Scriptures Flashcards
1
Q
Isotonic point
A
Isotonic point- any external solution, has same solute conc and water conc, compared to body fluids (no net movement of water will take place).
2
Q
Uncommon functions of triglycerides
A
electrical insulation and buoyancy and physical protection (for organs).
3
Q
The hydrophilic heads of the phospholipid bilayers face towards…
A
an aqueous solution
4
Q
where is the cambium / meristem located?
A
Cambium / meristem is whats in between the xylem and phloem (xylem bigger and towards the middle).
5
Q
what do electron microscopes require the specimen to be in?
A
a vacuum, so they can’t be alive.
6
Q
give 2 examples of autoimmune diseases
A
Autoimmune disease, arthritis (painful inflammation of membranes at joints), Lupus (antibodies to cell nuclei cause swelling and pain).
7
Q
what does helpful microflora do?
A
Helpful microflora compete with pathogens on skin.
8
Q
Mast cells, and damaged white blood cells in the damaged connective tissue and around blood vessels near the damaged tissue, release…
A
chemicals such as histamine, which increases blood flow to area. Histamine also increase capillary permeability, enabling the leak of plasma fluid, white blood cells and antibodies from blood into damaged tissue, causing swelling. Pathogens then targeted by white blood cells for destruction.
9
Q
Phagocytes (Neutrophil or Macrophage) present
A
pathogen’s antigens to the specific immune system.
10
Q
Antigen presenting cells recruit…
A
specific T and B cells in clonal selection and expansion for specific immune responses. Clonal selection involves selecting correct cell, and its subsequent division by mitosis is clonal expansion.
11
Q
B cells, form plasma cells, with the function of…
A
releasing antibodies
12
Q
B memory cells and T memory cells
A
for long term immunity (long-lived cells that remain dormant in lymphatic system / immune system).
13
Q
T killer cells
A
attack and kill (by releasing chemicals), infected body cells displaying antigens.
14
Q
T helper cells
A
release cytokines to stimulate B cells.
15
Q
T regulatory cells
A
shuts down immune response when finished.
16
Q
how are helper T cells activated?
A
A T helper cell with a complementary-shaped CD4 receptor on its surface can bind to this antigen on the antigen-presenting cell, leading to the activation of the T helper cells.
17
Q
Monohybrid inheritance
A
inheritance of a single gene
18
Q
Dihybrid inheritance
A
inheritance of 2 genes
19
Q
what is codominance, give example
A
where both alleles expressed in the phenotype.
E,g Blood type.
20
Q
whats the meaning of pure breeding parents?
A
both homozygous and opposites
GG (homozygous dominant), gg (homozygous recessive).
21
Q
Haemophilia
A
e.g sex-linked genetic disorder, patients suffer having blood, clots extremely slowly (due absence protein-clotting factor).
If male inherit recessive allele on their X chrom, cannot have dominant allele on their Y chrom, so develop condition.
22
Q
if the rate of apoptosis is too low, what could it lead to?
A
tumors could being to form
23
Q
what are mutations caused by?
A
caused by mutagens (chemical / agents)
24
Q
what are the different types of mutations, associated with the sequence of amino acids?
A
Insertion and Deletion (cause frameshift), Duplication and Inversion.
Point mutation involves a base substitution, can be silent (has no effect), missense (changes AA’s primary structure), or nonsense (introduces early stop codon, truncating the protein).
25
Phenotypic Variation
caused by enviro-factors (which can influence gene expression), not passed on through genes.
26
Homoebox genes
ancient, highly conserved genes, code for homeodomain sequences in protein that regulate anatomical development.
27
Role of Hox genes
regulate the axes of embryos, dictating the position of anatomical features. The spatial and temporal expression of Hox genes controls where and when parts of body develop.
28
what is tightly regulated for Euk and Pro cells?
transcription of genes
29
in Pro cells what regulates the transcription of metabolic genes?
the lac operon
30
explain how the lac operon works?
When lactose is present, inhibits the repressor protein, allowing RNA polymerase to transcribe lacZ and Y (the structural genes) for lactose metabolism.
31
in Euk, how does transcription factors control transcriptions?
by binding to promoter regions of genes and encouraging or inhibiting, binding of RNA polymerase.
32
Phenotypic variation, caused by genetic changes during when?
cell division
33
when do chromosomal mutations occur?
Chrom mutations, occur in meiosis (e.g Downs / Turner syndrome).
34
Types of chrom mutations
Duplication, Inversion, Deletion, Insertion and Translocation.
35
Meiosis produces ... ... ..., due to ...
Meiosis produces genetically distinct gametes, due to allele shuffling in crossing over and independent assortment.
36
Non-disjunction mutation involves...
changes to the chromosomal number during meiosis, as a result of homologous pairs of chroms not separating during first division (meaning some gametes have extra chroms and other have fewer than normal number).
