AP BIO FR Ch. 11

Question 1

Briefly explain the role of each

numbered step in regulating target gene expression

Answer 1

Step 1 = hormone/ligand binding to receptor to initiate/trigger/induce signaling OR signal
reception

Step 2 = an intracellular cascade that transduces/amplifies/transfers the signal from plasma
membrane to nucleus (or other cellular effectors)

Step 3 = transcription/expression of target genes is stimulated/repressed

Question 2

How is cell membrane structure related to signal transduction

Answer 2

Cell membrane is a phospholipid bilayer that incorporates proteins associated with its membrane. It includes receptor molecules that are embedded in the membrane.
Receptor proteins undergo shape changes when a stimulus is present and the signal is transmitted through the membrane. The proteins then influence other cellular events such as activating tyrosine kinase receptor proteins that result in a response in the cell.

Question 3

Communication between plant cells

Answer 3

2 bacterial cells communicate. Two sexes in yeast a and alpha each secrete a specific factor that binds only to receptors on the other type. When exposed to the other’s mating factors, a pair of cells of opposite type change shape and grow towards each other and fuse. The new cell contains both genes of both parents.