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Flashcards in IMMS Deck (205):
1

Water distribution: how much water is there in:
a) the ECF?
b) the ICF?

a) 14L
b) 28L

2

Water distribution: how much water is there in the (ECF):
a) interstitial fluid
b) plasma

a) interstitial - 11L
b) plasma - 3L

3

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

K+

4

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

Na+, Cl-, HCO3-

5

What is the definition of osmosis?

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

6

What is the definition of osmolarity?

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

7

What is the definition of oncotic pressure?

Oncotic pressure is a form of osmotic pressure exerted by proteins, notably albumin, that tends to pull fluid into its solution.

8

What is the definition of osmotic pressure?

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

9

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

Cause - water deficit (poor intake, diabetes insipidus etc).
Risks - Dehydration.
(High sodium = low H2O which dehydrates the brain).

10

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

Causes: Excess water due to IV fluids, diuretics.
Risks: Over hydration - headache, confusion.

11

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

Causes: renal failure, acidosis, diuretic inhibitors.
Risks: Cardiac arrest.

12

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

Causes: D+V, alkalosis, diuretics.
Risks: weakness and dysrhythmia.

13

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

Causes: hyperparathyroidism, Vit D toxicity, malignancy.
Risks: renal stones and metastatic calcification.

14

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

Causes: renal disease, Vit D deficiency, intestinal malabsorption.
Risks: tetany (spasms).

15

What is the function of rough ER?

Protein synthesis

16

What is the function of smooth ER?

Lipid synthesis

17

What is the function of the golgi apparatus?

Processes and modifies ER products.

18

What is the cis face of the golgi apparatus?

The cis face is nearest the nucleus and receives ER vesicles.

19

What does the medial Golgi do?

It modifies products by adding sugars forming oligosaccharides

20

What does the trans face of the golgi do?

It sorts molecules into vesicles.

21

What are the functions of vesicles?

Transports and stores materials. These are membrane bound organelles.

22

What are desmosomes?

Attach cells via the intermediate filaments.

23

What are tight junctions?

Binds cells together to prevent leakage of molecules in between them.

24

What is the function of gap junctions?

Conduct electrical signals.

25

List 4 functions of a plasma membrane.

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.

26

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

1. Cholesterol
2. Glycoproteins
3. Glycolipids
4. Integral proteins

27

Define genotype.

The genetic constitution of an individual.

28

Define phenotype.

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

29

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

28L

30

What is an example of type 1 collagen?

Bone, skin and teeth.

31

What is an example of type 2 collagen?

Cartilage.

32

What is an example of type 3 collagen?

Arteries, liver, kidneys, spleen, uterus

33

What is an example of type 4 collagen?

Basement membranes

34

What is an example of type 5 collagen?

Placenta

35

Define allele.

An alternative form of a gene at a specific locus.

36

Give an example of an autosomal dominant condition.

Huntingtons disease.

37

Give an example of an autosomal recessive condition.

Cystic fibrosis.

38

Summarise autosomal dominant inheritance.

- 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.

39

Summarise autosomal recessive inheritance.

- 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.

40

Give an example of an X linked recessive condition.

Duchenne muscular dystrophy

41

What is a mis-sense mutation?

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).

42

What is a non-sense mutation?

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

43

What are the products of glycolysis?

2 ATP, 2 NADH, 2 Pyruvate

44

What is the rate limiting enzyme in glycolysis?

Phosphofructokinase-1

45

Where in a cell does glycolysis take place?

Cytoplasm

46

Where in a cell does the Krebs cycle take place?

The matrix of the mitochondria

47

Define metabolism.

Chemical reactions that occur in a living organism.

48

Define BMR.

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

49

How much energy do carbohydrates provide?

4kcal/g

50

How much energy do proteins provide?

4kcal/g

51

How much energy do lipids provide?

7kcal/g

52

How much energy does alcohol provide?

9kcal/g

53

How much energy is stored as triglycerides?

15kg

54

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

350g
- 200g in the liver
- 150g in muscle

55

How much energy is stored as protein?

6kg

56

What factors increase BMR?

Being overweight, pregnancy, low temperature, exercise, hyperthyroidism

57

What factors decrease BMR?

Increasing age, being female, starvation, hypothyroidism

58

What are reactive oxygen species?

Reactive molecules and free radicals derived from O2

59

Name 3 exogenous sources of ROS?

Smoking, UV radiation, drugs

60

Name an endogenous source of ROS?

Produced as a by product of O2 metabolism

61

Name 3 ketone bodies

- acetoacetate
- acetone
- beta hydroxybutyrate

62

Where does ketogenesis usually occur?

