Exam 3 Practice Qs - Bio 2212
For glycolysis to begin: - there must be an input of energy from ATP - glucose must enter the mitochondria - oxygen must be available - some hydrogen acceptors must be available
there must be an input of energy from ATP
The conversion of 1 mol of pyruvate to 3 mol of CO2 via pyruvate dehydrogenase and the citric acid cycle also yields _____ mol of NADH, _____ mol of FADH2, and _____ mol of ATP (or GTP). - 3; 1; 1 - 2; 2; 2 - 4; 1; 1 - 4; 2; 1
4; 1; 1 1 mol NADH produced during pyruvate oxidation and 3 moles during citric acid cycle (one cycle)
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? - 8% - 16% - 42% - 58%
8%
Which of the following combinations of base pairs will be found in a molecule of DNA? - A + C = G + T - G + C = T + A - A = G and C = T - A = C
A + C = G + T
Which of the following properties is associated with a cyclin-dependent kinase (Cdk)? - A Cdk is inactive, or "turned off," in the presence of a cyclin - A Cdk is an enzyme that attaches phosphate groups to other proteins - The number of Cdk molecules increases during the S and G2phases and decrease during M - A Cdk is an enzyme that catalyzes the attachment of kinetochores to microtubules
A Cdk is an enzyme that attaches phosphate groups to other proteins
Which of the following statements best explains why photosynthesis using C4 or CAM systems may be described as a metabolic compromise? - The CAM pathway allows more CO2 into the plant but also increases the rate of water loss - Both pathways minimize photorespiration but also expend more ATP in the process of carbon fixation - The C4 pathway decreases water loss but also increases the rate of photorespiration - Both pathways increase the rate of photosynthesis but also increase the rate of water loss
Both pathways minimize photorespiration but also expend more ATP in the process of carbon fixation
Which of the summary statements below best describes the results of the following reaction? C6H12O6 + 6O2 —> 6CO2 + 6H2O + Energy - CO2 is reduced and O2 is oxidized - O2 is oxidized and H20 is reduced - C6H12O6 is oxidized and O2 is reduced - O2 is reduced and CO2 is oxidized
C6H12O6 is oxidized and O2 is reduced
A typical eukaryotic cell has enough available ATP to meet its needs for about 30 seconds. What is likely to happen to an individual when they exhaust their ATP supply? - Anabolic processes will be activated to produce new mitochondria - The athlete will have to sit down and rest - ATP will be transported into the cells from the circulatory system - Catabolic processes will be activated to generate additional ATP
Catabolic processes will be activated to generate additional ATP
Which of the following molecules is maintained at a relatively constant level throughout the cell cycle but requires a cyclin to become catalytically active? - PDGF - Cdk - MPF - cyclin
Cdk
ATTEMPT 2 QUESTION 8 ADD PHOTO In which cell of the accompanying figure would elevated oxygen concentrations have the greatest inhibitory effect on carbon fixation reactions? - Cell 1 only - Cell 2 only - Neither cell 1 nor cell 2 - Both cell 1 and cell 2
Cell 2 only
Which of the following effects might be caused by reduced or very little active telomerase activity? - Cells age and begin to lose function - Cells may become cancerous - Telomere lengthens in germ cells - Cells maintain normal functioning
Cells age and begin to lose function
What is the name of the microtubule-organizing center found in animal cells as an identifiable structure present during all phases of the cell cycle? - centriole - centrosome - kinetochore - centromere
Centrosome
ATTEMPT 3 QUESTION 17 ADD PHOTO The accompanying figure shows the absorption spectrum for chlorophyll aand the action spectrum for photosynthesis. Which of the following statements best explains the low rate of photosynthesis at 550 nm? - Chlorophyll a does not absorb 550 nm light well - Other photosynthetic pigments absorb light in addition to chlorophyll a - Green and yellow wavelengths inhibit the absorption of red and blue wavelengths - Oxygen given off during photosynthesis interferes with the absorption of light
Chlorophyll a does not absorb 550 nm light well
What two components constitute an active MPF? - cyclin and tubulin - a growth factor and mitotic factor - cyclin and a cyclin-dependent kinase - ATP synthetase and a protease
Cyclin and a cyclin-dependent kinase
What cellular conditions favor increased activity of the electron transport chain and oxidative phosphorylation? - High ADP concentrations - High NAD+concentrations - Low NADH concentrations - Low oxygen concentrations
High ADP concentrations
At what stage of the cell cycle is the cyclin component of MPF destroyed? - in early G2 - at mid-S phase - in late M - in late G1
In late M
If an animal cell suddenly loses the ability to produce GTP, what will most likely happen to its signaling system? - It will not be able to activate receptor tyrosine kinases - It will use ATP instead of GTP to activate G proteins on the cytoplasmic side of the plasma membrane - It will not be able to activate G proteins on the cytoplasmic side of the plasma membrane - It will be able to carry out reception and transduction but would not be able to respond to a signal
It will not be able to activate G proteins on the cytoplasmic side of the plasma membrane
Which of the following molecules triggers the cell's passage past the G2 checkpoint into mitosis? - Cdk - MPF - cyclin - PDGF
MPF
Where is the Krebs cycle carried out in eukaryotic cells? - Inner membrane of the mitochondria - Mitochondrial matrix - Nucleus - Cytosol
Mitochondrial matrix
Depletion of which of the following molecules from the mitochondria will most directly inhibit the citric acid cycle? - CO2 - NAD+ - NADH - ATP
NAD+
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is: - O2 - water - NAD+ - pyruvate
O2
Which of the following statements best explains why testosterone, a lipid-soluble signaling molecule that crosses the membranes of all cells, affects only target cells? - Only target cells possess the cytosolic enzymes that transduce the signal from testosterone to adenylyl cyclase - Only target cells contain the intracellular receptors for testosterone - Only target cells retain the appropriate genes regulated by testosterone - Testosterone initiates a phosphorylation cascade only in target cells
Only target cells contain the intracellular receptors for testosterone
If yeast cells of mating type α with normal mating factor receptors are genetically modified to produce only mating factor a, they will mate with which of the following cells? - only normal mating type a cells - only normal mating type α cells - only with each other - only normal mating type α cells, or with each other
Only with each other
Which of the following statements best describes the effect of a mutation that alters the structure of the a factor so that it no longer binds to the corresponding receptor on α cells? - The a cells will fail to initiate the shape changes necessary for mating after binding α factor - The α cells will fail to initiate the shape changes necessary for mating - The α cells will fail to secrete the α factor - The a cells will mate with other a cells rather than α cells
The α cells will fail to initiate the shape changes necessary for mating
Which of the following describes the function of the pigment molecules in a light-harvesting complex in the thylakoid membranes? - They split water and release oxygen from the reaction-center chlorophyll - They absorb and transfer light energy to the reaction-center chlorophyll - They transfer electrons to NADP+ - They synthesize ATP from ADP and Pi
They absorb and transfer light energy to the reaction-center chlorophyll
