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Flashcards in Science for Medicine summary Deck (225)
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1
Q

What is metabolism?

A

The chemical processes in a living organism that allow food to be used for tissue growth

2
Q

What two major reaction types does metabolism consist of?

A

Summative/Anabolic

Degradative/Catabolic

3
Q

What reactions occur with a positive ∆G value and are not spontaneous?

A

Anabolic

4
Q

What reactions occur with a negative ∆G value and are spontaneous?

A

Catabolic

5
Q

What is ∆G?

A

Change in free energy

6
Q

What is a metabolic intermediate?

A

A molecule which is the precursor or metabolite of a biologically significant molecule

7
Q

Name a functional group that is polar and soluble?

A
Hydroxyl
Carboxyl
Carbonyl
Amine
Phosphate
8
Q

Name a biomolecule in which the carboxyl functional group is found

A

Amino acids
Proteins
Fatty acids
Acetic acids

9
Q

What is meant by Hydrophobic?

A

Non-polar molecules that do not interact with water

10
Q

What is meant by Hydrophilic

A

Polar molecules that interact with water

11
Q

What is an amphipathic molecule?

A

A molecule which contains both hydrophobic and hydrophilic parts

12
Q

Give an example of an amphipathic molecule

A

Phospholipids

Hydrophobic fatty acid tails, hydrophilic phosphate head

13
Q

What is the major difference between eukaryotes and prokaryotes?

A

Eukaryotes contain a nucleus and membrane bound organelles whereas prokaryotes contain no membrane bound nucleus or organelles

14
Q

What does the nucleus contain?

A

DNA, nucleoprotein and some RNA

15
Q

Where is the site of ribosomal RNA synthesis and ribosomal assembly?

A

Nucleoli

16
Q

What are the two types of Endoplasmic Reticulum?

A

Rough

Smooth

17
Q

Which type of Endoplasmic Reticulum is responsible for lipid biosynthesis and membrane synthesis and repair?

A

Smooth

18
Q

What type of Endoplasmic Reticulum synthesises, packages and secretes proteins?

A

Rough

19
Q

What organelles are known as the “protein factories” of the cell?

A

Ribosome

20
Q

What shape are mitochondria?

A

Cigar shaped

21
Q

What is the folded inner membrane of a mitochondrion known as?

A

Cristae

22
Q

What are Lysosomes?

A

Cellular stomachs

They contain amorphous granular materials which help break down bacteria and debris

23
Q

The packaging and processing of secretory proteins, as well as the synthesis of complex polysaccharides, occurs in what organelle?

A

Golgi apparatus

24
Q

Peroxisomes contain catalases and oxidases, what function do these have?

A

Catalases regulate hydrogen peroxide concentration

Oxidases are involved in the ß-oxidation of long chain fatty acids

25
Q

What is the name given to the irregular structure formed by a single circular chromosome in prokaryotes?

A

Nucleoid

26
Q

What is the main function of fimbriae?

A

Adherance

27
Q

What is the main function of flagella?

A

Movement

28
Q

What does the nuclear membrane/envelope consist of?

A

A double lipid bilayer - inner nuclear membrane and outer nuclear membrane

29
Q

What molecules are peptide bonds usually formed between?

A

Amino acids

30
Q

A peptide bond is formed in a reaction between what two functional groups?

A

Carboxyl and amino

31
Q

The formation of a peptide bond is what kind of reaction?

A

Condensation / dehydration synthesis

32
Q

What is released in the formation of a peptide bond?

A

A water molecule

33
Q

Disulphide bridges are formed between cysteine residues (thiol group) by what process?

A

Oxidative folding

34
Q

The formation of disulphide bridges is involved in the formation of what protein structure?

A

Tertiary

35
Q

Sickle cell anaemia is caused by a change in how many nucleotides?

A

One

36
Q

What kind of mutation occurs in sickle cell anaemia?