In the liver

63

When would ketogenesis occur?

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

64

What molecules make up ATP?

1 adenine, 1 ribose, 3 phosphate

65

Define buffer.

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

66

Name 3 biological buffers.

1. Protein
2. Haemoglobin
3. Bicarbonate

67

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

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

(Arrows are reversible)

68

How do protein buffers work?

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.

69

What can cause respiratory acidosis?

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

70

What happens to the PaCO2 levels in respiratory acidosis?

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

CO2 production is greater than CO2 elimination

71

What can cause respiratory alkalosis?

Hyperventilation in response to hypoxia.
CO2 elimination exceeds O2 reabsorption.

72

List 3 causes of metabolic acidosis?

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

73

List 2 causes of metabolic alkalosis.

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

74

What do fatty acids produce.
Where is this product used?

Acetyl CoA
Used in the Krebs cycle

75

Name 4 ways in which ATP can be produced?

- Krebs cycle.
- Glycolysis.
- Oxidative phosphorylation.
- Substrate level phosphorylation.

76

What is gonadal mosaicism?

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.

77

What type of cells are produced in mitosis?

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

78

What is mitosis used for?

Growth and repair.

79

What are the 4 phases of the cell cycle?

G1, S, G2 and M

80

What phases of the cell cycle make up interphase?

G1, S and G2

81

What happens in prophase?

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

82

What happens in prometaphase?

Spindles form. Nuclear membrane completely breaks down.

83

What happens in metaphase?

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

84

What happens in anaphase?

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

85

What happens in telophase?

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

86

What happens in cytokinesis?

The cytoplasm divides producing 2 genetically identical daughter cells.

87

What type of cells are produced in meiosis?

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

88

What is meiosis used for?

The production of gametes.

89

How is genetic diversity introduced in meiosis?

- Metaphase 1 = random assortment.
- Prophase 1 = crossover.

90

Name 3 molecules that make a nucleotide.

1. Pentose sugar.
2. Phosphate.
3. Nitrogenous base.

91

What is splicing?

The removal of exons from pre-mRNA

92

List 3 features of the genetic code.

1. Non-overlapping
2. Universal
3. Degenerative

93

What condition is trisomy 21?

Down's syndrome

94

Define lyonisation.

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

95

What is a triglyceride?

A glycerol backbone with 3 fatty acids.

96

What 2 carbohydrates form sucrose?

Glucose and fructose

97

What 2 carbohydrates form maltose?

Glucose and Glucose

98

What 2 carbohydrates form Galactose?

Glucose and lactose

99

What is the respiratory burst?

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

100

Name 2 equations that form hydroxyl radicals.

1. Fenton's
2. Haber-Weiss

101

What is Fenton's equation?

Fe2+ + H2O2 -> Fe3+ + OH• + OH-

102

What is the Haber Weiss equation?

O2- + H2O2 -> O2 + OH• + OH-

103

Give 3 examples of endocytosis.

1. Phagocytosis.
2. Pinocytosis.
3. Receptor mediated.

104

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

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

105

Name 3 types of cell receptors.

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

106

Name 3 ways in which we intake fluids.

1. Drink.
2. Food.
3. IV Fluids.

107

Define insensible losses.

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

108

Name 3 hormones involved in water homeostasis.

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

109

What is oedema?

Excess H2O in the interstitial fluid.

110

Name the 4 types of oedema.

1. Lymphatic.
2. Venous.
3. Hypoalbuminaemic.
4. Inflammatory.

111

What is serous effusion?

Excess H2O in a body cavity.

112

Name 2 places DNA can be found.

1. Nucleus of a cell.
2. Mitochondria (purely maternal DNA).

113

What is the function of topoisomerase?

It unwinds the DNA double helix by relieving the supercoils.

114

In what direction does DNA polymerase read?

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

115

What is the product of transcription?

mRNA

116

Where does translation occur?

At a ribosome.

117

Briefly describe translation.

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

118

What are the 4 bases in RNA?

Adenine, Cytosine, Guanine, Uracil.

119

What is non-disjunction?

The failure of chromatids to separate.
For example; Down's syndrome - trisomy 21. Turner's syndrome - Monosomy of X chromosome.

120

What enzyme of glycolysis is inhibited in acidosis?

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

121

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

Anaphase.

122

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

Phosphoglyceratekinase.

123

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

Triose phosphate isomerase.

124

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

ATP synthase.

125

Is the mitochondrial membrane permeable or impermeable to ions?

Impermeable.

126

What are steroid hormones synthesised from?

Cholesterol.

127

What will epiblasts in a 3-week embryo become?

Ectoderm.

