the maximum effect, making the drug more potent

Answer 667

Response is sub-maximal, even when all receptors occupied

Answer 668

Full Agonist

Answer 669

Both agonist and antagonist bind to same (orthosteric) site on receptor - Decrease in potency, no effect on efficacy (EMAX)

Answer 670

Agonist binds to allosteric site on receptor, causing change in receptor's shape that prevents the ligand from binding - Decreased efficacy (EMAX), no effect on potency

Answer 671

Competes with agonist for the same binding site on receptor - Overcome by increasing conc of ligand Rightward shift on dose-response curve

Answer 672

Antagonist combines in a solution with chemical being antagonised - Reduces effective conc of active chemical

Answer 673

2 agonists that produce opposing physiological actions, canceling each other out - Eg: adrenaline relaxes bronchial smooth muscle, counteracting bronchoconstriction caused by histamine

Answer 674

Antagonist reduces conc of the active drug at its site of action through processes such as increased metabolism - Eg: phenobarbitone increases hepatic metabolism of the anticoagulant drug warfarin, reducing effectiveness

Answer 675

- Autocrine signals: acting on the cell that produces them - Paracrine signals: targets nearby cells - Endocrine signals: targets specific cells far away from source (hormones)

Answer 676

- Hydrophobic: unable to freely move through ECM and require carrier proteins to facilitate their entry into cells - Hydrophilic: move freely through ECM and bind to surface receptors on cell

Answer 677

1. Reception: receptor binds to ligand 2. Transduction: receptor protein changes, activates intracellular molecules (second messengers) 3. Cell Response

Answer 678

- G-protein coupled receptors - Enzyme coupled receptors - Ion channel receptors

Answer 679

Milliseconds

Answer 680

1. Ligand binds to receptor, leading to channel opening 2. Ions (Ca²⁺, Na⁺, K⁺) flow through channel passively 3. Ion flow triggers intracellular signalling pathways

Answer 681

Inhibits binding of nicotine to nicotinic acetylcholine receptors - partial agonist and helps ease nicotine withdrawal symptoms

Answer 682

1. Agonist binding induces conformational change in receptor 2. Receptor's channel opens, providing conduction pathway for ions 3. Ions flow down their electrochemical gradient. Eg: at nicotinic acetylcholine receptor, Na⁺ ions move out, K⁺ ions move in, resulting in membrane depolarisation and cellular excitation

Answer 683

Peripheral membrane protein composed of 3 polypeptide subunits: ⍺, β, and 𝛾 - ⍺ subunit holds GTP or GDP

Answer 684

1. ⍺ subunit leaves G-protein 2. GDP is exchanged for GTP through guanine nucleotide exchange 3. Triggers activation of other proteins in signalling pathway

Answer 685

1. ⍺ subunit hydrolyses GTP, converting it back to GDP 2. Deactivates G protein 3. ⍺ subunit recombines with β𝛾 subunit

Answer 686

Receptors that are bound and activated by adrenaline and noradrenaline

Answer 687

- Salbutamol: binds to B2 adrenoreceptors, leading to bronchodilation - desired effect for asthma - Theophylline: used for chronic asthma, but mechanism of action is different

Answer 688

1. G proteins are activated, and GDP is converted to GTP 2. Alpha subunit is free to leave G protein and stimulate adenylylcyclase, causing bronchodilation 3. G proteins recombine with alpha subunit and GTP, deactivating G proteins

Answer 689

Single-pass transmembrane proteins - have an enzyme domain that is a kinase, responsible for phosphorylating other molecules

Answer 690

Can't phosphorylate their own tyrosine side chains - To activate themselves, they dimerise, meaning 2 receptor tyrosine kinases bind together. Cross-phosphorylate each other, increasing affinity for their binding sites and initiating a cellular response

Answer 691

Transcription of key proteins

Answer 692

- Receptors - Enzymes - Ion Channels - Carrier Proteins

Answer 693

Absorption, Distribution, Metabolism, Excretion

Answer 694

Occurs when small, lipid-soluble, non-polar drugs move directly through cell barriers, taking advantage of high conc gradient

Answer 695

Larger, water-soluble drugs, and polar drug - May exhibit saturation kinetics, which can lead to drug accumulation in compartments and adverse effects

