Microbiology HW 2 questions
Which of the following is true of anabolic reactions? a. Anabolic reactions break down complex organic compounds into simpler ones. b. Anabolic reactions produce energy, which is used to convert ADP to ATP. c. Anabolic and catabolic reactions both build complex organic molecules from simpler ones; however, anabolic reactions use ATP, whereas catabolic reactions transfer energy to create ATP. d. Anabolic reactions use ATP and small substrates as building blocks to synthesize larger molecules.
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Which of the following molecules traps energy released during oxidation reduction reactions?
ATP
Which of the following are products of light-dependent photosynthetic reactions and are necessary for the light-independent photosynthetic reaction to occur?
ATP and NADPH
Which of the following statements accurately describes the difference between aerobic and anaerobic respiration?
Aerobic respiration uses oxygen as the final electron acceptor, and anaerobic respiration uses either an inorganic molecule, such as nitrate ions or sulfate ions, or organic molecule, such as an acid or alcohol.
During the infection, there are many different environments that P. multocida will encounter. In order to cause an infection like the one in Sam's forearm, P. multocida must regulate its metabolic pathways in order to adapt to the changing environments. The process of glycolysis is regulated at several steps by allosteric inhibition. Which of the following are features of allosteric inhibition? a. Allosteric inhibition can be irreversible. b. Allosteric inhibition can be reversed. c. The allosteric inhibitor binds to a site distinct from the active site resulting in decreased affinity of the enzyme for the substrate. d. Allosteric inhibition can be overcome by increasing the amount of substrate in the reaction. e. In order to function, allosteric inhibitors must have structural similarity to the enzyme substrate.
Allosteric inhibition can be irreversible. a. Allosteric inhibition can be irreversible. b. Allosteric inhibition can be reversed. c. The allosteric inhibitor binds to a site distinct from the active site resulting in decreased affinity of the enzyme for the substrate.
The chemical reactions involved in synthesizing proteins and cell peptidoglycan are examples of __________ reactions.
Anabolic
Which of the following is true of catabolism?
Catabolic reactions are exergonic; they break down complex organic molecules into simpler ones.
In which direction is DNA synthesized?
DNA is synthesized in the 5′ to 3′ direction.
Which of the following statements is true about enzymes?
Each enzyme has a characteristic three-dimensional shape.
What is the a DNA strand complementary to CGAATCA? a.
GCTTAGT
Cellular Respiration Equation INPUTS OUTPUTS
Glucose + O2 CO2 + H2O + ATP (fuel) Gas we inhale (Gas we inhale) water
Which of the following molecules carry electrons during various stages of glucose catabolism?
NADH and FADH2
Which of the following statements is accurate concerning glucose metabolism?
Pyruvic acid, product of glycolysis, is the starting block for both the Krebs cycle and fermentation.
During conjugation, DNA is transferred from one bacterium to another. Often, it is plasmid DNA that is transferred. Which of the following plasmid names correctly matches the information that is carries?
R factors: antibiotic-resistance genes
An apoenzyme that loses its coenzyme subunit will be non-functional. True False
True
Both respiration and photosynthesis require the use of an electron transport chain. True False
True
Catabolic reactions are generally degradative and hydrolytic. True False
True
Glycolysis is utilized by cells in both respiration and fermentation. True False
True
In general, ATP is generated in catabolic pathways and expended in anabolic pathways. True False
True
You are analyzing a segment of DNA and observe an area of sequence that appears to act as a promoter element. Based on this what can you conclude?
You have found the beginning of a gene
What is the net number of ATP molecules produced during glycolysis? a. 2 b. 3 c. 1 d. 4
a. 2
Use the genetic code in your textbook to solve this problem: The mRNA copied from a given gene is as follows: UACAAAGAAAUU. If base 2 were changed to U, what effect would this have? a. A missense mutation will occur. b. A nonsense mutation will occur. c. Transcription will stop. d. A frameshift mutation will result.
a. A missense mutation will occur.
What could you conclude about an enzyme's activity? a. A particular enzyme is very specific to the reaction it catalyzes. b. A particular enzyme is capable of catalyzing many different reactions. c. Enzymes are rigid molecules that never change their shape. d. A particular enzyme can only be used only once.
a. A particular enzyme is very specific to the reaction it catalyzes.
Which one of the following nucleotide sequences is most likely affected by ultraviolet light? a. AGTTTC b. TATATA c. GATCGG d. GACACC
a. AGTTTC
Why is ATP required for glycolysis? a. ATP makes it easier to break apart glucose into two three-carbon molecules. b. ATP is used to convert PEP into pyruvic acid. c. ATP is used to convert DHAP into G3P. d. ATP is used to reduce NAD+ to NADH.
a. ATP makes it easier to break apart glucose into two three-carbon molecules.
Which of the following is true of aerobic respiration compared to anaerobic respiration? a. Aerobic respiration uses oxygen as a final hydrogen acceptor, whereas anaerobic respiration uses an inorganic molecule other than oxygen as the final electron acceptor. b. Aerobic respiration uses oxygen as a final electron (hydrogen) acceptor, whereas anaerobic respiration uses an organic molecule. c. Aerobic respiration is less efficient than all forms of anaerobic respiration, producing less ATP and largerend-products. d. Aerobic respiration and anaerobic respiration both require oxygen as a final electron acceptor.
a. Aerobic respiration uses oxygen as a final hydrogen acceptor, whereas anaerobic respiration uses an inorganic molecule other than oxygen as the final electron acceptor.
Which of the following is true of catabolism? a. Catabolic reactions are exergonic; they break down complex organic molecules into simpler ones. b. An example of a catabolism is the creation of sugar from carbon dioxide and water. c. Catabolic reactions use energy from ATP, converting it to ADP. d. Catabolic reactions build up complex organic compounds from simpler ones.
a. Catabolic reactions are exergonic; they break down complex organic molecules into simpler ones.
Which of the following hypotheses was developed following Griffith's 1928 experiment? a. DNA from dead encapsulated bacteria can transform living nonencapsulated bacteria into living encapsulated bacteria. b. Some pathogenic bacteria cannot be heat-killed. Bacterial virulence is related to temperature resistance. c. Dead encapsulated bacteria can cause disease. d. Streptococcus pneumoniae causes disease.
a. DNA from dead encapsulated bacteria can transform living nonencapsulated bacteria into living encapsulated bacteria.
Of the choices below, which is the LAST to happen during DNA replication? a. DNA ligase joins all the new pieces together. b. Primase synthesizes primers for each strand. c. The two template strands of DNA are unwound. d. Primers are removed and replaced with DNA.
a. DNA ligase joins all the new pieces together.
All of the following steps are involved in the aerobic electron transport chain. Which step happens last? a. Electrons are transferred to O2. b. NAD+ is formed. c. NADH is oxidized. d. Electrons flow between membrane-bound electron carriers. e. Protons move to the outside of the membrane
a. Electrons are transferred to O2.
Why do all enzymatic reactions need activation energy? a. Energy is required to disrupt a substrate's stable electron configuration. b. Energy allows only the substrate to bind. c. Energy is needed for the enzyme to find its substrate. d. Energy is required by an enzyme so that it can be reused.
a. Energy is required to disrupt a substrate's stable electron configuration.
