Cell Signaling 1

Nicotine from cigarette smoke acts as a ligand and associates with specific cells in the nervous system. Nicotine eventually produces feelings of pleasure and well-being. Below are the events that happen in the cellular response to nicotine. Place the events in the correct order to describe the steps in the signaling pathway. A. The acetylcholine receptor is an ion channel, and, when a ligand binds, the ion channel opens. B. An influx of ions carries the signal to the reward areas of the brain. C. Nicotine binds to the transmembrane protein that normally binds the neurotransmitter acetylcholine. D. The signal causes release of dopamine in the brain, which causes good feelings. E. Nicotine is quickly eliminated from the body (causing cravings for more cigarettes to produce good feelings). a) C, A, B, D, E b) C, D, B, A, E c) A, B, C, D, E d) B, A, C, D, E e) A, D, B, C, E

a) C, A, B, D, E

According to Figure 9.6, what is a key difference between cell signaling by a cell-surface receptor and cell signaling by an intracellular receptor? (can't put the picture in) a)Cell-surface receptors bind polar signaling molecules; intracellular receptors bind nonpolar signaling molecules. b)Cell-surface receptors typically bind to signaling molecules that are smaller than those bound by intracellular receptors. c)None of the other answer options is correct. d)Cell-surface receptors bind to specific signaling molecules; intracellular receptors bind any signaling molecule. e)Signaling molecules that bind to cell-surface receptors lead to cellular responses restricted to the cytoplasm; signaling molecules that bind to intracellular receptors lead to cellular responses restricted to the nucleus.

a)Cell-surface receptors bind polar signaling molecules; intracellular receptors bind nonpolar signaling molecules.

Which of the following CORRECTLY lists the types of cellular communication from shortest to longest distance traveled by the signaling molecule to reach its responding cell? a)autocrine, paracrine, endocrine b)autocrine, endocrine, paracrine c)paracrine, autocrine, endocrine d)endocrine, paracrine, autocrine

a)autocrine, paracrine, endocrine

Choose from the following terms to fill in the blanks in the CORRECT order. A. ligand B. signaling cell C. receptor D. responding cell In communication between cells, the _____ produces the signaling molecule, also known as the _____; the _____ produces the _____, to which the signaling molecule binds, a) B, C, A, D b) B, A, D, C c) D, C, B, A d) A, B, C, D

b) B, A, D, C

In cell communication, which one of the following is a requirement of the responding cell? a)It must be a prokaryotic cell. b)It must have receptor proteins. c)It must produce signaling molecules. d)It must be a eukaryotic cell.

b)It must have receptor proteins.

A cell that responds to an environmental condition by the release of a chemical is an example of which of the following elements of cellular communication? a)a signaling molecule b)a signaling cell c)a G protein-coupled receptor d)a receptor tyrosine kinase e)None of the other answer options is correct.

b)a signaling cell

Which type of receptor is involved in rapid responses of muscle cells and neurons? a)receptor kinase b)ligand-gated ion channel c)intracellular receptor d)G protein-coupled receptor

b)ligand-gated ion channel

Communication between neurons is an example of which type of cell signaling? a)endocrine b)paracrine c)contact-dependent d)autocrine e)All of these choices are correct.

b)paracrine

How are steroid hormone receptors and cell-surface receptors similar? a)Both types cause G proteins to exchange GDP for GTP. b)When bound to their ligand, both types enter the nucleus to activate transcription. c)Both types undergo a conformational change when they bind to their ligand. d)When activated, both types carry signals across the plasma membrane.

c)Both types undergo a conformational change when they bind to their ligand.

What does a ligand-gated channel do? a)It activates a G protein. b)It triggers the activity of a phosphatase. c)It allows ions to move across the plasma membrane. d)It binds small, nonpolar signaling molecules.

c)It allows ions to move across the plasma membrane.

Of the choices below, what is the MOST likely reason that paracrine signaling does not activate the cell that is producing the signaling molecule? a)The cell's receptors have a mutation. b)The concentration of the signaling molecule is not high enough. c)The cell does not have the proper receptor. d)The neighboring cells are too far away.

c)The cell does not have the proper receptor.

protein on a cell surface that binds to a signaling molecule is an example of which of the following elements of cellular communication? a)a responding cell b)a signaling cell c)a receptor protein d)a signaling molecule e)None of the other answer options is correct.

c)a receptor protein

Which of the following would NOT be considered a cell-surface receptor? a)a receptor that causes GDP to be exchanged for GTP in a G protein b)a receptor that must form a dimer after binding the ligand to transmit a signal c)a receptor that binds a nonpolar steroid hormone and activates transcription d)a receptor that allows ions to enter the cell when a ligand binds

c)a receptor that binds a nonpolar steroid hormone and activates transcription

Where would you expect to find the receptor for a nonpolar ligand? a)on the cell surface b)in the nucleus of the cell c)either in the nucleus of the cell or in the cytosol d)in the cytosol

c)either in the nucleus of the cell or in the cytosol

What determines the specificity of a receptor protein? a)the cytoplasmic domain b)the transmembrane domain c)the ligand-binding site d)the extracellular domain

c)the ligand-binding site

The first event that happens after a signaling molecule binds to a receptor is: a)the receptor transmits the message in a process called signal transduction. b)the signal is quickly terminated to ensure a moderate response. c)the receptor is activated. d)there is a cellular response.

c)the receptor is activated.

How does an "activated" receptor transfer information into the cell? a)by decreased phosphorylation of the receptor b)by altering the ligand-binding site of the receptor c)through a conformational change of the receptor d)by increased translation of the receptor

c)through a conformational change of the receptor

To have communication between cells, you must have a: a)signaling molecule. b)responding cell. c)receptor. d)All of these choices are correct.

d)All of these choices are correct.

Which of the following types of cellular activities can be a response to cell signaling? a)Enzyme activities are changed. b)Cell division is triggered. c)Gene expression patterns are changed. d)All of these choices are correct. e)Cell signals are released to communicate with other cells.

d)All of these choices are correct.

In the context of cell signaling, to what does the term ligand refer? a)a type of gated channel b)the extracellular domain of a receptor protein d)the proteins activated as part of a signal transduction pathway e)a signaling molecule

e)a signaling molecule