Module-Insulin

Question 1

Insulin is a (steroid/peptide) hormone synthesized in the (alpha/beta/delta) cells of the pancreas

Answer 1

Peptide; Beta

Question 2

Pattern of Insulin activation from precursor molecules

Answer 2

Pre-Pro-Insulin–> Pro-Insulin–> Insulin

Question 3

Conversion of Pre-Pro-Insulin to Pro-Insulin occurs where in the cell

Answer 3

Rough Endoplasmic Reticulum

Question 4

Conversion of Pro-Insulin to Insulin occurs where in the cell

Answer 4

Secretory vesicles (cleave off C-peptide)

Question 5

What is cleaved from the Pro-Insulin molecule to convert it into Insulin

Answer 5

C-peptide

Question 6

Insulin is composed of _____ chains held together by ___________________ bonds

Answer 6

2 (alpha and beta); disulfide

Question 7

Stimuli for Insulin release (4 total)

Answer 7

Inc. blood sugar
Inc. amino acids
Parasympathetic NS
Incretins (GLP-1 and GIP)

Question 8

Glucose enters Beta cells via GLUT (1/2/3/4) transporters to trigger Insulin release

Answer 8

GLUT 2

Question 9

How does Glucose entering Beta Cells trigger Insulin release

Answer 9

ATP generated–> K channels close–> Ca channels open–> Ca enters–> Insulin granules fuse w/ membrane and release

Question 10

Insulin binds to (internal/external) receptors of target cells

Answer 10

External (remember it’s a peptide, so can’t enter cell)

Question 11

The Insulin receptor is a _________________ ___________ that activates Ras and P13K mediated pathways

Answer 11

tyrosine kinase

Question 12

Insulin acts mainly on what tissues

Answer 12

Liver
Muscle
Adipose

*NOT brain, shouldn’t have to rely on Insulin, needs constant supply

Question 13

Insulin’s net effect is to (increase/decrease) glucose levels

Answer 13

Dec. glucose levels

Question 14

The Insulin receptor has what subunits?

Answer 14

2 alpha and 2 beta (linked by disulfide bonds)

Question 15

Insulin binds to (alpha/beta) subunits of the receptor

Answer 15

Alpha

*beta causes autophosphorylation

Question 16

(Alpha/Beta) subunits of the Insulin receptor cause autophosphorylation

Answer 16

Beta

Question 17

Purpose of Insulin receptor autophosphorylation

Answer 17

Activate catalytic activity and trigger internal response

Question 18

Insulin activates what metabolic pathways? (4 total)

Answer 18

Glycolysis (liver, muscle and adipose)\
Glycogen synthesis (liver and muscle)
Protein synthesis (muscle)
FA synthesis (liver and adipose)

Question 19

Insulin stimulates GLUT4 translocation in what tissue?

Answer 19

Muscle (for glucose uptake –> glycolysis and glycogen synthesis)