AP Biology Cell communication

An example of LOCAL cell communication is:

• White blood cells bumping into each other sharing antigen info

• Neurons communicating across a synapse

• Hormones traveling through the blood stream to target tissues

An example of DIRECT cell communication is:

• White blood cells bumping into each other sharing antigen info

• Neurons communicating across a synapse

• Hormones traveling through the blood stream to target tissues

The figure above shows a model of a ligand precursor being cleaved to produce an active ligand that binds to a specific receptor. Which of the following is most likely to reduce the binding of the active ligand to its receptor?

• A change in the cytoskeletal attachment of transmembrane proteins

• The presence of a large amount of the precursor form of the ligand

• An increase in the ratio of the number of unsaturated to the number of saturated fatty acid tails of the membrane lipids

• A mutation in the receptor gene that causes a substitution of a charged amino acid for a nonpolar amino acid in the ligand binding site of the receptor

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

• ligand
• second messenger
• protein kinase
• receptor protein

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

• phosphorylation cascade
• cAMP
• signal receptors
• phosphatase

What determines whether a signal molecule binds on the surface or enters the cell?

• size
• polarity
• ability to cross the membrane
• all of these are correct

The binding of a ligand to a ligand-gated ion channel can cause the channel to ___.

• open

• close

• both answers can be correct

A cell converting a chemical signal into a cellular response is known as __.

• energetics

• transduction

• ligand response

• transformation

After a ligand binds, the intracellular domain of a receptor protein changes _____, initiating transduction of the signal.

• color

• size

• shape

Which of the following is a chemical message that usually travels through the bloodstream to target cells?

• hormone

• local regulator

• endocrine cell

• plasmodesmata