Why are enzymes important to biological systems? a. Enzymes decrease the amount of activation energy required for chemical reactions to occur. b. Enzymes are reuseable. c. Enzymes prevent unwanted chemical by-products from forming. d. Enzymes increase the energy barrier required of chemical reactions
a. Enzymes decrease the amount of activation energy required for chemical reactions to occur.
Which of the following statements about glycolysis is true? a. Glycolysis is also called the Embden-Meyerhof pathway. b. All cells perform glycolysis. c. Glycolysis is the main source of NADH in the cell. d. Glycolysis produces glucose.
a. Glycolysis is also called the Embden-Meyerhof pathway.
How is nevirapine used to treat HIV infections? a. It alters the active site of reverse transcriptase, decreasing that enzyme's activity. b. It increases the immune system's ability to detect the virus. c. It binds to the active site of HIV reverse transcriptase, decreasing that enzyme's activity. d. It decreases the virus's ability to find host cells.
a. It alters the active site of reverse transcriptase, decreasing that enzyme's activity.
Which of the following is an acid produced by fermentation? a. Lactic acid and propionic acid b. Lactic acid c. Ethanol d. Propionic acid e. Pyruvic acid
a. Lactic acid and propionic acid
When proteins are oxidized, all of the following are true EXCEPT which one? a. Microbes produce extracellular enzymes to reduce proteins to their fatty acid and glycerol components so that each component can enter the Krebs cycle. b. The amino group is removed through deamination and converted to nitrogenous waste such as NH4+. c. Enzymes break down proteins into component amino acids. d. After deamination of the protein, the organic acid enters the Krebs cycle.
a. Microbes produce extracellular enzymes to reduce proteins to their fatty acid and glycerol components so that each component can enter the Krebs cycle.
When proteins are oxidized, all of the following are true EXCEPT which one? a. Microbes produce extracellular enzymes to reduce proteins to their fatty acid and glycerol components so that each component can enter the Krebs cycle. b. The amino group is removed through deamination and converted to nitrogenous waste such as NH4+. c. Enzymes break down proteins into component amino acids. d. After deamination of the protein, the organic acid enters the Krebs cycle.
a. Microbes produce extracellular enzymes to reduce proteins to their fatty acid and glycerol components so that each component can enter the Krebs cycle.
In an enzymatic reaction involving oxidation of a substrate, which of the following would be required? a. NAD+ b. FADH2 c. ATP d. O2 e. H2O
a. NAD+
Glycolysis produces energy in which form? a. NADH and ATP b. NADH c. NADH, ATP, and pyruvic acid d. Pyruvic acid e. ATP
a. NADH and ATP
What would be the likely outcome if you increased the concentration of substrate for an enzyme in the presence of a noncompetitive inhibitor? a. No change in enzyme activity would be observed. b. A decrease in the amount of inhibitor would be observed. c. A decrease in the concentration of enzyme would be observed. d. You would begin to see an increase in the enzyme's rate of activity.
a. No change in enzyme activity would be observed.
What is the key difference between photoheterotrophs and photoautotrophs? a. Photoheterotrophs use organic compounds as their carbon source; photoautotrophs use carbon dioxide as their carbon source. b. Photoheterotrophs produce oxygen as a by-product; photoautotrophs do not. c. Photoheterotrophs use hydrogen sulfide for reducing power; photoautotrophs do not. d. Photoautotrophs only use bacteriochlorophyll; photoheterotrophs only use chlorophyll a.
a. Photoheterotrophs use organic compounds as their carbon source; photoautotrophs use carbon dioxide as their carbon source.
Which of the following types of organisms uses hydrogen sulfide for reducing power? a. Purple sulfur bacteria b. Cyanobacteria c. Algae d. Green nonsulfur bacteria Purple nonsulfur bacteria
a. Purple sulfur bacteria
During conjugation, DNA is transferred from one bacterium to another. Often, it is plasmid DNA that is transferred. Which of the following plasmid names correctly matches the information that it carries? a. R factors: antibiotic-resistance genes b. F factor: plasmids that carry antibiotic resistance c. R factor: fertility factor d. dissimilation factors: antibiotic-resistance genes.
a. R factors: antibiotic-resistance genes
Which of the following statements regarding redox reactions is true? a. Redox reactions involve an oxidation reaction coupled with a reduction reaction. b. Redox reactions are only seen in the electron transport chain. c. No metabolic reactions are redox reactions. d. Redox reactions must either be oxidizing reactions or reducing reactions.
a. Redox reactions involve an oxidation reaction coupled with a reduction reaction.
Why does lack of oxygen result in the halt of ATP synthesis? a. The chain shuts down and can no longer pump hydrogen ions across the membrane, and the proton gradient cannot be maintained. b. It causes one of the cytochromes in the electron transport chain to be permanently stuck in the reduced state. c. Oxygen prevents uncoupling of the electron transport chain.
a. The chain shuts down and can no longer pump hydrogen ions across the membrane, and the proton gradient cannot be maintained.
The P. multocida that are growing within Sam's abscess are breaking glucose down via glycolysis in order to obtain energy. This process occurs via a series of enzymatic reactions. During a chemical reaction, an enzyme functions as a biological catalyst and lowers the activation energy. How does an enzyme lower the activation energy of a reaction? a. The enzyme increases the effectiveness of reactant collisions thereby increasing the number of reactant molecules that reach activation energy. b. The breakdown of the enzyme provides energy to the reactants allowing them to reach activation energy more quickly. c. As the enzyme is utilized, heat is released causing an increase in the reaction rate and a subsequent lowering in the energy of activation. d. The enzyme increases the potential energy available to the reactants, thereby decreasing the activation energy that must be reached.
a. The enzyme increases the effectiveness of reactant collisions thereby increasing the number of reactant molecules that reach activation energy.
Microbes are often identified using biochemical tests that detect specific enzymes of metabolic pathways. E.coli typically ferments lactose, whereas the dysenterybacterium, Shigella, does not. If a pure culture of each bacterium were placed in a tube containing lactose as the only food source, and a chemical indicator changed color if the tube became acid, what would the tubes look like after the bacteria were incubated? a. The tube with E. coli would indicate a pH change, and the Shigella tube would indicate no change. b. Both tubes would show the evidence of lactose fermentation by turning acidic and changing the pH indicator. c. Neither tube will show any change. d. Both tubes would show the evidence of lactose fermentation by turning alkaline.
a. The tube with E. coli would indicate a pH change, and the Shigella tube would indicate no change.
NO3-+ 2H+ NO2- + H2O Nitrate ion Nitrite ion Which of the following is true about this reaction? a. This process occurs anaerobically. b. This process requires O2. c. This process requires the electron transport system. d. This process requires light. e. This process requires O2 and the electron transport system
a. This process occurs anaerobically.