The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis. About 10% of Springer spaniels suffer from canine PFK deficiency. Dogs affected with this disorder most likely display which of the following symptoms? - They carry out elevated levels of oxidative phosphorylation - They are lethargic and readily tire from exercise - They constantly have low blood sugar - They die as embryos
They are lethargic and readily tire from exercise
Why are carbohydrates and fats frequently considered high-energy foods? - They contain many electrons associated with hydrogen atoms - They are strong oxidizing molecules - They contain no nitrogen atoms - They contain many oxygen atoms
They contain many electrons associated with hydrogen atoms
Which of the following statements best explains the ability of CAM plants to synthesize sugars in the daytime while keeping their stomata closed to reduce water loss? - They fix CO2 into sugars in the bundle-sheath cells - They fix CO2 into pyruvate in the mesophyll cells - They fix CO2 into organic acids during the night - They use photosystem 1 and photosystem 2 at night
They fix CO2 into organic acids during the night
Why do neurons and some other specialized cells divide infrequently? - They have entered into G0 - They no longer produce MPF - They can no longer degrade cyclins - They no longer have active nuclei
They have entered into G0
In a diploid cell with four chromosome pairs (2n = 8), how many sister chromatids will be found in a nucleus at prophase of mitosis? - 16 - 4 - 32 - 8
16
How many ATP molecules (net yield) are produced per molecule of glucose degraded during glycolysis? - 2 - 4 - 36 - 38
2
To break down a glucose molecule completely, how many "turns" of the Krebs cycle are required? - 2 - 1 - 3 - 4
2
Glycolysis results in the net production of which of the following sets of molecules per glucose molecule? - 6 CO2, 2 pyruvate, and 2 ATP - 2 NAD+, 2 pyruvate, and 2 ATP - 2 NADH, 2 pyruvate, and 2 ATP - 4 NADH, 2 pyruvate, and 4 ATP
2 NADH, 2 pyruvate, and 2 ATP
If there are 40 centromeres in a cell at anaphase of mitosis, how many chromosomes will be found in each daughter cell following cytokinesis? - 80 - 40 - 20 - 10
20
Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration? - 2 - 4 - 30-32 - 18-24
30-32
For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle (see the accompanying figure)? - 4 - 6 - 2 - 32
4
A loss of function of Apaf1, the human homologue of ced-4 in nematodes, is most likely to result in which of the following? - extensive tissue damage due to excess apoptosis - excess activation of the human analog of the ced-3 protease - activation of a developmental pathway found in the nematode but not in humans - a form of cancer in which normal apoptosis fails
a form of cancer in which normal apoptosis fails
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely ________. - an animal cell in anaphase of mitosis - a plant cell in the process of cytokinesis - a plant cell in metaphase of mitosis - an animal cell in the process of cytokinesis
a plant cell in the process of cytokinesis
The oxygen consumed during cellular respiration is directly involved in which of the following processes or events? - the oxidation of pyruvate to acetyl CoA - the citric acid cycle - glycolysis - accepting electrons at the end of the electron transport chain
accepting electrons at the end of the electron transport chain
Which of the following events characterizes the beginning of anaphase? - attachment of sister chromatids to each other by cohesin - disappearance of the nuclear membrane - enzymatic cleavage of cohesin - loss of kinetochores from the chromatids
enzymatic cleavage of cohesin
Which of the following processes is driven by the free energy released as electrons move through photosystem II and I in the thylakoid membranes? - establishment of a proton gradient - synthesis of ATP through substrate-level phosphorylation - excitement of electrons in the reaction center of photosystem I - phosphorylation of NAD+ to NADPH
establishment of a proton gradient
Which of the following occurs during apoptosis? - lysis of the cell - direct contact between signaling cells - fragmentation of the DNA - release of proteases outside the cell
fragmentation of the DNA
In mechanism, photophosphorylation is most similar to: - substrate-level phosphorylation in glycolysis - oxidative phosphorylation in cellular respiration - carbon fixation - reduction of NADP+
oxidative phosphorylation in cellular respiration
Most plants and animals use __________ as their final hydrogen acceptor in cellular respiration. - oxygen - sulfur - nitrogen - magnesium
oxygen
The energy used to generate most of the ATP formed in aerobic respiration is released when electrons are passed from NADH to: - FADH - CO2 - acetyl-CoA - oxygen
oxygen
Which of the following enzymes essentially reverses the reaction catalyzed by adenylyl cyclase? - phosphorylase - phosphodiesterase - protein kinase - protein phosphatase
phosphodiesterase
An inhibitor of which of the following enzymes could be used to block the release of calcium from the endoplasmic reticulum? - serine/threonine kinases - phosphodiesterase - phospholipase C - adenylyl cyclase
phospholipase C
In mitochondria, exergonic redox reactions: - are the source of energy driving prokaryotic ATP synthesis - provide the energy that establishes the proton gradient - reduce carbon atoms to carbon dioxide - are coupled via phosphorylated intermediates to endergonic processes
provide the energy that establishes the proton gradient
If fermentation follows glycolysis, - the two NADH molecules produced during glycolysis will (depending of the organism) be used to reduce pyruvate to either lactate or ethanol and CO2 - CO2 will be one of the products as pyruvate is converted to lactate - ATP will be required to convert pyruvate to either lactate or ethanol and CO2 - oxidative phosphorylation occurs either on the plasma membrane or on derivatives on the plasma membrane
the two NADH molecules produced during glycolysis will (depending of the organism) be used to reduce pyruvate to either lactate or ethanol and CO2
Which of the following statements best describes the function of the α factor secreted by yeast cells? - It binds to receptors on a cells to stimulate mating between a cells - It binds to receptors on α cells to stimulate mating between α cells - It binds to receptors on α cells to stimulate mating between a cells and α cells - It diffuses through the membranes of a cells, binds to DNA and initiates transcription of a factor genes
It binds to receptors on α cells to stimulate mating between acells and α cells
How does the enzyme telomerase meet the challenge of replicating the ends of linear chromosomes? - It catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replication without telomerase activity - It causes specific double-strand DNA breaks that result in blunt ends on both strands - It adds a single 5' cap structure that resists degradation by nucleases - It adds numerous GC pairs, which resist hydrolysis and maintain chromosome integrity
It catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replication without telomerase activity
Which answer best describes the role of telomerase in replicating the ends of linear chromosomes? - It adds a 5' cap structure to the chromosome ends that resists degradation by nucleases - It catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replication without telomerase activity - It adds numerous GC pairs, which resist hydrolysis and maintain chromosome integrity - It causes specific double-strand DNA breaks that result in blunt ends on both strands
It catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replication without telomerase activity