Answer 696

Process of moving drugs against their conc gradient using carrier proteins and ATP - used for water-soluble drugs and can exhibit saturation kinetics

Answer 697

Consists of tight junctions between brain and blood vessels supplying the brain - These tight junctions regulate passage of molecules into brain

Answer 698

Process of bulk uptake of large molecules through cell membrane - Drug is encased in a vesicle and released inside cell

Answer 699

Only unionised form can diffuse across lipid bilayer - Degree of ionisation depends on drug pKa and local pH

Answer 700

Drugs getting trapped in compartments with specific pH levels - Weak bases: better absorbed in acidic environments - Weak acids: better absorbed in alkaline environments Different compartments have different pH levels that affect drug absorption

Answer 701

Lipophilic - easily cross cell membranes to undergo metabolism

Answer 702

Mouth and walls of small intestine: transported to the liver via portal vein for further processing

Answer 703

Vd = Dose / Drug Plasma

Answer 704

1. Administer known dose of drug 2. Obtain blood sample and separate plasma from RBCs 3. Measure conc of the drug in plasma ([drug]*plasma) 4. Calculate Vd using the formula: Vd = Dose / [drug]*plasma

Answer 705

Albumin: most abundant plasma protein, high affinity for hydrophobic drugs - Reduces ability for drug to diffuse to target organ and reduces transport to non-vascular components

Answer 706

Extent to which drug spreads between plasma and tissue compartments - Low Vd: drugs retained in vascular compartments - mostly in plasma - High Vd: drugs retained in non-vascular compartments – adipose, muscle etc

Answer 707

Process of converting a drug into either an active or inactive form within the body

Answer 708

Drugs administered in inactive form, which are then metabolised to their active state within body

Answer 709

Liver - Phase I and Phase II

Answer 710

Process in which drugs, especially those taken orally, are transported via portal vein to liver before entering systemic circulation - In liver, hepatic enzymes metabolise drug, leading to reduction in drug bioavailability - IV and IM admin. methods bypass first-pass metabolism

Answer 711

Amount of drug that reaches systemic circulation for that route of administration F = Quantity of drug reaching Systemic Circulation (AUC) / Quantity of drug administered (Dose)

Answer 712

Changing a drug through oxidation, reduction, hydrolysis - result in formation of active and/or toxic drug metabolites.

Answer 713

Oxidation: facilitated by cytochrome P450 (CYP 450) enzymes - influenced by interactions with other drugs - Hydrolytic reactions on ester and amide bonds. An example of drug toxicity related to this phase is seen in conversion of paracetamol to toxic metabolite by P450 enzymes when taken in large doses, overwhelming the detoxification process

Answer 714

Process of combining a drug with polar molecules to form a water-soluble metabolite (Conjugate) - involves reactive groups produced during Phase I Conjugation terminates all biological activity of drug, and resulting products are excreted via kidneys. Unlike Phase I, some drugs, such as codeine, can go directly to Phase II metabolism

Answer 715

Conjugation reaction where naturally present molecules in body, eg: glucose, are added to a drug -facilitated by enzyme Uridine Diphosphate-glucuronosyltransferase: utilises uridine diphosphate glucuronic acid as cofactor to link drug with glucose, forming water-soluble conjugate that can be excreted

Answer 716

- Poor metabolisers: have genetic variations that lead to slower metabolism of drugs, resulting in higher drug plasma levels - dangerous side effects - Rapid metabolisers: have genetic variations that lead to faster drug metabolism, reducing drug's intended action - Birth: metabolic enzymes may not be fully developed, and in elderly individuals, enzymatic activity tends to decrease, further complicating drug metabolism

Answer 717

Urine, Faeces, Bile

Answer 718

Occur simultaneously: 1. Absorption at the beginning 2. At the Peak: absorption equals elimination 3. After the peak: mainly elimination takes place

Answer 719

NO - excreted in urine

Answer 720

CL = Rate of Drug Clearance / {Drug} Plasma

Answer 721

When rate of elimination is directly proportional to conc of medication in body - VMAX: max rate of drug elimination - Km: half of max. rate of elimination

Answer 722

By renal filtration of blood plasma

Answer 723

Volume of plasma cleared of drug per unit time (L/hour or mL/minute) - helps determine required dosage rate to maintain desired drug conc in the plasma - represents a flow parameter and doesn't specify amount of drug removed from body

