2023 Unit 4 AP: Practice Questions

The three stages of cell signalling are

• paracrine, local, and synaptic
• reception, transduction, and response
• transcription, translation, and folding
• alpha, beta, and gamma

1.  Each of the following numbered processes are involved in signal transduction pathways:  
 I.  Response  
II.  Amplification  
 III.  Reception  
IV.  Transduction
Which of the following represents the sequence of events in a typical signal transduction pathway?

• I, II, III, IV
• III, I, IV, II
• II, IV, I, III
• III, IV, II, I

A signal molecule that binds to a plasma-membrane protein is a

• ligand
• second messenger
• protein kinase
• receptor protein

What type of transmembrane receptor is being shown?

• G-protein receptor
• tyrosine kinase receptor
• gated ion channel

Protein kinases activate other relay proteins by adding a(n) ____ to them.

• phosphate
• ATP molecule
• cAMP
• GTP

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

What determines whether a cell is a target cell for a particular signal molecule?

• phosphorylation cascade
• cAMP
• signal receptors
• phosphatase

G proteins are a family of proteins involved in transmitting chemical signals originating from outside a cell into the inside of the cell. G proteins function as molecular switches.
Which of the following best describes the role in which the G protein is most intimately involved in the process shown above?

• Production of the ligand molecule.
• Reception of the signal.
• Transduction of the signal.
• Production of response to signal.

What is being depicted in the image?

• Amplification of the signal molecule

• Enzymatic proteins inhibiting process of the signal transduction pathway

• Kinase groups adding dimer groups to other enzymes

• Diffusion of molecules within the cell due to the signaling molecule

Testosterone does not affect all cells of the body because __________.

• testosterone cannot cross the plasma membrane

• not all cells have cytoplasmic receptors for testosterone

• not all cells in the body have membrane receptors for testosterone

• it is a local regulator

• it affects only cells that have ion-channel receptors