Which of the following statements best describes the electron transport chain? - it is driven by ATP hydrolysis - it consists of a series of redox reactions - it occurs in the cytoplasm of both prokaryotic and eukaryotic cells - it includes a series of hydrolysis reactions associated with mitochondrial membranes
It consists of a series of redox reactions
Which of the following events would be most likely to produce cells with several nuclei? - multiple S phases without mitosis - repeated cytokinesis without mitosis - repeated mitosis without cytokinesis - repeated mitosis with simultaneous cytokinesis
Repeated mitosis without cytokinesis
Which of the following events occurs during interphase of the cell cycle? - separation of the spindle poles - replication of the DNA - condensation of the chromosomes - spindle formation
Replication of the DNA
The generation of hydrogen ion concentration gradients across the membranes of mitochondria produces ATP by means of: - ATP synthases - glycolytic pathways - hydrogen pumps - phosphate pumps
ATP synthases
In the absence of oxygen, yeast cells can obtain energy by fermentation, which results in the net production of which of the following sets of molecules? - ATP, CO2, and ethanol - ATP, CO2, and acetyl CoA - ATP, NADH, and ethanol - ATP, CO2, and lactate
ATP, CO2, and ethanol
Which of the following statements best describes a typical cAMP-mediated signal transduction event? - A hormone activates the second messenger by directly binding to it - Adenylyl cyclase is activated after the hormone binds to the cell and before phosphorylation of proteins occurs - The second messenger is the last part of the system to be activated - The second messenger amplifies the hormonal response by attracting more hormones to the cell being affected
Adenylyl cyclase is activated after the hormone binds to the cell and before phosphorylation of proteins occurs
Which of the following statements is a correct distinction between autotrophs and heterotrophs? - Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic - Only heterotrophs require chemical compounds from the environment - Cellular respiration is unique to heterotrophs - Only heterotrophs have mitochondria
Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic
Binding of epinephrine to its receptor results in which of the following events? - A decrease in blood glucose levels - Stimulation of glycogen synthesis - Elevation of cytosolic concentrations of cyclic AMP - Inhibition of glycogen phosphorylase
Elevation of cytosolic concentrations of cyclic AMP
The oxygen released by photosynthesis is produced by which of the following processes? - the electron transfer system of photosystem 2 - chemiosmosis - the electron transfer system of photosystem 1 - splitting water molecules
Splitting water molecules
Which of the following molecules best describes the primary form in which plants stockpile extra sugar produced by photosynthesis? - cellulose - starch - sucrose - glucose
Starch
In which cellular structure are enzymes of the Calvin cycle localized? - interior of the thylakoid (thylakoid space) - outer membrane of the chloroplast - stroma of the chloroplast - thylakoid membrane
Stroma of the chloroplast
Which of the following processes would be most directly affected if a thylakoid membrane is punctured so that the interior of the thylakoid is no longer separated from the stroma? - synthesis of ATP - flow of electrons from photosystem 2 to photosystem 1 - reduction of NADP+ - splitting of water
Synthesis of ATP
In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which of the following atoms or molecules of the last nucleotide in the polymer? - the 3' OH - C6 - the 5' phosphate - a nitrogen from the nitrogen-containing base
The 3' OH
Yeast growing in a medium containing glucose are moved to a medium without glucose but containing acetyl-CoA. Which of the following is the most likely effect on the amount of ATP and CO2 yeast cells will be able to produce with only acetyl-CoA as a fuel source versus glucose as the fuel source? - The amount of ATP produced per fuel molecule will decrease, but the amount of CO2 produced per fuel molecule will increase - The mount of both ATP and CO2 produced per fuel molecule will increase - The amount of ATP produced per fuel molecule will increase, but the amount of CO2 produced per fuel molecule will decrease - The amount of both ATP and CO2 produced per fuel molecule will decrease
The amount of both ATP and CO2 produced per fuel molecule will decrease
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol prevents microtubule depolymerization, which interferes with which of the following processes? - chromosome condensation - cytokinesis - chromosome separation - centriole duplication
chromosome separation
The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin B? - spindle formation - spindle attachment to kinetochores - cell elongation during anaphase - cleavage furrow formation and cytokinesis
cleavage furrow formation and cytokinesis
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the: - oxidation of glucose and other organic compounds - flow of electrons down the electron transport chain - concentration gradient across the membrane holding ATP synthase - transfer of phosphate to ADP
concentration gradient across the membrane holding ATP synthase
Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of which of the following molecules? - adenylyl cyclase - cAMP - phosphorylated proteins - activated G proteins
-cAMP
For a glucose molecule which is completely oxidized during the process of cellular respiration, what is the correct sequence of series of reactions? 1 = glycolysis, 2 = electron transport chain, 3 = Krebs cycle - 1 --> 3 --> 2 - 1 --> 2 --> 3 - 2 --> 1 --> 3 - 3 --> 1 --> 2
1 --> 3 --> 2
In a diploid cell with 5 chromosome pairs (2n = 10), how many centromeres will be found in a nucleus at G2 of the cell division cycle? - 40 - 10 - 5 - 20
10
Substrate-level phosphorylation accounts for approximately what percent of the ATP formed by the reactions of glycolysis? - 2% - 0% - 100% - 38%
100%
Which of the following properties is associated with a cyclin-dependent kinase (Cdk)? - The number of Cdk molecules increases during the S and G2 phases and decrease during M - A Cdk is an enzyme that attaches phosphate groups to other proteins - A Cdk is an enzyme that catalyzes the attachment of kinetochores to microtubules - A Cdk is inactive, or "turned off," in the presence of a cyclin
A Cdk is an enzyme that attaches phosphate groups to other proteins
Some cases of human melanoma have been shown to result from inhibition of apoptosis in these cells. The human analogue of which of the following defects in C. elegans could cause these cancers? - A ced-3 protein that is always inactive - A ced-9 protein that is always inactive - A ced-4 protein that is always inactive - A death-signaling molecule receptor that is always active
A ced-4 protein that is always inactive
Not all intercellular signals require transduction. Which one of the following signals may be processed without transduction? - a lipid-soluble signal - a signal that is weakly bound to a nucleotide - a signal that binds to the extracellular matrix - a signal that binds to a receptor in the cell membrane
A lipid-soluble signal
The light reactions supply the Calvin cycle with: - CO2 and ATP - ATP and NADPH - H2O and NADPH - light energy
ATP and NADPH
The light reactions supply the Calvin cycle with: - light energy - CO2 and ATP - H2O and NADPH - ATP and NADPH
ATP and NADPH
The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis and is inhibited by high levels of which of the following molecules? - AMP and ATP - ATP and citrate - citrate and CO2 - glucose and NAD+
ATP and citrate
The enzymes of the citric acid cycle are inhibited by: - acetyl-CoA and fructose 6-phosphate - AMP and/or NADH - ATP and/or NAD+ - ATP and/or NADH
ATP and/or NADH
