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MED PHASE 1 > IMMS > Flashcards

IMMS Flashcards

1
Q

Water distribution: how much water is there in:

a) the ECF?
b) the ICF?

A

a) 14L

b) 28L

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2
Q

Water distribution: how much water is there in the (ECF):

a) interstitial fluid
b) plasma

A

a) interstitial - 11L

b) plasma - 3L

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3
Q

What is the predominant electrolyte(s) in the ICF?

A

K+

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4
Q

What is the predominant electrolyte(s) in the ECF?

A

Na+, Cl-, HCO3-

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5
Q

What is the definition of osmosis?

A

Movement of H2O across a partially permeable membrane from an area of high water potential to an area of low water potential.

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6
Q

What is the definition of osmolarity?

A

The number of solute particles per L of fluid. (A high osmolarity has more solute particles per L).

OR:
Conc of a solution expressed as total number of solute particles per litre.

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7
Q

What is the definition of oncotic pressure?

A

Oncotic pressure is a form of osmotic pressure exerted by proteins, notably albumin, that tends to pull fluid into its solution.
- water moves from interstitial fluid into plasma.

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8
Q

What is the definition of osmotic pressure?

A

The pressure that must be applied to a solution by pure solvent to prevent inward osmosis through a partially permeable membrane.

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9
Q

Electrolyte homeostasis: what is the cause(s) of hypernatremia? And what are the risks?

A

Cause -
Poor water intake/deficit (diabetes insipidus, osmotic diuresis) renal failure.

Sodium excess - mineralocorticoid (aldosterone excess)

Risks - Cerebral Intracellular Dehydration.
(High sodium = low H2O which dehydrates the brain)… as lower H2O concentration since H2O leaves intracellular to go extracellular as olute conc increases.

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10
Q

Electrolyte homeostasis: What is the cause(s) of hyponatremia and what are its risks?

A

Causes: Excess water due to IV fluids, diuretics.
Sodium loss due to diuretics.
Risks: Cerebral intracellular over hydration - headache, confusion.

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11
Q

Electrolyte homeostasis: What is the cause(s) of hyperkalemia and what are its risks?

A

Causes: renal failure, acidosis, diuretic/ACE inhibitors.
Risks: Cardiac arrest/myocardial infarction.

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12
Q

Electrolyte homeostasis: What is the cause(s) of hypokalemia and what are its risks?

A

Causes: Diarrhoea+ Vomitting, alkalosis, diuretics.
Risks: weakness and arrhythmia.

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13
Q

Electrolyte homeostasis: What is the cause(s) of hypercalcemia and what are its risks?

A

Causes: primary hyperparathyroidism, Vit D toxicity, malignancy/skeletal metastases.
Risks: renal stones and metastatic calcification.

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14
Q

Electrolyte homeostasis: What is the cause(s) of hypocalcemia and what are its risks?

A

Causes: renal disease, Vit D deficiency, intestinal malabsorption, Parathyroidectomy.

Risks: tetany (spasms).

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15
Q

What is the function of rough ER?

A

Site of protein synthesis

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16
Q

What is the function of smooth ER?

A

Site of membrane lipid synthesis

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17
Q

What is the function of the golgi apparatus?

A

Processes and modifies ER products.

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18
Q

What is the cis face of the golgi apparatus?

A

The cis face is nearest the nucleus and receives ER vesicles.
Protein phosphorylation occurs here.

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19
Q

What does the medial Golgi do?

A

It modifies products by adding sugars forming oligosaccharides by adding sugars to lipids and peptides.

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20
Q

What does the trans face of the golgi do?

A

Proteolysis of peptides into active forms.

It sorts molecules into vesicles.

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21
Q

What are the functions of vesicles?

A

Transports and stores materials. These are membrane bound organelles.

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22
Q

What are desmosomes?

A

Attach cells via the intermediate filaments.

Physical joint between cells and connect the cytoskeletons

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23
Q

List 4 functions of a plasma membrane.

A
  1. Physical boundary for the cell.
  2. Regulates the movement of substances.
  3. Has receptors for cell to cell signalling.
  4. Attaches the cell to the external environment.
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24
Q

Name 4 molecules you’d find in a plasma membrane.

