BIO FINAL EXAM Questions with 100% Complete Solutions Latest Updates 2024 GRADE A+., Exams of Nursing

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BIO FINAL EXAM Questions with 100%

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Which of the following statements about asexual reproduction is true? a. It requires meiosis. b. In asexual reproduction, there is genetic variation among the offspring. c. In asexual reproduction, two gametes fuse to produce a zygote. d. It produces offspring that are genetically identical to the parent. correct answer: d. It produces offspring that are genetically identical to the parent Interphase involves all of the following steps except a. DNA replication. b. the synthesis of cellular components necessary for mitosis. c. the conservation of energy for later stages of mitosis. d. the condensation of chromatin. correct answer: d. the condensation of chromatin. Knowledge of the cell cycle has led to improved means of treating cancer. Taxol prevents the microtubules of the spindle fiber from functioning normally. Taxol prevents the cell cycle from entering a. G1. b. S. c. prophase. d. interphase. correct answer: c. prophase. Which statement about the cell cycle is not true? a. It consists of interphase, mitosis, and cytokinesis. b. The cell's DNA replicates during G1. c. A cell can remain in G1 for weeks or much longer. d. DNA is not replicated duing G2 correct answer: b. The cell's DNA replicates during G1. The difference between asexual and sexual reproduction is that a. asexual reproduction occurs only in bacteria, whereas sexual reproduction occurs in plants and animals. b. asexual reproduction results from meiosis, whereas sexual reproduction results from mitosis. c. asexual reproduction results in an organism that is identical to the parent, whereas sexual reproduction results in an organism that is not identical to either parent. d. asexual reproduction results from the fusion of two gametes, whereas sexual reproduction produces clones of the parent organism. correct answer: c. asexual reproduction results in an organism that is identical to the parent, whereas sexual reproduction results in an organism that is not identical to either parent.

7. One difference between mitosis and meiosis I is that a. homologous chromosome pairs synapse during mitosis. b. chromosomes do not replicate in the interphase preceding meiosis. c. homologous chromosome pairs synapse during meiosis but not during mitosis. d. spindles composed of microtubules are not required during meiosis. correct answer: c. homologous chromosome pairs synapse during meiosis but not during mitosis. Which of the following statements about DNA replication and cytokinesis in Escherichia coli is true? a. DNA replication occurs in the nucleus. b. DNA replication occurs during the S phase of the cell cycle. c. Cell reproduction is initiated by reproductive signals, which result in DNA replication, DNA segregation, and cytokinesis. d. The E. coli chromosome is linear. correct answer: c. Cell reproduction is initiated by reproductive signals, which result in DNA replication, DNA segregation, and cytokinesis. Chromosome number is reduced during meiosis because the process consists of a. two cell divisions without any chromosome replication. b. a single cell division without any chromosome replication. c. two cell divisions in which half of the chromosomes are destroyed. d. two cell divisions and only a single round of chromosome replication. correct answer: d. two cell divisions and only a single round of chromosome replication. In meiosis, a. meiosis II reduces the chromosome number from diploid to haploid. b. DNA replicates between meiosis I and meiosis II. c. each chromosome in prophase I consists of four chromatids. d. homologous chromosomes separate from one another in anaphase I. correct answer: d. homologous chromosomes separate from one another in anaphase I. In meiosis II, a. four genetically identical cells are generated. b. sister chromatids are separated. c. DNA replication occurs. d. crossing over occurs. correct answer: b. sister chromatids are separated. Which of the following statements about meiosis is true? a. The chromosome number in the resulting cells is halved. b. DNA replication occurs before meiosis I and meiosis II. c. The daughter cells are genetically identical to the parental cell. d. The chromosome number of the resulting cells is the same as that of the parent cell. correct answer: a. The chromosome number in the resulting cells is halved. Human males have _______ sex chromosomes. a. XX b. XY c. XO d. 23 correct answer: b. XY

