Biochemistry

Question 1

What type of hormone is insulin?

Answer 1

Peptide hormone

Question 2

Which cells secrete insulin?

Answer 2

Pancreatic beta-cells

Question 3

What do pancreatic alpha cells secrete?

Answer 3

Glucagon

Question 4

Which cells secrete somatostatin?

Answer 4

Delta cells

Question 5

Where specifically is insulin made?

Answer 5

Rough ER

Question 6

What is insulin made from?

Answer 6

preproinsulin

Question 7

What else is produced alongside insulin?

Answer 7

C-peptide

Question 8

What proteins make up the ATP sensitive K channel?

Answer 8

Kir6

SUR1

Question 9

Which type of diabetes is caused by mutations in Kir6?

Answer 9

Neonatal diabetes

Question 10

Mechanism of T1DM?

Answer 10

Autoimmune destruction of pancreatic beta cells

Question 11

Mechanism of T2DM?

Answer 11

beta cells try to compensate for hyperglycaemia (caused by insulin resistance) then the beta cells lose function due to over-compensation

Question 12

Mechanism of MODY?

Answer 12

Defective glucose sensing in pancreas and/or loss of insulin secretion

Question 13

Where are the targets for insulin signalling?

Answer 13

Liver
Muscle
Adipose tissue

Question 14

Does insulin inhibit lipolysis?

Answer 14

Yes

Question 15

List some biological effects that are “switched on” by insulin?

Answer 15

Amino acid uptake in muscle
Glucose uptake in muscle and adipose tissue
Lipogenesis in adipose tissue and liver
Glycogen synthesis in liver and muscle
DNA and protein synthesis

Question 16

What is leprechaunism caused by?

Answer 16

mutations in the gene for insulin receptor which results in severe insulin resistance

Question 17

What is rabson Mendenhall syndrome?

Answer 17

Severe insulin resistance that results in developmental abnormalities, hyperpigmentation, hyperinsulinaemia and DKA

Question 18

What causes DKA?

Answer 18

build up of ketone bodies

When glucose is not available, fatty-acids are oxidised for energy. Excess acetyl-CoA is then converted to ketone bodies which leaves to acidosis

Question 19

How do you treat DKA?

Answer 19

Insulin

Rehydration

Question 20

How does glucose enter pancreas?

Answer 20

through GLUT2 transporters

Question 21

What happens to glucose after it enters pancreas?

Answer 21

Phosphorylated to glucose-6-phosphate

Question 22

Which enzymes phosphorylate glucose?

Answer 22

Glucokinase

hexokinase

Question 23

What happens in the pancreas once glucose is phosphorylated?

Answer 23

Insulin is released

Intracellular ATP increases
ATP inhibits ATP sensitive K channel
Depolarises cell membrane 
Ca2+ channel opens
Secretory vesicles fuse
Insulin is released

Question 24

When is insulin released?

Answer 24

When blood glucose >5mM

Question 25

Insulin release in biphasic | true or false

Answer 25

true

Question 26

What is the general rule for sodium and water?

Answer 26

Water follows sodium

Question 27

Which hormone controls water balance?

Answer 27

ADH

Question 28

Where is ADH released from?

Answer 28

posterior pituitary

Question 29

What is the result of increased ADH?

Answer 29

small volume, concentrated urine (high osmolality)

Question 30

What is the result of decreased AFH?

Answer 30

high volume, diluted urine (low osmolality)

Question 31

What does ADH cause?

Answer 31

water reabsorption

Question 32

Which hormone controls sodium balance?

Answer 32

Steroids

Question 33

Where are steroid hormones released from?

Answer 33

Adrenals

Question 34

What else is sodium balance known as?

Answer 34

Mineralocorticoid activity

Question 35

What does an increased mineralocorticoid activity cause?

Answer 35

Na+ gain

Question 36

What does an decreased mineralocorticoid activity cause?

Answer 36

Na+ loss

Question 37

Where is sodium confined to?

Answer 37

extracellular fluid

Question 38

What does Addison's disease cause?

Answer 38

Decreased sodium

Question 39

What is diabetes insipidus?

Answer 39

Pituitary can't secrete ADH so there's too much water therefore too much sodium