A
  1. Cholesterol
  2. Glycoproteins
  3. Glycolipids
  4. Integral proteins
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25
Q

Define genotype.

A

The genetic constitution of an individual.

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26
Q

Define phenotype.

A

The appearance of an individual due to the environment and genetics.

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27
Q

Water distribution: How much water is there in the ICF?

A

28L

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28
Q

What is an example of type 1 collagen?

A

Bone, skin and teeth.

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29
Q

What is an example of type 2 collagen?

A

Cartilage.

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30
Q

What is an example of type 3 collagen?

A

Arteries, liver, kidneys, spleen, uterus

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31
Q

What is an example of type 4 collagen?

A

Basement membranes

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32
Q

What is an example of type 5 collagen?

A

Placenta

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33
Q

Define allele.

A

An alternative form of a gene at a specific locus.

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34
Q

Give an example of an autosomal dominant condition.

A

Huntingtons disease.

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35
Q

Give an example of an autosomal recessive condition.

A

Cystic fibrosis.

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36
Q

Summarise autosomal dominant inheritance.

A
  • Manifests in the heterozygous state.
  • Male to Male transmission is seen.
  • Both males and females are affected equally.
  • The disease is present in several generations.
  • There is a 50% chance of offspring having the disease.
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37
Q

Summarise autosomal recessive inheritance.

A
  • Manifests in the homozygous state.
  • The disease is often not seen in every generation.
  • 25% chance of offspring having the disease.
  • 50% chance of offspring being carriers.
  • Healthy siblings have a 2/3 chance of being carriers.
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38
Q

Give an example of an X linked recessive condition.

A

Duchenne muscular dystrophy

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39
Q

What is a mis-sense mutation?

A

A single nucleotide change results in a codon coding for a different amino acid. This can result in a non functional protein or can have no effect (degenerative nature of the genetic code).

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40
Q

What is a non-sense mutation?

A

A single nucleotide change that produces a premature stop codon. This results in an incomplete/non-functional protein.

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41
Q

What are the products of glycolysis?

A

2 ATP, 2 NADH, 2 Pyruvate

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42
Q

What is the rate limiting enzyme in glycolysis?

A

Phosphofructokinase-1

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43
Q

Where in a cell does glycolysis take place?

A

Cytoplasm

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44
Q

Where in a cell does the Krebs cycle take place?

A

The matrix of the mitochondria

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45
Q

Define metabolism.

A

Chemical reactions that occur in a living organism.

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46
Q

Define BMR.

A

The energy needed to stay at live rest. (24kcal/Kg/day)

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47
Q

How much energy do carbohydrates provide?

A

4kcal/g

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48
Q

How much energy do proteins provide?

A

4kcal/g

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49
Q

How much energy do lipids provide?

A

9kcal/g

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50
Q

How much energy does alcohol provide?

A

7kcal/g

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51
Q

How much energy is stored as triglycerides?

A

15kg

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52
Q

How much energy is stored as glycogen? And where is it stored?

A

350g

  • 200g in the liver
  • 150g in muscle
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53
Q

How much energy is stored as protein?

A

6kg

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54
Q

What factors increase BMR?

A

Being overweight, pregnancy, low temperature, exercise, hyperthyroidism

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55
Q

What factors decrease BMR?

A

Increasing age, being female, starvation, hypothyroidism

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56
Q

What are reactive oxygen species?

A

Reactive molecules and free radicals derived from O2

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57
Q

Name 3 exogenous sources of ROS?

A

Smoking, UV radiation, drugs

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58
Q

Name an endogenous source of ROS?

A

Produced as a by product of O2 metabolism

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59
Q

Name 3 ketone bodies

A
  • acetoacetate
  • acetone
  • beta hydroxybutyrate
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60
Q

Where does ketogenesis usually occur?

A

In the liver

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61
Q

When would ketogenesis occur?

A

During high rates of fatty acid oxidation too much acetyl CoA is produced; this overwhelms the Krebs cycle and so you get ketone body formation

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62
Q

What molecules make up ATP?

A

1 adenine, 1 ribose, 3 phosphate

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63
Q

Define buffer.

A

A solution that resists changes in pH when small amounts of acid/base are added.

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64
Q

Name 3 biological buffers.

