Cell Signaling Review

What typically initiates a signal transduction pathway?

• The binding of a ligand to a receptor protein

• The production of secondary messengers

• The release of hormones into the bloodstream

• The production of ATP

Which of the following is an example of a receptor involved in signal transduction?

• Ligand-gated ion channels

• G-protein-coupled receptors

• Tyrosine kinase receptors

• All of the above

In a phosphorylation cascade, which molecule is often used as a secondary messenger?

• ATP

• cAMP

• DNA

• Glucose

Why don't all cells respond to the same signal in signal transduction pathways?

• Some cells are not capable of receiving signals

• Only target cells have specific receptor proteins for the signal

• The ligands can't enter the cells

• All cells respond equally to signals

What is a common feature of signal transduction pathways involving G-protein-coupled receptors?

• The activation of a G-protein

• The direct release of glucose

• The binding of DNA to the receptor

• The destruction of receptor proteins

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

What type of signaling is shown here?

• autocrine (self-signaling)

• juxtacrine (direct cell-to-cell contact)

• endocrine (long-distance)

• paracrine (short distance)

This is an example of

• paracrine signalling

• endocrine signalling

• autocrine signalling

• juxtacrine signalling

Identify the structures through which animal cells and plant cells use for direct communication.

• Animal cells - plasmodesmata ; Plant cells - gap junctions

• Animal cells - neurons ; Plant cells - hormones

• Animal cells - gap junctions ; Plant cells - plasmodesmata

• Animal cells - hormones ; Plant cells - neurons

What is the function of protein phosphatase in signal transduction pathways?

• To synthesize DNA

• To deactivate enzymes

• To transport ions

• To dephosphorylate other proteins