IMMS

Question 1

What is euchromatin?

Answer 1

Loosely packed chromosomes. Hyper accessible chromatin so genes activatable. It is unmethylated DNA.

Question 2

What is heterochromatin?

Answer 2

Tightly packed chromosomes. DNA inaccessible to transcription factors. Silent genes.

Question 3

Exon shuffling allows…

Answer 3

New proteins to be made e.g. in immune system

Question 4

What does splice site mutation affect?

Answer 4

Accurate intron removal affected

Question 5

What is non-sense mediated decay?

Answer 5

Pathway which removes mRNA with premature stop codons

Question 6

Define ALLELIC HETEROGENEITY

Answer 6

Lots of different mutations in one gene e.g. cystic fibrosis

Question 7

Define Locus Heterogeneity

Answer 7

Mutations in different genes give the same clinical condition e.g. hypertrophic cardiomyopathy

Question 8

What is Dominant-negative mutations?

Answer 8

Where the protein from the mutant allele interferes with the protein from the normal allele.
E.g. a dimer where one mutant and one normal allele would result in only 25% normal dimers

Question 9

What is cytoskeleton

Answer 9

Filament proteins supporting structure of cell

Question 10

What is lipofuscin?

Answer 10

Lipid containing residues in post mitotic cells e.g. in heart, liver, nerve cells

Question 11

What does cholesterol do in the cell membrane?

Answer 11

Cholesterol provides some rigidity to the free flowing phospholipid bilayer

Question 12

Some uses of actin in body

Answer 12

1) They maintain the internal structure of cells
2) They are in adherens junctions which joins actin bundles between neighbouring cells
3) Actin - myosin proteins used in muscles for contraction

Question 13

What are lipid rafts

Answer 13

Areas were there are high cholesterol and more saturated fatty acids than usual in cell membranes.

Question 14

Types of endocytosis

Answer 14

1) Phagocytosis
2) Pinocytosis
3) Receptor mediated e.g. depressed areas - coated pits

Question 15

What % of total body weight is water, and the average volume of water in a 70kg male.

Answer 15

60% of Total Body Weight is water

Which is 42L of a 70kg man

Question 16

What percentage of body weight is Intracellular?

Answer 16

40% (28L)

Question 17

What percentage of total body water is Extracellular fluid?

Answer 17

35% of total body water

Question 18

What is the percentage of total body water is intravascular? Give an average volume of plasma in a 70kg male.

Answer 18

7% of total body water

3L in a 70kg man

Question 19

What is the average volume of interstitial fluid in a 70kg male?

Answer 19

11L

Question 20

2 components making up extracellular fluid

Answer 20

1) Blood plasma/Intravascular
2) Interstitial
Transcellular (mucus/CSF…)- maybe

Question 21

Define Osmolality

Answer 21

Measure of the number of the osmoles of solute per kilogram of solvent (Osm/kg)

Question 22

Define Osmolarity

Answer 22

The number of osmoses of solute per litre of solvent/solution (Osm/L)

Question 23

Define Osmotic Pressure

Answer 23

Pressure applied to a solution by a pure solvent, required to prevent inward osmosis through a semipermeable membrane.

Question 24

Define Oncotic Pressure

Answer 24

Form of osmotic pressure exerted by proteins that tend to pull fluid into its solution

Question 25

Causes of Oedema

Answer 25

Inflammation - leakage, Venous - increased venous end pressure, Lymphatic blocked, Hypoalbuminaemic

Question 26

Qualities and examples of a steroid hormone.

Answer 26

1) Slow acting 2) Synthesised from cholesterol 3) Lipid Soluble 4) Made and released by cell (no storage) 5) Uses transport proteins to move through blood 6) Diffuses through cell membranes 7) Intracellular response Examples - Testosterone, oestrogen, cortisol

Question 27

Name the 4 pathways how dietary components are metabolised

Answer 27

1) Storage - anabolic 2) Biosynthetic -anabolic 3) Oxidative - catabolic 4) Waste Disposal - catabolic

Question 28

Energy values from 4 fuel types

Answer 28

Carbohydrates - 4 kcal/g Protein - 4 kcal/g Alcohol - 7 kcal/g Lipid - 9 kcal/g

Question 29

In fed state what does pancreas do.

Answer 29

Pancreas releases insulin which causes glucose and phosphate uptake. Increased glycogenesis, decreases glycogenolysis, less lipolysis, less proteolysis.