37
how do enzymes actually denature when the temp is too high?
Denaturing of enzymes, when temp to high the hydrogen bonds what breaks, changing structure and shape.
38
how can high blood glucose levels be damaging and potential fatal to an organism
Blood Glucose conc in blood too high, causes water potential drop, water diffuses out from cells by osmosis into bloodstream, causing cells to be flaccid and die.
39
how are multiple negative feedback mechanisms more beneficial, then just one?
Negative feedback can only maintain internal environment within a specific range.
Multiple negative feedback mechanisms provide a greater degree of control of the internal environment.
40
Positive feedback, mechanism amplifies a ... into a ...
Positive feedback, mechanism amplifies a small change into a big change.
41
what anatomical adaptations does the liver have for increasing SA?
Liver has highly vascularised and lobular structure, give increased SA. Liver cells, called hepatocytes, have microvilli, further increase SA.
42
Ornithine cycle
process combining ammonia and carbon dioxide, form urea, much less toxic and soluble in water, so it can be excreted into the urine.
43
how have the renal tubules of each nephron adapted to become more efficient at reabsorption?
The renal tubule of each nephron, lined with microvilli, increase SA for reabsorption.
44
what happens during the process of Ultrafiltration
most blood forced out, into the glomerular capsule due to the high pressure caused by the difference in diameter between the afferent (much wider) and efferent arterioles.
45
In the nephron, at which parts is water and ions reabsorbed into the blood?
Water is also reabsorbed into the blood by osmosis in the descending limb of the loop of Henle. Ions reabsorbed in ascending limb.
The ion conc gradient set up in the area between the limbs drives osmosis in the descending limb.
46
How is ADH secreted?
Osmoreceptors in the hypothalamus detect water composition in the blood. Hypothalamus secretes ADH, and signals posterior pituitary gland to release it into the bloodstream.
47
how does ADH work, and what is the risk of a high conc of ADH?
When ADH reaches cells in collecting ducts, become more permeable to water, so reabsorb more water. High conc of ADH constrict blood vessels, increasing blood pressure.
48
Glomerular filtration rate (GFR) indicates what?
how well the kidneys are functioning and estimates the amount of blood passing through the kidneys per minute.
49
what does kidney failure effect?
the balance of electrolytes in the body.
50
what are the 2 types of dialysis?
Hemodialysis and Peritoneal dialysis
51
What happens to a plant of rate of photosynthesis is greater than rate of respiration?
If the rate of photosynthesis is greater than rate respiration, excess oxygen expelled out the plant, via diffusion.
52
how does the Iselt of Langerhans help to regulate blood glucose levels?
The islets of Langerhans, areas produce and secrete insulin and glucagon into the blood to help regulate blood glucose levels.
53
where are the substances for exocrine glands secreted into, and endocrine glands?
Exocrine glands secrete substances into ducts, endocrine into blood.
54
Amylase needs ... to complete active site.
Cl- cofactor
55
what is Cytolysis?
Cytolysis , cell burst if water potential outside to high.
56
What do enzymes need to function?
Many enzymes need non-protein ‘helper’ in order to function, either be inorganic cofactors, or coenzymes (organic non-protein).
57
what is Crenation?
Crenation (the shrivelling process of cell), occurs when water potential outside cell is low
58
Prosthetic groups, cofactors permanently bind to...
protein (haem to haemoglobin).
59
When pH level is above optimum, what happens to the active site?
Above optimum pH level, charge of aa’s that make up active site, altered.
60
Give an example of an extracellular enzyme and its function
Extracellular enzyme. e.g human amylase (breaks down starch) and trypsin.
61
Give an example of an intracellular enzyme and its function.
Role intracellular enzyme, Catalyse - breaks down harmful hydrogen peroxide (by product from metabolic reactions), to oxygen and water.
62
What happens in catabolic reactions vs anabolic reactions
Catabolic reactions- large mols broken down, releasing energy. Anabolic opposite.
63
What is the induced fit model?
Induced fit model- active site change shape, to add strain, reducing activation energy.
64
What is the secondary protein structure?
Secondary, due H bonds forming alpha-helices or beta-pleated sheets.
65
What is the tertiary protein structure?
Tertiary, overall 3D shape, forming ionic, disulfide and hydrogen bonds, plus hydrophobic interactions.
66
What is the quaternary protein structure?
Quaternary formed when multiple polypeptides bind, often with prosthetic groups.
67
What are prosthetic groups?
non-protein groups that associated with polypeptide chains of a protein.
68
What part of the phospholipid bilayer, repels polar (charged substances)?
Phospholipids bilayers act as barrier to most water-soluble substances (the non-polar fatty acid tails prevent polar molecules or ions from passing across the membrane).