Which of the following is not true of the citric acid cycle? - All enzymes of the cycle are located in the cytoplasm, except succinate dehydrogenase, which is bound to the inner mitochondrial membrane - In the presence of malonate, one would expect succinate to accumulate - Oxaloacetate is used as a substrate but is not consumed in the cycle - Succinate dehydrogenase channels electrons directly into the electron transfer chain
All enzymes of the cycle are located in the cytoplasm, except succinate dehydrogenase, which is bound to the inner mitochondrial membrane
Exposing inner mitochondrial membranes to ultrasonic vibrations will fragment the membranes and pieces will reseal "inside out" to form small vesicles. The fact that these vesicles can transfer electrons from NADH to oxygen and synthesize ATP suggests that which of the following components must be present? - all the electron transport system and the proteins that add CoA to acetyl groups - only the ATP synthase system - only the electron transport system - all the electron transport system and ATP synthase
All the electron transport system and ATP synthase
High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. Citric acid binds to the enzyme at a different location than the active site. This is an example of which of the following? - the specificity of enzymes for their substrates - positive feedback regulation - allosteric regulation - competitive inhibition
Allosteric regulation
During which phase of mitosis do the chromatids become chromosomes? - anaphase - metaphase - telophase - prophase
Anaphase
Which of the following statements best describes density-dependent inhibition? - As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor - As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing - As cells become more numerous, the level of waste products increases, which slows metabolism and inhibits growth - As cells become more numerous, they begin to squeeze against each other, restricting their size
As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing
Many G protein-coupled receptors contain seven transmembrane α-helical domains. If the amino terminus of such a protein is located on the extracellular side of the membrane, where would a coupled G protein most likely interact with this receptor? - at the loop between helix 5 and helix 6 - along the exterior margin - at the carbonyl end - at the amino end
At the loop between helix 5 and helix 6
A student isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture? - DNA polymerase - DNA ligase - Okazaki fragments - primase
DNA ligase
In bacteria, which of the following proteins is responsible for removing nucleotides from the RNA primer that is used for initiation DNA synthesis? - DNA ligase - DNA pol 3 - Primase - DNA pol 1
DNA pol 1
In E. coli, which enzyme catalyzes the elongation of a new DNA strand in the 5' → 3' direction? - helicase - DNA ligase - DNA polymerase 3 - primase
DNA polymerase 3
What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized? - The origins of replication occur only at the 5' end - Helicases and single-strand binding proteins work at the 5' end - DNA polymerase can join new nucleotides only to the 3' end of a pre-existing strand, and the strands are antiparallel - DNA ligase works only in the 3' --> 5' direction
DNA polymerase can join new nucleotides only to the 3' end of a pre-existing strand, and the strands are antiparallel
After DNA replication, the resulting daughter DNA double helix contains one strand of the original parental DNA and one new strand. What is the explanation for this phenomenon? - DNA replication is semiconservative - RNA synthesis is conservative - DNA replication is conservative - DNA replication is not conservative
DNA replication is semiconservative
New biosensors, applied like a temporary tattoo to the skin, can alert endurance athletes that they are about to "hit the wall" and will find it difficult to continue exercising. These biosensors monitor lactate present in sweat during strenuous exercise. Which of the statements below best explains the use of lactate as an indicator of exercise capacity? - During anaerobic respiration, lactate levels increase when muscles cells need more energy; however, muscles cells eventually fatigue, thus athletes should modify their activities to increase aerobic respiration - During aerobic respiration, muscle cells cannot produce enough lactate to fuel muscle cell contractions, and muscles begin to cramp, thus athletic performance suffers - During anaerobic respiration, muscle cells receive too little oxygen and begin to convert lactate to pyruvate (pyruvic acid), thus athletes experience cramping and fatigue - During aerobic respiration, muscles cells produce too much lactate, which causes a rise in the pH of the muscle cells, thus athletes must consume increased amounts of sports drinks, high in electrolytes, to buffer the pH
During anaerobic respiration, lactate levels increase when muscles cells need more energy; however, muscles cells eventually fatigue, thus athletes should modify their activities to increase aerobic respiration
Cell A has half as much DNA as cells B, C, and D in a mitotically active tissue. Cell A is most likely in: - G1 - G2 - prophase - metaphase
G1
Which of the following statements best describes the relationship between an enzyme and its function? - kinase: addition of a tyrosine - phosphodiesterase: removal of phosphate groups - adenylyl cyclase: conversion of cAMP to AMP - GTPase: hydrolysis of GTP
GTPase: hydrolysis of GTP
In the process of cellular respiration, what is consumed and what is produced? - water is consumed and ATP is produced - glucose is consumed and carbon dioxide is produced - carbon dioxide is consumed and water is produced - ATP is consumed and oxygen is produced - oxygen is consumed and glucose is produced
Glucose is consumed and carbon dioxide is produced
Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells? - Enzymatic activity was proportional to the amount of calcium added to a cell-free extract - Receptor studies indicated that epinephrine was a ligand - Glycogen breakdown was observed only when epinephrine was administered to intact cells - Glycogen breakdown was observed only when epinephrine and glycogen phosphorylase were mixed
Glycogen breakdown was observed only when epinephrine was administered to intact cells
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? - the electron transport chain - reduction of pyruvate to lactate - glycolysis - the citric acid cycle
Glycolysis
Which of the following sequences correctly represents the flow of electrons during photosynthesis? - NADPH --> O2 --> CO2 - H2O --> NADPH --> Calvin Cycle - H2O --> photosystem 1 --> photosystem 2 - NADPH --> electron transport chain --> O2
H2O --> NADPH --> Calvin Cycle
Certain receptor tyrosine kinases (RTKs) that promote excessive cell division are found at high levels in various cancer cells. HER2 is an RTK that is present at excessively high levels in some breast cancer cells. Herceptin is a protein that binds to HER2 and inhibits cell division. Herceptin may be an effective treatment for breast cancer treatment under which of the following conditions? - If the patient's cancer cells have excessive levels of HER2 - If the patient has excessive levels of other RTKs in cancer cells - If the patient lacks functional HER2 proteins - If injection of HER2 in the patient's cancer cells inhibits cell division
If the patient's cancer cells have excessive levels of HER2
How is photosynthesis similar in C4 plants and CAM plants? - In both cases, only photosystem I is used - Both types of plants make sugar without the Calvin cycle - In both cases, rubisco is not used to fix carbon initially - Both types of plants make most of their sugar in the dark.