At the milestone that defines anaphase, the chromosomes a. separate. b. come together. c. are at opposite poles. d. line up. correct answer: a. separate. Genetic recombination occurs during a. prophase of meiosis I. b. the interphase preceding meiosis II. c. the mitotic telophase. d. fertilization. correct answer: a. prophase of meiosis I. Unattached earlobes are a dominant trait. Finn and Maggie both have unattached earlobes but their daughter, Celia, does not. If Finn and Maggie have a second child, what is the probability that it will have attached earlobes? a. 1⁄4 b. 1⁄ c. 3⁄4 d. 1⁄8 correct answer: a. 1⁄ What fraction of offspring of the cross AaBb × AaBb is homozygous for all the dominant alleles, assuming that they are on different chromosomes? a. 1⁄4 b. 1⁄ c. 1⁄16 d. 1⁄32 correct answer: c. 1⁄ If the same allele has two or more phenotypic effects, it is said to be a. codominant. b. a marker. c. linked. d. pleiotropic. correct answer: d. pleiotropic. In a simple Mendelian monohybrid cross, true-breeding tall plants are crossed with short plants, and the F1 plants, which are all tall, are allowed to self-pollinate. What fraction of the F generation are both tall and heterozygous? a. 1⁄4 b. 1⁄ c. 2⁄3 d. 1⁄2 correct answer: d. 1⁄ Very few genes have been located on the Y chromosomes. Y-linked genes include a gene called testis-specific protein Y. A male with this gene will a. usually pass it to his sons, but occasionally also to a daughter. b. only pass the gene to his sons. c. only pass the gene to his daughters. d. only pass the gene to his grandsons correct answer: b. only pass the gene to his sons. In tomatoes, tall is dominant to short, and smooth fruits are dominant to hairy fruits. A plant homozygous for both dominant traits is crossed with a plant homozygous for both recessive traits. The F1 progeny are tested and crossed with the following results: 68 tall, smooth fruits; 72

dwarf, hairy fruits; 32 tall, hairy fruits; and 28 dwarf, smooth fruits. These data indicate that the genes are a. on different chromosomes. b. linked, but do not cross over. c. linked and show 10 percent recombination. d. linked and show 30 percent recombination. e. linked and show 60 percent recombination. correct answer: d. linked and show 30 percent recombination. In epistasis a. nothing changes from generation to generation. b. one gene alters the effect of another. c. a portion of a chromosome is deleted. d. a portion of a chromosome is inverted. correct answer: b. one gene alters the effect of another. A pea plant with red flowers is test crossed, and one-half of the resulting progeny have red flowers, while the other half has white flowers. Therefore, the genotype of the test-crossed parent was a. RR. b. Rr. c. rr. d. either RR or Rr. correct answer: b. Rr. In mice, short hair is dominant to long hair. If a short-haired individual is crossed with a long- haired individual and both long- and short-haired offspring result, one can conclude that a. the short-haired individual is homozygous. b. the short-haired individual is heterozygous. c. the long-haired individual is homozygous. d. the long-haired individual is heterozygous. correct answer: b. the short-haired individual is heterozygous. In dogs, phenotype A (erect ears and barking while following a scent) is caused by dominant alleles; phenotype B (droopy ears and silent while following a scent) is caused by recessive alleles. A dog that is homozygous for both traits of phenotype A is mated to a dog with phenotype B. If the genes for the two traits are unlinked, which of the following is (are) the expected F1 phenotypic ratio(s)? a. 9:3:3: b. 1: c. 16: d. 1:2:1 correct answer: c. 16: Fourteen percent of the DNA nucleotides from a certain organism contain T. What amounts of the other bases would you expect to be present in this particular DNA? a. 14 % A, 36 % C, 14 % G b. 14 % A, 36 % C, 36 % G c. 14 % T, 38 % C, 36 % G