69
What is pepsin?
protein-digesting stomach enzyme. Many acidic R groups withstanding denaturing.
70
What is the structure of insulin?
A’ chain with alpha-helix and ‘B’ chain with beta-pleated sheet joined by disulfide links
71
What is the function of insulin?
Binds muscle and fat for glucose uptake.
72
what are the two types of Endocytosis, and under what conditions does each occur?
Endocytosis, phagocytosis for solids and pinocytosis for liquids. First stage, membrane invaginates when in contact.
73
Neutrophils features
Multi-lobed nucleus, easier to squeeze small gaps, get to site infection.
Granular cytoplasm, many lysosomes.
74
What is the structure of globular proteins?
spherical shape, core of hydrophobic interactions, surface hydrophilic interactions, water-soluble.
75
What is the structure of fibrous proteins?
repeating stretches of aa’s, insoluble.
76
What are amino acids composed of?
amino group, carboxyl group, hydrogen, one of 20 variable ‘R’ groups, which vary size, charge, polarity.
77
Palisade cell features
closely packed, form continuous layer,
thin cell walls increase diffusion rate,
large vacuole to maintain turgor pressure.
chloroplast can move within cytoplasm, absorb more light.
78
How is the opening and closing of stomata controlled?
Guard cell- when lose water, become less swollen, close to prevent water loss.
Cell wall thicker on one side, does not change symmetrically as vol changes.
79
Squamous Epithelium features
flat, thin appearance, present when rapid diffusion essential, forms lining of lungs.
80
Xylem tissue features
role transport water and minerals, composed of vessel elements and elongated dead cells. Walls strengthened with lignin, provides support.
81
Phloem features
responsible transport organic nutrients (particularly sucrose). Composed coulombs of sieve tube cells separated by sieve plates.
82
what is the role of spindle fibres?
Spindle fibres role, pull chromosomes to opposite poles.
83
Describe the process of protein synthesis...
transcribed mRNA leaves nucleus, via nuclear pores and attaches ribosomes at RER, which translate into polypeptide, which enters RER. Vesicles from cisternae take protein to golgi, which modifies and packages protein and releases into vesicles bound for destination.
84
What size molecule are lipids?
Lipids are macromolecules (very large organic mols).
85
What are ester bonds, where are they formed and found?
type covalent bond formed in condensation reactions, between fatty acids and glycerol.
86
what is a tumor and name the two types and how they vary
Tumours- an abnormal mess of cells, (result of damage or spontaneous mutations).
Benign- stops growing and don't travel to other regions of body.
Malignant- continues to grow unchecked and uncontrolled.
87
What is the structure of cellulose?
long chain beta-glucose joined by 1-4 glycosidic bonds.
88
What are the properties of cellulose?
straight, unbranched chains, run parallel, due to beta-glucose inverting alternately, allowing hydrogen bonds to form, provides strength as they produce microfibrils. Insoluble doesn't effect water potential, but permeable to solutes.Microfibrils run different directions, for extra strength
89
Explain the stages of the cell cycle (G1,G2, etc)
Cell Cycle:
G1- cell groups and new organelles and proteins made.
G1 checkpoint- cell checks chemicals needed for replication present and for damage to DNA.
Synthesis- cell replicates DNA, ready divide by mitosis.
G2- cell keeps growing and proteins needed for cell division are made.
G2 checkpoint- cell checkpoint if all DNA has been replicated without damage.
M phase- mitosis and cytokinesis
Metaphase checkpoint.
90
What is the function of starch?
plant based energy storage molecule
91
what does a nerve contain?
A nerve contains many neurone (cells).
92
What are the properties of starch?
Insoluble, no effect on water potential. Compact granules, takes up little space. Branchin, multiple sites for rapid hydrolysis.
93
why are there (many) mitochondria present in the pre-synaptic bulb.
The release of vesicles (containing neurotransmitters) require ATP, therefore there are mitochondria present in the pre-synaptic bulb.
94
What are the properties of glycogen?
Glycogen has exact same properties, difference, animal-based energy storage polysaccharide.
95
What is the structure of ATP?
composed 3 phosphate groups, a ribose sugar and the base, adenine.
96
How does ATP change to ADP
It is hydrolysed.
97
Lipids are ... in water, so will not dissolve, hence why ... used.
insoluble, ethanol
98
what do Voltage-gated calcium channels detect?
Voltage-gated calcium channels, detect when action potential arrives at end of axon.
99
How can the concentration of reducing sugars be measured?
Conc of reducing sugars can be quantitatively measured using colorimetry or using reagent test strip (dipped into sample solution and colour compared to those on calibration card).
100
On membrane of the post synaptic neurone, there are...
On membrane of the post synaptic neurone, there are neurotransmitter receptors.
101
What is Benedict's test used for? Describe the process.
