Topic 5 study questions with answers

Topic 5 study questions with answers - Study questions...

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Study questions – Topic 5 Cell-to-cell signalling Multiple choice questions (1 mark per answer) 1. Which of the following is not a cell surface receptor? (a) A ligand-gated channel (b) A ligand-activated transcription factor (c) A receptor tyrosine kinase (d) A G protein-coupled receptor (e) All of the above are cell surface receptors. 2. When a trimeric G protein is activated by a cell surface receptor… (a) The ß subunit exchanges its bound GDP for GTP. (b) The GTP bound to the subunit is dephosphorylated to form bound GDP. (c) It dissociates into a free ß subunit and an  subunit. (d) It dissociates into a free subunit to which GTP is bound and a ß subunit. (e) None of the above 3. The membrane-associated enzyme that produces the second messengers IP 3 and DAG is. .. (a) Adenylyl cyclase (b) Na + ,K + -ATPase (c) Cellulose (d) Phospholipase C (e) Phosphatidylinositol phospholipase C 4. Acetylcholine acts at a G protein-linked receptor on heart muscle to make the heart beat more slowly. The effect is mediated by the subunit of the G protein, which acts on a membrane K + channel. Which one of the following would enhance this effect of acetylcholine? (a) A high concentration of a non-hydrolyzable analogue of GTP. (b) Mutations in the acetylcholine receptor that weaken the interaction between the receptor and acetylcholine. (c) Mutations in the subunit of the G protein that resulted in a loss of GTPase activity. (d) Mutations in the acetylcholine receptor that weaken the interaction between the receptor and the G protein. (e) Both a and c would enhance the effect of acetylcholine in this signalling pathway. 5.
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Topic 5 study questions with answers - Study questions...

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