Biology-Homework Questions
Which of the following statements describes the function of inositol trisphosphate (IP3) as a second messenger? a. Inositol trisphosphate binds to an IP3-gated calcium channel, causing the release of calcium ions from the endoplasmic reticulum. b. Inositol trisphosphate binds to an IP3-gated calcium channel, causing the uptake of calcium ions from the endoplasmic reticulum. c. IP3 catalyzes the conversion of ATP to cAMP. d. IP3 catalyzes the conversion of cAMP to AMP. e. IP3 activates a G protein. f. IP3 has no effect on cellular calcium concentrations.
a. Inositol trisphosphate binds to an IP3-gated calcium channel, causing the release of calcium ions from the endoplasmic reticulum.
How does adenylyl cyclase help transmit signals within a cell? a. It converts ATP to cAMP, which then broadcasts the signal to the rest of the cell. b. It converts cAMP to ATP, which then broadcasts the signal to the rest of the cell. c. It activates a G protein. d. It deactivates a G protein. e. It binds to a G protein-coupled receptor.
a. It converts ATP to cAMP, which then broadcasts the signal to the rest of the cell.
Which statement correctly describes the difference between alcohol fermentation and lactic acid fermentation? a. Lactic acid fermentation produces lactate, and alcohol fermentation produces ethanol. b. Alcohol fermentation produces lactate, and lactic acid fermentation produces ethanol. c. Only lactic acid fermentation produces NAD+ to facilitate the production of ATP in glycolysis. d. Alcohol fermentation is an aerobic pathway, and lactic acid fermentation is an anaerobic pathway. e. None of the listed responses is correct.
a. Lactic acid fermentation produces lactate, and alcohol fermentation produces ethanol.
What happens during the process of paracrine signaling? a. Numerous cells simultaneously receive and respond to the molecules of growth factor produced by a single cell in their vicinity. b. Communication between adjacent cells occurs between membrane-bound cell-surface molecules. c. Molecules diffuse across the synapse between adjacent nerve cells. d. Specialized cells release hormone molecules, which travel via the circulatory system to other parts of the body, where they reach target cells that can recognize and respond to the hormones.
a. Numerous cells simultaneously receive and respond to the molecules of growth factor produced by a single cell in their vicinity.
Why does testosterone not affect all cells in the body? a. Only certain cells have cytoplasmic receptors for testosterone. b. Only certain cells have membrane receptors for testosterone. c. Testosterone is a local regulator. d. Testosterone binds only to G protein-receptor proteins. e. Testosterone binds only to receptor tyrosine kinases. f. Testosterone binds only to ligand-gated ion channels.
a. Only certain cells have cytoplasmic receptors for testosterone.
All of the processes involved in cellular respiration produce ATP. Which of the following processes produces the most ATP? a. Oxidative phosphorylation b. Glycolysis c. Citric acid cycle d. Substrate-level phosphorylation e. Fermentation
a. Oxidative phosphorylation
Unless the chromosomes were stained to show band patterns, a karyotype would be least likely to show which of the following? a. Part of a chromosome turned around. b. An extra chromosome. c. A large part of a chromosome duplicated. d. A missing chromosome. e. The attachment of a large part of a chromosome to another chromosome.
a. Part of a chromosome turned around.
In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs? a. Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH. b. Pyruvate is reduced and decarboxylated, and the resulting electrons oxidize an NAD+ to an NADH. c. Pyruvate is oxidized and decarboxylated, and the resulting electrons are donated to NADH to produce NAD+. d. Pyruvate is reduced to acetyl-coA, which involves the reduction of pyruvate, the addition of a carbon dioxide from the environment, and its reduction by NADH. e. Pyruvate is ionized directly to acetyl-coA.
a. Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH.
Most of the electrons removed from glucose by cellular respiration are used for which of the following processes? a. Reducing NAD+ to NADH in glycolysis and the citric acid cycle AND producing a proton gradient for ATP synthesis in the mitochondria. b. Reducing NAD+ to NADH in glycolysis and the citric acid cycle c. Producing a proton gradient for ATP synthesis in the mitochondria d. Driving substrate-level phosphorylation in glycolysis c. Producing a proton gradient for ATP synthesis in the mitochondria AND driving substrate-level phosphorylation in glycolysis
a. Reducing NAD+ to NADH in glycolysis and the citric acid cycle AND producing a proton gradient for ATP synthesis in the mitochondria.
Which of the following statements best describes the process of hormonal signaling? a. Specialized cells release hormone molecules, which travel via the circulatory system to other parts of the body, where they reach target cells that can recognize and respond to the hormones. b. Messenger molecules secreted by the signaling cell travel short distances to their target cells. c. Communication between adjacent cells occurs between membrane-bound cell-surface molecules. d. Growth factors stimulate nearby cells to grow and divide. Molecules diffuse across the synapse between adjacent nerve cells.
a. Specialized cells release hormone molecules, which travel via the circulatory system to other parts of the body, where they reach target cells that can recognize and respond to the hormones.
Which choice below is a basic difference between Mendel's particulate hypothesis and the hypothesis of blending inheritance? a. The blending inheritance hypothesis, but not the particulate hypothesis, maintained that after a mating, the genetic material provided by each of the two parents is mixed in the offspring, losing its individual identity. b. All of the listed responses are correct. c. The blending inheritance hypothesis, but not the particulate hypothesis, maintained that the traits governed by genes in the egg are different from the traits governed by genes in the sperm. d. The blending inheritance hypothesis, but not the particulate hypothesis, maintained that mutation is the major source of new gene combinations. e. The blending inheritance hypothesis, but not the particulate hypothesis, maintained that the two alleles at any given locus are always different.
a. The blending inheritance hypothesis, but not the particulate hypothesis, maintained that after a mating, the genetic material provided by each of the two parents is mixed in the offspring, losing its individual identity.
Which of the following events occurs during metaphase of mitosis? a. The chromosomes align along the metaphase plate of the cell. b. The nuclear envelope disappears. c. The chromosomes condense. d. The sister chromatids are pulled apart toward opposite sides of the cell. e. The nuclear envelope forms again. f. The mitotic spindle forms.
a. The chromosomes align along the metaphase plate of the cell
What is a locus? a. The precise location of a gene on a chromosome. b. A structure that appears during prophase I and consists of two paired genes. c. A type of spore made only by fungi. d. A cell with two chromosome sets.
a. The precise location of a gene on a chromosome.
Which of the following events occurs during anaphase of mitosis? a. The sister chromatids are pulled apart toward opposite sides of the cell. b. The chromosomes align along the metaphase plate of the cell. c. The nuclear envelope fragments. d. Spindle fibers attach to the centromeres of the chromosomes. e. The nuclear envelope forms again. f. The mitotic spindle forms.
a. The sister chromatids are pulled apart toward opposite sides of the cell.
Why are most autotrophs referred to as the producers of the biosphere? a. They are the ultimate sources of organic compounds for all nonautotrophic organisms. b. They produce ATP for other organisms. c. They consume other organisms in order to produce organic compounds. d. They produce organic compounds using molecular oxygen. e. All of the listed responses are correct.
a. They are the ultimate sources of organic compounds for all nonautotrophic organisms.
