Biochemistry

Question 1

What is the “normal” fasting blood glucose

Answer 1

4-6mM

Question 2

What is the fasting blood glucose level that indicates hypoglycaemia?

Answer 2

• <4mM

Question 3

What is the fasting blood glucose level that indicates pre-diabetes?

Answer 3

• 6-7mM

Question 4

Insulin is described as a _____ hormone

Answer 4

• peptide hormone

Question 5

What cell within the pancreas produces insulin?

Answer 5

• beta-cells

Question 6

What is unique about beta-cells?

Answer 6

• they have a glucose sensing ability

Question 7

Where is insulin produced within the beta cells?

Answer 7

• rough endoplasmic reticulum

Question 8

Proinsulin is cleaved by what?

Answer 8

• ca2+ dependant endopeptidases

Question 9

What is proinsulin cleaved into?

Answer 9

• insulin

- c-peptide

Question 10

What are the 4 different cell types found in the islets of langerhans?

Answer 10

• beta cells
• alpha cells
• delta cells
• PP cells

Question 11

What do alpha cells secrete?

Answer 11

• glucagon

Question 12

Name a short acting insulin supplement?

Answer 12

• lispro

Question 13

Name a long acting insulin supplement?

Answer 13

• glargine

Question 14

How is insulin secreted?

Answer 14

• glucose enters b-cell by GLUT2 transporters
• glucose is cleaved by glucokinase and enters glycolysis, TCA and oxidative phosphorylation
• increase in ATP
• ATP dependant K+ channels close
• depolarisation
• opening of Ca2+ dependant channels
• release of insulin from granules

Question 15

How many ATP molecules are produced per glucose molecule?

Answer 15

• 36

Question 16

What does biphasic release of insulin mean?

Answer 16

• 1st phase - prevents a sharp increase in blood glucose post ingestion
• 2nd phase - more tuned to insulin requirement

Question 17

Why might T2DM have hyperinsulinemia?

Answer 17

• increased insulin release due to downregulation and insulin resistance

Question 18

What is the FBG range for gestational diabetes?

Answer 18

• FBD>5.5mM

Question 19

MODY is described as what?

Answer 19

• defective glucose sensing and loss of insulin secretion

Question 20

MODY has mutations in what?

Answer 20

• TF 1
• TF 3
  (Transcription factor)

Question 21

What drug is used in MODY?

Answer 21

• Sulphonylurea

Question 22

Sulphonylureas_____

Answer 22

• inhibit the potassium channel

- increased release of insulin

Question 23

Diazoxide____

Answer 23

• inhibits insulin secetion

- opens potassium channel

Question 24

Other than regulating blood glucose levels what else is insulin involved in?

Answer 24

• DNA synthesis
• protein synthesis
• growth response

Question 25

Define insulin resistance?

Answer 25

- higher levels of insulin than normal is required to produce an action

Question 26

Donohue syndrome___

Answer 26

- autosomal recessive | - mutations in gene for the insulin receptor

Question 27

Symptoms of diabetic ketoacidosis?

Answer 27

- vomiting - dehydration - increased HR - ketone smell from breath

Question 28

Insulin normally inhibits____

Answer 28

- lipolysis