In both cases, rubisco is not used to fix carbon initially
In which reactions of cellular respiration does substrate-level phosphorylation occur? - only in glycolysis - in both glycolysis and the citric acid cycle - only in the citric acid cycle - only in the electron transport chain
In both glycolysis and the citric acid cycle
What is the effect of increased levels of hydrogen ions in the intermembrane space of the mitochondria? - Increased ATP production - Increased levels of water in intermembrane space - Decreased levels of oxidative phosphorylation - Decreased levels of chemiosmosis
Increased ATP production
If the proteins of the electron transport chain were labeled with a fluorescent tag, the fluorescence observed by microscopy will be localized to which of the following regions of the mitochondria? - outer membrane - inter membrane space - matrix - inner membrane
Inner membrane
Where is the oxidative phosphorylation carried out in eukaryotic cells? - Nucleus - Mitochondrial matrix - Inner membrane of the mitochondria - Cytosol
Inner membrane of the mitochondria
Which of the following statements best would best explain the inability of an animal cell to reduce the Ca2+ concentration in its cytosol? - Insufficient amounts of ATP are present in the cytosol - Excessive amounts of calcium are transported from the cytosol into the endoplasmic reticulum - Insufficient numbers of protein kinases are present in the cell - The calcium-gated ion channels in the cell membrane are inactive
Insufficient amounts of ATP are present in the cytosol
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? - It joins Okazaki fragments together - It unwinds the parental double helix - It stabilizes the unwound parental DNA - It synthesizes RNA nucleotides to make a primer
It joins Okazaki fragments together
Which of the following statements best describes how a reducing agent in is chemically altered in a biological redox reaction? - It loses a hydrogen atom and gains potential energy - It gains a hydrogen atom and loses potential energy - It gains a hydrogen atom and gains potential energy - It loses a hydrogen atom and loses potential energy
It loses a hydrogen atom and loses potential energy
Which of the following statements describes what happens to a molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction? - It gains electrons and gains potential energy - It gains electrons and loses potential energy - It loses electrons and loses potential energy - It loses electrons and gains potential energy
It loses electrons and loses potential energy
How does the toxin of Vibrio cholerae cause profuse diarrhea? - It signals IP3 to act as a second messenger for the release of calcium - It modifies a G protein involved in regulating salt and water secretion - It modifies adenylyl cyclase and triggers excess formation of cAMP - It modifies a ligand-gated ion channel
It modifies a G protein involved in regulating salt and water secretion
ATTEMPT 2 NUMBER 4 ADD PHOTO Which of the following statements best describes the accompanying figure? - It represents an adaptation that maximizes photorespiration - It represents a C3 photosynthetic system - It represents a C4 photosynthetic system - It represents a CAM photosynthetic system
It represents a C4 photosynthetic system
Upon completion of the citric acid cycle, most of the energy originally stored in each glucose molecule catabolized by cellular respiration is stored in which of the following molecules? - NADH - CO2 - ATP - Acetyl-CoA
NADH
What products of glucose oxidation are essential for oxidative phosphorylation? - Acetyl CoA - Pyruvate - NADPH and ATP - NADH and FADH2
NADH and FADH2
Which of the following molecules is the final electron acceptor for electrons from photosystem I? - Chlorophyll in photosystem 2 - NADP+ - Oxygen - Carbon dioxide
NADP+
Which of the following molecules is the primary reducing agent in the Calvin cycle reactions? - NADPH - NADP+ - NADH - ATP
NADPH
Which of the following processes is driven by chemiosmosis? - ATP hydrolysis - substrate-level phosphorylation - oxidative phosphorylation - reduction of NAD+ to NADH
Oxidative phosphorylation
When a glucose molecule loses a hydrogen atom in an oxidation-reduction reaction, the glucose molecule is: - an oxidizing agent - oxidized - hydrolyzed - reduced
Oxidized
Which of the following molecules is released by platelets in the vicinity of an injury? - PDGF - MPF - Cdk - cyclin
PDGF
A type of localized signaling in which a cell secretes a signal molecule that affects neighboring cells is best described as which of the following? - autocrine signaling - cell-cell contact-dependent signaling - paracrine signaling - hormonal signaling
Paracrine signaling
Given what you know about glycolysis and regulation of metabolism by this enzyme, what is the mechanism by which phosphofructokinase activity differs depending on ATP concentration? - Phosphofructokinase is an allosteric enzyme that is inhibited by ADP and stimulated by ATP - Phosphofructokinase is an allosteric enzyme that is inhibited by ATP and stimulated by AMP - Phosphofructokinase is an allosteric enzyme that is inhibited by AMP, ADP, and ATP - Phosphofructokinase is an allosteric enzyme that is stimulated by AMP, ADP, and ATP
Phosphofructokinase is an allosteric enzyme that is inhibited by ATP and stimulated by AMP
ATTEMPT 3 QUESTION 19 ADD PHOTO Considering this graph, under which condition is phosphofructokinase more active? - Phosphofructokinase activity is the same at low and high ATP concentration - Phosphofructokinase is more active at high ATPATP concentration - Phosphofructokinase is more active at low ATPATP concentration
Phosphofructokinase is more active at low ATPATP concentration
ATP is synthesized in plant cells by chemiosmosis in which of the following processes? - photosynthesis only - photosynthesis and cellular respiration - photosynthesis, cellular respiration, and fermentation - cellular respiration only
Photosynthesis and cellular respiration
Which of the following statements best describes the relationship between photosynthesis and cellular respiration? - Photosynthesis is catabolic; cellular respiration is anabolic - Cellular respiration runs the biochemical pathways of photosynthesis in reverse - Photosynthesis stores energy in complex organic molecules; cellular respiration releases energy from complex organic molecules - Photosynthesis occurs only in plants; cellular respiration occurs only in animals
Photosynthesis stores energy in complex organic molecules; cellular respiration releases energy from complex organic molecules
What is the immediate consequence of inhibition of the electron transport chain? - Prevent reduction of oxygen - Prevent reduction of NADH - Prevent oxidation of NAD+ - Prevent oxidation of oxygen
Prevent reduction of oxygen
Which of the following statements accurately describes differences between DNA replication in prokaryotes and DNA replication in eukaryotes? - The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes - Prokaryotic chromosomes have histones, whereas eukaryotic chromosomes do not - Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many - Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many