d. 14 % T, 36 % C, 36 % U correct answer: b. 14 % A, 36 % C, 36 % G A deoxyribose nucleotide is a a. deoxyribose plus a nitrogenous base. b. deoxyribose plus a nitrogenous base and a phosphate. c. ribose plus a nitrogenous base. d. nitrogenous base bonded at the 5' end to a sugar-phosphate backbone. correct answer: b. deoxyribose plus a nitrogenous base and a phosphate. Double-stranded DNA looks a little like a ladder that has been twisted into a helix, or spiral. The side supports of the ladder are a. individual nitrogenous bases. b. alternating bases and sugars. c. alternating bases and phosphate groups. d. alternating sugars and phosphates. e. alternating bases, sugars, and phosphates. correct answer: d. alternating sugars and phosphates. The strands that make up DNA are antiparallel. This means that a. the base pairings create unequal spacing between the two DNA strands. b. the 5´-to-3´ direction of one strand is counter to the 5´-to-3´ direction of the other strand. c. the twisting of the DNA molecule has shifted the two strands. d. purines bond with purines and pyrimidines bond with pyrimidines. correct answer: b. the 5´- to-3´ direction of one strand is counter to the 5´-to-3´ direction of the other strand. Why is RNA incorporated into the DNA molecule during DNA replication? a. RNA primase adds bases that act as primers. b. RNA primase is able to use DNA as a template. c. RNA primase must be incorporated into the holoenzyme complex. d. DNA polymerases can only add on to an existing strand. correct answer: d. DNA polymerases can only add on to an existing strand. Semiconservative replication of DNA involves a. each of the original strands acting as a template for a new strand. b. only one of the original strands acting as a template for a new strand. c. the complete separation of the original strands, the synthesis of new strands, and the reassembly of double-stranded molecules. d. the use of the intact double-stranded molecule as a template. correct answer: a. each of the original strands acting as a template for a new strand. One strand of DNA has the sequence 5´-ATTCCG-3´ The complementary strand for this is a. 5´-TAAGGC-3´ b. 5´-ATTCCG-3´ c. 5´-CGGAAT-3´ d. 5´-GCCTTA-3´ correct answer: c. 5´-CGGAAT-3´

In bacteria, the enzyme that removes the RNA primers is called a. DNA ligase. b. primase. c. helicase. d. DNA polymerase I. correct answer: d. DNA polymerase I. Amino acids are transported to the ribosome for use in building the polypeptide by a. mRNA molecules. b. tRNA molecules. c. DNA polymerase molecules. d. rRNA molecules. correct answer: b. tRNA molecules. The nucleotide sequence of a mRNA codon is composed of how many bases? a. 2 b. 3 c. 6 d. 64 correct answer: b. 3 Protein synthesis takes place on a. the plasma membrane. b. the nucleus. c. ribosomes. d. lysosomes. correct answer: c. ribosomes. Ribosome movement along the mRNA transcript is called a. transcription. b. translation. c. replication. d. translocation. correct answer: b. translation. Eukaryotic mRNA molecules are occasionally interspersed with non-coding sequences that must be removed before protein synthesis. These are called a. anticodons. b. introns. c. exons. d. nucleosomes. correct answer: b. introns.

. Transcription in prokaryotes is carried out by the enzyme _______, which unwinds and transcribes the gene. a. DNA polymerase b. DNA gyrase c. RNA ligase d. RNA polymerase correct answer: d. RNA polymerase In eukaryotes, the empty RNA molecules exit the ribosome from the a. E site.

b. P site. c. A site. d. active site. correct answer: a. E site. The termination of transcription is signaled by a. the stop codon. b. a sequence of nitrogenous bases. c. a protein bound to a certain region of DNA. d. tRNA. correct answer: b. a sequence of nitrogenous bases.

