Cell Communication

Which of the following processes could result in the net movement of a substance into a cell if the substance is more concentrated in the cell than in the surroundings? a)active transport b)facilitated diffusion c)diffusion d)osmosis

a)active transport

In cell signaling, how is the flow of specific ions regulated? a)opening and closing of ligand-gated ion channels b)transduction c)cytoskeleton rearrangement d)endocytosis

a)opening and closing of ligand-gated ion channels

Cell signals with short-lived local effects are called a)paracrine b)holocrine c)metacrine d)apocrine

a)paracrine

Which of the following component molecules of the plasma membrane is most important in the reception phase of cell signaling? a)protein b)phosphorylation c)cholesterol d)carbohydrates

a)protein

Which of the following are NOT involved in enzyme activation? a) A-kinase b) P nucleic acid c) G protein d) cAMP

b) P nucleic acid

Large molecules are moved out of the cell by which of the following processes? a) endocytosis b) exocytosis c) translocation d) passive diffusion

b) exocytosis

What is a G protein? a) a specific type of membrane receptor protein b) a protein on the cytoplasmic side of a membrane that becomes activated by a receptor protein c) a membrane-bound enzyme that converts ATP to cAMP d) a guanine nucleotide that converts between GDP and GTP to activate and inactivate relay proteins

b)a protein on the cytoplasmic side of a membrane that becomes activated by a receptor protein

In the cAMP pathway, the G protein stimulates a)phospholipase C b)adenylyl cyclase c) the endoplasmic reitculum d)calmodulin

b)adenylyl cyclase

Desmosomes are associated with _______ junctions. a) tight b)anchoring c) communicating d)adherens

b)anchoring

When a signal molecule arrives at a G protein linked receptor, a G protein a) becomes deactivated b) binds to the signal molecule c) becomes activated d) binds with a Ca++

c) becomes activated

Many signal transduction pathways use second messengers to a) transport a signal through the lipid bilayer portion of the plasma membrane b) relay a signal from the outside to the inside of the cell c) relay the message from the inside of the membrane throughout the cytoplasm d) diffuse directly into the nucleus, turning on genes

c) relay the message from the inside of the membrane throughout the cytoplasm

Cell surface receptors may be any of the following except: a)G protein linked b)enzymatic receptors c)single-pass transmembrane proteins for neurotransmitters d)chemically gated ion channels

c) single-pass transmembrane proteins for neurotransmitters

_____ is common second messenger a) cGTP b) cATP c)cAMP d)cMHC

c)cAMP

The signaling molecules that travel the farthest are called a) paracrine b) neurotransmitter c) endocrine d)intracellular

c)endocrine

In most cases, protein kinases a) hydrolyze proteins b) polymerize amino acid c) stimulate adenylyl cyclase d)add phosphate groups to proteins

d) add phosphate groups to proteins

Synaptic signaling involves a)endocrine signals b)paracrine signals c)autocrine signals d)neurotransmitters

d) neurotransmitters

One protein kinase cascade begins with the phosphorylation of the a) tap protein b) gat protein c) sat protein d) ras protein

d) ras protein

Which of the following signal molecules pass through the plasma membrane and bind to intracellular receptors that move into the nucleus and function as transcription factors to regulate gene expression? a) epinephrine b) neurotransmitter released into synapse between nerve cells c) yeast mating factors alpha and a d) testosterone, a steroid hormone.

d) testosterone, a steroid hormone

Which of the following can activate a protein by transferring a phosphate group to it? a)cAMP b)G protein c) protein phosphatase d) protein kinase

d)protein kinase

Narrow gaps between nerve cells through which paracrine signals travel are called a) desmosomes b)maculae c)integrins d)synapses

d)synapses

Which of the following uses passive transport, without protein channels, to move materials across the cell membrane? a) the depolarization of a muscle cell b)the uptake of glucose by the microvilli of cells lining the stomach c)the movement of insulin across the cell membrane d)the movement of carbon dioxide across the cell membrane

d)the movement of carbon dioxide across the cell membrane