Question 30

Vitamin C uses

Answer 30

Collagen synthesis - helps wounds heal, antioxidant, improves iron absorption, keeps immune system healthy

Question 31

Vitamin B12 uses

Answer 31

Used to regenerate folate and in DNA, protein and fatty acid synthesis. B12 deficiency can cause a type of anaemia

Question 32

Functions of glycolysis

Answer 32

Provides ATP Generates precursors for biosynthesis. Intermediates converted to ribose-5-phosphate (nucleotides), serine, glycine, cysteine (amino acids). Pyruvate to alanine. Pyruvate substrate for fatty acid synthesis Glycerol-3-phosphate is backbone of triglycerides

Question 33

What does fructose-1,6- bisphosphate activate in the liver and RBCs

Answer 33

Pyruvate kinase activated

Question 34

Name the enzyme producing citrate from oxaloacetate and acetyl-CoA in TCA cycle

Answer 34

citrate synthase

Question 35

Enzyme producing isocitrate from citrate in citric acid cycle

Answer 35

aconitase

Question 36

What is the molecule produced after isocitrate in Kreb's cycle and the enzyme facilitating the reaction.

Answer 36

Isocitrate to alpha- ketogluarate. Enzyme - isocitrate dehydrogenase.

Question 37

What reaction (substrate and all products) does alpha-ketogluarate dehydrogenase facilitate. TCA cycles

Answer 37

Substrates: alpha- ketogluarate + CoA Products: Succinyl-CoA, NADH + H+ , Carbon dioxide

Question 38

How many carbons does an acetyl CoA, citrate, isocitrate, alpha - ketogluarate, succinate and malate have. Citrate cycle

Answer 38

``` Acetyl-CoA - 2 Citrate - 6 Isocitrate -6 alpha-ketogluarate - 5 Succinate - 4 Malate -4 ```

Question 39

Enzyme between succinyl-CoA and succinate. What extra substrate/products are there. TCA cycle

Answer 39

Enzyme - Succinyl CoA thiokinase Substrate- Succinyl-CoA + Pi Products- Succinate + GTP + CoA

Question 40

Name enzyme after succinate in TCA cycle and products

Answer 40

Enzyme- Succinate dehydrogenase | Products - Fumarate + FADH2

Question 41

The enzyme between 1) fumarate and malate 2) malate and oxaloacetate in Krebs' cycle

Answer 41

1) fumerase between fumerate and malate | 2) Malate dehydrogenase between malate and oxaloacetate (uses water and produces an NADH)

Question 42

Which coenzyme results in more ATP being formed during oxidative phosphorylation

Answer 42

NADH more than FADH2

Question 43

Where does glycolysis take place?

Answer 43

Cytosol

Question 44

Where does link and TCA cycle take place

Answer 44

Mitochondrial matrix

Question 45

Where does oxidative phosphorylation take place

Answer 45

Inner mitochondrial matrix

Question 46

What is gluconeogenesis

Answer 46

It is the generation of glucose using non-carbohydrate sources.

Question 47

Two causes of ketoacidosis

Answer 47

Diabetic and alcoholic (poor diet). | Ketoacidosis occurs when the body is unable to utilise glucose for energy.

Question 48

Where does ketogenesis occur

Answer 48

Ketogenesis occurs in hepatocytes, but ketone bodies are used extrahepatically

Question 49

Buffer definition

Answer 49

Solution which resists changes in pH when small quantities of strong acid or base is added.

Question 50

Name 4 cellular defences against oxygen toxicity

Answer 50

Antioxidant enzymes, cellular compartmentation, antioxidant vitamins, repair

Question 51

What do antioxidant enzymes do?

Answer 51

Superoxide dismutase - converts superoxide anion to hydrogen peroxide and oxygen Catalase - hydrogen peroxide to water and oxygen, protects WBC from their own respiratory burst Glutathione peroxidase - Hydrogen peroxide and lipid peroxide reduction.

Question 52

3 examples of antioxidant vitamins

Answer 52

Vitamin E, Vitamin C, Carotenoids. (Vitamin C: hydrophilic, regenerates reduced vitamin E) (Carotenoids precursor of vitamin A) (Vit E found in liver, egg yolks and cereals)

Question 53

What is a morula?

Answer 53

A 16 cell solid ball of cells, with no cavity within it. When a cavity forms it becomes a blastocyst

Question 54

What is cleavage

Answer 54

It is when the early zygote splits into many cells without growing.

Question 55

What shape are epiblast and hypoblasts cells

Answer 55

Epiblast - Columnar | Hypoblast - Cuboidal