What is the net production of ATP in glycolysis? a. Two ATP b. Eight ATP c. Six ATP d. Four ATP
a. Two ATP
What is one difference between ubiquinones and cytochromes? a. Ubiquinones are not made of protein; cytochromes are. b. Ubiquinones can only be oxidized; cytochromes can only be reduced. c. Ubiquinones can only be reduced; cytochromes can only be oxidized. d. Ubiquinones cannot carry electrons; cytochromes can.
a. Ubiquinones are not made of protein; cytochromes are.
A mutation occurs that results in a codon change from UGU to UGA. UGU encodes a cysteine amino acid, and UGA is a stop codon. Therefore, this is an example of __________. a. a nonsense mutation b. a frameshift mutation c. a missense mutation d. a transposon
a. a nonsense mutation
When fermentation tests are used to help identify bacteria, which of the following end-products is typically detected by a color change? a. acid b. NADP c. d.
a. acid
The proton motive force is __________. a. an electrochemical gradient formed across a membrane b. the accumulation of water formed in respiration c. the movement of flagella d. ATP accumulation in the mitochondria e. the movement of water across a membrane
a. an electrochemical gradient formed across a membrane
Enzymes are important in living organisms because they __________. a. bring together reactants or properly orient a molecule for a reaction b. increase local temperatures to increase rates of reactions c. bind irreversibly to substrates and remove them from the cellular pool d. interact with and destroy unwanted cellular substrates e. catalyze the covalent bonding of NAD+ molecules to substrates
a. bring together reactants or properly orient a molecule for a reaction
A strictly fermentative bacterium produces energy a. by glycolysis only. b. by aerobic respiration only. c. only in the absence of oxygen. d. only in the presence of oxygen. e. by fermentation or aerobic respiration.
a. by glycolysis only.
According to the animation, the reactions that occur between glucose and pyruvic acid____. a. can either be anabolic or catabolic. b. are only anabolic. c. are neither catabolic nor anabolic. d. are only catabolic.
a. can either be anabolic or catabolic.
In E. coli, Hfr cells __________. a. can pass main chromosome genes to a recipient cell b. lack the genes typically carried on the F factor c. do not form sex pili d. typically pass the entire F factor to F- cells e. fuse with gram-positive cells by way of sticky surface materials
a. can pass main chromosome genes to a recipient cell
Which one of the following is a method of vertical gene transmission? a. cell division b. transformation c. transduction d. conjugation
a. cell division
The process of generating ATP using a proton gradient is referred to as_____. a. chemiosmosis. b. the electron transport chain. c. water damming.
a. chemiosmosis
Which of the following compounds is NOT an enzyme? a. coenzyme A b. cellulase c. dehydrogenase d. β-galactosidase e. sucrase
a. coenzyme A
You inoculate a bacterial culture into a tube containing glucose and peptides. The pH indicator shows that the pH decreased after 24 hours and then increased at 48 hours. What has caused the increase in pH? a. deamination b. compounds in the Krebs Cycle c. oxidation of glucose d. fermentation of glucose
a. deamination
Which one molecule could provide the carbon source, the energy source, and the electron source for a chemoheterotroph? a. glucose b. nitrogen c. carbon dioxide d. sulfur e. ATP
a. glucose
The Pentose Phosphate Pathway a. is an example of anabolism. b. is a part of photosynthesis. c. is another name for fermentation. d. is an example of catabolism.
a. is an example of anabolism.
The chemical 5-bromouracil is a mutagen because it __________. a. is similar in structure but not base-pairing ability to thymine b. is similar in structure and base-pairing ability to thymine c. inserts between "stacked base pairs," affecting the accuracy of DNA replication d. causes thymine-thymine dimers to form e. is similar in structure and base-pairing ability to uracil
a. is similar in structure but not base-pairing ability to thymine
Which organism is not correctly matched to its energy source? a. photoautotroph; CO2 b. anoxygenic autotroph; light c. photoheterotroph; light d. chemoautotroph; iron e. chemoheterotroph; glucose
a. photoautotroph; CO2
The antibiotic kasugamycin blocks binding of tRNA-Fmet (the bacterial tRNA that carries formylmethionine) to a ribosome. From this information, you can conclude that kasugamycin prevents __________. a. protein synthesis
a. protein synthesis
The tryptophan operon contains genes that encode the enzymes involved in tryptophan biosynthesis. An abundance of tryptophan will "turn off" the operon. This operon is an example of a ____________. a. repressible operon b. transformable operon c. constitutive operon d. inducible operon
a. repressible operon
A frameshift mutation in a gene encoding a protein usually __________. a. results in the production of a nonfunctional peptide b. results in a modified but functional protein c. results in a single amino acid change upstream from the mutation d. affects the mRNA but not the peptide e. improves the function of the encoded protein
a. results in the production of a nonfunctional peptide
What type of reaction is in the figure? a. transamination b. decarboxylation c. oxidation d. dehydrogenation e. reduction
a. transamination
For a cell, which of the following compounds has the greatest amount of energy per molecule? a. ATP b. acetyl CoA pyruvate c. NADH d. ADP
acetyl CoA pyruvate
When fermentation tests are used to help identify bacteria, which is the following end-products is typically detected by a color change?
acid
Some amino acids are synthesized by adding an amine group to pyruvic acid or to one of the Krebs cycle intermediates. This process is known as __________.
amination
Building proteins from amino acids and building peptidoglycan from sugars and peptides are ___________.
anabolic reactions
Which of these statements is true about transduction? a. Bacteria-bacteria contact is required. b. A virus is required for transfer of genetic material. c. Segments of DNA move from one region of DNA to another. d. Naked DNA is passed from bacterium to bacterium. e. Recombination does not occur.
b. A virus is required for transfer of genetic material.
Which of the following molecules traps energy released during oxidation reduction reactions? a. ADP b. ATP c. NAD d. NADP
b. ATP
Which of the following statements accurately describes the difference between aerobic and anaerobic respiration? a. Aerobic respiration uses O2 as the final electron acceptor, whereas anaerobic respiration uses H2O. b. Anaerobic respiration uses oxygen as the final electron acceptor, and aerobic respiration uses either an inorganic molecule, such as nitrate ions or sulfate ions, or an organic molecule, such as an acid or alcohol. c. Aerobic respiration uses oxygen as the final electron acceptor, and anaerobic respiration uses either an inorganic molecule, such as nitrate ions or sulfate ions, or an organic molecule, such as an acid or alcohol. d. Aerobic respiration uses an organic molecule as the final electron acceptor, and anaerobic respiration uses an inorganic molecule as the final electron acceptor.
b. Aerobic respiration uses oxygen as the final electron acceptor, and anaerobic respiration uses either an inorganic molecule, such as nitrate ions or sulfate ions, or an organic molecule, such as an acid or alcohol.
Where would you expect to find electron transport chains in a prokaryote? a. Along the inner mitochondrial membrane b. Along the plasma membrane c. Along the outer mitochondrial membrane d. Along the cell wall e. Free-floating in the cytoplasm
b. Along the plasma membrane
Which of the following statements regarding competitive inhibitors is true? a. The inhibitor will destroy the substrate. b. Competitive inhibitors decrease the rate of enzyme activity. c. The inhibitor will degrade the substrate. d. The inhibitor will destroy the enzyme.
b. Competitive inhibitors decrease the rate of enzyme activity.