At which phase of the cell cycle do centrioles begin to move apart in animal cells? - anaphase - prophase - telophase - metaphase
Prophase
Binding of a growth factor to its receptor is most likely to immediately activate which of the following molecules? - cAMP - adenylyl cyclase - protein kinase - phosphorylase
Protein kinase
Activation of which of the following molecules generally requires protein phosphorylation? - ligand-gated ion channels - G protein-coupled receptors - receptor tyrosine kinases - steroid hormone receptors
Receptor tyrosine kinases
Which of the following signal transduction proteins typically functions by forming dimers after binding to a signal molecule? - receptor tyrosine kinases - steroid receptors - G protein-coupled receptors - ligand-gated ion channels
Receptor tyrosine kinases
Which of the following processes occurs in the Calvin cycle? - reduction of NADPH - reduction of CO2 - production of ATP - release of oxygen
Reduction of CO2
Which of the following statements best describes the events of apoptosis? - The cell's DNA and organelles become fragmented, the cell shrinks and forms blebs, and the cell's parts are packaged in vesicles that are digested by specialized cells - The cell dies, it is lysed, its organelles are phagocytized, and its contents are recycled - The cell's nucleus and organelles are lysed, and then the cell enlarges and bursts - The cell's DNA and organelles become fragmented, the cell dies, and it is phagocytized
The cell's DNA and organelles become fragmented, the cell shrinks and forms blebs, and the cell's parts are packaged in vesicles that are digested by specialized cells
Which of the following statements best describes cells in culture that do not exhibit either density-dependent inhibition or anchorage dependence? - The cells follow an altered series of cell cycle phases - The cells have nonfunctional MPF - The cells show characteristics of tumors - The cells are unable to form spindle microtubules
The cells show characteristics of tumors
Which of the following statements describes a likely effect of a drug that inhibits testosterone binding to its receptor in human cells? - The cytosolic levels of cAMP would decrease - The expression of certain genes would increase or decrease - The cytosolic calcium concentration would increase - The activity of G proteins would decrease
The expression of certain genes would increase or decrease
Exposing inner mitochondrial membranes to ultrasonic vibrations will fragment the membranes and pieces will reseal to form small vesicles that contain the intermembrane space. These vesicles can transfer electrons from NADH to oxygen and synthesize ATP. Which of the following statements best describes what will happen to the vesicles when NADH is added? - The inside of the vesicles will become acidic - Protons will be pumped out of the interior of the vesicle to the exterior using energy from ATP hydrolysis - ATP will be produced from ADP and Pi in the interior of the vesicle - The inside of the vesicles will become alkaline
The inside of the vesicles will become acidic
Which of the following statements correctly describes the difference between the leading strand and the lagging strand in DNA replication? - The leading strand is synthesized continuously in the 5'- 3' direction, while the lagging strand is synthesized discontinuously in the 5'- 3' direction - The leading strand is synthesized in the 3'- 5' direction in a discontinuous fashion, while the lagging strand is synthesized in the 5'- 3' direction in a continuous fashion - There are different DNA polymerases involved in elongation of the leading strand and the lagging strand - The leading strand requires an RNA primer, whereas the lagging strand does not
The leading strand is synthesized continuously in the 5'- 3' direction, while the lagging strand is synthesized discontinuously in the 5'- 3' direction
Which of the following statements correctly describes the difference between the leading and the lagging strands of DNA in DNA replication? - The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction - The leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end - The leading strand is synthesized at twice the rate of the lagging strand - The lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together
The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? - The pH of the matrix increases - ATP synthase pumps protons by active transport - The electrons gain free energy - NAD+ is oxidized
The pH of the matrix increases
Researchers found a strain of bacteria that had mutation rates one hundred times higher than normal. Which of the following statements correctly describes the most likely cause of these results? - The proofreading mechanism of DNA polymerase was not working properly - There were one or more base pair mismatches in the RNA primer - The single-strand binding proteins were malfunctioning during DNA replication - The DNA polymerase was unable to add bases to the growing nucleic acid chain
The proofreading mechanism of DNA polymerase was not working properly
What role do phosphatases play in signal transduction pathways? - They activate protein kinases by phosphorylation - They inactivate protein kinases to turn off signal transduction - They transfer a phosphate group from one protein in the pathway to the next molecule in the series - They amplify the second messenger cAMP
They inactivate protein kinases to turn off signal transduction
Which of the following statements best describes steroid receptors? - They are embedded in the plasma membrane - They are typically bound to the external surface of the nuclear membrane - They are lipids or glycolipids - They may be inside the nucleus of a target cell
They may be inside the nucleus of a target cell
In chloroplasts, the photosynthetic electron transport chain acidifies which of the following cellular compartments? - cytosol - mitochondrial matrix - thylakoid space - stroma
Thylakoid space
Protein phosphorylation is commonly involved with which of the following? - ligand binding by receptor tyrosine kinases - activation of G protein-coupled receptors - activation of protein kinase molecules - release of Ca2+ from the ER lumen
activation of protein kinase molecules
Which of the following responses is stimulated by cell signaling the formation of biofilms? - secretion of substances that inhibit growth of foreign bacteria - inhibition of quorum sensing - formation of mating complexes - aggregation of bacteria
aggregation of bacteria
Metaphase is characterized by: - alignment of chromosomes on the equator of the cell - cytokinesis - separation of the centromeres - separation of sister chromatids
alignment of chromosomes on the equator of the cell
What types of cells carry out ATP synthesis by chemiosmosis? - all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors - only animal cells in mitochondria, exclusively using oxygen as the electron acceptor - all cells, both prokaryotic and eukaryotic, exclusively using oxygen as the electron acceptor - only eukaryotic cells, both plant and animal, using either oxygen or other electron acceptors