How does carbon dioxide enter the leaf? a. Through the stomata b. Through the chloroplasts c. Through the roots d. Through the thylakoids e. Through the vascular system
a. Through the stomata
Chlorophyll molecules are in which part of the chloroplast? a. Thylakoid membranes b. Stroma c. Stomata d. Plasma membrane e. Thylakoid lumen
a. Thylakoid membranes
A small amount of ATP is made in glycolysis by which of the following processes? a. Transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation b. Harnessing energy from the sun c. Transport of electrons through a series of carriers d. Transfer of electrons and hydrogen atoms to NAD+ e. Attachment of a free inorganic phosphate (Pi) group to ADP to make ATP
a. Transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation
Metabolic pathways are typically redox processes. In photosynthesis, what molecule is oxidized and what molecule is reduced? a. Water is oxidized and carbon dioxide is reduced. b. Carbon dioxide is oxidized and water is reduced. c. G3P is oxidized and ATP is reduced. d. ADP is oxidized and NADPH is reduced. e. Glucose is oxidized and oxygen is reduced. f. Pyruvate is oxidized and NAD+ is reduced.
a. Water is oxidized and carbon dioxide is reduced.
You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark? a. While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation. b. Even though it can't carry out the light reactions, the plant can still produce sugars because the Calvin cycle doesn't require light. c. Even though the plant received no visible light, it was able to use the short-wave part of the electromagnetic spectrum (gamma rays and X-rays) to carry out photosynthesis. d. When light energy is not available, plants can derive energy from inorganic molecules. e. None of the listed responses is correct.
a. While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation.
The region of a chromosome holding the two double strands of replicated DNA together is called __________. a. a centromere b. chromatin c. a centriole d. a chromatid e. an aster
a. a centromere
The life cycle called __________ in plants has two multicellular stages: the __________ and the __________. a. alternation of generations; haploid gametophyte; diploid sporophyte b. alternation of generations; diploid gametophyte; haploid sporophyte c. reduction division; haploid gametophyte; diploid sporophyte d. reduction division; diploid gametophyte; haploid sporophyte e. germ cell production; haploid gametophyte; diploid sporophyte
a. alternation of generations; haploid gametophyte; diploid sporophyte
Sister chromatids differ from nonsister chromatids in that sister chromatids __________. a. are products of the S phase of the cell cycle and are two copies of one chromosome b. always come from nonsister chromatids c. are part of nonhomologous chromosomal sets d. are part of only the maternal set e. are never found in the paternal set
a. are products of the S phase of the cell cycle and are two copies of one chromosome
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called __________. a. chromatin b. a chromatid c. a centromere d. a chromoplast e. a centrosome
a. chromatin
Regardless of whether an organism is an animal, a plant, a fungus, or an algal cell, all zygotes are __________ and are formed during the __________ of two __________ gametes. a. diploid; fertilization; haploid b. haploid; fertilization; diploid c. clones; meiotic division; diploid d. clones; mitotic division; diploid
a. diploid; fertilization; haploid
Cytokinesis refers to __________. a. division of the cytoplasm b. division of the entire cell c. division of the nucleus d. reduction in the number of chromosomes e. movement of a cell from one place to another
a. division of the cytoplasm
Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step __________. a. enables the cell to recycle the reduced NADH to oxidized NAD+ b. removes poisonous oxygen from the environment c. extracts a bit more energy from glucose d. prevents pyruvate from accumulating e. enables the cell to make pyruvate into substances it can use
a. enables the cell to recycle the reduced NADH to oxidized NAD+
The function of cellular respiration is to __________. a. extract usable energy from glucose b. reduce CO2 c. extract CO2 from the atmosphere d. synthesize macromolecules from monomers e. produce carbohydrates
a. extract usable energy from glucose
Allelic variation is an important source of __________ in a population. a. genetic diversity b. clonal diversity c. asexual reproduction d. mitosis
a. genetic diversity
A pair of genetic structures carrying genes that control the same inherited characters are called __________. a. homologous chromosomes b. sister chromatids c. nonsister chromatids d. autosomes e. clones f. zygotes
a. homologous chromosomes
Chromatids are __________. a. identical copies of each other if they are part of the same chromosome b. found only in aberrant chromosomes c. held together by the centrioles d. the bacterial equivalent of eukaryotic chromosomes composed of RNA
a. identical copies of each other if they are part of the same chromosome
Characteristic of the bdelloid rotifer is that it _________ a. is an example of an animal that has not reproduced sexually in 40 million years b. has never experienced genetic diversity c. is more plantlike and therefore undergoes alternation of generation d. produces diploid gametes e. is fungus-like and therefore haploid
a. is an example of an animal that has not reproduced sexually in 40 million years
When a platelet contacts a damaged blood vessel, it is stimulated to release thromboxane A2. Thromboxane A2 in turn stimulates vascular spasm and attracts additional platelets to the injured site. In this example thromboxane A2 is acting as a __________. a. local regulator b. neurotransmitter c. transcription factor d. protein kinase e. G protein
a. local regulator
The spread of cancer cells to other locations in the body is known as __________. a. metastasis b. chemotherapy c. density-dependent inhibition d. transformation e. a benign tumor
a. metastasis
The effect of the environment on a phenotype is referred to as __________. a. multifactorial b. polygenetic c. epistatic d. pleiotropic e. multiple allelic
a. multifactorial
Second messengers tend to be water-soluble and small. This accounts for their ability to __________. a. rapidly move throughout the cell by diffusion b. rapidly cross the plasma membrane c. pass quickly from cell to cell d. move from substrate to substrate during a phosphorylation cascade e. cross the nuclear membrane and interact with DNA
a. rapidly move throughout the cell by diffusion
Checkpoints in the cell cycle control system __________. a. regulate the cell cycle through a variety of stop and go signals b. ensure that a cell keeps dividing c. only stop cells from dividing d. only signal cells to undergo mitosis e. stop cancer cells from dividing
a. regulate the cell cycle through a variety of stop and go signals
Genetic diversity requires __________. a. sexual reproduction, independent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization b. sexual reproduction, nonindependent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization c. sexual reproduction, independent assortment, crossing over between sister chromatids of homologous chromosomes, and nonrandom fertilization d. asexual reproduction, independent assortment, crossing over between sister chromatids of homologous chromosomes, and random fertilization e. asexual reproduction, independent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization
a. sexual reproduction, independent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization
One event occurring during prophase is __________. a. the beginning of the formation of a spindle apparatus b. the synthesis of a new nuclear envelope c. the alignment of chromosomes in a single plane d. cytokinesis e. division of the centromere