. Which of the following is not part of RNA processing in eukaryotes? a. Reverse transcription b. Addition of a 5´ cap c. Addition of a poly A tail d. Intron removal correct answer: a. Reverse transcription The type of mutation that involves the insertion or a deletion of a single base in the coding region of proteins is called a. a missense mutation. b. a nonsense mutation. c. a point mutation. d. an aberration. correct answer: c. a point mutation. Which of the following enzymes are used by bacteria to defend themselves against bacteriophage? a. DNA polymerase b. Reverse transcriptase c. Phosphofructokinase d. Restriction endonuclease correct answer: b. Reverse transcriptase DNA, because it has a _______ charge, moves to the _______ end of the field in gel electrophoresis; _______ DNA molecules migrate the most quickly. a. positive; positive; larger b. positive; negative; smaller c. negative; positive; larger d. negative; positive; smaller correct answer: d. negative; positive; smaller People with PKU often have too much of the amino acid _______ and too little of the amino acid _______. a. phenylalanine; alanine b. phenylalanine; tyrosine c. tyrosine; phenylalanine d. tyrosine; alanine correct answer:? "Mad cow disease" is most likely due to a. an alteration in protein conformation.

b. a change in the amino acid sequences of a protein. c. a missing protein. d. the number of triplet repeats of a protein. correct answer: a. an alteration in protein conformation. Proteins that bind to regulatory sequences have shapes that fit into the a. promoter. b. operator. c. minor groove of DNA. d. major groove of DNA. correct answer: d. major groove of DNA. Which of the following mutations would probably be the least deleterious? a. A missense mutation in the second codon b. A frame-shift mutation in the second codon c. A silent mutation in the second codon d. A missense mutation in the last codon correct answer: c. A silent mutation in the second codon Restriction enzymes a. cut single-stranded DNA. b. cut double-stranded DNA at any palindromic sequence. c. cleave DNA to very small pieces. d. cleave double-stranded DNA at specific palindromic sequences. correct answer: d. cleave double-stranded DNA at specific palindromic sequences. The basic tool of genetic regulation is the ability of certain proteins to bind to specific a. regulatory RNA sequences. b. regulatory DNA sequences. c. promoter parts of the gene. d. enzymes of the cell. correct answer: b. regulatory DNA sequences. Viruses are composed of a. nucleic acids only. b. proteins only. c. nucleic acids and proteins. d. nucleic acids and proteins, although a few also have organelles. correct answer: c. nucleic acids and proteins. The most efficient means of regulating protein synthesis is by a. selective blocking of transcription. b. translation of the mRNA. c. inhibition of the protein. d. degradation of the protein. correct answer: a. selective blocking of transcription. _______ acts as a co-repressor to block transcription of the tryptophan operon. a. cAMP

b. Lactose c. Tryptophan d. CRP correct answer: c. Tryptophan It is found that a certain enzyme is synthesized whenever the solution in which the cells are growing lacks substance X. This phenomenon is most likely an example of _______ gene regulation. a. inducible b. positive c. negative d. repressible correct answer: d. repressible When the operator is unbound, the binding of the CRP-cAMP complex _______ the binding of RNA polymerase at the promoter. a. prevents b. decreases c. increases d. blocks correct answer: c. increases What effect does the presence of ample glucose have on the amount of lac operon transcription? a. It increases the cAMP concentration, which in turn causes a decreased rate of transcription. b. It decreases the cAMP concentration, which in turn causes an increased rate of transcription. c. It increases the rate of transcription. d. It decreases the rate of transcription. correct answer: d. It decreases the rate of transcription. RNA polymerase II by itself cannot bind to the chromosome and initiate transcription. It can bind and act only after regulatory proteins called _______ factors have been assembled. a. translation b. posttranslation c. initiation d. transcription correct answer: d. transcription In the first successful cloning of a sheep, cells from the ewe's udder were modified to become appropriate donor cells. In order for these udder cells to be suitable donor cells, they were a. arrested in the G1 phase of the cell cycle. b. arrested in the G2 phase of the cell cycle. c. supplied with extra nutrients. d. Both a and c correct answer: a. arrested in the G1 phase of the cell cycle. Which of the following is the correct ranking of stem cells with respect to the number of cell types into which they can differentiate (from greatest to least)? a. Pluripotent > totipotent > multipotent b. Pluripotent > multipotent > totipotent c. Totipotent > pluripotent > multipotent d. Totipotent > multipotent > pluripotent correct answer: c. Totipotent > pluripotent > multipotent