all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors
Many G protein-coupled receptors contain seven transmembrane α-helical domains. If the amino terminus of such a protein is located on the extracellular side of the membrane, where would you expect to find the carboxyl terminus of the protein? - at the cytosolic surface of the plasma membrane - covalently bound to the amino end of the protein - embedded in the phospholipid bilayer of the membrane - at the exterior surface of the plasma membrane
at the cytosolic surface of the plasma membrane
In the cells of many eukaryotic species, the nuclear envelope has to disappear to permit which of the following events in the cell cycle? - attachment of microtubules to kinetochores - separation of the centrosomes - condensation of the chromosomes - DNA synthesis
attachment of microtubules to kinetochores
A drug could inhibit the release of glucose from liver cells by having which of the following effects on the liver cells? - increasing glycogen phosphorylase activity - activating epinephrine receptors - increasing cAMP production - blocking G protein activity
blocking G protein activity
A protein kinase is an enzyme that functions in which of the following ways? - by serving as a receptor for various signal molecules - by serving as a second messenger molecule - by activating a G protein - by adding a phosphate group to activate or inactivate other proteins
by adding a phosphate group to activate or inactivate other proteins
Consider this pathway: epinephrine --> GPCR --> G protein --> adenylyl cyclase --> cAMP. Identify the second messenger. - cAMP - G protein - GTP - adenylyl cyclase
cAMP
Which of the following occurs during the Calvin cycle? - carbon fixation - reduction of NADP+ - release of oxygen - generation of CO2
carbon fixation
In the cells of some organisms, mitosis occurs without cytokinesis. This will result in: - cells with more than one nucleus - cells that are unusually small - cells lacking nuclei - cell cycles lacking an S phase.
cells with more than one nucleus
A signal transmitted via phosphorylation of a series of proteins is generally associated with which of the following events? - conformational changes to each protein in the series - production of ATP in the process of signal transduction - binding of a hormone to an intracellular receptor - activation of a ligand-gated ion channel
conformational changes to each protein in the series
One difference between cancer cells and normal cells is that cancer cells: - are unable to synthesize DNA - are arrested at the S phase of the cell cycle - continue to divide even when they are tightly packed together - cannot function properly because they are affected by density-dependent inhibition
continue to divide even when they are tightly packed together
The synthesis of ATP by oxidative phosphorylation is an example of which of the following processes? - active transport - a reaction with a positive delta G - coupling of an endergonic reaction to an exergonic reaction - allosteric regulation
coupling of an endergonic reaction to an exergonic reaction
Which of the following molecules is synthesized at specific times during the cell cycle and forms an active complex with a kinase? - MPF - PDGF - Cdk - cyclin
cyclin
The elongation of the leading strand during DNA synthesis: - progresses away from the replication fork - occurs in the 3' --> 5' direction - produces Okazaki fragments - depends on the action of DNA polymerase.
depends on the action of DNA polymerase.
The activation of receptor tyrosine kinases is characterized by: - dimerization and phosphorylation - dimerization and IP3 binding - a phosphorylation cascade - GTP hydrolysis
dimerization and phosphorylation
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to: - disruption of mitotic spindle formation - suppression of cyclin production - myosin denaturation and inhibition of cleavage furrow formation - inhibition of DNA synthesis.
disruption of mitotic spindle formation
When glucose is used as the energy source, the largest amount of ATP is produced in: - substrate-level phosphorylation - electron transfer phosphorylation - the Krebs cycle - glycolysis
electron transfer phosphorylation
In chemiosmosis, the most direct source of energy used to convert ADP + Pito ATP is energy released: - from substrate-level phosphorylation - from movement of protons through ATP synthase, down their electrochemical gradient - as electrons are transported across the inner mitochondrial membrane as electrons flow through the electron transport chain
from movement of protons through ATP synthase, down their electrochemical gradient
Which of the following best predicts the effect of removal of oxygen from a facultative anaerobic organism's environment? - glucose consumption increases, while the growth rate decreases - glucose consumption and the growth rate both increase - glucose consumption decreases, while the growth rate increases - glucose consumption decreases, while the growth rate remains unchanged
glucose consumption increases, while the growth rate decreases
Which of the following sequences describes the path by which electrons travel downhill energetically in aerobic respiration? - glucose → pyruvate → electron transport chain → NADH → ATP - glucose → NADH → electron transport chain → oxygen - food → glycolysis → citric acid cycle → NADH → ATP - glucose → pyruvate → ATP → oxygen
glucose → NADH → electron transport chain → oxygen
In a nucleosome, the DNA is wrapped around: - histones - ribosomes - polymerase molecules - a thymine dimer
histones
Viagra causes dilation of blood vessels and increased blood flow to the penis, which helps to maintain an erection. Viagra acts by inhibiting which of the following events? - hydrolysis of GTP to GDP - hydrolysis of cGMP to GMP - formation of cGMP from GTP - dephosphorylation of cGMP
hydrolysis of cGMP to GMP
Under which conditions will plant cell mitochondria actively oxidize pyruvate and carry out oxidative phosphorylation? - only in cells that store glucose in the form of starch and only in the dark - only in photosynthetic cells in the light, while photosynthesis occurs concurrently - in photosynthesizing cells in the light, and in other cells in the dark - in all cells, with or without light
in all cells, with or without light
Lipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect only target cells because - only target cells retain the appropriate DNA segments - intracellular receptors are present only in target cells - only target cells have enzymes that break down aldosterone - only in target cells is aldosterone able to initiate the phosphorylation cascade that turns genes on
intracellular receptors are present only in target cells
Under Fermentation conditions, muscle cells produce: - ethyl alcohol - lactate - acetaldehyde - pyruvate
lactate
Binding of a signaling molecule to which type of receptor leads directly to a change in the distribution of substances on opposite sides of the membrane? - intracellular receptor - G protein-coupled receptor - phosphorylated receptor tyrosine kinase dimer - ligand-gated ion channel
ligand-gated ion channel