A

Nucleotide Substitution - A is substituted with T, changing codon sequence for amino acid 6 from GAG to GTG

37
Q

Haemoglobin in a person with sickle cell anaemia is referred to as what?

A

HbS

38
Q

What is covalent bonding?

A

Sharing of electron pairs between two non-metal atoms

Stable balance of attractive and repulsive forces

39
Q

What is glucose converted to in the liver?

A

Glycogen

40
Q

Is glycogen formed directly from glucose?

A

No

41
Q

What does Glycogenin do in the conversion of glucose to glycogen?

A

Covalently binds glucose from UDP-glucose to form chains of approximately 8 sub units

42
Q

What extends chains until they are broken by glycogen branching enzyme?

A

Glycogen synthase

43
Q

What is the net gain of ATP per glycolysis cycle?

A

2 ATP

44
Q

What phases does glycolysis consist of?

A

Preparatory Phase

Payoff Phase

45
Q

Do the reversible reactions in glycolysis have a positive or negative ∆G value?

A

Positive

46
Q

In the preparatory phase: from 1 molecule of glucose, 2 molecules of what are produced to enter the payoff phase?

A

G-3-P

47
Q

There are 2 irreversible reactions in the preparatory phase, what kind of reactions are they?

A

Phosphorylation

phosphorylation of glucose, phosphorylation of F-6-P to F-1,6-bisP

48
Q

What catalyst is involved in the conversion of triose sugars in reaction 5 of the preparatory phase?

A

Triose phosphate isomerase

49
Q

How many molecules of ATP are used in the preparatory phase per glycolysis cycle?

A

2 ATP

50
Q

What steps of the payoff phase are energy coupled reactions?

A

Steps 6 and 7

oxidation of G-3-P to 1,3-bisPG and phosphate transfer from 1,3-bisPG to ADP

51
Q

How many molecules of NADH are produced in the oxidation of G-3-P to 1,3-bisPG?
(if you take into account that reactants are doubled from this step of glycolysis)

A

2 NADH

52
Q

What molecule is produced in the dehydration of 2-PG to PEP?

A

H2O

53
Q

During what reactions of the payoff phase are ATP molecules produced?

A

Step 7 - phosphate transfer from 1,3-bisP to ADP, 2 ATPs produced
Step 10 - Transfer of phosphate from PEP to ADP, 2 ATPs produced

54
Q

What reactions in the payoff phase are highly exergonic so spontaneous?

A

Step 7 - phosphate transfer from 1,3-bisP to ADP, 2 ATPs produced
Step 10 - Transfer of phosphate from PEP to ADP, 2 ATPs produced

55
Q

Reactants are doubled from what step in glycolysis?

A

Step 6 - oxidation of G-3-P to 1,3-bisP

56
Q

What molecule needs to be regenerated in order for glycolysis to occur?

A

NAD+

57
Q

In what step of glycolysis is pyruvate produced?

A

Step 10 - transfer of phosphate from PEP to ADP

58
Q

What kind of reaction is the process of NAD+ being reduced and NADH being oxidised?

A

Redox balance

59
Q

What is the fate of pyruvate produced in glycolysis under aerobic conditions in animal cells?

A

Converted into Acetyl CoA which enters the citric acid cycle

60
Q

What kind of cells do not rely solely on glucose as an energy source (under normal conditions i.e. not during starvation) and what do they use instead?

A

Muscle cells
Fatty acids
(specifically oxidative type 1 muscle fibre)

61
Q

For every citric acid cycle how many CO2 molecules are produced?

A

2

62
Q

What 3 other molecules are produced in the citric acid cycle (not CO2)?

A

3 NADH
1 FADH2
1 GTP

63
Q

Where in a cell does glycolysis occur?

A

Cytoplasm

64
Q

What is oxidative phosphorylation and where does it occur?

A

Mechanism for ATP synthesis

Occurs in mitochondria

65
Q

Where in a cell does fatty acid synthesis occur?

A

Cytosol

66
Q

The Krebs cycle and citric acid cycle occur where?

