3 Cellular response to stress

Question 1

What are the three types of stress?

Answer 1

Heat, Oxidative, and Low Oxygen (Hypoxia)

Question 2

What is the role of Chaperones?

Answer 2

Facilitate proper folding, stabilize unfolded polypeptides, prevent incorrect folding, refold misfolded proteins, assemble and dismantle large multiprotein complexes.

Question 3

Describe the steps in Hsp-70 mediated protein folding:

Answer 3

1. Protein binds to substrate binding domain (SBD)
2. Accessory proteins stimulate hydrolysis of ATP.
   
   1. Locks protein into SBD
3. ADP exchanged for ATP by accessory proteins.
4. SBD converted to open form, releasing folded protein.

Question 4

Describe the steps in Hsp-90 mediated protein folding

Answer 4

1. Hsp90 dimer in open position
2. ATP binds and dimer moves to closed position.
3. ATP hydrolyzed
4. Client protein folded and released.

Question 5

What are the three markers of lipid oxidative stress?

Answer 5

Hydroxynonenals

Malondialdehyde

Isoprostanes

Question 6

What are the three markers of Glycoxidation?

Answer 6

Advanced glycation products

Question 7

What is the stable aldehyde product of Lipid Peroxidation?

Answer 7

4-Hydroxynonenal

Question 8

What are the effects of 4-Hydroxynonenal and how is it formed?

Answer 8

• Can modify amino acid side chains in proteins by binding to nitrogen on the side chains.
  
  • Leads to Chronic inflamation.
• Forms by lipid peroxidation.

Question 9

What is a common product of DNA Oxidation?

Answer 9

8-Nitroguanine