Which of the following statements is true about enzymes? a. Enzymes are used up in the reactions they catalyze. b. Each enzyme has a characteristic three-dimensional shape. c. Enzymes raise the activation energy of the reaction. d. Enzymes have active sites that interact with a variety of different molecules.
b. Each enzyme has a characteristic three-dimensional shape.
Based on the animation, how many electron carriers are reduced in the Krebs cycle only? a. Three b. Four c. Five d. Six
b. Four
Based on the animation, how many electron carriers are reduced in the Krebs cycle only? a. Three b. Four c. Five d. Six
b. Four
In which organism would you likely find a chlorosome? a. Purple nonsulfur bacteria b. Green sulfur bacteria c. Cyanobacteria d. Algae e. Purple sulfur bacteria
b. Green sulfur bacteria
What is the role of pyruvic acid in fermentation? a. It is the organic acid end-product of fermentation. b. It takes the electrons from NADH, oxidizing it back into NAD+. c. It becomes the final electron acceptor for the electron transport chain in the absence of oxygen. d. It provides the protons to be used in the electron transport chain.
b. It takes the electrons from NADH, oxidizing it back into NAD+.
During glycolysis, electrons from the oxidation of glucose are transferred to __________. a. NADH b. NAD c. FAD d. FADH
b. NAD
Which of the following molecules carry electrons during various stages of glucose catabolism? a. glucose b. NADH and FADH2 c. pyruvic acid d. acetyl CoA
b. NADH and FADH2
Which of the following statements about DNA replication is FALSE? a. Primase synthesizes the primers. b. Only one strand of the parent DNA serves as a template for a newly synthesized complementary strand. c. DNA polymerase is required to add new nucleotides to the growing ends of the DNA strands. d. DNA ligase joins the small DNA fragments of the lagging strand.
b. Only one strand of the parent DNA serves as a template for a newly synthesized complementary strand.
Which of the following statements is accurate concerning glucose metabolism? a. Glucose is split in glycolysis and produces large amounts of ATP. b. Pyruvic acid, the product of glycolysis, is the starting block for both the Krebs cycle and fermentation. c. Fermentation produces large amounts of ATP. d. The electron transport chain is the final step for both fermentation and aerobic respiration.
b. Pyruvic acid, the product of glycolysis, is the starting block for both the Krebs cycle and fermentation.
Which of the following enzymes and their function is MISMATCHED? a. DNA polymerase: synthesizes DNA and proofreads b. RNA polymerase: makes DNA c. DNA helicase: unwinds two strands of DNA d. DNA ligase: joins pieces of DNA together
b. RNA polymerase: makes DNA
According to the animation, what does the electron transport chain do to the concentration of hydrogen ions (protons)? a. The concentration of protons inside the membrane is equal to the concentration outside of the membrane. b. The concentration of protons is higher outside the membrane than inside. c. The concentration of protons is lower outside the membrane than inside.
b. The concentration of protons is higher outside the membrane than inside.
One of the environmental changes that P. multocida encounters during infection is the limitation of nutrients and oxygen. One of the changes that P. multocida (a facultative anaerobe) makes in this environment is to switch to anaerobic metabolism. Predict which of the following is most likely to occur as a result of the switch from aerobic to anaerobic metabolism. a. The amount of ATP produced will be relatively the same as aerobic metabolism because P. multocida will be able to respire anaerobically. b. The organisms will grow more slowly because they will produce less ATP compared to aerobic metabolism. c. Glycolysis, the Kreb's cycle, and electron transport will function as usual except that a different compound will be used as a final electron acceptor. d. During anaerobic metabolism, different electron carriers will be utilized; these will ultimately lead to less ATP production and slower growth of the organism.
b. The organisms will grow more slowly because they will produce less ATP compared to aerobic metabolism.
Which of the following is a trait unique to photosynthetic eukaryotes? a. The presence of chlorophyll a b. The presence of chloroplasts c. The presence of thylakoid membranes d. Using water for reducing power e. Living in aerobic environments
b. The presence of chloroplasts
Which of the following statements concerning translation is correct? a. Each set of three nucleotides in the mRNA is called an anticodon. b. The ribosome stops protein synthesis when it reaches a nonsense codon in the mRNA. c. Amino acids are brought to the ribosome by the mRNA. d. tRNAs enter the ribosome at the E site and leave from the A site
b. The ribosome stops protein synthesis when it reaches a nonsense codon in the mRNA
How do stabilizing proteins work on the DNA? a. They form the replication fork. b. They bind to the single-stranded DNA. c. They use ATP to break the hydrogen bonds. d. They bind to the double-stranded DNA.
b. They bind to the single-stranded DNA.
How does a competitive inhibitor slow enzyme catalysis? a. They produce products toxic to the enzymes. b. They compete with the substrate for the enzyme's active site. c. They bind to the substrate. d. They degrade the substrate.
b. They compete with the substrate for the enzyme's active site.
How many net ATPs can be made from one molecule of glucose in glycolysis? a. Six b. Two c. Four d. One
b. Two
A mutation occurs that results in a codon change from UGU to UGA. UGU encodes a cysteine amino acid, and UGA is a stop codon. Therefore, this is an example of __________. a. a frameshift mutation b. a nonsense mutation c. a transposon d. a missense mutation
b. a nonsense mutation
A reaction that involves the transfer of electrons from one molecule to another is referred to as a. an oxidation reaction. b. a redox reaction. c. a reduction reaction.
b. a redox reaction.
Which of the following terms refers to pathways that can function both in anabolism and catabolism? a. light-dependent pathways b. amphibolic pathways c. homolactic fermentation pathways d. chemiosmotic pathways
b. amphibolic pathways
The reactions involved in producing larger compounds from smaller compounds is called_______. a. catabolism. b. anabolism. c. metabolism.
b. anabolism.
Which group of organisms has members representing each of the following nutritional classifications: chemoheterotrophs, chemoautotrophs, photoheterotrophs, and photoautotrophs? a. protists b. bacteria c. animals d. plants
b. bacteria
Nitrobacter bacteria use carbon dioxide for their carbon source and nitrate ions as an energy source. This organism is a __________. a. photoheterotroph b. chemoautotroph c. photoautotroph d. chemoheterotroph
b. chemoautotroph
Thiobacillus bacteria use the Calvin-Benson cycle to reduce CO2 and the oxidation of sulfide ions for energy. This organism is a __________. a. photoautotroph b. chemoautotroph c. chemoheterotroph d. photoheterotroph e. photochemotroph
b. chemoautotroph
In cellular respiration of glucose, what are the three principal stages? a. Calvin-Benson cycle, electron transport chain, and glycolysis b. glycolysis, Krebs cycle, and the electron transport chain c. chemiosmosis, photophosphorylation, and reduction d. fermentation, Krebs cycle, and electron transport chain
b. glycolysis, Krebs cycle, and the electron transport chain
The complete oxidation of glucose typically involves which three stages? a. photosynthesis, fermentation, and oxidation b. glycolysis, Krebs cycle, and the electron transport chain c. substrate phosphorylation, pentose phosphate shunt, and the Calvin cycle d. chemiosmosis, photophosphorylation, and reduction
b. glycolysis, Krebs cycle, and the electron transport chain
Microorganisms that catabolize sugars into ethanol and Hydrogen gas would most likely be categorized as _______________. a. aerobic respirers. b. heterolactic fermenters. c. alcohol fermenters. d. anaerobic respirers. e. homolactic fermenters.
b. heterolactic fermenters.