a. the beginning of the formation of a spindle apparatus
During binary fission in a bacterium __________. a. the origins of replication move apart b. the two DNA molecules float free in the cell and are guided to daughter cells by a spindle-like apparatus c. the two DNA molecules divide in half, forming four DNA fragments d. the two DNA molecules attach to the centrioles f. the two DNA molecules break up into plasmids
a. the origins of replication move apart
Evidence that cell signaling evolved early in the history of life comes from __________. a. the similarity of the mechanisms in organisms that have a very distant common ancestor b. comparative studies of mitochondrial DNA c. comparative studies of ribosomal RNA d. the fossil record e. the study of protein receptors embedded in the nuclear membrane
a. the similarity of the mechanisms in organisms that have a very distant common ancestor
At the end of mitosis, __________ daughter cells that are genetically __________ are formed, while at the end of meiosis, __________ daughter cells that are genetically __________ are formed. a. two; identical; four; distinct b. four; identical; two; distinct c. four; distinct; two; identical d. two; distinct; four; identical e. two; identical; two; distinct
a. two; identical; four; distinct
Both mitochondria and chloroplasts __________. a. use chemiosmosis to produce ATP b. obtain electrons from water c. reduce NAD+, forming NADP d. release oxygen as a by-product e. are surrounded by a single membrane
a. use chemiosmosis to produce ATP
If a heterozygous plant is allowed to self-pollinate, what proportion of the offspring will also be heterozygous? a. 14 b. 1/2 c. 13 d. 23 e. All of them
b. 1/2
Human blood groups are governed by three alleles, IA, IB, and i. IA and IB are codominant and i is recessive to both. A man who has type B blood and a woman who has type A blood could have children of which of the following phenotypes? a. A, B, or O b. A, B, AB, or O c. AB or O d. A or B only e. AB only
b. A, B, AB, or O
The Calvin cycle could not occur without the light reactions. Which of the following statements describes why this is the case? a. ADP and NADP+ produced in the light reactions provide the energy for the production of sugars in the Calvin cycle. b. ATP and NADPH produced in the light reactions provide the energy for the production of sugars in the Calvin cycle. c. Molecular oxygen produced in the light reactions provides the energy for the production of sugars in the Calvin cycle. d. G3P produced in the light reactions is oxidized in the Calvin cycle. e. RuBP produced in the light reactions facilitates the fixation of carbon from carbon dioxide in the Calvin cycle. f. Photons of light produced in the light reactions provide the energy for the production of sugars in the Calvin cycle.
b. ATP and NADPH produced in the light reactions provide the energy for the production of sugars in the Calvin cycle.
The light reactions of photosynthesis supply the Calvin cycle with __________. a. Light energy. b. ATP and NADPH. c. CO2 and ATP. d. H2O and NADPH. e. Sugar and O2.
b. ATP and NADPH.
Which of the following statements is a correct distinction between autotrophs and heterotrophs? a. Only heterotrophs require chemical compounds from the environment. b. Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic. c. Cellular respiration is unique to heterotrophs. d. Only heterotrophs have mitochondria. e. Only heterotrophs require oxygen.
b. Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.
Of the following, which occurs during the Calvin cycle? a. Light energy is converted to chemical energy. b. CO2 is reduced. c. ATP and NADPH are synthesized. d. Excited electrons are conveyed from chlorophyll to an electron acceptor. e. Photons are absorbed.
b. CO2 is reduced.
Which of the following statements describes what happens to cells undergoing apoptosis? a. Cells undergo lysis. b. Cells shrink and form lobes, which are eventually shed as membrane fragments. c. Cells enter the cell cycle and undergo mitosis. d. An external signal triggers a phosphorylation cascade. e. A hormone triggers the death signal inside the cell. The protein ced-9 remains active.
b. Cells shrink and form lobes, which are eventually shed as membrane fragments.
Fermentation by itself produces no ATP but keeps glycolysis going, which produces a small amount of ATP. How does fermentation do this? a. Fermentation reduces NAD+ to NADH, which facilitates the production of ATP in glycolysis. b. Fermentation oxidizes NADH to NAD+, which facilitates the production of ATP in glycolysis. c. Fermentation oxidizes the carbons in pyruvate to CO2, which is then used in glycolysis. d. Fermentation produces NADH, which fuels the electron transport chain and facilitates chemiosmosis. e. Fermentation produces lactate, which keeps glycolysis going.
b. Fermentation oxidizes NADH to NAD+, which facilitates the production of ATP in glycolysis.
After a signaling molecule binds to a G protein-coupled receptor, what activates the associated G protein? a. GDP displaces GTP on the G protein. b. GTP displaces GDP on the G protein. c. A ligand binds to a receptor tyrosine kinase. d. Receptor tyrosine kinase proteins form a dimer. e. An ion-gated channel opens. f. A hormone binds to an intracellular receptor.
b. GTP displaces GDP on the G protein.
What is the role of oxygen in the electron transport chain? a. It is oxidized with carbon to form CO2. b. It is reduced to form water. c. It is reduced to form CO2. d. It is oxidized to form ADP. e. Oxygen has no role in the electron transport chain.
b. It is reduced to form water.
What effect does ligand binding have on receptor tyrosine kinase proteins? a. Ligand binding causes them to activate a G protein. b. Ligand binding causes them to phosphorylate and form dimers. c. Ligand binding causes them to dephosphorylate and form dimers. d. Ligand binding causes them to open ligand-gated ion channels. e. Ligand binding has no effect on receptor tyrosine kinase proteins. f. Ligand binding causes them to convert ATP to cAMP.
b. Ligand binding causes them to phosphorylate and form dimers.
Testosterone and estrogen are lipid-soluble signal molecules that cross the plasma membrane by simple diffusion. If these molecules can enter all cells, why do only specific cells respond to their presence? a. Nontarget cells possess enzymes that immediately degrade the molecules as they enter the cell. b. Nontarget cells lack the intracellular receptors that, when activated by the signal molecule, can interact with genes in the cell's nucleus. c. Nontarget cells lack the inactive enzymes that the signal molecules activate. d. The signal molecules diffuse from the cell before an effective concentration can be achieved. e. In nontarget cells, these signal molecules cross the membranes of the endoplasmic reticulum and are captured by vesicles.
b. Nontarget cells lack the intracellular receptors that, when activated by the signal molecule, can interact with genes in the cell's nucleus.
Which of the following events does not occur during interphase of the cell cycle? a. Duplication of the chromosomes b. Separation of the sister chromatids c. Growth of the cell d. Production of new mitochondria e. Protein production f. Production of the endoplasmic reticulum
b. Separation of the sister chromatids
Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope? a. Metaphase b. Telophase c. S phase d. Interphase e. Anaphase
b. Telophase
Which of the following statements describes a cell that undergoes mitosis but not cytokinesis? a. The cell has one nucleus. b. The cell contains more than one nucleus. c. The cell does not contain a nucleus. d. The cell has undergone transformation and become a cancer cell. e. The cell has not proceeded through interphase.
b. The cell contains more than one nucleus.
Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes? a. Oxidative phosphorylation b. The citric acid cycle c. Substrate-level phosphorylation d. Glycolysis e. Anabolic pathways
b. The citric acid cycle
Which of the following events does not occur during prophase of mitosis? a. The mitotic spindle forms. b. The mitotic spindle breaks down. c. The chromosomes condense. d. Nucleoli disappear. e. The centrosomes move away from each other. f. Each duplicated chromosome appears as two identical sister chromatids.
b. The mitotic spindle breaks down.
The energy from the electrons in NADH and FADH2 fuel what process in the electron transport chain? a. The movement of H+ through ATP synthase b. The pumping of H+ across the cristae of the mitochondrion c. The oxidation of oxygen d. The electrons in NADH and FADH2 are not involved in the electron transport chain.
b. The pumping of H+ across the cristae of the mitochondrion
The light reactions of photosynthesis use chemiosmosis to produce ATP that will be used in the Calvin cycle. The electrochemical gradient that drives this chemiosmosis is formed across which structure(s)? a. Stroma b. Thylakoid membrane c. Cristae d. Outer membrane of the chloroplast e. Stomata f. Photosystem II
b. Thylakoid membrane
Where do the electrons entering photosystem II come from? Chlorophyll molecules in the antenna complex a. ATP b. Water c. The electron transport chain d. Light e. Chlorophyll molecules in the antenna complex
b. Water
If an organism that is homozygous dominant is crossed with a heterozygote for that trait, the offspring will be __________. a. present in a 9:3:3:1 ratio b. all of the dominant phenotype c. 1/4 of the recessive phenotype d. all homozygous dominant e. all homozygous recessive
b. all of the dominant phenotype
Mendel studied __________, heritable features that vary among individuals; each variant is called a __________. a. traits; character b. characters; trait c. flowers; character d. None of the listed responses is correct. e. characters; flower
b. characters; trait
A red bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red and white hairs. This is an example of genes that are __________. a. epistatic b. codominant c. polygenic d. nonhomologous e. completely dominant
b. codominant
During interphase, the genetic material of a typical eukaryotic cell is __________. a. dispersed in the cytoplasm as long strands of chromatin b. dispersed in the nucleus as long strands of chromatin c. condensed and the chromosomes are often visible under the light microscope d. attached to microtubule spindle fibers e. transported through the nuclear pores
b. dispersed in the nucleus as long strands of chromatin
Achondroplasia, a type of dwarfism, and Huntington's disease are examples of __________, with the exception that the Huntington's allele is __________. a. recessive inherited disorders; lethal b. dominant inherited disorders; lethal c. incomplete dominance; lethal d. dominant inherited disorders; nonlethal e. recessive inherited disorders; nonlethal
b. dominant inherited disorders; lethal
In the overall process of glycolysis and cellular respiration, __________ is oxidized and __________ is reduced. a. oxygen; ATP b. glucose; oxygen c. ATP; oxygen d. carbon dioxide; water e. glucose; ATP
b. glucose; oxygen
A small molecule that specifically binds to a larger molecule is called a(n) __________. a. A protein b. ligand c. protein kinase d. competitive inhibitor e. DAG
b. ligand
The process called __________ reduces the chromosome number by __________. a. mitosis; two consecutive cell divisions b. meiosis; two consecutive cell divisions c. meiosis; dividing without chromosome duplication d. mitosis; dividing without chromosome duplication e. mitosis; destroying one set of information prior to division
b. meiosis; two consecutive cell divisions
The energy used to produce ATP in the light reactions of photosynthesis comes from __________. a. the oxidation of sugar molecules b. movement of H+ through a membrane c. splitting water d. carbon fixation e. fluorescence
b. movement of H+ through a membrane
In liver cells, epinephrine stimulates the breakdown of glycogen. As the signal-transduction pathway progresses, __________. a. the signal is reduced b. the signal is amplified c. the number of molecules involved decreases d. the number of molecules involved remains constant e. glycogenesis is stimulated
b. the signal is amplified
Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________. a. one; diploid b. two; diploid c. two; haploid d. one; haploid e. three; triploid
b. two; diploid
The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from __________. a. carbon dioxide b. water c. glucose d. radioisotopes e. light
b. water
The term "true-breeding plants" means __________. a. that Mendel obtained all of his information from true-breeding plants because they have the strongest character b.. that self-pollinating plants will always produce the same trait of a particular character c. that pea plants will breed only with other pea plants d. that pea plants choose with whom they mate e. that pea plants will produce plants that have a different trait of a particular character
b.. that self-pollinating plants will always produce the same trait of a particular character
The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit? a. 11 b. 22 c. 44 d. 88 e. 132
c. 44
Which of the following statements correctly describes the difference(s) between mitosis and binary fission? a. There are no differences between binary fission and mitosis. b. Binary fission involves the replication and division of multiple chromosomes, whereas mitosis involves the replication and division of a single chromosome. c. Binary fission involves the replication and division of a single chromosome, whereas mitosis involves the division of multiple, replicated chromosomes. d. A cell plate forms across the middle of two cells dividing by binary fission, but this does not occur in mitosis. e. Binary fission in bacteria is completed by microtubules, but mitosis does not involve these structures.
c. Binary fission involves the replication and division of a single chromosome, whereas mitosis involves the division of multiple, replicated chromosomes.
What is the difference between a benign tumor and a malignant tumor? a. Benign tumors arise by transformation; malignant tumors do not. b. Cells of benign tumors metastasize; those of malignant tumors do not. c. Cells of benign tumors do not metastasize; those of malignant tumors do. d. Benign tumors will not kill you; malignant tumors will. e. Benign tumors do not arise by transformation; malignant tumors do.
c. Cells of benign tumors do not metastasize; those of malignant tumors do.
In which part of cell are calcium ions usually found? a. Nucleus b. Golgi apparatus c. Endoplasmic reticulum d. Mitochondrion e. Chloroplast f. Cytosol
c. Endoplasmic reticulum
What is the result when a diploid cell undergoes meiosis? a. Two diploid cells b. Two haploid cells c. Four haploid cells d. Four diploid cells e. Two haploid cells and two diploid cells
c. Four haploid cells
A G protein is active when __________. a. GDP replaces GTP b. it is bound by its ligand and transported to the nucleus c. GTP is bound to it d. it is phosphorylated by a protein kinase e. Ca2+ binds to a G-protein-coupled receptor
c. GTP is bound to it
Which of the following occurs in meiosis, but not mitosis? a. The cells formed have the same combination of genes as found in the initial cell. b. The nuclear envelope disappears. c. Homologous chromosomes separate. d. Sister chromatids undergo disjunction. e. A spindle apparatus forms.
c. Homologous chromosomes separate.