A
  1. Protein
  2. Haemoglobin
  3. Bicarbonate
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65
Q

What is the equation to demonstrate the mechanism of a bicarbonate buffer?

A

H2O + CO2 -> H2CO3 -> HCO3- + H+

Arrows are reversible

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66
Q

How do protein buffers work?

A

If the pH falls H+ binds to the amino group of the protein.

If the pH rises H+ can be released from the carboxyl group of the protein.

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67
Q

What can cause respiratory acidosis?

A

Inadequate ventilation due to airway obstruction (COPD, asthma).

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68
Q

What happens to the PaCO2 levels in respiratory acidosis?

A

PaCO2 increases leading to an increase in H+ ions and so pH decreases.

CO2 production is greater than CO2 elimination

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69
Q

What can cause respiratory alkalosis?

A

Hyperventilation in response to hypoxia.

CO2 elimination exceeds O2 reabsorption.

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70
Q

List 3 causes of metabolic acidosis?

A

Renal failure, loss of HCO3-, excess H+ production.

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71
Q

List 2 causes of metabolic alkalosis.

A

Vomiting (loss of H+), increased reabsorption of HCO3-.

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72
Q

What do fatty acids produce.

Where is this product used?

A

Acetyl CoA

Used in the Krebs cycle

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73
Q

Name 4 ways in which ATP can be produced?

A
  • Krebs cycle.
  • Glycolysis.
  • Oxidative phosphorylation.
  • Substrate level phosphorylation.
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74
Q

What is gonadal mosaicism?

A

When there are 2 different populations of cells in the gonads. One population is normal and the other is mutated. All gametes from the mutated line are effected.

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75
Q

What type of cells are produced in mitosis?

A

2 diploid daughter cells which are genetically identical to the parent cells.

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76
Q

What is mitosis used for?

A

Growth and repair.

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77
Q

What are the 4 phases of the cell cycle?

A

G1, S, G2 and M

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78
Q

What phases of the cell cycle make up interphase?

A

G1, S and G2

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79
Q

What happens in prophase?

A

Chromatin condenses into chromosomes. Nuclear membrane begins to break down.

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80
Q

What happens in prometaphase?

A

Spindles form. Nuclear membrane completely breaks down.

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81
Q

What happens in metaphase?

A

The chromosomes line up along the midline of the cell. The spindles attach to the centromeres.

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82
Q

What happens in anaphase?

A

The chromosomes are pulled apart and the sister chromatids are pulled towards the nuclear poles.

83
Q

What happens in telophase?

A

The nuclear membrane reforms and the chromosomes unravel to form chromatin. The spindle fibres disappear.

84
Q

What happens in cytokinesis?

A

The cytoplasm divides producing 2 genetically identical daughter cells.

85
Q

What type of cells are produced in meiosis?

A

4 haploid daughter cells that are genetically different to the parent cell.

86
Q

What is meiosis used for?

A

The production of gametes.

87
Q

How is genetic diversity introduced in meiosis?

A
  • Metaphase 1 = random assortment.

- Prophase 1 = crossover.

88
Q

Name 3 molecules that make a nucleotide.

A
  1. Pentose sugar.
  2. Phosphate.
  3. Nitrogenous base.
89
Q

What is splicing?

A

The removal of exons from pre-mRNA

90
Q

List 3 features of the genetic code.

A
  1. Non-overlapping
  2. Universal
  3. Degenerate
91
Q

What condition is trisomy 21?

A

Down’s syndrome

92
Q

Define lyonisation.

A

One of the female X chromosomes becomes inactivated early in embryogenesis.

93
Q

What is a triglyceride?

A

A glycerol backbone with 3 fatty acids.

94
Q

What 2 carbohydrates form sucrose?

A

Glucose and fructose

95
Q

What 2 carbohydrates form maltose?

A

Glucose and Glucose

96
Q

What 2 carbohydrates form lactose?

A

Glucose and galactose

97
Q

What is the respiratory burst?

A

WBC’s using ROS in phagocytosis to damage the membrane of invading cells.

98
Q

Name 2 equations that form hydroxyl radicals.

A
  1. Fenton’s

2. Haber-Weiss

99
Q

What is Fenton’s equation?