According to the animation, oxidative phosphorylation a. is an anabolic process. b. is a catabolic process. c. requires a net input of energy. d. makes larger compounds from smaller ones
b. is a catabolic process.
All of the following pairs are correctly matched except __________. a. metabolic pathways; sequences of chemical reactions b. oxidation; reaction where electrons are gained c. catabolism; breakdown of organic compounds d. metabolism; sum of all chemical reactions e. anabolism; building of complex molecules
b. oxidation; reaction where electrons are gained
NADH molecules formed during glycolysis and in the Krebs cycle are __________. a. transported out of the cell during oxidative phosphorylation b. oxidized when electrons are passed to the electron transport chain c. oxidized when electrons are passed to NADP+ d. stored in the mitochondria e. oxidized when electrons are needed in anabolic pathways
b. oxidized when electrons are passed to the electron transport chain.
What is the final electron acceptor in the electron transport chain? a. NAD+ b. oxygen c. cyt a d. FMN
b. oxygen
Carbon fixation occurs during __________. a. the complete oxidation of glucose b. photosynthesis c. fermentation d. anaerobic respiration
b. photosynthesis
Glycolysis literally means _____________. a. sugar producing. b. sugar splitting. c. Embden-Meyerhof. d. energy producing.
b. sugar splitting.
During the light-independent reactions of photosynthesis, organisms __________. a. use molecular oxygen to produce ATP b. synthesize sugars
b. synthesize sugars
All of these statements are true of plasmids EXCEPT: a. they can be transferred between bacteria during conjugation. b. they are essential for survival of the organism in most situations. c. they may contain antibiotic resistance genes. d. they are small, circular molecules of DNA that can carry genes for heavy metal resistance. e. they may encode genes that enhance the pathogenicity of an organism.
b. they are essential for survival of the organism in most situations.
What is the purpose of DNA replication? a. to make an RNA molecule b. to make an identical copy of DNA c. to synthesize a protein d. to generate mutations
b. to make an identical copy of DNA
Your lab partner has mixed a dead tryptophan+ strain of Bacillus subtilis with a live tryptophan- strain and observes that her B. subtilis culture is now tryptophan+. The most likely explanation for this is __________. a. conjugation b. transformation c. specialized transduction d. mutation e. generalized transduction
b. transformation
Which of the following situations does not result in a breakdown of the proton gradient? a. Cyanide poisoning b. Uncoupling proteins c. Oxygen deprivation
b. uncoupling proteins
Fermentations differ from anaerobic respiration in all of the following ways EXCEPT that fermentation does NOT________. a. oxidize glucose b. use the electron transport chain c. require molecular oxygen d. oxidize NADH
b. use an electron transport chain
Which group of organisms has members representing each of the following nutritional classifications: chemoheterotrophs, chemoautotrophs, photoheterotrophs, and photoautotrophs?
bacteria
What is the consequence of a missense mutation? a. A missense mutation could lead to a shift in the reading frame of the mRNA. b. A missense mutation introduces a stop codon into an open reading frame. c. A missense mutation leads to the incorporation of the wrong amino acid into the protein. d. A missense mutation has no effect on the amino acid sequence of the protein.
c. A missense mutation leads to the incorporation of the wrong amino acid into the protein.
Which of the following would you predict to be a feedback inhibitor of the glycolytic enzyme phosphofructokinase? a. FAD b. ADP c. ATP d. NAD+ e. fructose
c. ATP
Which of the following are products of the light-dependent reactions, on which the light-independent reactions are dependent? a. O2 and ATP b. glucose and O2 c. ATP and NADPH d. O2 and NADPH
c. ATP and NADPH
What is the function of GTP? a. An electron carrier b. A scaffolding for carbon atoms c. An energy carrier d. An oxidizer to produce CO2
c. An energy carrier
What is the function of GTP? a. electron carrier b. A scaffolding for carbon atoms c. An energy carrier d. An oxidizer to produce CO2
c. An energy carrier
Where does the energy required for anabolic reactions come from? a. Heat b. Unused energy from metabolism c. Catabolic reactions
c. Catabolic reactions
Which of the following correctly matches enzyme components with their correct definition and/or function? a. Apoenzymes are the nonprotein component of an enzyme. b. Apoenzymes are typically inorganic molecules, such as iron, zinc, or magnesium. c. Coenzymes are the organic cofactors important to enzyme activity. d. Cofactors are the protein components of enzymes.
c. Coenzymes are the organic cofactors important to enzyme activity.
How does cyanide poisoning result in the decrease of ATP production? a. Cyanide permanently oxidizes cytochrome a3, preventing other components to change into the reduced state. This causes the proton gradient to break down, stopping ATP synthesis. b. Cyanide uncouples the proton gradient from the process of ATP synthesis. c. Cyanide permanently reduces cytochrome a3, preventing other components to change into the oxidized state. This causes the proton gradient to break down, stopping ATP synthesis. d. Cyanide permanently binds to oxygen, preventing its use as the final electron acceptor.
c. Cyanide permanently reduces cytochrome a3, preventing other components to change into the oxidized state. This causes the proton gradient to break down, stopping ATP synthesis.
Which of these statements is NOT true of translation? a. A single mRNA may have several ribosomes attached. b. A molecule of tRNA can bind to both an mRNA molecule and an amino acid. c. Each amino acid is coded for by a single codon. d. Three different nonsense codons code for termination of protein synthesis. e. The "language" of nucleotides is changed to the "language" of amino acids.
c. Each amino acid is coded for by a single codon.
Why does FADH2 yield less ATP than NADH? a. FADH2 electrons ultimately do not go to oxygen. b. FADH2 binds directly to the ATP synthase enzyme. c. FADH2 electrons enter the electron transport chain at a lower energy level. d. Electrons from FADH2 cannot pump hydrogen ions out of the cell.
c. FADH2 electrons enter the electron transport chain at a lower energy level.
For the peptide with the amino acid sequence, proline-alanine-glycine (pro-ala-gly), the DNA template strand could have the sequence __________. a. CCG GCC GGG b. GGC CGA CCG c. GGU CGA CCA d. CGC GCC GGA e. CCU GCC GGC
c. GGU CGA CCA
Which of the following statements about fermentation is true? a. It allows the electron transport chain to continue in the absence of oxygen. b. It provides additional protons to allow the electron transport chain to continue. c. It is an alternative way to return electron carriers to their oxidized state. d. It is an alternative way for a cell to produce oxygen.
c. It is an alternative way to return electron carriers to their oxidized state.