Different results are achieved when an eight-cell sea urchin embryo is bisected horizontally as opposed to when it is bisected vertically. This observation supports which of the following statements? a. Cellular determinants are equally distributed in the embryo. b. Differentiation has occurred by the eight-cell stage. c. Inducers have determined cell fate. d. Polarity exists in the embryo by the eight-cell stage. correct answer: d. Polarity exists in the embryo by the eight-cell stage. The primary inducer of the vulva in C. elegans comes from the _______ cell. a. primary vulval precursor b. lens placode c. homeotic d. anchor correct answer: d. anchor Cell differentiation a. results from the loss of particular genes from the nucleus of the differentiated cell. b. results from the differential expression of genes that are responsive to environmental signals. c. involves the persisting totipotency of early embryonic cells in the mature organism. d. precedes cell determination. correct answer: b. results from the differential expression of genes that are responsive to environmental signals. Apoptosis a. occurs during embryonic development of invertebrates, but not vertebrates. b. prompts cell differentiation. c. is controlled by similar genes in humans and nematodes. d. does not occur during morphogenesis. correct answer: c. is controlled by similar genes in humans and nematodes. Induction occurs when a. nuclear genes are lost in some tissues. b. one cell contacts another and fails to alter its developmental fate. c. a cell or tissue sends a chemical signal to another, causing differentiation of that cell or tissue. d. factors are unequally distributed in the cytoplasm of an egg. correct answer: c. a cell or tissue sends a chemical signal to another, causing differentiation of that cell or tissue. Which processes occur when bacterial cells divide? a.Replication of DNA b. Segregation of replicated DNA c.Addition of new material to the plasma membrane d.All of the above correct answer: d.All of the above The bacterial genome exist as a a. single, circular, protein-coated, double stranded DNA molecule. b. single, circular, uncoated, double stranded DNA molecule.

c. single, circular, uncoated, double stranded RNA molecule. d. single, linear, uncoated, double stranded DNA molecule. e. many, circular, uncoated, double stranded DNA molecules. correct answer: b. single, circular, uncoated, double stranded DNA molecule. The two versions of each chromosome in body cells are called a. chromatids b. homologous chromosomes c. sister chromosomes d. daughter chromosomes e. genes e correct answer: b. homologous chromosomes The phase of the cell cycle during which the cytoplasm divides to form two cells is a. G b. S c. M d. C e. G d correct answer: c. M d. C Where do cells spend most of their time? a. Interphase b. Mitosis c. Cytokinesis d. Meiosis correct answer: a. Interphase What is it called when a cell spends all its time in interphase? a. G b.G c. G d. G e. Cancer correct answer: a. G What is occuring during S phase a. nothing the cell is resting b. cytokineisi c. DNA synthesis d. Nuclear division correct answer: c. DNA synthesis In humans the diploid number of chromosomes is 46. The haploid number is 23. Prior to mitosis in the cell cycle, the cell is in the G2 phase. Which of the statements is true? a. The homologous chromosomes are lined up on the equator. b. The homologous chromosomes have all been copied through DNA replication and are now sister chromatids.