A

Fe2+ + H2O2 -> Fe3+ + OH• + OH-

100
Q

What is the Haber Weiss equation?

A

O2- + H2O2 -> O2 + OH• + OH-

101
Q

Give 3 examples of endocytosis.

A
  1. Phagocytosis.
  2. Pinocytosis.
  3. Receptor mediated.
102
Q

Name 3 mechanisms by which a molecule can move across a plasma membrane.

A
  1. Diffusion - movement down a concentration gradient.
  2. Facilitated diffusion.
  3. Active transport - uses ATP, against concentration gradient.
103
Q

Name 3 types of cell receptors.

A
  1. Ion channel receptors.
  2. G-protein coupled receptors.
  3. Enzyme linked receptors.
104
Q

Name 3 ways in which we intake fluids.

A
  1. Drink.
  2. Food.
  3. IV Fluids.
105
Q

Define insensible losses.

A

Water loss that we are unaware of. It is comprised only of solvent and can not be measured.

106
Q

Name 3 hormones involved in water homeostasis.

A
  1. Aldosterone.
  2. ADH - antidiuretic hormone.
  3. ANP - atrial natriuretic peptide.
107
Q

What is oedema?

A

Excess H2O in the interstitial fluid.

108
Q

Name the 4 types of oedema.

A
  1. Lymphatic.
  2. Venous.
  3. Hypoalbuminaemic.
  4. Inflammatory.
109
Q

What is serous effusion?

A

Excess H2O in a body cavity.

110
Q

Name 2 places DNA can be found.

A
  1. Nucleus of a cell.

2. Mitochondria (purely maternal DNA).

111
Q

What is the function of topoisomerase?

A

It unwinds the DNA double helix by relieving the supercoils.

112
Q

In what direction does DNA polymerase read?

A

3’ to 5’ (but replication occurs in the 5’ to 3’ direction).

113
Q

What is the product of transcription?

A

mRNA

114
Q

Where does translation occur?

A

At a ribosome.

115
Q

Briefly describe translation.

A

A tRNA with a complementary anticodon to the codon on mRNA binds. Peptide bonds from between amino acids = polypeptide chain.

116
Q

What are the 4 bases in RNA?

A

Adenine, Cytosine, Guanine, Uracil.

117
Q

What is non-disjunction?

A

The failure of chromatids to separate.

For example; Down’s syndrome - trisomy 21. Turner’s syndrome - Monosomy of X chromosome.

118
Q

What enzyme of glycolysis is inhibited in acidosis?

A

Phosphofructosekinase-1 (PFK-1 is pH dependent).

119
Q

Which phase of mitosis is this: The chromosomes are moving towards opposite poles of the cell and there are no nuclear membranes.

A

Anaphase.

120
Q

What enzyme catalyses the formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate?

A

Phosphoglyceratekinase.

121
Q

What enzyme catalyses the formation of glyceraldehyde-3-phosphate from dihydroxyacetone phosphate?

A

Triose phosphate isomerase.

122
Q

Oxidative phosphorylation: What enzyme transports protons into the mitochondrial matrix?

A

ATP synthase.

123
Q

Is the mitochondrial membrane permeable or impermeable to ions?

A

Impermeable.

124
Q

What are steroid hormones synthesised from?

A

Cholesterol.

125
Q

What will epiblasts in a 3-week embryo become?

A

Ectoderm.

126
Q

How many days after fertilisation does implantation occur?

A

7-8 days.

127
Q

How long is pregnancy?

A

40 weeks.

128
Q

What does the blastocyst divide into?

A

Embryoblast (inner cell mass) and Trophoblast (outer cell mass).

129
Q

What does the embryoblast divide into?

A

Epiblast and Hypoblast = bi-laminar disc.

130
Q

What does the trophoblast divide into?

A

Cytotrophoblast (inner) and Syncytiotrophoblast (outer).

131
Q

How is the primary utero-placental circulation established?

A

Lacunae form in the syncytiotropohoblast and maternal blood enters.

132
Q

What happens in the third week of embryonic life?

A

Gastrulation - formation of a tri-laminar embryonic disc.

133
Q

What is the function of chorionic villi?

A

Allows the transfer of nutrients from maternal blood to foetal blood.