Which of the following correctly describes the lac operon? a. It is an inducible operon that is turned on in the presence of glucose. b. It is repressible operon that is turned on in the presence of lactose. c. It is an inducible operon that is turned on if lactose is present and glucose is absent. d. It is a constitutive operon that is unaffected by the presence of lactose.
c. It is an inducible operon that is turned on if lactose is present and glucose is absent.
What is the fate of the NAD+ newly regenerated by fermentation? a. It is converted into an organic acid. b. It is oxidized into carbon dioxide. c. It returns to glycolysis to pick up more electrons. d. It is converted into ethanol.
c. It returns to glycolysis to pick up more electrons.
Iron is considered an essential element for many bacteria. Based on the animation, how would lack of iron affect energy production of a bacterium? a. Lack of iron would not have any affect on this system. b. Lack of iron would mean that most of the oxygen could be reduced to form water, improving energy yields. c. Lack of iron would mean lack of heme, and thus lower amounts of functioning cytochrome proteins. This would mean lower energy yields.
c. Lack of iron would mean lack of heme, and thus lower amounts of functioning cytochrome proteins. This would mean lower energy yields
Which of the following can be used as a final electron acceptor for aerobic respiration? a. Carbonate ion b. Sulfate ion c. Molecular oxygen d. Nitrate ion, sulfate ion and carbonate ion can all be used as a final electron acceptor. e. Nitrate ion
c. Molecular oxygen
What is meant by substrate-level phosphorylation? a. Production of ATP using energy from a proton gradient b. Reduction of NAD+ to NADH c. Production of ATP by transferring phosphates directly from metabolic products to ADP d. Splitting of glucose into two pyruvic acid molecules
c. Production of ATP by transferring phosphates directly from metabolic products to ADP
How does the proton gradient help ATP synthase to make ATP? a. Protons move along the membrane. b. Protons move from inside the membrane to outside the membrane. c. Protons move from outside the membrane to inside the membrane. d. Protons are not involved with this step; only electrons are.
c. Protons move from outside the membrane to inside the membrane.
Based on the concept map only, which of the following is most likely to be true of microbial metabolism? a. The energy from 2 ATP is necessary to drive the electron transport chain. b. Acetyl-CoA is produced by substrate-level phosphorylation. c. The Krebs cycle produces molecules necessary for function of the electron transport chain. d. Acetyl-CoA is converted directly into 2 ATP
c. The Krebs cycle produces molecules necessary for function of the electron transport chain.
If high amounts of sulfanilamide are in the presence of an enzyme whose substrate is PABA, what outcome is expected? a. PABA products will increase in concentration. b. The substrate will destroy the inhibitor. c. The enzyme will stop functioning. d. Sulfanilamide products will be in higher concentration.
c. The enzyme will stop functioning.
How does a noncompetitive inhibitor reduce an enzyme's activity? a. The inhibitor degrades the enzyme. b. The inhibitor degrades the enzyme's normal substrate. c. The inhibitor binds to the enzyme in a location other than the active site, changing the shape of the active site. d. The inhibitor inactivates the enzyme.
c. The inhibitor binds to the enzyme in a location other than the active site, changing the shape of the active site.
What is the driving force of energy production in steps 6 and 7? a. The energy potential of a proton gradient b. The reduction of three-carbon compounds c. The oxidation of three-carbon compounds d. The reduction of NAD+ to NADH
c. The oxidation of three-carbon compounds
Which step involves the release of carbon dioxide? a. The first and eighth steps b. The second step c. The third and fourth steps d. The seventh step
c. The third and fourth steps
How many molecules of ATP can be generated from one molecule of NADH? a. Four b. One c. Three d. Two
c. Three
You are analyzing a segment of DNA and observe an area of sequence that appears to act as a promoter element. Based on this, what can you conclude? a. You have found the end of a gene. b. You have found a place where DNA replication begins. c. You have found the beginning of a gene. d. You have found an anticodon.
c. You have found the beginning of a gene.
The chemical reaction involved in synthesizing proteins and cell wall peptidoglycan are examples of _________ reactions. a. photosynthetic b. autotrophic c. anabolic d. catabolic
c. anabolic
Like glucose, amino acids are catabolized for energy, but these must be converted to a form where they can enter the Krebs cycle for oxidation. All of the following reactions occur in the catabolism of amino acids EXCEPT __________. a. dehydrogenation b. decarboxylation c. carbon fixation d. deamination
c. carbon fixation
Organisms that use carbon dioxide as a carbon source and energy sources such as ammonia or hydrogen sulfide are called __________. a. photoautotrophs b. chemoheterotrophs c. chemoautotrophs d. saprophytes e. photoheterotrophs
c. chemoautotrophs
A coenzyme assists an enzyme by accepting or donating matter. What does NAD+ transfer? a. phosphate groups b. CoA c. electrons d. ATP e. acetyl groups
c. electrons
Which one molecule could provide the carbon source, the energy source, and the electron source for a chemoheterotroph? a. carbon dioxide b. sulfur c. glucose d. nitrogen e. ATP
c. glucose
The use of amino acids to make proteins a. is a completely efficient reaction. b. involves the production of ATP. c. is an example of anabolism. d. is an example of catabolism.
c. is an example of anabolism.
In metabolism, energy that is not used _________. a. is stored in the form of ATP. b. is used to break down large molecules into smaller ones. c. is given off as heat. d. is used to build up large compounds from smaller ones.
c. is given off as heat.
Using the genetic code in your textbook, determine the polypeptide encoded by the RNA sequence AUGUUUCUUUAA. a. asp-lys-phe b. phe-lys-lys-his c. met-phe-leu d. tyr-lys-glu-ile
c. met-phe-leu
The major source of the genetic diversity among microorganisms upon which natural selection operates is __________. a. conjugation b. transduction c. mutation d. transformation
c. mutation
Which of the following four stages of glucose oxidation requires molecular oxygen? a. Krebs cycle b. glycolysis c. oxidative phosphorylation d. production of acetyl CoA
c. oxidative phosphorylation
If a cell is starved for ATP, which of the following pathways would most likely be shut down? a. glycolysis b. Krebs cycle c. pentose phosphate pathway d. Krebs cycle and glycolysis
c. pentose phosphate pathway
In the figure, the path labeled (2) is the flow of a. glucose. b. electrons. c. protons. d. water. e. energy.
c. protons.
Which of the following mechanisms does not generate ATP using an electron transport chain? a. aerobic respiration b. photophosphorylation c. substrate-level phosphorylation d. anaerobic respiration
c. substrate-level phosphorylation
During an oxidation reaction, a. the acceptor molecule gains an electron and becomes oxidized. b. the acceptor molecule loses an electron and becomes oxidized. c. the donor molecule loses an electron and becomes oxidized. d. the donor molecule gains an electron and becomes oxidized.
c. the donor molecule loses an electron and becomes oxidized.
