AP Biology: Signal Transduction Pathways

To respond to a signal, a cell must have a(n) molecule that can detect the signal.

• receptor

• ligand

• responder

Chemical signals reaching a cell deep inside a multicellular organism may come from

• the brain

• the lymphatic system

• glands

• other cell types

• all of the answer choices listed

Tags

NGSS.HS-LS1-2

In a signal transduction pathway, the signal activates a(n)

• receptor

• hormone

• effector molecule

Signals that travel to distant cells through the circulatory system are known as

• neurotransmitters

• white blood cells

• hormones

Vitamin A is a relatively small, lipid-soluble molecule that can behave as a hormone. Most likely its receptor

• is an ion channel receptor.

• is a protein kinase receptor.

• involves a G protein.

• is not connected to the cell membrane.

A molecule that binds to the particular three-dimensional structure of another molecule’s receptor site is known as a(n)

• responder.

• receptor.

• ligand

In general, all cell signaling causes

• increased expression of genes.

• an influx of ions.

• protein kinase activity.

• a change in receptor conformation

Which statement about ligands and receptors is true?

• For most ligand–receptor complexes, binding is favored.

• Ligand–receptor interactions are reversible.

• Many drugs that alter human behavior prevent the binding of receptors’ specific ligands.

• Ligand–receptor interactions often induce conformational changes in channels.

• All the answer choices are correct

In what way do ligand–receptor interactions differ from enzyme–substrate reactions?

• The ligand signal is not usually metabolized into useful products

• Inhibitors never bind to the ligand-binding site

• Reversibility never occurs in ligand–receptor interactions.

Signal ligands can be divided into two groups according to the location of their receptors. Which of the following are the two classes of receptors?

• Plasma membrane and ion channel

• Membrane and intracellular

• G protein–linked and protein kinase