134
Q

What part of the tri-laminar disc are somites formed from?

A

Paraxial plate mesoderm.

135
Q

What part of the tri-laminar disc is the circulatory system formed from?

A

Lateral plate mesoderm.

136
Q

What does the ectoderm form?

A

CNS, PNS, skin, posterior pituitary and sweat glands.

137
Q

What does the endoderm form?

A

Respiratory tract, GI tract, urinary tract, auditory tube, liver, pancreas, thyroid and parathyroid glands.

138
Q

What happens in the 4th week of embryonic life?

A

The flat tri-laminar disc folds into a cylindrical embryo.

139
Q

What are the 3 layers of the walls of arteries and veins called?

A

Intima, Media, Adventitia

140
Q

What causes trisomy 21?

A

Failure of the chromatids to separate; non-dysjunction.

141
Q

Name 2 electron accepting coenzymes.

A
  1. NAD.

2. FAD.

142
Q

Approximately how many ATP molecules are produced from oxidation of NADH?

A

2.5.

143
Q

Approximately how many ATP molecules are produced from oxidation of FADH2?

A

1.5.

144
Q

Briefly describe what happens in anaerobic respiration.

A

NAD is regenerated from NADH. Pyruvate, from glycolysis, forms lactate. Lactate dehydrogenase catalyses this reaction. NAD goes back to glycolysis so ATP can be produced.

145
Q

What is the normal pH range of the human body?

A

7.35-7.45

146
Q

What is the importance of acylcarnitine?

A

It is required to transport fatty acids into the mitochondria for beta oxidation.

147
Q

What is the product of fatty acid beta oxidation?

A

Acetyl CoA.

148
Q

Where does the acetyl CoA from beta oxidation go?

A

To the krebs cycle.

149
Q

What are removed in splicing of pre-mRNA?

A

Introns.

150
Q

What is gametogenesis?

A

Precursor cells undergo cell division and differentiation to form haploid gametes.

151
Q

Gametogenesis: when do meiotic divisions occur in a male?

A

At puberty.

152
Q

Gametogenesis: when is meiosis 1 complete in a female?

A

At ovulation.

153
Q

Gametogenesis: when is meiosis 2 complete in a female?

A

If fertilisation occurs.

154
Q

What is Mendel’s second law?

A

The law of independent assortment. The alleles of one gene sort into gametes independently of the alleles of another gene.

155
Q

Why can X linked genes not be passed from father to son?

A

Because the dad is XY and gives only the Y chromosome to his son and the X to his daughter.

156
Q

Can males ever be carriers of X linked conditions?

A

No. They are either affected or they do not carry the gene.

157
Q

Would an X linked dominant condition be more common in males or females?

A

X linked dominant conditions occur twice as frequently in females as they do in males.

158
Q

Would an X linked recessive condition be more common in males or females?

A

More common in males.

159
Q

Would an affected male of an x-linked recessive condition and an unaffected female have any affected children?

A

No affected children but all the daughters would be carriers.

160
Q

What is multifactorial disease?

A

A disease due to genetic and environmental factors e.g. diabetes or schizophrenia.

161
Q

Define karyotype.

A

The number and appearance of chromosomes in the nucleus of a eukaryotic cell.

162
Q

Define penetrance.

A

The proportion of people with a gene who show the expected phenotype.

163
Q

Define sex limitation.

A

Both sexes have a gene but its expression is limited to only one of the sexes and it is turned off in the other.

164
Q

Define variable expression.

A

Variation in clinical features of a genetic disorder between individuals with the same gene alteration.

165
Q

Name 2 allosteric activators of PFK-1.

A
  1. AMP.

2. Fructose-2,6-bisphosphate.

166
Q

Name 3 allosteric inhibitors of PFK-1.

A
  1. Acidosis.
  2. ATP.
  3. Citrate.
167
Q

Lipids have hydrophobic and hydrophillic parts. What is this called?

A

Amphipathic.

168
Q

What layer of the tri-laminar disc does the epiblast form?

A

Ectoderm.

169
Q

What cells does the epiblast give rise to?

A

Amnioblasts that line the amniotic cavity.

170
Q

What cells does the hypoblast give rise to?

A

Cells that line the blastocyst cavity.

171
Q

What is the chorion composed of?