128

How many days after fertilisation does implantation occur?

7-8 days.

129

How long is pregnancy?

40 weeks.

130

What does the blastocyst divide into?

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

131

What does the embryoblast divide into?

Epiblast and Hypoblast = bi-laminar disc.

132

What does the trophoblast divide into?

Cytotrophoblast (inner) and Syncytiotrophoblast (outer).

133

How is the primary utero-placental circulation established?

Lacunae form in the syncytiotropohoblast and maternal blood enters.

134

What happens in the third week of embryonic life?

Gastrulation - formation of a tri-laminar embryonic disc.

135

What is the function of chorionic villi?

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

136

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

Paraxial plate mesoderm.

137

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

Lateral plate mesoderm.

138

What does the ectoderm form?

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

139

What does the endoderm form?

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

140

What happens in the 4th week of embryonic life?

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

141

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

Intima, Media, Adventitia

142

What causes trisomy 21?

Failure of the chromatids to separate; non-dysjunction.

143

Name 2 electron accepting coenzymes.

1. NAD.
2. FAD.

144

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

2.5.

145

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

1.5.

146

Briefly describe what happens in anaerobic respiration.

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.

147

What is the normal pH range of the human body?

7.35-7.45

148

What is the importance of acylcarnitine?

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

149

What is the product of fatty acid beta oxidation?

Acetyl CoA.

150

Where does the acetyl CoA from beta oxidation go?

To the krebs cycle.

151

What are removed in splicing of pre-mRNA?

Introns.

152

What is gametogenesis?

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

153

Gametogenesis: when do meiotic divisions occur in a male?

At puberty.

154

Gametogenesis: when is meiosis 1 complete in a female?

At ovulation.

155

Gametogenesis: when is meiosis 2 complete in a female?

If fertilisation occurs.

156

What is Mendel's second law?

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

157

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

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

158

Can males ever be carriers of X linked conditions?

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

159

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

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

160

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

More common in males.

161

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

No affected children but all the daughters would be carriers.

162

What is multifactorial disease?

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

163

Define karyotype.

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

164

Define penetrance.

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

165

Define sex limitation.

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

166

Define variable expression.

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

167

Name 2 allosteric activators of PFK-1.

1. AMP.
2. Fructose-2,6-bisphosphate.

168

Name 3 allosteric inhibitors of PFK-1.

1. Acidosis.
2. ATP.
3. Citrate.

169

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

Amphipathic.

170

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

Ectoderm.

171

What cells does the epiblast give rise to?

Amnioblasts that line the amniotic cavity.

172

What cells does the hypoblast give rise to?

Cells that line the blastocyst cavity.

173

What is the chorion composed of?

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

174

What is the role of ATP synthase in oxidative phosphorylation?

It transports H+ into the mitochondrial matrix.

175

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

It transports H+ out of the mitochondrial matrix.

176

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

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

177

Where does oxidative phosphorylation occur?

In the mitochondrial matrix.

178

What transports H+ out of the mitochondrial matrix?

Cytochrome-C oxidase complex.

179

A gene sequence is coded in ...

Single strand DNA.

180

A promoter sequence is coded in ...

Single strand DNA.

181

What is a promoter sequence?

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

182

What is a transcriptome?

All the messenger RNA molecules in a cell.

183

Which protein structure is created by covalent bonds?

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

184

What type of bond is a peptide bond?

A covalent bond.

185

What is a single nucleotide polymorphism?

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

186

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

Autosomal recessive.

187

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

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

188

What are the sub-units of haemoglobin?

2 alpha and 2 beta subunits.

189

A mutation in what gene results in HbS production?

HBB gene.

190

How do HbS sub-units cause sickling?

They bind to the cytoskeleton which causes sickling.

191

What is the affect on HbS in hypoxia?

The HbS sub-units polymerise.

192

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

Insensible losses will increase by 10%.

193

Why is sodium doubled in the plasma osmolality equation?

To account for negatively charged ions.

194

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?

Blood osmolality would be high.
Urine osmolality would be low - very dilute urine.

195

What are Mendel's 3 laws?

1. Law of dominance.
2. Law of independent assortment.
3. Law of segregation.

196

How many hydrogen bonds form between adenine and thymine?

2.

197

How many hydrogen bonds form between cytosine and guanine?

3.

198

How many genes are there in the human genome?

20,000.

199

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

Telomerase.

200

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

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

201

What is Knudson's two hit hypothesis?

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.

202

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.

Anticipation.

203

Give 4 functions of tight junctions.

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.

204

What enzyme does high insulin levels stimulate?

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

205

How does insulin increase the breakdown of glucose to pyruvate?

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