Please only help if you will be detailed. I\'m so lost and vague answers are not
ID: 302922 • Letter: P
Question
Please only help if you will be detailed. I'm so lost and vague answers are not helpful. If you could be detailed/help explain, I would appreciate it a lot. Thank you.
QUESTION #5 [6 pts] Several years ago, you detect what you think is a previously unknown polypeptide in a mouse's blood sample. You suspected that this peptide can act as a hormone of some kind, and after many experiments, you believe you have characterized the signaling pathway this hormone triggers a) You identify that this hormone triggers an increase in cAMP levels within the cell. What function is CAMP serving and how does it affect the magnitude of the hormone's signal? [2 pts] b) When conferring with a colleague, you find that her data suggests the activation of a different set of genes in her hepatocytes compared to the myocytes you have been studying. How can you explain this discrepancy? [1 pt c) This hormone also causes the transcriptional activation of a phosphodiesterase that degrades cAMP. What kind of regulation is this? What is the purpose of this kind of regulation? [1 pt d) When you try to publish your work, however, a reviewer notes that the mechanism you propose for regulation in (c) would not be effective without the activity of another regulatory protein and urgesExplanation / Answer
A. cAMP acts as a second messanger which is activated when the signaling molecule binds to G- protein coupled receptor. As ATP changes into cAMP large amount of cAMP's are produced by phosphorylation of ATP which increases the magnitude of the hormone signal also known as amiplification of the signal.
B. As the cell type changes from myocytes to hepatocytes the presence of receptors on the surface of the cell also changes along with their internal machinery. So the same signalling molecule can show different effect based on the cell type or the receptor it binds on the cell.
For example neurotransmitter acetycholine inhibits the rate of contraction in heart muscle cells where as it stimulates the contraction of skeletal muscle cells.
C. This is a type of autoregulation. Phosphodiesterase degrades the cAMP into AMP by breaking the phosphodiester bond and decreases the cAMP that helps to maintain a desired signal level.
D. This regulator must be a protein kinase A (PKA) which has 2 regulatory subunits and two catalytic subunits . As the cAMP increase 4 cAMP molecules bind to the 2 regulatory subunits oof PKA ( 2 cAMP's on 1 regulatory subunit) and detach from the catalytic subunits (activated) . These activated catalytic subunits undergoes activating a number of downstream compounds.