FunMedEOYS4

Question 1

explain the ras pathway and how mutation leads to kras cancer

Answer 1

• when ras switched on: (normally ras is switched on by binding to GTP) can switch on ERK and AKT pathways. (ras regulates the pathways by turning on / off the ERK and AKT pathways)

- mutated ras (kras): hydrolysis of bound GTP (first stage in pathway) occurs v slowly. GTP is bound to ras in unhydroloysed form - ras is permenantly switched on. continois proliferation and growth.

Question 2

innate immunity tries to take out pathogens. the system uses complement blood proteins. name 2 that do this and their role

Answer 2

Uses complement blood proteins that

• opsonise (act as markers for phagocytes)
• cytolyse (directly attack via membrane attack complex (MAC))
• enhance inflammation

Question 3

which bacteria do exotoxins and which do endotoxins?

Answer 3

exootoxins: gram postive & gram negative

endotoxins: gram negative -> from the LPS layer of wall !

Question 4

what can type 2,3, & 4 hypersensitivty be

Answer 4

Type II: IgG/IgM to patients own RBCs due to M. pneumonia

Type III: complement activation causing inflammation e.g. S. pyogenes causing glomerulonephritis

Type IV: T cell mediated e.g. TB granulomas

1-4: ACID

Question 5

•Increased K+ permeability of the post-synaptic membrane will result in which type of potential?

Answer 5

Inhibitory post synpatic signal

Question 6

the normal pH range of blood = ?

can u name a location in the body which is alkali?

Answer 6

•The normal pH of blood: 7.35-7.45

• If blood pH <7.35 = Acidosis = Acidaemia
• If blood pH >7.45 = Alkalosis = Alkalaemia

alkali: small intestine - pH of 8

Question 7

whats a buffer?

Answer 7

A solution that can resist pH change upon the addition of an acid or a base.

Question 8

what is the equation for bicarobate buffer? what enzume?

Answer 8

Co2 + H20 ⇌ H2C03 ⇌ HCO3- + H+

enyme: carbonic anhydrase

Question 9

acid / base disorders:

If the problem is with the respiratory system, the kidneys can compensate by altering HCO3-. How is this altered for acidosis & alkalsosi?

Answer 9

If the problem is with the respiratory system, kidneys:

• In acidosis: increases HCO3-
• In alkalosis: ¯ HCO3-

Question 10

acid / base disorders:

If the problem is metabolic, the lungs can compensate by altering Co2 levels. How is this altered for acidosis & alkalsosi?

Answer 10

• the lungs can compensate by altering CO2 Levels
• In acidosis: increases­ RR (decreases CO2)
• In alkalosis: decreaeses¯ RR (increases CO2)

Question 11

Answer 11

Question 12

Answer 12

Question 13

What are each of these body cavities?

Answer 13

A. Abdomen

B. Mediastinum

C. Pleural

D. Cranial

E. Pelvic

Question 14

Answer 14

Question 15

Answer 15

Question 16

Answer 16

Question 17

which nuclei in the hypothalamus recieve information regarding:

a) warm temperatures [1]
b) cold temperatures [2]

Answer 17

- preoptic area (POA) monitors core temperature: recieves input from warm receptors from skin and and internal receptors

• paraventricular (PVN) and dorsomedial hypothalamic (DMH) nuclei: recieve input from cold

Question 18

how many ATPs are used [1] and produced [1] in glycolysis?

Answer 18

2 used

4 produced

Question 19

what are the products of Krebs cycle? [4]

Answer 19

• produces: Co2, 3NADH, 1 FADH2, 1GTP. feeds into oxidative phosphorylation pathway

Question 20

what is structure of aspirin like in

i) stomach [1]
ii) blood [1]

Answer 20

what is structure of aspirin like in

i) stomach [1] R-COOH. lipid soluble
ii) blood [1] R-COO- water soluble

Question 21

what is the defintion of a prodrug [1]

Answer 21

A prodrug is a medication or compound that, after administration, is metabolized (i.e., converted within the body) into a pharmacologically active drug.

Question 22

label A-D stages of cancer development:

A
B
C
D

Answer 22

label A-D stages of cancer development:

A: hyperplasia
B: metaplasia
C: dysplasia
​D: anaplasia

Question 23

what are the different modes of actions for antiobiotics? (2)
what are the spectrums for antiobiotics? (2)

Answer 23

Mode of actions

Bactericidal : Kills bacteria

Bacteriostatic: Inhibit bacterial replication

Spectrum

Broad: both aerobes and anaerobes

Narrow: either aerobes or anaerobes or a specific gram +/-

Question 24

what are the different modes of actions for antiobiotics? (2)
what are the spectrums for antiobiotics? (2)

Answer 24

Mode of actions

Bactericidal : Kills bacteria

Bacteriostatic: Inhibit bacterial replication

Spectrum

Broad: both aerobes and anaerobes

Narrow: either aerobes or anaerobes or a specific gram +/-

Question 25

name two ways that cancer can be caused by mutations to transcription factors [2]

Answer 25

C-MYC overexpression: breast / colon cancer
C-MYC translocation: burkitt lymphoma

Question 26

what type of cell is this? [1]
what does it secrete [2]

Answer 26

mast cell
heparin and histamine