c. The homologous chromosomes have not been replicated yet. d.The homologous chromosomes are now in the haploid or n condition. correct answer: b.The homologous chromosomes have all been copied through DNA replication and are now sister chromatids. Which of the following cell functions are maintained by cell division a. Growth and reproduction b. Death c. Metabolism d. Movement e. Organization correct answer: a. Growth and reproduction During bacterial cell division, the single cell is separated into two cells by a. centrosomes b. spindle fibers c. nucleosomes d. pinching of the plasma membrane correct answer: d. pinching of the plasma membrane A complete cell cycle consists of a.mitosis and meiosis b. G1, the S phase, and G c. prophase, metaphase, anaphase,and telophase d. Interphase, mitosis, and cytokinesis correct answer: d. Interphase, mitosis, and cytokinesis Which statement about the cell cycle is not true? a. It consists of interphase, mitosis, and cytokinesis. b. The cell's DNA replicates during G1. c. A cell can remain in G1 for weeks or much longer. d. DNA is not replicated during G2. correct answer: b. The cell's DNA replicates during G1. Cytoplasmic organelles are partitioned between two daughter cells during a. G b. S c. G d. M e. C correct answer: e. C Mature nerve cells are incapable of cell division. These cells are probably in a. G b. the S phase c. G d. mitosis correct answer: a. G A chromatid is a. one of the pairs of homologous chromosomes. b. a homologous chromosome.

c. a newly replicated bacterial chromosome. d. one-half of a newly replicated eukaryotic chromosome. correct answer: d. one-half of a newly replicated eukaryotic chromosome. Chromosomes start to condense & the spindle starts to form in a. anaphase b. prophase c. prometaphase d. telophase e. metaphase correct answer: b. prophase Cytokinesis occurs right after a. prophase b. G c. anaphase d. telophase correct answer: d. telophase Which of the following statements below is false, when contrasting cytokinesis in animal and plant cells? a. In animal cells, cytokinesis results from the interaction of actin filaments and myosin b. In animal cells the cell membrane pinches in and divides the cytoplasm into two cells c. In plant cells, Golgi vesicles fuse at the cell plate to form the new cell membranes d. In plant cells, microfilaments constrict the plasma membrane to complete cytokinesis correct answer: d. In plant cells, microfilaments constrict the plasma membrane to complete cytokinesis You are studying cell cycle progression in yeast cells. If you could prevent cdc2 from associating with mitotic cyclin, the cells would a. arrest in G1. b. arrest in G2. c. arrest in M. d. arrest in S. correct answer: b. arrest in G2. Which of the following statements about cyclin-dependent kinases (Cdk's) or cyclin is false? a. Different Cdk's act at different points in the cell cycle. b. A Cdk can catalyze the phosphorylation of retinoblastoma protein. c. Phosphorylated retinoblastoma protein is inactive. d. Cdk's use ATP as a substrate. e. Cyclin is made continuously during the cell cycle. correct answer: e. Cyclin is made continuously during the cell cycle. Imagine that there is a mutation in the Cdk gene such that its gene product is nonfunctional. What kind of effect would this mutation have on a white blood cell? a. The cell would be unable to replicate its DNA. b. The cell would be unable to enter mitosis. c. The cell would be unable to reproduce itself. d. The cell would not be able to phosphorylate its associated cyclin.

e. all of the above correct answer: e. all of the above If you wanted to convert a proto-oncogene to an oncogene, which of the following methods would you choose? a. growth factor exposure b. genetic damage c. pair the proto-oncogene with a tumor-suppressor gene d. halt cell cycle progression correct answer: b. genetic damage Which of the following statements best fits as an analogy for a cell with a mutation in a tumor- suppressor gene? a. The gas pedal of a car gets stuck while pushed down. b. The gas pedal of a car does not work at all. c. The brake pedal of a car gets stuck while pushed down. d. The brake pedal of a car does not work at all. correct answer: d. The brake pedal of a car does not work at all. All zygotes are a. multicellular. b. diploid. c. animals. d. clones. e. gametes. correct answer: b. diploid. The initiation of the S phase and the M phase of the cell cycle depends on a pair of molecules called _______ and _______. a. actin; myosin b. Cdk's; cyclin c. ligand; receptor d. MSH; MSH-receptor e. ATP; ATPase correct answer: b. Cdk's; cyclin When cyclin binds Cdk, a. the cell transitions from G2 to S b. kinase activation occurs c. chromosomes condense d. the cell quickly enters M phase correct answer: b. kinase activation occurs Which of the following is not a checkpoint for cell cycle control in a eukaryotic cell? a. G1/S b. G2/M c. Spindle d. PDGF correct answer: d. PDGF Which statement best explains the way that an abnormal p53 causes normal cells to become cancer cells? The abnormal p53 protein

