Cell Biology Questions
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Which metabolic pathway is common to both cellular respiration and fermentation?oxidative phosphorylationglycolysischemiosmosisthe oxidation of pyruvate to acetyl CoAthe citric acid cycle
Which of the following membrane activities requires energy from ATP hydrolysis?facilitated diffusion of chloride ions across the membrane through a chloride channelmovement of sodium ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluidmovement of water into a cell through aquaporinsmovement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cellmovement of carbon dioxide out of a paramecium
The oxygen consumed during cellular respiration is involved directly in which process or event?the citric acid cyclethe oxidation of pyruvate to acetyl CoAthe phosphorylation of ADP to form ATPaccepting electrons at the end of the electron transport chainglycolysis
The primary role of oxygen in cellular respiration is toserve as an acceptor for electrons and hydrogen, forming water.serve as an acceptor for released carbon, forming CO2.donate high energy electrons to the electron transport chain.combine with acetyl CoA, forming pyruvate.
In the complete reactions of aerobic respiration, the energy for the majority of ATP synthesis is provided bya proton gradient across a membrane.splitting water to produce oxygen.the production of carbon dioxide and oxygen in the electron transport chain.transfer of electrons from organic molecules to acetyl CoA.high-energy phosphate bonds from organic molecule intermediates in the citric acid cycle.
An organism is discovered that thrives in both the presence and absence of oxygen in the air. Curiously, the consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organismmust utilize a molecule other than oxygen to accept electrons from the electron transport chain.is photosynthetic.is a normal member of the animal kingdom.is an obligate anaerobe.is a facultative anaerobe.
During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the highest energy level?NAD+FADH2ATPFADNADH
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?It is used to synthesize ADP.It is released to the environment.It is used to power yet more cellular work.It is used to store energy in the form of ATP.
Which of the following will be found in nearly all eukaryotic cells?cell wallnucleoidmitochondriacapsulechloroplast
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?glycolysis and the citric acid cyclethe citric acid cycle and oxidative phosphorylationoxidation of pyruvate to acetyl CoA and the citric acid cycleglycolysis and the oxidation of pyruvate to acetyl CoA
When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the NAD+ molecule becomesreduced.redoxed.dehydrogenated.oxidized.hydrolyzed.
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?glycolysisoxidative phosphorylationchemiosmosiselectron transportthe citric acid cycle
The ATP produced in glycolysis is generated byphotophosphorylation.oxidative phosphorylation.substrate-level phosphorylation.electron transport.chemiosmosis.
When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the glucose molecule becomesoxidized.an oxidizing agent.hydrogenated.reduced.hydrolyzed.
Which catabolic processes may have been used by cells on ancient Earth before free oxygen became available?only glycolysis and fermentationglycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation, using an electron acceptor other than oxygenonly oxidative phosphorylation, using an electron acceptor other than oxygenonly glycolysis and pyruvate oxidationonly glycolysis and the citric acid cycle
Which of the following is true of enzymes?Enzyme function is increased if the 3-D structure or conformation of an enzyme is altered.Enzymes increase the rate of chemical reaction by providing activation energy to the substrate.Nonprotein cofactors alter the substrate specificity of enzymes.Enzyme function is independent of physical and chemical environmental factors such as pH and temperature.Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
A severe fever can result in death if not brought under control becauseit may result in binding inappropriate substrates by cellular enzymes.it may destroy the primary structure of cellular enzymes.it may increase the rate of cellular chemical reactions.it may alter the tertiary structure of cellular enzymes.
Which of the following statements about enzyme-catalyzed reactions is true?Energy from ATP is required to activate the enzyme before it can catalyze the reaction.The free-energy change of the reaction is greater than when the same reaction occurs in the absence of an enzyme.Enzymes always drive reactions toward chemical equilibrium.The rate of the reaction is greater than when the same reaction occurs in the absence of an enzyme.
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 true for all exergonic reactions?The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants.The products have more total energy than the reactants.A net input of energy from the surroundings is required for the reaction to proceed.The reaction proceeds with a net release of free energy.