The complete oxidation (catabolism) of glucose typically involves three stages. The greatest amount of ATP is produced in which stage? a. glycolysis b. Krebs cycle c. the electron transport chain d. photosynthesis
c. the electron transport chain
Which means of genetic transfer among bacteria involves a virus? a. transformation b. mutation c. transduction d. conjugation
c. transduction
Nitrobacter bacteria use carbon dioxide for their carbon source and nitrate ions as an energy source. This organism is a _________.
chemoautotroph
Refer to the figure. In aerobic respiration, where is water formed? a b c d e
d
Assume a cell is grown in a culture medium containing radioactively labeled thymidine. After three cell divisions, what percentage of the cells would contain the radioactive label? a. 0% b. 87.5% c. 50% d. 100%
d. 100%
A new antibiotic is produced that inhibits the synthesis of acetyl-CoA and the electron transport chain in bacteria. For each glucose molecule that is metabolized, how many fewer ATP molecules will be produced? a. 34 b. 38 c. 2 d. 36 e. 4
d. 36
What is the intermediate product formed by pyruvic acid during alcoholic fermentation? a. Lactic acid b. Ethanol c. Formic acid d. Acetaldehyde e. Carbon dioxide
d. Acetaldehyde
Why might some cells uncouple the electron transport chain? a. A cell does not require ATP. b. Too much ATP is bad for the cell. c. Uncoupling proteins offset the effect of cyanide. d. Cells can use the energy from the proton gradient for functions other than producing ATP, such as heat generation
d. Cells can use the energy from the proton gradient for functions other than producing ATP, such as heat generation
What enables competitive inhibitors to bind to a specific enzyme? a. Competitive inhibitors form unique covalent bonds with enzyme structures. b. Competitive inhibitors cover the entire surface of an enzyme. c. Competitive inhibitors have unique sugars that are attracted to the enzyme. d. Competitive inhibitors have structures that resemble the enzyme's substrate.
d. Competitive inhibitors have structures that resemble the enzyme's substrate.
Which of the following is a bacterium that performs oxygenic photosynthesis? a. Green nonsulfur bacteria b. Purple nonsulfur bacteria c. Green sulfur bacteria d. Cyanobacteria e. Purple sulfur bacteria
d. Cyanobacteria
Which enzyme breaks the hydrogen bonds during replication? a. Stabilizing proteins b. ATP c. Replication fork d. DNA helicase
d. DNA helicase
What occurs at the bridge step? a. The formation of oxaloacetate b. The formation of succinyl CoA c. The production of GTP d. Decarboxylation of pyruvic acid
d. Decarboxylation of pyruvic acid
What occurs at the bridge step? a. The formation of oxaloacetate b. The formation of succinyl CoA c. The production of GTP d. Decarboxylation of pyruvic acid
d. Decarboxylation of pyruvic acid
What is meant by the statement "Enzymes are biological catalysts"? a. Enzymes are products of biological systems. b. Enzymes produce biological organisms. c. Enzymes produce products useful for biology. d. Enzymes speed up the chemical reactions in living cells.
d. Enzymes speed up the chemical reactions in living cells.
Which step is the step for which glycolysis is named? a. First b. Second c. Third d. Fourth e. Fifth f. Sixth
d. Fourth
At the doctor's office, the doctor drains the abscess and takes a sample for culturing. She also prescribes some broad-spectrum antibiotics to treat the obvious infection. A couple days later, the doctor tells Sam that his wound contained a number of bacteria including Pasteurella multocida. When the dog bit Sam's arm P. multocida entered the wound and started to establish an infection. In order to do so, the bacteria have to grow, which requires energy. One of the most common energy sources used by bacteria is glucose. Why is glucose such a good source of energy for bacteria? a. Glucose contains six oxygen atoms, which can be used for oxidative phosphorylation and the generation of many ATP molecules. b. Glucose contains six carbon atoms, which can be quickly incorporated into organic cellular constituents needed for growth. c. Glucose is a highly oxidized compound, containing many carbon-hydrogen bonds and a lot of potential energy. d. Glucose is a highly reduced compound, containing many carbon-hydrogen bonds and a lot of potential energy.
d. Glucose is a highly reduced compound, containing many carbon-hydrogen bonds and a lot of potential energy.
In which direction does the replication fork move? a. It moves ahead of the unzipped DNA. b. It moves from the double-stranded DNA to the single-stranded DNA. c. It moves towards the stabilizing proteins. d. It moves ahead of the newly synthesized DNA.
d. It moves ahead of the newly synthesized DNA.
All of these statements are true about DNA replication EXCEPT: a. DNA polymerase is required to add new nucleotides to the growing ends of the DNA strands. b. RNA polymerase synthesizes the primers. c. DNA ligase joins the small DNA fragments of the lagging strand. d. Only one strand of the parent DNA serves as a template for a newly synthesized complementary strand.
d. Only one strand of the parent DNA serves as a template for a newly synthesized complementary strand.
Which of the following is needed as a reactant for the first step of the citric acid cycle? a. Malic acid b. Succinyl CoA c. Citric acid d. Oxaloacetic acid
d. Oxaloacetic acid
What carbon molecules remain at the end of glycolysis? a. Dihydroxyacetone phosphate (DHAP) b. Glucose c. Glyceraldehyde 3-phosphate (G3P) d. Pyruvic acid
d. Pyruvic acid
What ensures that the single strands of DNA do not come back together? a. The replication fork b. ATP c. DNA helicase d. Stabilizing proteins
d. Stabilizing proteins
Where does the energy come from to power the formation of GTP? a. Water b. NADH c. ATP d. Succinyl CoA
d. Succinyl CoA
Why is reduction the term used to describe the gain of an electron? a. The electron acceptor gets smaller. b. The number of molecules in the reaction decreases. c. The amount of energy in the molecule decreases. d. The electron acceptor's net charge decreases.
d. The electron acceptor's net charge decreases
Which of these answers is NOT true for positive (direct) selection? a. The selective medium is designed so that only the mutant cells grow on that medium. b. The mutant will grow on the selective medium, so there is no need for replica plating. c. An example would be the detection of bacteria resistant to ampicillin by incorporation of ampicillin into the plating medium. d. The procedure detects altered genotypes regardless of the phenotype. It enables detection of a rare mutant from a population containing an extremely large number of bacteria.
d. The procedure detects altered genotypes regardless of the phenotype.
What is the fate of metabolites during respiration? a. They are oxidized completely to form pyruvic acid. b. They are reduced to from NADH and FADH2. c. They are rearranged to form GTP. d. They are oxidized completely to carbon dioxide and water
d. They are oxidized completely to carbon dioxide and water
What is the fate of metabolites during respiration? a. They are oxidized completely to form pyruvic acid. b. They are reduced to from NADH and FADH2. c. They are rearranged to form GTP. d. They are oxidized completely to carbon dioxide and water
d. They are oxidized completely to carbon dioxide and water.
