Translational control

Question 1

How does degradation of mRNA regulate the process of protein synthesis

Answer 1

• the more resistant the molecule - the longer it will last in the cytoplasm
• greater quantity of protein synthesised

Question 2

How do inhibitory proteins regulate protein synthesis?

Answer 2

• binding of inhibitory proteins to mRNA
• prevents it binding to ribsomes
• and therefore the synthesis of proteins

Question 3

How does the activation of initiation factors regulate protein synthesis?

Answer 3

• activation of initiation factors which aid the binding of mRNA to ribosomes
  
  • the eggs of many organism produce large quantaties of mRNA
  • which is not required until after fertilasation
  • at which point initiation factors are activated

Question 4

What are protein kinases?

Answer 4

• enzymes that catalyse the addition of phosphate groups to proteins

Question 5

What is the effect of the addition of a phophate groups result in?

Answer 5

• changes tertiary structure
• and so the functiopn of a protein
• many enzumes are activated by phosphorlation

Question 6

Why are protein kinases important?

Answer 6

• important regulators of cell activity

Question 7

How are protein kinases activated?

Answer 7

often by the secondary messengar cAMP

Question 8

WHaa tis post-translational control?

Answer 8

• modifications to the proteins that have been synthesised

Question 9

what are the types of post-translational control?>

Answer 9

• addition of non-protein groups
  
  • e.g. carbohydrate chains, lipids, or phosphates
• modifying amino acids
  
  • also the formation of bonds
  • e.g. disulfide bridges
• folding or shortening of proteins
• modification by cAMP
  
  • e.g. in the lac operon
    
    • cAMP binds to the cAMP receptor protein
    • increaseing the rate of transcription of the structural genes