A

Mitochondrial matrix

67
Q

Where in a cell does the pentose-phosphate pathway occur?

A

Cytosol

68
Q

The electron transport chain is the final stage in what?

A

Respiration

69
Q

Where does the electron transport chain take place and how many proteins in the membrane does it involve?

A

Mitochondrial matrix and intramembrous space

4 proteins

70
Q

What two proteins in the electron transport chain reduce a molecule and pass the electrons to Ubiquinone to form Ubiquinol?

A

NADH-Q Oxidoreductase - reduces NADH

Succinate Q Reductase - reduces FADH2

71
Q

Where does Q Cytochrome C Oxidoreductase pump H+ ions?

A

Into the intramembrous space

72
Q

What does Cytochrome C Oxidase do?

A

Takes electrons from cytochrome C and passes them to oxygen

Pumps protons into intramembrous space

73
Q

What does the pumping of protons in the electron transport chain set up?

A

A proton gradient across the inner membrane of the mitochondrion

74
Q

Proton motive force does what?

A

Allows proton gradient to work

75
Q

What does ATP-synthase do with the energy released as the protons pass through the membrane protein and what is this system known as?

A

Use it to add ADP + Pi to form ATP

Binding change mechanism

76
Q

What are the purposes of lipids?

A
Stored form of energy 
Structural component of cell membranes 
Needed as enzyme cofactors 
Used in hormones 
Used for the synthesis of vitamins A, D, E and K
Used as a signalling molecule
77
Q

What are the 3 major lipid classes?

A

Fatty acids
Triglycerides
Phospholipids

78
Q

What are Linoleic acid and A-Linoleic acid examples of?

A

Essential fatty acids

79
Q

How must essential fatty be obtained by humans?

A

From plants in our diet

80
Q

Give an example of a good fat

A

Plant oils e.g. sunflower oil

81
Q

What are bad fats high in?

A

Saturated fatty acids

82
Q

Trans fatty acids are found in what?

A

(Really) bad fats

83
Q

What class of lipids coalesce into droplets in water?

A

Triglycerides

84
Q

What are phospholipids composed of?

A

Glycerol + 2 fatty acids + phosphate

85
Q

What class of lipids are amphipathic?

A

Phospholipids

86
Q

What class of lipids are a major component of adipose tissue?

A

Triglycerides

87
Q

What are the main dietary lipids?

A

Triglycerols

88
Q

Triglycerols are digested in the small intestine through the use of what?

A

Pancreatic enzymes
Emulsification by bile salts
Peristalsis

89
Q

Why is homeostasis important?

A

The body needs the internal environment (extracellular fluid) to be maintained in a state compatible with cell survival

90
Q

What proportion of the extracellular fluid is interstitial fluid?

A

80%

91
Q

What proportion of the extracellular fluid is plasma?

A

20%

92
Q

What is negative feedback control?

A

Detection of change in an internal factor by receptors
Change fed to integrating centre and compared to reference level
If there is a difference, signal is sent to an effector and the change is negated

93
Q

The magnitude of an error signal is proportional to what?

A

Size of the response and the deviation

94
Q

The skin detecting minor changes in temperature before core temperature is affected is an example of what kind of control?

A

Feed-forward control

changes anticipated before significant changes occur

95
Q

What proportion of total body water is intracellular fluid?

A

2/3

96
Q

What is tonicity?

A

The relative concentration of two solutions separated by a semi-permeable membrane that determine the direction and extent of diffusion

97
Q

What is osmolarity?

A

The measure of solute concentration i.e. number of osmoles of solute per litre of solution

98
Q

What is osmolality?

A

The measure of osmoles of solute per kilogram of solvent

99
Q

If the ECF has a higher osmolarity than the ICF, will the solution be hypertonic or hypotonic?

A

Hypertonic

100
Q

What would happen to cells in a hypertonic solution?

