Lecture 9

Question 1

Peptide Hormones mode of action

Answer 1

• Can not penetrate target cells
• Bind to surface receptors and activate intracellular processes through second messengers

Question 2

Steroid Hormones

Answer 2

• Penetrate plasma membrane and bind to internal receptors (usually in the nucleus)
• Influence expression of genes of the target cell
  -It takes several hours to days to show effect due to lag for protein synthesis

Question 3

2 Main Types of Receptors

Answer 3

1. Intracellular receptors
2. Plasma membrane receptors

Question 4

Intracellular receptors

Answer 4

• Bind lipid soluble hormones
• Cytosolic and nuclear
• Directly alter gene transcription (cause genomic effects)

Question 5

Plasma membrane receptors

Answer 5

• G protein-coupled receptors
• Receptor-enzyme receptors
• Receptor-Channel
  Integrin Receptor

Question 6

G Protein -Coupled Receptors (GPCR)

Answer 6

• Membrane-spamming proteins
  
  • Cytoplasmic tail linked to a G protein

Question 7

When GPCRs are activated, they…

Answer 7

1. Open ion channels in the membrane
2. Alter enzyme activity on the cytoplasmic side of the membrane

Question 8

G protein: Gs

Answer 8

Target: Adenylyl cyclase
Activity: Stimulatory

Question 9

G protein: Gq

Answer 9

Target: Phospholipase C
Activity: Simulatory

Question 10

G protein: Gi

Answer 10

Target: Adenylyl cyclase
Activity: Inhibitory

Question 11

Liver- Fight or Flight Responses mediated by GPCR

Answer 11

Glucose release (epinephrine)

Question 12

Fat- Fight or Flight Responses mediated by GPCR

Answer 12

Fatty acid release (epinephrine)

Question 13

Heart- Fight or Flight Responses mediated by GPCR

Answer 13

Muscle contraction (epinephrine)

Question 14

Skeletal muscle blood vessels- Fight or Flight Responses mediated by GPCR

Answer 14

Less vasoconstriction (norepinephrine)

Question 15

Intestine, skin and kidney-Fight or Flight Responses mediated by GPCR

Answer 15

Vasoconstriction (norepinephrine)