Answer 724

Time it takes for plasma conc of medication to decrease by half - Useful when designing therapeutic dosing regimen

Answer 725

t½ = (0.693 x Vd) / CL

Answer 726

Achieved after approximately 5 half-lives of drug administration - when rate of drug administration = rate of elimination (stable conc of drug in plasma)

Answer 727

Rate of elimination is constant - elimination mechanisms become saturated, and elimination rate reaches max capacity (VMAX) - rate of elimination doesn't depend on drug's conc in body

Answer 728

- Clearance (CL) increases → t½ decreases - caused by Cytochrome P450 induction - Clearance (CL) decreases → t½ increases - caused by Cytochrome P450 inhibition, cardiac, hepatic, or renal failure - Volume of distribution (Vd) increases → t½ increases - as seen in cases of pathological fluid accumulation or obesity with increased adipose tissue - Volume of distribution (Vd) decreases → t½ decreases - related to aging and decreased muscle mass

Answer 729

Steady state - closely maintained - stress on cells results in attempt at adaptation

Answer 730

[Drug]plasma × CL

Answer 731

Increase in cell number due to stimuli - Physiological (normal) - eg: breast tissue in puberty, response after loss of tissue Pathological (hormonal imbalances) - eg: excess oestrogen → endometrial hypoplasia, hyperplasia of lymph nodes in response to infection - Reversed upon stimulus withdrawal

Answer 732

Increase in cell size - occurs in response to mechanical stress - often in non-dividing cells - eg: skeletal muscle - can lead to dysfunction (e.g. heart failure)

Answer 733

Stimulate cell division and growth 3 types: - Intrinsic tyrosine kinase receptors - 7-transmembrane G protein-coupled receptors - Receptors without intrinsic tyrosine kinase activity

Answer 734

Reduction in cell size - Physiological (e.g. embryological structures, post-menopausal uterus) Pathological (e.g. decreased workload, blocked blood supply, loss of innervation) - Mechanisms: reduced cellular components, protein degradation - Hormones promote degradation (thyroid hormone) or growth (insulin)

Answer 735

Caps which protect chromosome ends from degradation and fusion - smaller with each division

Answer 736

- Foreign bodies - Immune reaction - Necrosis: STRONG inflammatory response

Answer 737

Vasodilation - mediated by histamine and nitric oxide - increased blood flow, Calor (warmth), Rubor (redness)

Answer 738

- Stasis (slowed blood flow due to vasodilation) - Margination (WBC accumulation near vessel wall) - Rolling (WBCs roll along cell wall) - Adhesions (binding of WBCs to vessel wall via selectins and integrins) - Transendothelial migration (WBCs move through leaky vascular endothelium. Mediated by histamine, bradykinin, substance and leukotrienes. Pass through junctions - diapedesis, transcytosis)

Answer 739

D: WBCs squeeze through blood vessel walls to reach infection site T: cells transport molecules across their interior and release them on other side

Answer 740

- Vascular cell adhesion molecule (VCAM) - Intracellular adhesion molecule (ICAM)

Answer 741

Process in which WBCs follow a chemical gradient to move along it, leading them to site of inflam. - Cytokines, such as C5a and C3a, are potent chemotactic factors

Answer 742

Increases - leaky vessels - results in loss of proteins from blood, causing changes in osmotic pressure. Therefore, water follows the proteins out of the vessel, leading to swelling

Answer 743

1. Recognition and Attachment - involve opsonins, mannose receptors, recognition of bacterial surface glycoproteins and glycolipids containing terminal mannose residues. Opsonins include complement and IgG 2. Engulfment - phagosome is formed as the cell engulfs foreign particle - joins with a lysosome to form phagolysosome 3. Killing and Degradation - achieved through generation of reactive oxygen species by NADPH oxidase and reactive nitrogen species by nitric oxide synthase

Answer 744

- Calor (heat) - Dolor (pain) - Rubor/Erythema (redness) - Tumor (swelling)

Answer 745

Prostaglandins, Bradykinin

Answer 746

Acute inflammation: characterised by presence of neutrophils Swelling due to tumor/cyst may lack this inflammatory cell presence