A

The cells will shrink as water leaves via osmosis

101
Q

If the ECF has a lower osmolarity than the ICF, will the solution be hypertonic or hypotonic?

A

Hypotonic

102
Q

What would happen to cells in a hypotonic solution?

A

They would swell (and burst)

103
Q

What kind of solution has an equal number of penetrating and non-penetrating solutes on either side of the membrane?

A

Isosmotic

104
Q

What kind of solution has an equal number of non-penetrating solutes on either side of the membrane?

A

Isotonic

105
Q

What is endocytosis?

A

Invagination of membrane to form a vesicle around a target substance

106
Q

What process involves the fusion of a vesicle membrane with the plasma membrane followed by the expulsion of the vesicle contents?

A

Exocytosis

107
Q

The sodium-potassium pump does what?

A

Pumps 2 K+ into the cell, pumps 3 Na+ out of the cell

108
Q

What is the resting membrane potential and why is it this value rather than the theoretical value?

A

-70mV

Due to the permeability of the membrane to other ions and leaky ion channels

109
Q

What is the axon hillock?

A

Specialised part of the soma that connects to axon

Last site in soma where the membrane potentials propagated from synaptic inputs are summated before transmission to axon

110
Q

What are the main cells responsible for the functions of the nervous system?

A

Neurones

111
Q

Why are dendrites important?

A

They are an important route for information from other neurones

112
Q

The information for making an action potential is collected where?

A

Initial segment

113
Q

Where is the neurotransmitter released from?

A

Axon Terminal

114
Q

Are action potentials graded or all or nothing?

A

All or nothing

115
Q

What kind of potentials are self-propagating?

A

Action potentials

116
Q

When the threshold for firing an action potential is reached, voltage gated Na+ channels open and Na+ rushes in causing what?

A

Huge depolarisation of the neuron

117
Q

Graded potentials transmit over what distances?

A

Short

118
Q

Are inhibitory graded potentials hyperpolarising or depolarising?

A

Hyperpolarising

119
Q

Voltage gated channels change their conformation when

A

Changes in electrical potential act on charged regions of the channel proteins

120
Q

Acetylcholine receptors are an example of what kind of gated channel?

A

Ligand gated

121
Q

What are the 3 types of neurones?

A

Afferent (sensory)
Interneurones
Efferent (motor)

122
Q

What neurones carry a signal to effector cells/tissue?

A

Efferent (motor)

123
Q

Larger axons allow

A

Faster transmission

124
Q

The normal effect of a receptor is mimicked by

A

Agonists

125
Q

The normal action of a receptor is blocked by

A

Antagonists

126
Q

As agonist concentration increases, it’s effect

A

Increases

127
Q

What are the largest family of membrane receptors?

A

G protein coupled receptors

128
Q

G protein coupled receptors coupled to Adenylyl Cyclase can increase/decrease the concentration of cAMP and do what to PKA?

A

Activate/inhibit

129
Q

What is albumin?

A

The main protein of human blood plasma

130
Q

What is the main function of albumin?

A

To regulate colloidal osmotic pressure of blood

131
Q

What does epithelial tissue cover and separate?

A

Covers surfaces and separates body compartments

132
Q

Does epithelial tissue have contact inhibition?

A

No

133
Q

Cell-cell junctions contain desmosomes to provide

A

Firm anchorage

134
Q

What do gap junctions allow?

A

Cell-cell communication

135
Q

Hemidesmosomes are found in what junctions?

A

Cell-ECM

136
Q

Give an example of simple squamous epithelium

A

Alveoli

Capillaries

137
Q

Give an example of simple cuboidal epithelium

A

Lining of nephrons

138
Q

Give an example of simple columnar epithelium

A

Lining of the digestive tract

139
Q

Give an example of stratified squamous epithelium

A

Epidermis

140
Q

Give an example of stratified cuboidal epithelium

A

Ducts of sweat glands

141
Q

Give an example of stratified columnar epithelium

A

Pharynx

142
Q

What simple epithelium type is thin to allow easy diffusion?