Which of the following is a function of mitosis in humans? a. Production of eggs b. Production of sperm c. Multiplication of body cells d. Decreasing the number of chromosomes e. Increasing genetic variability
c. Multiplication of body cells
During the energy payoff phase of glycolysis, __________. a. glucose is phosphorylated after it is split into two three-carbon molecules b. NADH is produced c. NADH and ATP are produced d. ATP is produced e. glucose is phosphorylated before it is split into two three-carbon molecules
c. NADH and ATP are produced
In a typical pea experiment, two true-breeding plants with distinct traits of a single character are called the __________, and the offspring are called the __________, which will always be __________. a. P (or parental) generation; F2 (or second filial) generation; true breeding b. F1 (or first filial) generation; F2 (or second filial) generation; hybrid c. P (or parental) generation; F1 (or first filial) generation; hybrid d. P (or parental) generation; F1 (or first filial) generation; true breeding e. F1 (or first filial) generation; F2 (or second filial) generation; true breeding
c. P (or parental) generation; F1 (or first filial) generation; hybrid
What is the general name for an enzyme that transfers phosphate groups from ATP to other molecules? a. Ligand-gated ion channel b. G protein c. Protein kinase d. G protein-coupled receptor e. Hormone f. Ligand
c. Protein kinase
Carbon dioxide and oxygen enter and exit a leaf by diffusion. Which structure(s) on a leaf allow(s) this process to happen? a. Chloroplast b. Stem c. Stomata d. Thylakoids e. Stroma f. Granum
c. Stomata
Which part of the catabolism of glucose by cellular respiration requires molecular oxygen (O2) and produces CO2? a. Glycolysis b. The citric acid cycle c. The combination of the citric acid cycle and electron transport d. The electron transport chain e. The combination of glycolysis and the citric acid cycle
c. The combination of the citric acid cycle and electron transport
Which of the following metabolic pathways produce(s) the most ATP, per glucose molecule metabolized, during cellular respiration? a. Glycolysis b. Fermentation c. The electron transport chain and oxidative phosphorylation d. Substrate-level phosphorylation e. Citric acid cycle
c. The electron transport chain and oxidative phosphorylation
The ATP synthase in a human cell obtains energy for synthesizing ATP directly from which of the following processes? a. The oxidation of NADH and FADH2 b. The oxidation of glucose c. The flow of H+ across the inner mitochondrial membrane through the ATP synthase enzyme d. The movement of electrons through a series of carriers e. The reduction of oxygen
c. The flow of H+ across the inner mitochondrial membrane through the ATP synthase enzyme
How does the process of mitosis differ between most eukaryotes and other eukaryotes such as diatoms and dinoflagellates? a. The nuclear envelope remains intact in most eukaryotes but fragments in diatoms and dinoflagellates. b. Microtubules do not facilitate the movement of chromosomes in diatoms and dinoflagellates. c. The nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates. d. The chromosomes are not duplicated prior to mitosis in diatoms and dinoflagellates. e. Sister chromatids are not separated during mitosis in diatoms and dinoflagellates.
c. The nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates.
Which of the following events occurs during prometaphase of mitosis? a. The centrosomes move away from each other. b. The chromosomes align along the metaphase plate of the cell. c. The nuclear envelope fragments. d. The mitotic spindle forms. e. The nuclear envelope forms again. f. The sister chromatids are pulled toward opposite sides of the cell.
c. The nuclear envelope fragments.
Pea plants are tall if they have the genotype TT or Tt, and they are short if they have genotype tt. A tall plant is mated with a short plant. Which outcome below would indicate that the tall parent plant was heterozygous? a. The ratio of tall offspring to short offspring is 3:1. b. All of the offspring are short. c. The ratio of tall offspring to short offspring is 1:1. d. All of the offspring are tall.
c. The ratio of tall offspring to short offspring is 1:1.
What is the total production of ATP, NADH, and FADH2 in the citric acid cycle from one molecule of glucose? a. One ATP, three NADH, and one FADH2 b. Four ATP only c. Two ATP, six NADH, and two FADH2 d. 32 ATP only e. The citric acid cycle does not produce any of these molecules.
c. Two ATP, six NADH, and two FADH2
Which of the following events occurs during telophase of mitosis? a. The nuclear envelope fragments. b. The chromosomes align on the metaphase plate. c. Two distinct daughter nuclei form in the cell. d. The sister chromatids separate. e. The chromosomes condense. f. DNA replicates.
c. Two distinct daughter nuclei form in the cell.
Color in squash is controlled by epistatic interactions in which color is recessive to no color. At the first locus white squash (W) is dominant to colored squash (w). At the second locus yellow (Y) is dominant to green (y). What is the phenotype of a squash with the genotype wwYy? a. White b. Green c. Yellow d. Green with yellow stripes e. White with yellow stripes
c. Yellow
The process of phosphorylation is very important as a cellular mechanism for regulating protein activity. Phosphorylation does this by ___________. a. inactivating proteins b. activating proteins c. activating or inactivating proteins d. opening ligand-gated ion channels e. cell-to-cell recognition f. synaptic signaling
c. activating or inactivating proteins
Somatic cells in humans differs from gametes in that human somatic cells __________. a. are always haploid b. replicate by a process called meiosis c. contain two sets of each of the 23 chromosome types d. are important in sexual reproduction e. do not contain sex chromosomes
c. contain two sets of each of the 23 chromosome types
Observations of cancer cells in culture support the hypothesis that cancer cells __________. a. produce molecules that inhibit the growth factors required for cell division b. exhibit anchorage dependence c. do not exhibit density-dependent inhibition d. spend the majority of their time in the G0 phase e. all of the listed responses are correct
c. do not exhibit density-dependent inhibition
A life cycle in which the only multicellular form is haploid is most typical of __________. a. primates b. plants c. fungi d. protists e. fish
c. fungi
During the energy investment phase of glycolysis, __________. a. glucose is phosphorylated after it is split into two three-carbon molecules b. NADH is produced c. glucose is phosphorylated before it is split into two three-carbon molecules d. ATP is produced e. carbon dioxide is produced
c. glucose is phosphorylated before it is split into two three-carbon molecules
If a plant variety is true-breeding for a dominant trait, then __________. a. if the plant were crossed with a heterozygote, one-half of the progeny would show the dominant trait, and one-half would show the recessive trait b. if the plant were allowed to self-pollinate, the dominant and recessive traits would consistently appear in a 3:1 ratio among the progeny c. if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait d. the plant is heterozygous for the trait e. the variety is unable to mutate
c. if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait
A molecule becomes more oxidized when it __________. a. changes shape b. gains a hydrogen c. loses an electron d. loses a (H+) ion e. loses a hydrogen f. gains an electron
c. loses an electron
Human ABO groups are best described as an example of __________. a. autosomal dominant alleles b. codominant alleles c. multiple alleles d. a pleiotropic effect e. Mendelian dominant and recessive alleles
c. multiple alleles
