You Are Interested in Cell-Size Regulation and Discover That Signaling

question 41

Essay

You are interested in cell-size regulation and discover that signaling through an enzyme-coupled receptor is important for the growth (enlargement) of mouse liver cells.Activation of the receptor activates adenylyl cyclase, which ultimately leads to the activation of PKA, which then phosphorylates a transcription factor called TFS on threonine 42.This phosphorylation is necessary for the binding of TFS to its specific sites on DNA, where it then activates the transcription of Sze2, a gene that encodes a protein important for liver cell growth.You find that liver cells lacking the receptor are 15% smaller than normal cells, whereas cells that express a constitutively activated version of PKA are 15% larger than normal liver cells.Given these results, predict whether you would expect the cell's size to be bigger or smaller than normal cells if cells were treated in the following fashion.
A.You change threonine 42 on TFS to an alanine residue.
B.You create a version of the receptor that is constitutively active.
C.You add a drug that inhibits adenylyl cyclase.
D.You add a drug that increases the activity of cyclic AMP phosphodiesterase.
E.You mutate the cAMP-binding sites in the regulatory subunits of PKA, so that the complex binds cAMP more tightly.

Recognize the unique characteristics and functions of B cells in antibody production.

Understand the principles and mechanisms of gas exchange across different organisms.

Describe the structural adaptations in various animals that facilitate efficient gas exchange.

Explain the concept of countercurrent exchange and its role in maximizing oxygen absorption in aquatic organisms.

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Definitions:

Evolutionary Psychology

A theoretical approach in psychology that seeks to explain mental and psychological traits—such as memory, perception, or language—as adaptations, i.e., as the functional products of natural selection.

Evolutionary Psychology

A theoretical approach in psychology that examines mental and psychological traits—such as memory, perception, or language—as adaptations, i.e., as the functional products of natural selection.

Freud's Theory

Refers to Sigmund Freud's psychoanalytic theory, which emphasizes unconscious processes and childhood experiences in shaping personality and behavior.

Evolutionary Psychology

A theoretical approach in psychology that explores how evolutionary principles explain psychological traits and behaviors.