A

The extra-embryonic mesoderm and the 2 layers of trophoblast.

172
Q

What is the role of ATP synthase in oxidative phosphorylation?

A

It transports H+ into the mitochondrial matrix.

173
Q

What is the role of cytochrome-C oxidase complex in oxidative phosphorylation?

A

It transports H+ out of the mitochondrial matrix.

174
Q

What generates the energy needed to phosphorylate ADP -> ATP?

A

The movement of H+ in and out of the mitochondrial matrix.

175
Q

Where does oxidative phosphorylation occur?

A

In the mitochondrial matrix.

176
Q

What transports H+ out of the mitochondrial matrix?

A

Cytochrome-C oxidase complex.

177
Q

A gene sequence is coded in …

A

Single strand DNA.

178
Q

A promoter sequence is coded in …

A

Single strand DNA.

179
Q

What is a promoter sequence?

A

The promoter region controls when and where the RNA polymerase will attach to DNA so transcription can commence.

180
Q

What is a transcriptome?

A

All the messenger RNA molecules in a cell.

181
Q

Which protein structure is created by covalent bonds?

A

Primary structure (peptide bonds between amino acids are covalent).

182
Q

What type of bond is a peptide bond?

A

A covalent bond.

183
Q

What is a single nucleotide polymorphism?

A

A single nucleotide substitution in DNA resulting in variation amongst a population.

184
Q

What type of inheritance pattern is seen with sickle cell disease?

A

Autosomal recessive.

185
Q

What is the mechanism by which sickle cell RBC’s block capillaries?

A

They activate endothelial cells and cause inflammation, this results in blockage of the capillaries.

186
Q

What are the sub-units of haemoglobin?

A

2 alpha and 2 beta subunits.

187
Q

A mutation in what gene results in HbS production?

A

HBB gene.

188
Q

How do HbS sub-units cause sickling?

A

They bind to the cytoskeleton which causes sickling.

189
Q

What is the affect on HbS in hypoxia?

A

The HbS sub-units polymerise.

190
Q

What is the affect on insensible losses if temperature increases by 1 degree?

A

Insensible losses will increase by 10%.

191
Q

Why is sodium doubled in the plasma osmolality equation?

A

To account for negatively charged ions.

192
Q

If a patient has diabetes insipidus and is not producing any ADH what is her blood and urine osmolality after 3 hours of water deprivation going to look like?

A

Blood osmolality would be high.

Urine osmolality would be low - very dilute urine.

193
Q

What are Mendel’s 3 laws?

A
  1. Law of dominance.
  2. Law of independent assortment.
  3. Law of segregation.
194
Q

How many hydrogen bonds form between adenine and thymine?

A

2.

195
Q

How many hydrogen bonds form between cytosine and guanine?

A

3.

196
Q

How many genes are there in the human genome?

A

20,000.

197
Q

What enzyme, expressed normally in embryonic cells and abnormally in neoplastic cells, lengthens telomeres?

A

Telomerase.

198
Q

Give 2 reasons why cancers are more commonly in the elderly.

A
  1. The elderly are more likely to have accumulated mutations.
  2. Their immune system is weaker and so they’re more vulnerable.
199
Q

What is Knudson’s two hit hypothesis?

A

The idea that a sporadic cancer requires 2 acquired mutations whereas an inherited cancer requires only 1 acquired mutation and 1 inherited. Therefore you are more likely to develop an inherited cancer as the chance of one mutation is greater than the chance of 2.

200
Q

What is it called when a child shows a phenotype for a disease younger than their father/mother does? e.g. in huntington’s disease.

A

Anticipation.

201
Q

Give 4 functions of tight junctions.

A
  1. Holds cells together.
  2. Generates a concentration gradient across the epithelium.
  3. Allows the passage of water and glucose.
  4. Prevents the passage of large molecules.
202
Q

What enzyme does high insulin levels stimulate?

A

PFK-1 due to increasing fructose-2,6-bisphosphate levels.

203
Q

How does insulin increase the breakdown of glucose to pyruvate?

A

It stimulates PFK-1 indirectly through increasing fructose-2,6-bisphosphate levels and so increases the rate of glycolysis.

MED PHASE 1 (4 decks)

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