Cell Biology Questions
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The active site of an enzyme is the region thatbinds substrates for the enzyme.binds allosteric regulators of the enzyme.binds noncompetitive inhibitors of the enzyme.is inhibited by the presence of a coenzyme or a cofactor.
The mechanism by which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described asnoncooperative inhibition.metabolic inhibition.irreversible inhibition.feedback inhibition.
Which of the following is a statement of the first law of thermodynamics?The entropy of the universe is decreasing.Energy cannot be transferred or transformed.The entropy of the universe is constant.Energy cannot be created or destroyed.
A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water — equal to the volume of blood lost — is transferred directly into one of his veins. What will be the most probable result of this transfusion?The patient's red blood cells will shrivel up because the blood fluid has become hypotonic compared to the cells.It will have no unfavorable effect as long as the water is free of viruses and bacteria.The patient's red blood cells will swell because the blood fluid has become hypotonic compared to the cells.The patient's red blood cells will shrivel up because the blood fluid has become hypertonic compared to the cells.
Energy transformations are always associated with an increase in thefree energy of the universe.entropy of the universe.entropy of the system.free energy of the system.
Water passes quickly through cell membranes becauseit is a small, nonpolar molecule.the bilayer is hydrophilic.water movement is tied to ATP hydrolysis.it moves through hydrophobic channels.it moves through aquaporin channel proteins.
Submerging a red blood cell in distilled water will result inthe cell becoming turgid.lysis of the cell.plasmolysis of the cell.the cell becoming flacid.
A protein that spans the phospholipid bilayer one or more times isa peripheral protein.an extracellular matrix protein.a glycoprotein.a transmembrane protein.
Transport of potassium ions into an animal cell by the sodium-potassium pump requireshigh intracellular concentrations of sodium.low intracellular concentrations of potassium.high intracellular concentrations of potassium.energy from ATP.low intracellular concentrations of sodium.
Which of the following is true of metabolism in its entirety in all organisms?Metabolism depends on a constant supply of energy from food.Metabolism manages the increase of entropy in an organism.Metabolism consists of all the energy transformation reactions in an organism.Metabolism specifically refers to the biochemical pathways involved in synthesis of macromolecules.
A chemical reaction that has a positive ΔG is best described asendergonic.entropicspontaneous.exergonic.
Which of the following is an example of potential rather than kinetic energy?water rushing over Niagara Fallsa molecule of glucosethe muscle contractions of a person mowing grasslight flashes emitted by a firefly
Submerging a plant cell in distilled water will result inthe cell becoming turgid.the cell becoming flaccid.plasmolysis of the cell.lysis of the cell membrane.bursting of the cell.
Mammalian blood contains the equivalent of 0.15 M NaCl. Seawater contains the equivalent of 0.45 M NaCl. What will happen if red blood cells are transferred to seawater?Water will leave the cells, causing them to shrivel and collapse.NaCl will passively diffuse into the red blood cells.NaCl will be exported from the red blood cells by facilitated diffusion.The blood cells will take up water, swell, and eventually burst.
What is the voltage across a membrane called?water potentialmembrane potentialosmotic potentialelectrochemical gradientchemical gradient
The cellular process of breaking down large molecules into smaller ones is defined asdehydration.catalysis.anabolism.catabolism.metabolism
Which of the following statements about diffusion is correct?It is an active process in which molecules move from a region of lower concentration to one of higher concentration.It is a passive process in which molecules move from a region of lower concentration to a region of higher concentration.It is very rapid over long distances.It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.It requires an expenditure of energy by the cell.
Proteins that allow the diffusion of ions across membranes in the direction of their concentration gradients are most likelyaquaporins.carrier proteins.active transport pumps.channel proteins.
The cellular process of synthesizing large molecules from smaller ones is defined ascatalysis.metabolism.catabolism.dehydration.anabolism.
An integral membrane protein would have to behydrophobic.amphipathic, with at least one hydrophobic region.hydrophilic.exposed to water on only one surface of the membrane.