Energy released from the electron transport chain is used to pump H+ ions into which location in eukaryotic cells? - mitochondrial inner membrane - cytoplasm adjacent to the mitochondrial outer membrane - mitochondrial matrix - mitochondrial intermembrane space
mitochondrial intermembrane space
G1 is associated with which of the following cellular events? - break down of the nuclear membrane - normal growth and cell function - the beginning of mitosis - DNA replication
normal growth and cell function
In E. coli, to repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act? - nuclease, DNA polymerase, DNA ligase - nuclease, DNA polymerase, RNA primase - helicase, DNA polymerase, DNA ligase - DNA ligase, nuclease, helicase
nuclease, DNA polymerase, DNA ligase
The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an uncommon base, opposite thymine. What combination of proteins could repair such damage? - nuclease, DNA polymerase, DNA ligase - telomerase, primase, DNA polymerase - telomerase, helicase, single-strand binding protein - DNA ligase, replication fork proteins, adenylyl cyclase
nuclease, DNA polymerase, DNA ligase
The electron transfer chain of cellular respiration is located: - on the inner membrane of mitochondria - on the inner membrane of chloroplasts - on the inner membrane of thylakoids - throughout the cytoplasm of the cell
on the inner membrane of mitochondria
E. coli cells grown on medium are transferred to medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment? - one high-density and one low-density band - one intermediate-density band - one high-density and one intermediate-density band - one low-density and one intermediate-density band
one low-density and one intermediate-density band
Semiconservative replication involves a template. What is the template? - one strand of the DNA molecule - single-stranded binding proteins - DNA polymerase - an RNA molecule
one strand of the DNA molecule
Inhibition of which of the following metabolic pathways would result in a decrease of CO2 production compared to fully functional cellular respiration? - glycolysis and the oxidation of pyruvate to acetyl CoA - fermentation and glycolysis - oxidation of pyruvate to acetyl CoA and the citric acid cycle - oxidative phosphorylation and fermentation
oxidation of pyruvate to acetyl CoA and the citric acid cycle
Within the citric acid cycle, malate dehydrogenase converts malate to oxaloacetate. The reaction utilizes NAD+ from which an NADH molecule is produced. This reaction serves as an example of: - oxidation reduction - combustion - elimination - decarboxylation
oxidation reduction
Inhibition of which of the following processes would reduce or eliminate generation of a proton-motive force in mitochondria? - lowering of pH in the mitochondrial matrix - the reduction of NAD+ by the first electron carrier in the electron transport chain - the flow of protons through ATP synthase down their concentration gradient - pumping of hydrogen ions from the mitochondrial matrix across the inner membrane and into the intermembrane space
pumping of hydrogen ions from the mitochondrial matrix across the inner membrane and into the intermembrane space
The end product of glycolysis is: - pyruvate - citrate - acetyl-CoA - oxaloacetate
pyruvate
What is the oxidizing agent in the following reaction? (charged molecules in parenthesis so charge vs. adding isn't confused) Pyruvate + NADH + (H+) --> Lactate + (NAD+) - oxygen - NADH - lactate - pyruvate
pyruvate
What is the function of the enzyme topoisomerase in DNA replication? - relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix - elongating new DNA at a replication fork by adding nucleotides to the existing chain - reattaching the hydrogen bonds between the base pairs in the double helix - building RNA primers using the parental DNA strand as a template
relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix
Which of the following occurs during S phase? - condensation of the chromosomes - replication of the DNA - separation of sister chromatids - spindle formation
replication of the DNA
The mitotic spindle plays a critical role in which of the following processes? - separation of sister chromatids - splitting of the cell (cytokinesis) following mitosis - triggering the compaction and condensation of chromosomes - dissolving the nuclear membrane
separation of sister chromatids
When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway? - response molecule - relay molecule - signal molecule - transducer
signal molecule
In his work with pneumonia-causing bacteria and mice, Griffith found that: - the protein coat from pathogenic cells was able to transform nonpathogenic cells - heat-killed pathogenic cells caused pneumonia - some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic - the polysaccharide coat of bacteria caused pneumonia.
some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic
The reaction of the citric acid cycle that produces an ATP equivalent (in the form of GTP) by substrate level phosphorylation is the conversion of: - succinyl-CoA to succinate - citrate to isocitrate - fumarate to malate - malate to oxaloacetate
succinyl-CoA to succinate
Most CO2 from catabolism is released during: - glycolysis - the citric acid cycle - lactate fermentation - electron transport
the citric acid cycle
Glycolysis takes place in: - the cytoplasm - mitochondria - chloroplasts - thylakoids
the cytoplasm
The decline of MPF activity at the end of mitosis is due to: - the destruction of the protein kinase Cdk - decreased synthesis of Cdk - the degradation of cyclin - the accumulation of cyclin
the degradation of cyclin
What are telomeres? - the structures that hold two sister chromatids together - enzymes that elongate the DNA strand during replication - the sites of origin of DNA replication - the ends of linear chromosomes
the ends of linear chromosomes
Which of the following events takes place in the electron transport chain? - the breakdown of an acetyl group to carbon dioxide - substrate-level phosphorylation - the harnessing of energy from high-energy electrons derived from glycolysis and the citric acid cycle - the breakdown of glucose into six carbon dioxide molecules
the harnessing of energy from high-energy electrons derived from glycolysis and the citric acid cycle
Which of the following statements best describes why phosphorylation cascades are useful in cellular signal transduction? - they are species specific - they always lead to the same cellular response - they amplify the original signal many times - they counter the harmful effects of phosphatases
they amplify the original signal many times
Which process is more directly driven by light energy? - transfer of energy from pigment molecule to pigment molecule - creation of a pH gradient by pumping protons across the thylakoid membrane - ATP synthesis - reduction of NADP+ molecules
transfer of energy from pigment molecule to pigment molecule
Which process is most directly driven by light energy? - creation of a pH gradient by pumping protons across the thylakoid membrane - reduction of NADP+ molecules - transfer of energy from pigment molecule to pigment molecule - ATP synthesis
transfer of energy from pigment molecule to pigment molecule