UNIT 4 AP BIO Review

What is a signaling molecule called?

• Activator

• Enhancer

• Ligand

• Repressor

What is the first step of signal transduction?

• Reception

• Response

• Transduction

All cells respond to the same ligand with the same response.

• True

• False

Choose the correct order of communication.

• reception, response, transduction

• transduction, reception, response

• response, transduction, reception

• reception, transduction, response

Phosphorylation cascades are often used for

• reception

• responses

• amplification

• termination

When glucose levels in the blood rise, your brain sends a signal to your pancreas. The pancreas releases insulin, which opens channels in cell membranes to allow glucose to enter the cell, lowering blood sugar levels. 

• Positive Feedback Response
• Negative Feedback Loop 

Tags

NGSS.HS-LS1-3

Which of the following statements best describes negative feedback in homeostasis?

• It amplifies the changes in a system to maintain equilibrium

• It reduces the output of a system to bring it back to its set point

• It maintains a steady state by enhancing the response of a system

• It initiates a response to an external stimulus to restore balance

• It is a rare phenomenon that occurs only in a few physiological systems

Tags

NGSS.HS-LS1-3

What do second messengers do?

• transport a signal through the lipid bilayer
• relay a signal from the outside to the inside of the cell
• relay message from the inside of the mebrane throughout the cytoplasm
• dampen the message

Adjacent plant cells have narrow channels called plasmodesmata that pass through the cell walls of the connected cells and allow a cytoplasmic connection between the cells.

Which of the following statements best describes a primary function of plasmodesmata?

• They allow the movement of molecules from one cell to another, enabling communication between cells.

• They prevent the cell membrane from pulling away from the cell wall during periods of drought.

• They eliminate the need to produce signaling molecules and eliminate the need for cells to have receptors for signaling molecules.

• They increase the surface area available for attachment of ribosomes and thus increase protein synthesis.

Which of the following would NOT result in the inhibition of this pathway?

• A change in the shape of the receptor

• The presence of a competitive ligand

• Increase in hormone concentration

• Loss of second messenger production