A

Squamous

143
Q

What epithelium type moves mucus when ciliated?

A

Simple columnar

144
Q

What type(s) of squamous epithelium provide protection

A

Cuboidal

Columnar (also secretion)

145
Q

Epithelial cells in the kidneys are arranged into what?

A

Nephrons

146
Q

What are glands?

A

Collections of multi or single cellular secretory epithelial cells

147
Q

What do endocrine glands do

A

Secrete into blood

148
Q

What do exocrine glands do

A

Secrete to surface

149
Q

Sweat glands are an example of what type of gland?

A

Exocrine

150
Q

What system produces a “fight or flight” response when activated?

A

Sympathetic

151
Q

Which system causes an increase in gut motility when activated?

A

Parasympathetic

152
Q

Stored energy is released at the activation of what system?

A

Sympathetic

153
Q

Ganglia are usually paravertebral in what system?

A

Sympathetic

154
Q

What is divergence?

A

When one preganglionic fibre activates lots of post ganglionic fibres

155
Q

Noradrenaline acts in what system on what receptors?

A

Sympathetic system

Alpha or Beta

156
Q

Acetylcholine acts on what receptors in the parasympathetic system?

A

Muscarinic

157
Q

The skull, vertebral column and ribs are parts of what skeleton?

A

Axial

158
Q

The shoulder girdle and pelvis are parts of what skeleton?

A

Appendicular

159
Q

What is the function of Osteoclasts?

A

Bone resorbing cells - absorb any area of damaged bone

160
Q

What is the function of Osteoblasts?

A

Laying down new bone

161
Q

What is the function of Osteocytes?

A

To act as sensors of mechanical pressure and damage

162
Q

What movement does the anterior compartment of the upper arm allow?

A

Flexion of elbow joint

163
Q

What compartment of the arm allows the extension of the elbow joint?

A

Posterior

164
Q

What is the major blood supply to the arm?

A

Brachial artery

165
Q

What plexus innervates the arm?

A

Brachial plexus

166
Q

The anterior compartment of the forearm is responsible for what movement(s)?

A

Flexion

Pronation

167
Q

The compartment allowing extension and supination of the arm is what?

A

Posterior compartment of forearm

168
Q

What nerve supplies all extensor muscles in the upper limb?

A

Radial nerve

169
Q

What compartment of the thigh are the hamstrings?

A

Posterior

170
Q

What movement are the hamstrings responsible for?

A

Flexion of knee

171
Q

What nerve supplies the anterior compartment of the thigh?

A

Femoral nerve

172
Q

The sciatic nerve supplies what thigh compartment?

A

Posterior

173
Q

Obturator nerve supplies what thigh compartment?

A

Medial

174
Q

What thigh compartment is responsible for adduction?

A

Medial

175
Q

What lower leg compartment everts the foot?

A

Lateral

176
Q

The deep fibular nerve supplies what lower leg compartment?

A

Anterior

177
Q

Ankle is flexed and foot is inverted by what compartment?

A

Posterior compartment of lower leg

178
Q

What movements occur at the subtalar and transverse talar joints?

A

Inversion and eversion of foot

179
Q

What kind of joints are present at the elbows and knees?

A

Synovial hinge

180
Q

What kind of joints are present at the hips and shoulders?

A

Synovial ball and socket

181
Q

What plexus is composed of fibres from vertebral levels L1-S5?

A

Lumbosacral

182
Q

If a ventral rami is damaged, what function will be lost?

A

Sensory and motor, as it is a mixed nerve

183
Q

If a nerve is cut at the motor ventral root, what function will be lost?

A

Motor

184
Q

Where is the T4 dermatome?

A

Skin over nipples

185
Q

Where is the T10 dermatome?

A

Skin over umbilicus

186
Q

What are the functions of the vertebral column?

A

Weight bearing
Protection
Permits movement
Site of muscle attachments

187
Q

What kind of joints are between vertebrae and intervertebral discs?

