Question

question 7 (mandatory) (1.25 points)
what is the key difference between a kinase and a phosphatase in a cellular signaling cascade?

• kinases are involved in signal reception, while phosphatases are involved in the response.
• kinases activate proteins by adding a phosphate group, while phosphatases inactivate proteins by removing one.
• kinases only act on serine and threonine residues, while phosphatases only act on tyrosine residues.
• kinases are a type of g protein, while phosphatases are a type of second messenger.

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Explanation:

Kinases add phosphate groups (activating proteins), phosphatases remove them (inactivating). Other options are wrong: kinases/phosphatases are in response, not just reception; they act on various residues; kinases aren't G proteins, phosphatases aren't second messengers.

Answer:

B. Kinases activate proteins by adding a phosphate group, while phosphatases inactivate proteins by removing one.