cAMP usually directly activates __________. a. phosphodiesterase b. receptor tyrosine kinases c. protein kinase A d. G proteins e. adenylyl cyclase
c. protein kinase A
In a phosphorylation cascade, __________ phosphorylate proteins, and __________ dephosphorylate them. a. protein phosphatases; protein kinases b. ligands; ligand-gated ion channels c. protein kinases; protein phosphatases d. G protein-coupled receptors; G proteins e. growth factors; hormones f. cAMPs; adenylyl cyclases
c. protein kinases; protein phosphatases
The stage of cell signaling in which a chemical signal is "detected" when the signaling molecule binds to a receptor protein located at the cell's surface is called __________. a. transduction b. response c. reception d. cell-to-cell recognition e. secretion f. exchange of mating factors
c. reception
Besides the fact that pea plants have a short generation time, the key to Mendel's successful plant-breeding experiments was that pea plants usually __________. a. animal-pollinate b. wind-pollinate c. self-pollinate d. cross-pollinate e. reproduce by making clones
c. self-pollinate
Mendel's law of segregation states that __________. a. non-true-breeding plants can be bred with non-true-breeding plants b. The law of segregation does not apply to pea plants. c. the two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes d. only true-breeding plants can be bred with true-breeding plants e. the two alleles for a heritable character do not segregate during gamete formation and end up in the same gametes
c. the two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes
The light reactions of photosynthesis occur in the __________. a. stroma b. stomata c. thylakoids d. mitochondrion e. inner membrane of the chloroplast
c. thylakoids
In incomplete dominance, the offspring __________. a. will resemble the dominant type 75% of the time b. will resemble the recessive type 50% of the time c. will have an appearance that's intermediate between those of the two parental types d. will resemble the dominant type 50% of the time e. will resemble the recessive type 25% of the time
c. will have an appearance that's intermediate between those of the two parental types
If the two traits that Mendel looked at in his dihybrid cross of smooth yellow peas with wrinkled green peas had been controlled by genes that were located near each other on the same chromosome, then the F2 generation __________. a. would have contained only individuals that were heterozygous at both loci b. None of the listed responses is correct. c. would have deviated from the 9:3:3:1 phenotypic ratio that is d. predicted by the law of independent assortment d. would have contained no individuals that were heterozygous at both loci
c. would have deviated from the 9:3:3:1 phenotypic ratio that is d. predicted by the law of independent assortment
Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid number of 8? a. 2 b. 4 c. 8 d. 16 e. 32
d. 16
A cell contains 40 chromatids at the beginning of mitosis. How many chromosomes will it contain at the completion of cytokinesis? a. 40 b. 80 c. 10 d. 20 e. 160
d. 20
How many chromatids does a human somatic cell contain after interphase and just prior to mitosis? a. 46 b. 23 c. 184 d. 92 e. 22 f. 69
d. 92
Ras, a small G protein located at the plasma membrane, is often mutated in different types of cancer. Ras normally signals to a cell that it should divide. Cancer cells divide uncontrollably. Which of the following changes to Ras would you expect to see in a cancer cell that has mutated Ras present? a. A mutation that leads to Ras being sent to the endomembrane system b. A mutation that means Ras cannot bind to GTP c. A mutation that means GDP is constantly bound to Ras d. A mutation that means Ras cannot hydrolyze GTP to GDP e. A mutation in which Ras cannot bind to its GPCR
d. A mutation that means Ras cannot hydrolyze GTP to GDP
Glucose is the primary fuel for cellular respiration. Which of the following molecules can also be used by cellular respiration to generate ATP? a. Amino acids b. Glycerol c. Fatty acids d. All of the listed responses are correct. e. None of the listed responses is correct.
d. All of the listed responses are correct.
__________ are a group of genetically identical individuals produced by a process called __________. a. Clones; sexual reproduction b. Gametes; meiosis c. Gametes; asexual reproduction d. Clones; asexual reproduction e. Homologs; meiosis
d. Clones; asexual reproduction
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? a. The citric acid cycle b. The electron transport chain c. Synthesis of acetyl CoA from pyruvate d. Glycolysis e. Reduction of pyruvate to lactate
d. Glycolysis
Most of the ATP in cellular respiration is produced by the process of chemiosmosis. How does this process produce ATP? a. Phosphates are stripped from phosphorylated sugars during the energy payoff phase. b. Pyruvate is oxidized, providing energy to add a phosphate to ADP. c. Through substrate-level phosphorylation d. H+ flows across the inner mitochondrial membrane through the enzyme ATP synthase. e. Electrons from NADH and FADH2 are used to add a phosphate to ADP.
d. H+ flows across the inner mitochondrial membrane through the enzyme ATP synthase.
How is nitric oxide different from other signal molecules? a. It binds to a membrane receptor. b. It can phosphorylate cAMP. c. It enters the cell through a ligand-gate ion channel. d. It is a gas. e. It activates a G protein.
d. It is a gas.
Which life cycle stage is found in plants but not animals? a. Gamete b. Zygote c. Multicellular diploid d. Multicellular haploid e. Unicellular diploid
d. Multicellular haploid
After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of __________. a. acetyl CoA b. ATP c. CO2 d. NADH e. FADH2
d. NADH
In what molecule(s) is the majority of the chemical energy from pyruvate transferred during the citric acid cycle? a. ATP b. ADP c. Glucose d. NADH and FADH2 e. Oxygen and carbon dioxide
d. NADH and FADH2
The light reactions of photosynthesis generate high-energy electrons, which end up in __________. The light reactions also produce __________ and __________. a. ATP; NADPH; oxygen b. oxygen; sugar; ATP c. chlorophyll; ATP; NADPH d. NADPH; ATP; oxygen e. water; sugar; oxygen
d. NADPH; ATP; oxygen
How many genes are present in the human genome? a. 23 b. 46 c. Hundreds d. Tens of thousands e. A virtually infinite number
d. Tens of thousands
During the Calvin cycle, what happens during the carbon fixation phase? a. G3P is produced. b. ATP is produced. c. RuBP (ribulose bisphosphate) is regenerated. d. The Calvin cycle incorporates each CO2 molecule, one at a time, by attaching it to a five-carbon sugar named ribulose bisphosphate. e. NADPH is produced. f. Molecular oxygen is produced.
d. The Calvin cycle incorporates each CO2 molecule, one at a time, by attaching it to a five-carbon sugar named ribulose bisphosphate.
What did Sutherland discover about glycogen metabolism in liver cells? a. Glucagon breaks down glycogen to glucose in liver cells. b. The hormone that breaks down glycogen into glucose enters the liver cell. c. Glucose is produced from glycogen when epinephrine binds to a cytoplasmic protein. d. The hormone epinephrine binds to a specific receptor on the plasma membrane of the liver cell. e. A cytoplasmic receptor triggers the signal transduction pathway that produces glucose from glycogen.
d. The hormone epinephrine binds to a specific receptor on the plasma membrane of the liver cell.
Which of the following statements about homologous chromosomes is correct? a. They are found in animal cells but not in plant cells. b. They pair up in prophase II. c. They are found in haploid cells. d. They have genes for the same traits at the same loci. e. They are found in the cells of human females but not in human males.
d. They have genes for the same traits at the same loci.