Answer 747

Proteins exit leaky blood vessels, leading to changes in osmotic pressure

Answer 748

- Resolution (healing) - Suppuration (pus, formation of abscesses) - Chronic inflammation (lymphocytes and macrophages) - Restitution (scar tissue) → one can lead to another

Answer 749

E: increased perfusion and slow blood flow C: increased vessel permeability

Answer 750

Loss of function

Answer 751

Neutrophils - phagocytic and cytotoxic abilities They are granulocytes

Answer 752

Complete restoration of tissue to normal after removal of inflammatory components - Involves processes such as macrophages clearing necrotic tissue and debris, and reabsorption of lost fluid into tissues and vessels

Answer 753

- Severity of infection - Duration of infection - Location of infection - determined by blood supply innervating area

Answer 754

Empyema can occur in a space filled with pus that is walled off - not effectively treated with antibiotics: low blood supply to abscess, which hinders delivery of inflammatory cells for healing - Surgical draining needed

Answer 755

Persistent injury - last for weeks to months

Answer 756

Lymphocytes and Macrophages - Ls produce various cytokines that help maintain inflam. and activate Ms to clear debris

Answer 757

Ziehl-Neelsen (ZN) stain - myco. can't be digested by Ms - Positive ZN stain = presence of mycobacteria

Answer 758

Formation of pus - contains neutrophils, bacteria, inflammatory debris

Answer 759

- Persistent infections - Autoimmune diseases - Hypersensitivity diseases

Answer 760

Small area of inflam. formed due to chronic inflam - consists of aggregated epithelioid cells

Answer 761

1. Mycobacteria 2. Parasites 3. Foreign bodies 4. Cancers

Answer 762

Sponge-like centre composed of epithelioid cells and multinucleated cells, surrounded by cuff of Ls

Answer 763

Trap pathogens and form a protective shell around them, preventing further damage - T cells play role in formation of granulomas by producing cytokines that activate macrophages to create granulomas

Answer 764

Formation of scarring during the repair process in response to tissue injury

Answer 765

YES - both endogenous and exogenous.

Answer 766

Irreversible - In organs like the heart, scarring can lead to loss of muscle tissue after events like MI. Scarring in liver is associated with cirrhosis

Answer 767

Programmed cell death - Eg: occurs during natural replacement of skin cells

Answer 768

- Lots of necrosis (intensity of injury) - Lots of fibrin - Poor blood supply - Length of time injury persists for

Answer 769

Apoptosis: can be intrinsic or extrinsic Necrosis (accidental cell death): due to external factors like infection or internal factors like ischemia (reduced blood flow)

Answer 770

Occurs when tissue becomes hypoxic - cell not completely destroyed - microenviron. too toxic for proteolysis, preventing cells from clearing up debris - common: seen in MI

Answer 771

Necrosis: pathological, affects adjacent groups of cells, causes increase in cell size, passive process, leads to an inflam. reaction Apoptosis: pathological or physiological, affects single cells, causes decrease in cell size, active process, and doesn't induce an inflam. reaction

Answer 772

- Occurs when dead cells disintegrate but aren't fully digested - ‘Cheesy’ - Ask for culture, PCR and look for Ziehl Neelson stain - A result of fungal or mycobacterialinfection - usually associated with TB

Answer 773

- Occurs when hydrolytic enzymes fully digest dead cells, resulting in formation of creamy substance (pus) with no cell structure remaining - associated with bacterial and fungal infections, brain injuries

Answer 774

1. Cells undergo shrinkage (Pyknosis) 2. Chromatins condense, leading to clumping and breaking up of nucleus 3. Cytoplasmic blebs form, causing cytoplasm to break up 4. Ms enter to clear away cellular debris

Answer 775

Initiated by death signaling proteins/receptors like TNF and Fas - TNF: associated with apoptosis in inflam. Fas: involved in recognising self, leading to apoptosis, especially in Ls - Mutations in Fas contribute to autoimmune diseases

Answer 776

- Oxidative stress from free radical damage (e.g. radiation) - Accumulation of metabolic by-products like Lipofuscin

Answer 777

- Physiological: normal growth, removal of self-reactive Ls, hormonal-dependent involution - Pathological: injury, chemo, viral infection

Answer 778

Involves mitochondria becoming leaky - Proteins like Bax and Bak cause release of cytochrome C, stimulating caspase activation

