Med Biochem

Question 0

Alterations that affect cell proliferation

Answer 0

• activation of oncogenes

- suppression of tumour suppressor genes

Question 1

Molecular hallmarks of cancer

Answer 1

• provide own growth signals
• insensitive to stop signals
• unlimited proliferative potential
• ‘avoidance of apoptosis
• sustained angiogenesis
• tissue invasion and metastatic ability
• unstable genome

Question 2

Sequential mutational events that lead to cancer

Answer 2

• altered cell
• overgrowth of abnormal cells
• tumour
• invasive cancer
• primary tumour
• cancer cell in blood stream
• tumour cell on wall of blood stream
• secondary tumour site

Question 3

Possible clinical presentation of diabetes

Answer 3

• hyperglycemia
• dehydration
• acidosis
• fruity sweet breath
• hyperventilation

Question 4

Problems assoc with hypoglycemia

Answer 4

• RBC and brain only use glucose as energy source
• 80% of glucose used per day
• only 10-20g of glucose in plasma
• hypoglycemia leads to coma

Question 5

Problems assoc with hyperglycemia

Answer 5

Short term

• osmotic diuresis (dehydration)
• advanced glycation products

Long term

• retinopathy
• neuropathy
• macroangiopathy
• diabetic foot
• macroangiopathy

Question 6

Ketone body synthesis

Answer 6

• during fasting or high fat low carb diet
• glucagon/insulin ratio is high
• gluconeogenesis is promoted
• oxaloacetate converted to malate and used for gluconeogenesis
• less oxaloacetate for TCA cycle in mitochindrion
• acetyl coA levels rise
• excess acetyl coA converted to ketone bodies in mitochindrion of liver

Question 7

Two products of acetoacetate

Answer 7

• dihydroxybutarate

- acetone

Question 8

What happens to glucose levels in fasting patients who consumes alcohol

Answer 8

• alcohol produces NADH
• in fasting conditions, body uses fats and proteins to produce ketones and amino acids
• some amino acids converted to glucose
• this needs NAD
• very little and with alcohol so glucose levels drop further

Question 9

Role of insulin

Answer 9

• increase glucose uptake
• increase protein synthesis
• increase fat deposition and decrease lipolysis
• increase K uptake
• decrease glycogenolysis and gluconeogenesis

Question 10

General features of hormone action

Answer 10

• tissue specificity
• multi step cascade amplification
• intracellular second messengers
• coordinate counter-reg of opposing pathways
• augmented or opposed by other hormones
• multiple mechanisms of termination of response

Question 11

Potassium in DKA patients

Answer 11

• acidosis could lead to displacement of K from intracellular compartment to ECF
• K given because fluid loss seen in diabetics is assoc with K loss
• although plasma levels are normal, total body K levels are depleted

Question 12

Factors that cause cancer

Answer 12

• genetic
• radiation
• chemicals
• viruses

Question 13

How HPV causes cervical cancer

Answer 13

• normally, RB binds E2F which prevents proliferation
• growth signals activate cycling D and E and cyclin dependent kinases
• causes phosphorylation of RB (decreases affinity for E2F)
• E2F released and initiates transcription genes and production of proteins