The F1 generation differed from the F2 in Mendel's experiments in that __________. a. none of the F1 showed the dominant phenotype, but one-half of the F2 did b. all of the F1 showed the dominant phenotype, whereas only half of the F2 did c. all of the F1 showed the dominant phenotype, and all of the F2 showed the recessive phenotype d. all of the F1 showed the dominant phenotype, but only three-fourths of the F2 did e. one-half of the F1 showed the dominant phenotype, and three-fourths of the F2 did
d. all of the F1 showed the dominant phenotype, but only three-fourths of the F2 did
An alternative version of a gene is called a(n) __________. a. character b. phenotype c. generation d. allele e. genotype
d. allele
The function of the mitotic cell cycle is to produce daughter cells that __________. a. have the same number of chromosomes as the parent cell but not the same genetic content b. have a random assortment of maternal and paternal chromosomes c. have the same number of chromatids as the parent cell had chromosomes d. are genetically identical to the parent cell (assuming no mutation has occurred)
d. are genetically identical to the parent cell (assuming no mutation has occurred)
G-protein-linked receptors __________, whereas receptor tyrosine kinases __________. a. act by phosphorylating a protein; open an ion channel when bound to a signal molecule b. are transmembrane proteins; are found only on the cytoplasmic side of the plasma membrane c. form a dimer when activated; catalyze the transfer of a phosphate group from ATP to an amino acid d. phosphorylate the amino acid guanine; phosphorylate the amino acid threonine d. are not enzymes; have enzymatic function
d. are not enzymes; have enzymatic function
The most important role of pigments in photosynthesis is to __________. a. screen out harmful ultraviolet rays b. store energy c. catalyze the hydrolysis of water d. capture light energy e. catalyze the synthesis of ATP
d. capture light energy
In photosynthesis, plants use carbon from __________ to make sugar and other organic molecules. a. water b. chlorophyll c. the sun d. carbon dioxide e. soil
d. carbon dioxide
Darwin realized the importance of heritable variation to evolution __________. a. by studying Gregor Mendel's work b. and incorporated Gregor Mendel's work into his writings c. and incorporated Gregor Mendel's work into his writings without giving Mendel credit for his ideas d. even though he never read any of Gregor Mendel's work
d. even though he never read any of Gregor Mendel's work
You would know a dividing cell was a plant cell rather than an animal cell if you saw that __________. a. it had two pairs of centrioles during prophase b. it had microtubules c. the nucleolus was visible during metaphase d. it had formed a cell plate e. it had formed a cleavage furrow
d. it had formed a cell plate
The major contribution of sex to evolution is that __________. a. it is the only mechanism for species to reproduce b. it provides a way in which somatic mutations can be inherited c. it provides a method to increase genetic variation and it is the only mechanism for species to reproduce d. it provides a method to increase genetic variation e. it is the only mechanism for species to reproduce and it provides a way in which somatic mutations can be inherited
d. it provides a method to increase genetic variation
In meiosis, __________ of __________ cross over and form __________. a. sister chromatids; homologous pairs; chiasmata b. nonhomologs; nonhomologous pairs; cohesion c. nonsister chromatids; nonhomologous pairs; chiasmata d. nonsister chromatids; homologous pairs; chiasmata e. sister chromatids; nonhomologous pairs; chiasmata
d. nonsister chromatids; homologous pairs; chiasmata
In humans, height and skin color have continuous variation in the population because of __________. a. multiple alleles b. epistasis c. incomplete dominance d. polygenic inheritance e. codominance
d. polygenic inheritance
The zipper-like complex that forms in meiosis occurs during __________ and is called the __________. a. metaphase I; synaptonemal complex b. prophase II; meiotic complex c. metaphase II; meiotic complex d. prophase I; synaptonemal complex e. prophase I; centromeric complex
d. prophase I; synaptonemal complex
Certain yeast cells secrete a molecule called the -factor. The purpose of this molecule is to __________. a. kill other yeast cells nearby, which may be competing for access to food b. kill bacteria nearby, which may be competing for access to food c. attract other yeast cells of the same mating type to assemble d. stimulate an a yeast cell to grow toward the cell e. enzymatically process food into a form that can be easily absorbed
d. stimulate an a yeast cell to grow toward the cell
Where does the Calvin cycle of photosynthesis occur? a. Thylakoids b. Granum c. Stomata d. Stroma e. Mitochondrion f. Outer membrane of the chloroplast
d. stroma
DNA replication occurs in __________. a. prophase of both mitosis and meiosis b. metaphase of meiosis only c. the G1 phase of interphase in reproductive cells only d. the S phase of interphase in both somatic and reproductive cells e. the cytokinesis portion of the cell's life cycle
d. the S phase of interphase in both somatic and reproductive cells
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because __________. a. they are species specific b. they always lead to the same cellular response c. they counter the harmful effects of phosphatases d. they amplify the original signal manyfold e. the number of molecules used is small and fixed
d. they amplify the original signal manyfold
In Labrador retrievers, a dog that has the genotype BBee, where BB produces black-pigmented fur and ee produces yellow-pigmented fur, would have __________ fur and would exhibit __________. a. black; dominance b. yellow; incomplete dominance c. brown; codominance d. yellow; epistasis e. brown; epistasis
d. yellow; epistasis
__________ occurs when a single gene affects the phenotype of many characters in an individual. a. Codominance b. Polygenic inheritance c. Incomplete dominance d. Epistasis e. A pleiotropic effect
e. A pleiotropic effect
Which of the following structures is/are part of the mitotic spindle? a. Kinetochore microtubules b. Nonkinetochore microtubules c. The aster d. Centrosome e. All of the listed responses are correct
e. All of the listed responses are correct
Which event or events occur during anaphase? a. The centromeres divide b. The centrioles are at opposite poles c. A spindle made of microtubules is present d. Identical chromatids move to opposite poles e. All of the listed responses are correct.
e. All of the listed responses are correct.
A photosystem consists of which of the following structures? a. Reaction-center complex b. Light-harvesting complexes c. Primary electron acceptor d. Chlorophyll molecules e. All of the listed structures are parts of a photosystem.
e. All of the listed structures are parts of a photosystem.
During aerobic respiration, molecular oxygen (O2) is used for which of the following purposes? a. At the end of glycolysis to oxidize pyruvate b. At the end of the citric acid cycle to regenerate citric acid c. Between glycolysis and the citric acid cycle to split a carbon from pyruvate, producing CO2 d. As a source of O2 in every reaction that produces CO2 e. At the end of the electron transport chain to accept electrons and form H2O
e. At the end of the electron transport chain to accept electrons and form H2O
In which process is glucose oxidized to form two molecules of pyruvate? a. Citric acid cycle b. Fermentation c. Electron transport chain d. Chemiosmosis e. Glycolysis
e. Glycolysis
Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration? a. Oxidation of glucose to pyruvate; reduction of pyruvate; TCA cycle; oxidative phosphorylation b. Glycolysis; reduction of pyruvate; TCA cycle; oxidative phosphorylation c. Glycolysis; oxidative phosphorylation; TCA cycle; oxidation of pyruvate d. Oxidation of pyruvate; TCA cycle; oxidation of glucose to pyruvate; oxidative phosphorylation e. Oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation
e. Oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation
The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why? a. It is often too cold at night for these reactions to take place. b. Carbon dioxide concentrations decrease at night. c. Plants usually open their stomata at night. d. At night, no water is available for the Calvin cycle. e. The Calvin cycle requires products only produced when the photosystems are illuminated.
e. The Calvin cycle requires products only produced when the photosystems are illuminated.
