10.3 - Types Of Hormones

Question 1

What are the protein hormones made of?

Answer 1

3 to over 200 amino acid chains

Question 2

Can protein hormones enter the cell? Why?

Answer 2

No, because they cannot cross the HYDROPHOBIC centre of target cell membranes

(because they are hydrophilic -> polar)

Question 3

Name the 16 protein hormones

Answer 3

1. Thyroxine
2. Glucagon
3. Insulin
4. Oxytocin
5. ADH
6. HCG
7. TRH
8. ACTH
9. Epinephrine
10. Calcitonin
11. FSH
12. LH
13. GnRH
14. Inhibin
15. PTH
16. ACRH

Question 4

Explain reaction pathway for protein hormones: for Glucagon

Answer 4

1. Glucagon binds to surface receptors on liver cells, which activates them
2. Activated receptors trigger a signal pathway (addition of phosphate group, which activates enzyme that causes breakdown of glycogen into glucose)

Question 5

Explain reaction pathway for protein hormones in general

Answer 5

1. Hydrophilic hormone binds to surface receptor in receptor protein at plasma membrane (target cell)
2. Chemical reactions occur when receptor protein brings in message from hormone
3. Signal leads to cellular response (change in cell)

Question 6

What is another word for protein hormones?

Answer 6

Water-soluble hormones

Question 7

Example of a target cell

Answer 7

Collecting duct cells told to reabsorb water (H2O)

Question 8

What are steroid hormones? Where are they derived? Can they cross the cell membrane?

Answer 8

• Derived from cholesterol
• Hydrophobic and non polar
• Able to cross cell membrane and enter target cells
• Consist of a 4 carbon sterol backbone
• Lipid based (therefore lipid soluble)

Question 9

What are the 5 steroid hormones?

Answer 9

1. Testosterone
2. Estrogen
3. Aldosterone
4. Cortisol
5. Progesterone

Question 10

Explain steps of reaction pathway for steroid hormones

Answer 10

1. Hydrophobic hormone passes freely through plasma membrane
2. Binds to steroid hormone receptor INSIDE cytosol or nucleus of cell
3. Both bind to control sequence of specific gene (on DNA) to turn gene off or on
4. This changes the amount of protein that the gene synthesizes, which changes cellular activity

Question 11

What is another word for steroid hormones?

Answer 11

Lipid-soluble hormones