A

Secondary cartilaginous

188
Q

What is the C2 vertebra commonly known as?

A

Axis

189
Q

The vertebra prominens is at what vertebral level?

A

C7

190
Q

T7 vertebra is the

A

Inferior tip of scapula

191
Q

Superior aspect of iliac crest is at what vertebral level?

A

L4

192
Q

The posterior superior iliac spine is at what vertebral level?

A

S2

193
Q

How many cervical, thoracic, lumbar, sacral and coccygeal vertebrae are there?

A
C - 7
T - 12
L - 5
S - 5
Cc - 3-5
194
Q

The head of the rib articulates with what?

A

Facet on the vertebral body

195
Q

The tubercle of the rib articulates with what?

A

The transverse process facet of vertebrae

196
Q

What kind of joint is found at the atlantoaxial joint?

A

Synovial pivot

197
Q

What kind of joint is found at the antlanto-occipital joint?

A

Synovial ellipsoid

198
Q

What movement occurs at the atlanto-occipital joint?

A

Flexion
Extension
Lateral flexion

199
Q

What are the main functions of the lymph system?

A

Tissue drainage

Return of plasma proteins

200
Q

Lymph fluid consists mainly of

A

Fluid and plasma proteins (but it gains lymphocytes as it flows through lymphatic capillaries)

201
Q

What type of lymphatic drainage follows arteries?

A

Deep

202
Q

Inguinal lymph nodes in and around the femoral triangle at the base of the lower limb are an example of what kind of lymph nodes?

A

Superficial

203
Q

What two ducts does lymph fluid drain to?

A

Right lymphatic duct

Thoracic duct

204
Q

The lymphatic ducts empty into the venous system at

A

The jugular/subclavian junction

205
Q

What is aetiology?

A

Cause of disease

206
Q

What is pathogenesis?

A

How a disease develops

207
Q

What is prognosis?

A

Prediction of probable outcome

208
Q

What are the functions of the cytoskeleton?

A

Strength
Support
Allows cell motility

209
Q

Abnormal bone marrow/blood can lead to

A

Leukaemia

210
Q

What layers does the skin consist of?

A

Epidermis (epithelia)
Dermis (connective tissue)
Hypodermis (fat)

211
Q

In what molecules in the body is nitrogen mainly found?

A

Amino acids
Ammonia
Urea

212
Q

What is the only amino acid that can obtain nitrogen from ammonia?

A

Glutamate

213
Q

Other amino acids obtain nitrogen from pre-existing amino acids through what reactions?

A

Transaminase

214
Q

Nitrogen is transferred using

A

Glutamine and alanine

215
Q

Nitrogen transferred from catabolised protein in muscle cells is transported back to the liver as alanine where it is converted back to glucose, what enzymes does this process involve?

A

Transferase enzymes

216
Q

Why is nitrogen transferred as glutamine and alanine rather than glutamate?

A

Glutamate has a negative charge so
- would require a cation
- won’t pass readily through cell membranes
Glutamine and alanine have no charge

217
Q

What is urea formed from?

A

Ammonia

218
Q

Ammonia is formed through?

A

Oxidative deamination (where glutamate loses nitrogen in the form of ammonia

219
Q

Ammonia is fed into what cycle?

A

The urea cycle, where it is converted to urea and excreted

220
Q

What is the most common urea cycle disorder?

A

Ornithine transcarbamylase (OTC) deficiency

221
Q

What kind of inheritance is involved in the most common urea cycle disorder?

A

X-linked

222
Q

What is Phenylketonuria?

A

An absence or deficiency of phenylalanine hydroxylase (PAH)

223
Q

What kind of disease is PKU?

A

Autosomal recessive

224
Q

If untreated, what will PKU lead to by 6 months of age?

A

Delayed mental development and neurological features

225
Q

How is PKU diagnosed?

A

Neonatal screening offered in UK, if screening test is positive, quantitative amino acid analysis is carried out to confirm diagnosis