According to the animation, what does oxygen get reduced to at the end of the electron transport chain? a. Electrons b. ATP c. NADH d. Water e. Protons
d. Water
Which of the following can cause changes in a sequence of several amino acids? a. a missense mutation b. a nonsense mutation c. a base substitution d. a frameshift mutation
d. a frameshift mutation
Some amino acids are synthesized by adding an amine group to pyruvic acid or to one of the Krebs cycle intermediates. This process is known as __________. a. hydrolysis b. carbon fixation c. catabolism d. amination
d. amination
Which of the following terms refers to pathways that can function both in anabolism and catabolism? a. chemiosmotic pathways b. homolactic fermentation pathways c. light-dependent pathways d. amphibolic pathways
d. amphibolic pathways
Which of the following requires cell-to-cell contact? a. transformation b. mutation c. transduction d. conjugation
d. conjugation
All of the following are required for the generation of ATP by chemiosmosis EXCEPT __________. a. formation of a proton motive force b. use of proton flow by ATP synthase c. passage of electrons through electron carrier chains d. conversion of pyruvic acid to lactic acid e. active transport of protons across a phospholipid membrane
d. conversion of pyruvic acid to lactic acid
One of the sites of allosteric regulation of the Krebs cycle is the conversion of pyruvic acid to acetyl CoA. Which of the following conditions would you expect to inhibit the conversion of pyruvic acid to acetyl CoA? a. low ATP and low NADH b. low ATP and high NADH c. high ADP and low NADH d. high ATP and high NADH e. high ATP and low NADH
d. high ATP and high NADH
Which of the following is not a step in translation? a. transport of amino acids by tRNA's b. pairing of codons with anticodons c, peptide bond formation d. joining of the Okazaki fragments e. initiation at the AUG start codon
d. joining of the Okazaki fragments
Lipases break down___________. a. carbohydrates. b. proteins. c. nucleic acids. d. lipids.
d. lipids.
Cyanobacteria are a type of a. chemoheterotroph. b. chemoautotroph. c. photoheterotroph. d. photoautotroph.
d. photoautotroph.
All of the following are potential end-products of fermentations except __________. a. ethanol b. lactic acid c. carbon dioxide d. pyruvic acid e. acetic acid
d. pyruvic acid
During the light-independent reactions of photosynthesis, organisms __________. a. use molecular oxygen to produce ATP b. ferment glucose c. produce molecular oxygen d. synthesize sugars
d. synthesize sugars
Fatty acids are oxidized in _________________. a. the pentose phosphate pathway. b. glycolysis. c. the Entner-Doudoroff pathway. d. the Krebs cycle. e. the electron transport chain.
d. the Krebs cycle
Which of the following processes directly produce the most ATP? a. the Krebs cycle b. Glycolysis c. synthesis of acetyl-CoA d. the electron transport chain
d. the electron transport chain
For the amino acid aspartic acid (asp), __________. a. the sequence of the DNA template would be CAG b. the corresponding tRNA would have the anticodon CTA c. the corresponding tRNA would have the anticodon GAC d. the sequence of the DNA template would be CTG e. the sequence of the DNA template would be GAC
d. the sequence of the DNA template would be CTG
A bacterial culture grown in a glucose-peptide medium causes the pH to increase. The bacteria are most likely a. fermenting the glucose. b. not growing. c. oxidizing the glucose. d. using the peptides.
d. using the peptides.
In the figure, where is ATP produced? a b c d e
e.
All of the following steps are involved in the aerobic electron transport chain. Which step happens last? a. NADH is oxidized. b. Protons move to the outside of the membrane. c. Electrons flow between membrane-bound electron carriers. d. NAD+ is formed. e. Electrons are transferred to O2.
e. Electrons are transferred to O2.
Which one of the following would be the most likely to yield a recombinant cell after mating? Which of these statements is not true of translation? a. F+ cell and F- cell Three different nonsense codons code for termination of protein synthesis. b. Hfr cell and F+ cell The "language" of nucleotides is changed to the "language" of amino acids. c. F- cell and F+ cell A single mRNA may have several ribosomes attached. d. A molecule of tRNA can bind to both an mRNA molecule and an amino acid. e. Hfr cell and F- cell Each amino acid is coded for by a single codon.
e. Hfr cell and F- cell Each amino acid is coded for by a single codon.
According to the animation, which compounds provide electrons to the system? a. FADH2 b. NADH c. Water d. Oxygen e. NADH and FADH2
e. NADH and FADH2
Which step(s) of the Krebs cycle does (do) not produce any usable energy? a. The sixth step b. The fifth step c. The first and eighth steps d. The third step e. The second and seventh steps
e. The second and seventh steps
Consider the polypeptide sequence encoded by the following DNA: TAC AAA GAA ATT. If base number 6 is changed to G, how will this affect the polypeptide? a. One amino acid will be changed. b. A nonsense mutation will result in premature termination of the polypeptide. c. A frameshift mutation will result. d. Translation will stop. e. There will be no change in the polypeptide.
e. There will be no change in the polypeptide.
Competitive inhibition of enzyme action involves __________. a. destruction of the enzyme substrate b. irreversible binding to the enzyme active site c. competition for binding at the enzyme allosteric site d. alteration of the enzyme's active site e. competition with the substrate for binding at the active site
e. competition with the substrate for binding at the active site
Unlike eukaryotes, in prokaryotes chemiosmosis __________. a. does not require ATP synthase b. electrons are eventually passed to organic molecules instead of inorganic acceptors c. moves iron instead of protons across the membrane d. does not require a membrane
e. occurs at the plasma membrane and not the mitochondria
Heterotrophs use organic molecules as energy and carbon sources. To produce 5-carbon intermediates needed for synthesis of nucleic acids, the cell utilizes the __________. a. cyclic photophosphorylation pathway b. glycolytic pathway c. Krebs cycle d. mixed acid fermentation pathway e. pentose phosphate pathway
e. pentose phosphate pathway
When the antibiotic chloramphenicol binds to the 50S portion of the ribosome, the effect is to __________. a. prevent peptide bond formation b. prevent tRNAs from binding to amino acids c. prevent RNA processing d. prevent transcription e. stop the ribosome from moving along the mRNA strand
e. stop the ribosome from moving along the mRNA strand
All of these statements are true of base substitutions EXCEPT __________. a. can result in the production of a shortened protein b. may be caused by radiation or chemical mutagens c. may cause no change in the protein encoded by the affected gene d. may be beneficial if the affected gene encodes an enzyme with enhanced activity e. mutations rarely involve base substitutions
mutations rarely involve base substitutions
Oxygen is bound to H+ and electrons, producing H2O in the final reaction of ______.
oxidative phosphorylation
Which of the following four stages of glucose oxidation requires molecular oxygen?
oxidative phosphorylation
Carbon fixation occurs during_________.
photosynthesis
A frameshift mutation in a gene encoding a protein usually __________.
results in the production of a nonfunctional peptide
Both transcription and DNA replication involve __________.
synthesis using a DNA template
During the light-independent reactions of photosynthesis, organisms __________.
synthesize sugars
The complete oxidation (catabolism) of glucose typically involves three stages. The greatest amount of ATP is produced in which stage?
the electron transport chain
In the lac operon of E. coli, __________.
the repressor protein binds to the operator in the absence of lactose
The Ames test is used __________. a. to determine if a chemical is mutagenic and possibly carcinogenic
to determine if a chemical is mutagenic and possibly carcinogenic
Transcription begins __________.
when RNA polymerase binds to the DNA at a site called the promoter
Auxotrophs __________.
will not grow on a plate that lacks the growth factor, but will grow on a complete medium that contains the growth factor
