Chapter 03 - Pathophysiology

Cell-to-cell communication through secretion of chemical signals into the extracellular fluid between them is called _____ signaling. a. neurocrine b. paracrine c. endocrine d. autocrine

B

Repolarization of a neuron after a depolarizing action potential is due to a. activation of the Na+-K+ pump. b. opening of voltage-gated calcium channels. c. efflux of potassium. d. extrusion of calcium.

C

Binding of a ligand to a type of G-protein-linked receptor called Gs stimulates the production of a. cAMP. b. cGMP. c. IP3. d. DAG.

A

An increase in extracellular potassium ion from 4.0 to 6.0 mEq/L would a. hyperpolarize the resting membrane potential. b. make it more difficult to reach threshold and produce an action potential. c. hypopolarize the resting membrane potential. d. alter the threshold potential.

C

Enzymes function to a. reverse the direction of reactions. b. control the amount of products made. c. increase the rate of reactions. d. provide the energy to drive reactions.

C

GTP-binding proteins (G proteins) function to a. activate receptors on the extracellular surface. b. degrade second-messenger molecules. c. activate intracellular enzyme systems. d. synthesize ATP.

C

Ion channels are triggered to open or close by all of the following mechanisms except a. mechanical stretch. b. change in membrane voltage. c. hydrolysis of ATP. d. binding to a chemical ligand.

C

Contains Krebs cycle enzymes in its matrix

Mitochondria

Transmits information about cell configuration to the nucleus

Cytoskeleton

Activation of the enzyme adenylyl cyclase by a stimulatory G protein results in the formation of a. phosphodiesterase. b. ATP. c. cGMP. d. cAMP.

D

Excitable cells are able to conduct action potentials because they have a. receptors for neurotransmitters. b. gap junctions. c. ligand-gated channels. d. voltage-gated channels.

D

Phospholipids spontaneously form lipid bilayers because they are a. polar. b. charged. c. insoluble. d. amphipathic.

D

Approximately 90% of the cell membrane is composed of protein, and 10% is lipid. True/False

F

Carbon dioxide is produced from β-oxidation of fats. True/False

F

Proteins made on the rough endoplasmic reticulum are transported to the cell's cytoplasm. True/False

F

The human genome contains about 30,000 genes. True/False

F

Processes and "addresses" proteins for export

Golgi apparatus

Contains digestive enzymes of the hydrolytic sort

Lysosomes

Diffusion and osmosis occur passively. True/False

T

Each molecule of O2 accepts four electrons from the mitochondrial electron transport chain to form two H2O. True/False

T

Glycolysis produces two ATP molecules per glucose molecule. True/False

T

Ion channels cannot transport ions against an electrochemical gradient. True/False

T

The lipid bilayer of the plasma membrane has low permeability to charged and polar molecules. True/False

T

Which of the following reactions would occur in the body spontaneously without energy input from direct (ATP) or secondary (gradient) energy sources? a. Sodium entry into the cell b. Calcium extrusion from the cell c. Translation d. Endocytosis/exocytosis

A

Glycolysis is the metabolic process of breaking down a glucose molecule to form a. CO2 and H2O. b. 2 ATP and 2 pyruvate. c. 34 ATP. d. oxygen and ATP.

B

The energy derived from the transport of electrons along the electron transport chain on the inner mitochondrial membrane is used to a. synthesize ATP. b. generate a proton (H+) gradient. c. reduce oxygen to water. d. produce NADH.

B

The primary purpose of glycolysis is to a. produce ATP. b. supply substrate to the Krebs cycle. c. produce energy. d. supply lactate during anaerobic conditions.

B

The resting membrane potential in nerve and skeletal muscle is determined primarily by a. extracellular sodium ion concentration. b. the ratio of intracellular to extracellular potassium ions. c. activation of voltage-gated sodium channels. d. activity of energy-dependent membrane pumps.

B

Mediate the movement of chromatids during mitosis

Microtubules

The four nucleotide bases that form DNA are C, G, A, and T. True/False

T