Biochemistry

Question 1

What do beta cells secrete?

Answer 1

insulin

Question 2

What do alpha cells secrete?

Answer 2

glucagon

Question 3

What do omega cells secrete?

Answer 3

Somatostatin

Question 4

What do PP cells secrete?

Answer 4

Pancreatic polypeptide

Question 5

What does insulin contain?

Answer 5

2 poly peptide chains linked by disulfide bonds

Question 6

How does glucose enter beta cells?

Answer 6

through the GLUT2 glucose transporter, its phosphorylated by glucokinase

Question 7

What does ATP inhibit?

Answer 7

ATP-sensitive K+ channel K(ATP)

Question 8

What does inhibition of K(ATP) lead to?

Answer 8

Depolarisation of the cell membrane

Question 9

What does cell membrane depolarisation lead to?

Answer 9

Opening of voltage-gated Ca2+ channels

Question 10

What does an increase in internal Ca2+ conc lead to?

Answer 10

fusion of secretory vesicles with the cell membrane and release of insulin

Question 11

What’s the subunit of inward rectifier subunit (K(IR))?

Answer 11

Kir6.1

Question 12

What’s the subunit of a sulphonylurea receptor?

Answer 12

SUR1

Question 13

Loss of insulin secreting beta cells is what type of diabetes?

Answer 13

1

Question 14

Defective glucose sensing in the pancreas and/or loss of insulin secretion is what?

Answer 14

MODY

Question 15

Initially hyperglycaemia with hyperinsulinemia so primary problem is reduced insulin sensitivity in tissues is what?

Answer 15

Type 2 diabetes

Question 16

Describe the insulin receptor?

Answer 16

A dimeric tyrosine kinase
Two extracellular alpha subunits with insulin binding domains
Two transmembrane beta subunits
Linked by disulfide bonds

Question 17

What happens to beta cells when alpha cells bind to insulin?

Answer 17

They self phosphorylate (autophosphorylation)

Question 18

What is Leprechaunism (Donohue Syndrome)?

Answer 18

rare autosomal recessive genetic trait
Mutations in gene are for insulin receptor
Severe insulin resistance

Question 19

What are features of Donohue syndrome?

Answer 19

Elfin facial expression
Growth retardation
Absence of subcutaneous fat, decreased muscle mass

Question 20

What is Rabson Mendenhall syndrome?

Answer 20

rare autosomal recessive 
Sever insulin resistance 
hyperglycaemia, hyperinsulinemia
Developmental problems
Acanthosis nigricans (hyperpigmentation)

Question 21

Where are ketone bodies formed?

Answer 21

In liver mitochondria

derived from acetyl-CoA from beta oxidation

Question 22

When are ketone bodies converted back to acetyl-CoA?

Answer 22

When they renter the TCA cycle

Question 23

Ketoacidosis is associated with which diabetes type?

Answer 23

1