Non-reducing sugars cannot reduce Benedict’s until glycosidic bond hydrolysed, test for non-reducing sugars: boil with HCl, break into monosaccharides (reducing sugars), then cool and add sodium hydrogen carbonate to neutralise.
102
How is the resting potential in neurones maintained?
Resting potential in neurones maintained, through sodium-potassium pumps, keeping more positive ions outside the nerve cell. Uses ATP, 3 sodium ions out, 2 potassium ions in.
Inorganic anions (carbon ions), also increase the -ve charge of the resting potential.
103
How do disaccharides bind together?
By glycosidic bonds(via condensation reaction).
104
Give some examples of disaccharides binding...
Glucose + Glucose = Maltose
Glucose + Galactose = Lactose
Glucose - Fructose = Sucrose
105
What are isomers, give an example.
molecules with same formula but different atom arrangement in space, e.g glucose (alpha and beta).
106
What are monosaccharides? Structure and function?
sweet tasting, soluble and full of carbon-hydrogen bonds for energy storage.
107
what are sphincter muscles?
Sphincter muscle, any ring of muscle that can constrict, found in arterioles
108
what is the purpose of the chlorine shift into erythrocytes?
Chloride shift of Cl^-1 into erythrocytes to maintain electrical neutrality.
109
Lub dub sound from heart, what does each sound represent?
lub closing of bicuspid valve,
dub closing semilunar valve.
110
What are polymers? Structure?
long chains of monomers bonded together by covalent bonds, in repeating pattern
111
What happens when two or more monomers undergo condensation
They bind together and form a polymer
112
What does a bacterial cell nucleoid contain?
essential genes for cell to function and synthesise proteins
113
What does a plasmid contain?
non-essential genes, might enhance survival, e.g antibiotic resistance.
114
How do all prokaryotes reproduce?
Binary fission
115
In a pressure time graph, for heart, the point where 2 lines intersect is a point in which...
a valve is opening or closing.
116
What is the structure and function of the capsule?
Waxy, surrounds cell wall, protection
117
What is the structure and function of the pili?
small projections for adhesion
118
What is the cell wall made of is prokaryotes?
peptidoglycan
119
What is the structure of DNA in a prokaryote?
The DNA is circular, not linear
120
What is the structure of centrioles?
bundles of microtubules arranged into two cylinders, perpendicular.
121
What is the cytoskeleton?
complex network of proteins.
122
What is the structure and function of the cytoskeleton?
Formed of microfilaments (actin), microtubules and intermediate filaments. Moves organelles around cell. Helps anchor organelles and provide cell shape and strength.
123
what is the difference between excitatory and inhibitaory signals?
Inhibitory signals cause the post-synaptic neuron to become less likely to fire an action potential,
Excitatory signals do opposite.
The binding of neurotransmitters to receptors can either cause the post-synaptic neuron to become more likely to fire an action potential (excitatory), or less likely to fire an action potential (inhibitory), depending on the type of receptor and neurotransmitter involved.
124
what is the resolution and magnification of light micro
LIght microscope, resolution 200nm, magnification 1500-2000.
125
Transmission Electron microscope festures:
TEM, specimen dehydrated and stained, electrons pass through specimen, mag= 2 million, resolution 0.1nm.
126
What is the structure of undulipodia and what is its function?
contain microtubules, single protrusion, role of motility.
127
What is the structure of flagellum and what is its function?
contain microtubules, single protrusion, role of motility.
128
Scanning Electron microscope features:
SEM, specimen often coated with metal film, electron bounce off specimen, magnification 15-200 thousand, resolution 20nm.
129
what is differential staining?
Differential staining, when different stains bind specific components.
130
What is the structure of cillia and where is it found
contain microtubules, multiple protrusions, found both eukaryotic and prokaryotic.
131
Stages of specimen preparation (for microscope)
Specimen preparation, dehydration, embed in wax preventing distortion, slicing into thin sections.
132
why do electron microscopes have better resolution?
Electron microscopes have better resolution, because they use electron beams, have lower wavelength.
133
What does the permanent vacuole act ss?
store of fluid, sugars, aa’s and pigments.
134
What is the rough endoplasmic reticulum(REM) the site of? What does it help do in the cell?
site protein synthesis and helps move substances around cell.
135
Name three different stains (used in microscopy), explaining their features (colour and what they bind too)
Stain, Acetic orcein: binds DNA, dark red colour,
Eosin: cytoplasm stains pink, Iodine in potassium
iodide: stains cellulose yellow, starch grains blue-black.
136
What is the smooth endoplasmic reticulum(SEM) the site of? What does it help do in the cell?
site of carbohydrate and lipid synthesis, storage and transport.
137
What does the rough endoplasmic reticulum(REM) contain and what does this do?
contains membranes called cisternae, provides large SA for ribosomes to attach,