During which process is molecular oxygen produced in photosynthesis? a. The light reactions by the excitation of electrons in chlorophyll b. The Calvin cycle during carbon fixation c. The Calvin cycle during G3P production d. The light reactions by cyclic electron flow e. The light reactions by linear electron flow f. The light reactions by chemiosmosis
e. The light reactions by linear electron flow
Huntington's disease is an example of a genetic disorder caused by __________. a. homozygous recessive alleles b. a nonlethal dominant allele c. a late-acting recessive allele d. multiple alleles e. a lethal dominant allele that afflicts an individual later in life
e. a lethal dominant allele that afflicts an individual later in life
Somatic cells in animals differ from gametes in that somatic cells __________. a. are always haploid b. replicate by a process called meiosis c. are important in sexual reproduction d. do not contain sex chromosomes e. are all of the cells of the body except for the gametes and their precursors
e. are all of the cells of the body except for the gametes and their precursors
A clone is the product of __________. a. asexual reproduction b. sexual reproduction c. mitosis d. meiosis e. asexual reproduction and mitosis f. sexual reproduction and meiosis
e. asexual reproduction and mitosis
A difference between the mechanisms of cAMP and Ca2+ in signal transduction is that cAMP __________ and Ca2+ __________. a. is always present at high levels in the cytosol; is present at low levels in the absence of a signal b. is stored in the endoplasmic reticulum; is never stored in the cell c. is tyrosine-kinase-receptor linked; is G-protein-receptor linked d. enters the cell via a transmembrane protein channel; enters the cell by diffusing across the plasma membrane e. is synthesized by an enzyme in response to a signal; is released from intracellular stores
e. is synthesized by an enzyme in response to a signal; is released from intracellular stores
Muscle tissues make lactate from pyruvate to do which of the following? a. speed up the rate of glycolysis b. get rid of pyruvate produced by glycolysis c. utilize the energy in pyruvate d. produce additional CO2 e. regenerate NAD+
e. regenerate NAD+
IP3 (inositol trisphosphate) is produced from __________. a. protein kinase A activation b. Ca2+ c. DAG d. phospholipase C e. the cleavage of a certain kind of phospholipid in the plasma membrane
e. the cleavage of a certain kind of phospholipid in the plasma membrane
When chloroplast pigments absorb light, __________. a. they become reduced b. they lose potential energy c. the Calvin cycle is triggered d. their photons become excited e. their electrons become excited
e. their electrons become excited
The stage of cell signaling in which the signal is converted to a form that can bring about a response in the cell is called __________. a. reception b. response c. paracrine signaling d. cell-to-cell recognition e. transduction f., ligand binding
e. transduction
G3P is used in which of the following processes? a. Production of glucose b. Production of starch c. Production of cellulose d. Production of sucrose e. Production of cell walls in growing plants f. All of the listed processes can use G3P.
f. All of the listed processes can use G3P.
In the light reactions of photosynthesis, ATP is produced by photophosphorylation. Which of the listed processes is most similar to photophosphorylation? a. Calvin cycle b. Glycolysis c. Citric acid cycle d. Photorespiration e. Carbon fixation f. Oxidative phosphorylation in cellular respiration
f. Oxidative phosphorylation in cellular respiration
A cell biologist examined the DNA content of a cell from a fruit fly larva during the G1 phase and determined that it had 150 units of DNA. After measuring the DNA content of the same type of cell after the G2 phase, it was discovered that the cell had 300 units of DNA. How is this possible? a. The DNA was replicated during the G2 phase of interphase. b. The DNA was replicated during the G1 phase of interphase. c. The DNA was replicated prior to interphase. d. The DNA was not replicated. This was the result of a mutation. e. The DNA was replicated after the G2 phase of interphase. f. The DNA was replicated during the S phase of interphase, which occurs between the two G phases.
f. The DNA was replicated during the S phase of interphase, which occurs between the two G phases.
Which of the following statements correctly describes the difference in carbon fixation between C3 and C4 plants? a. There is no difference in carbon fixation between C3 and C4 plants. b. The first product of carbon fixation in C4 plants is a three-carbon compound. c. C4 plants do not fix carbon from carbon dioxide, but C3 plants do. d. C4 plants fix carbon from glucose, but C3 plants do not. e. C4 plants use the CAM pathway, but C3 plants do not. f. The first product of carbon fixation in C4 plants is a four-carbon compound instead of a three-carbon compound.
f. The first product of carbon fixation in C4 plants is a four-carbon compound instead of a three-carbon compound.
What property of the pigment chlorophyll makes it appear green? a. Chlorophyll absorbs all of the visible spectrum of light except green, which it reflects. b. Chlorophyll absorbs only green light and reflects all of the other colors of the visible spectrum. c. Chlorophyll absorbs all light in the visible spectrum and reflects none of them. d. Chlorophyll reflects all of the colors in the visible spectrum. e. Chlorophyll reflects blue and yellow light. f. Chlorophyll reflects red and green light.
a. Chlorophyll absorbs all of the visible spectrum of light except green, which it reflects.
Which of the following pairs of pathways and their location in the cell is incorrectly matched? a. Citric acid cycle: cytosol b. Glycolysis: cytosol c. Electron transport chain: mitochondrion d. Oxidative phosphorylation: mitochondrion e. All of the responses are correctly matched.
a. Citric acid cycle: cytosol
In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle? a. Cytokinesis b. Anaphase c. The G1 phase d. Metaphase e. Prophase
a. Cytokinesis
Regarding the role of cohesin protein in maintaining cohesion between sister chromatids, which of the following statements is false? a. During meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms. b. During meiosis I, cohesion holds sister chromatids together along their lengths as chiasmata form between homologs. c. Cleavage of cohesins between sister chromatid arms at anaphase I allows homologs to separate. d. During meiosis I, cohesion holds sister chromatids together along their lengths as chiasmata form between homologs and during meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms e. During meiosis I, cohesion holds sister chromatids together along their lengths as chiasmata form between homologs and cleavage of cohesins between sister chromatid arms at anaphase I allows homologs to separate.
a. During meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms.
Cells must regulate their metabolic pathways so that they do not waste resources. What is the most common mechanism that regulates cellular respiration in most cells? a. Feedback inhibition of glycolysis b. Positive feedback c. Denaturing of the enzymes in glycolysis d. Slowing down ATP production from oxidative phosphorylation e. Slowing down ATP production from fermentation
a. Feedback inhibition of glycolysis
Which of the following processes occurs during the second phase, the reduction phase, of the Calvin cycle? a. G3P production b. RuBP (ribulose bisphosphate) regeneration c. Molecular oxygen production d. Carbon fixation e. NADPH production f. ATP production
a. G3P production