Answer 779

Extend life by reducing IGF signaling, which can silence specific genes

Answer 780

Acts as a sensor for DNA damage and can halt cell cycle - If DNA damage is irreparable, p53 stimulates caspases and induces apoptosis

Answer 781

Cancers and Autoimmune diseases

Answer 782

Neurodegenerative disorders

Answer 783

Endergonic, Reductive - Reducing Agent: NADPH + H+

Answer 784

Exergonic, Oxidative - Reducing Agent: NADH + H+

Answer 785

Oxidation of glucose to pyruvate - Efficient process

Answer 786

Yields lactate - Rapid, inefficient process

Answer 787

Stored as disaccharides - polyaccharides in liver

Answer 788

Ribose-5-phosphate

Answer 789

Via Na+/glucose symporters - passive facilitated diffusion through GLUTs (1-5)

Answer 790

Converts glucose to 2 pyruvate molecules per glucose, with net gain of 2 ATP

Answer 791

1. Hexokinase/glucokinase converts glucose to glucose-6-phosphate (irreversible) 2. Phosphoglucoisomerase converts glucose-6-phosphate to fructose-6-phosphate

Answer 792

Phosphofructokinase-1 (PFK) phosphorylates fructose-6-phosphate to fructose-1,6-bisphosphate, consuming 2 ATP

Answer 793

Aldolase - into 2 interconvertible 3C molecules (G3P and another)

Answer 794

Pyruvate kinase oxidises a 3C molecule to pyruvate, producing ATP

Answer 795

Lactic acid

Answer 796

1. Pyruvate takes H+ ions from NADH 2. Pyruvate converted into lactate, regenerating NAD

Answer 797

High-rate anaerobic glycolysis in cancer cells

Answer 798

Cancer cells have low Km hexokinase

Answer 799

Using enzymes around control points

Answer 800

- ADVs: rapid energy production, support for cell proliferation - DISs: production of H+ and lactate, inefficient ATP synthesis, high glucose consumption leading to weight loss in cancer patients

Answer 801

Glycolysis reduces NAD+ to NADH and H+ - NADH must be regenerated through oxidative metabolism of pyruvate

Answer 802

1. Pyruvate enters mitochondrial matrix 2. Pyruvate dehydrogenase converts pyruvate to acetyl-CoA 3. Acetyl-CoA combines with Oxaloacetate (C4) to form Citrate (C6) 4. C6 decarboxylated twice, yielding 2x CO2 5. Four oxidation reactions produce 3 NADH, H+, FADH2 6. 1 GTP formed, converted to ATP 7. Oxaloacetate (C4) regenerated

Answer 803

Matrix except Succinate Dehydrogenase - integrated into inner mitochondrial membrane

Answer 804

- 4 ATP, 10 NADH, 6 CO2, 2 FADH2 - 3 pairs of electrons transferred in conversion of NAD+ to NADH and H+ - 1 pair of electrons needed to reduce FAD to FADH2

Answer 805

High ADP and NAD+

Answer 806

High ATP, NADH, acetyl-CoA

Answer 807

Electron transfer potential of NADH+ and FADH2 is converted into the phosphoryl transfer potential of ATP

Answer 808

Change in free energy (ΔG) during ATP hydrolysis

Answer 809

Measured by the redox potential of a compound (E’0), indicating how easily it donates electrons

Answer 810

Reduced form of the compound has a lower affinity for electrons than hydrogen

Answer 811

By donating electrons to complexes in membrane

Answer 812

Enter from NADH through the malate-aspartate shuffle and from FADH2 through glycerol-3-phosphate

Answer 813

Proteins with heme groups - In resp chain, electrons are transferred from carriers with positive potentials to oxygen, resulting in conversion of oxygen to water

Answer 814

Complexes 1, 3, 4 pump H+ ions into the intermembrane space of mitochondria, creating proton gradient

Answer 815

- ATP is synthesised as H+ flows back into matrix through ATP synthase - 1 NADH yields 3 ATP, 1 FADH2 yields 2 ATP

Answer 816

Inhibit transfer of electrons to O2, preventing formation of proton gradient and synthesis of ATP

Answer 817

30-32 ATP molecules

FOUNDATIONS Flashcards

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