a. fails to carry out DNA repair. b. triggers too many cells to grow. c. damages the normal DNA. d. stimulates the death of normal cells. e. enhances tumor-suppressor genes. correct answer: a. fails to carry out DNA repair. All of the following animal cells are diploid except a. gametes b. muscles c. nerves d. skin e. reproductive organ e. correct answer: a. gametes The members of a homologous pair of chromosomes a. are identical in size and appearance b. contain identical genetic information c. separate to opposite poles of the cell during mitosis d. are found only in haploid cells e. are present only after the S phase correct answer: a. are identical in size and appearance Meiosis is used primarily a. to produce haploid gametes b. by animals but not plants c. for asexual reproduction d. to take a pause from the cell cycle correct answer: a. to produce haploid gametes At the end of the first meiotic division, each chromosome consists of a. Chiasmata b. a homologous chromosome pair c. four copies of each DNA molecule d. two chromatids e. a pair of polar microtubules correct answer: d. two chromatids Which of the following is not true of homologous chromosome pairs? a.They come from only one of the individual's parents b. They usually contain slightly different versions of the same genetic information c. They segregate from each other during meiosis I d. They synapse during meiosis I e. Each contains two sister chromatids at the beginning of meiosis I correct answer: a.They come from only one of the individual's parents Which of the following is not true of sister chromatids? a. They arise by replication during S phase b. They segregate from each other during each mitotic anaphase c. They usually contain identical versions of the same genetic information

d. They segregate from each other during meiosis I e. They are joined during prophase and metaphase at their common centromere correct answer: d. They segregate from each other during meiosis I Crossing over involves the exchange of genetic material between a. sister chromatids b. males and females c. sex chromosomes d. homologous chromosomes correct answer: d. homologous chromosomes Which of the following is true of chromatids? a. They are replicated chromosomes still joined together at the centromere b. They are identical in mitotic chromosomes c. They are identical in meiotic chromosomes d. Both 1 and 2 are true e. 1, 2, and 3 are all true correct answer: d. Both a and b are true a. They are replicated chromosomes still joined together at the centromere b. They are identical in mitotic chromosomes Chromosome number is reduced during meiosis because the process consists of a. two cell divisions without any chromosome replication b. a single cell division without any chromosome replication c. two cell divisions in which half of the chromosomes are destroyed d. two cell divisions and only a single round of chromosome replication correct answer: d. two cell divisions and only a single round of chromosome replication During meiosis, the sister chromatids separate during a. anaphase I b. anaphase II c. the S phase d. synapsis e. telophase II correct answer: b. anaphase II One difference between mitosis and meiosis I is that a. homologous chromosome pairs synapse during mitosis b. chromosomes do not replicate in the interphase preceding meiosis c. homologous chromosome pairs synapse during meiosis but not during mitosis d. spindles composed of microtubules are not required during meiosis e. sister chromatids separate during meiosis but not during mitosis correct answer: c. homologous chromosome pairs synapse during meiosis but not during mitosis Crossing spherical-seeded pea plants with wrinkled-seeded pea plants resulted in progeny that all had spherical seeds. This indicates that the wrinkled-seed trait is a. neutral b. dominant c. recessive

d. environmental correct answer: c. recessive True breeding plants a. produce the same offspring when crossed for many generations b. result from a monohybrid cross c. result from a dihybrid cross d. result from crossing over during prophase I of meiosis correct answer: a. produce the same offspring when crossed for many generations It has been found that at a certain locus of the human genome, 200 different alleles exist in the population. Each person has at most _______ alleles a. 1 b. 2 c. 100 d. e. 400 correct answer: b. 2 Let P = purple flowers and p = white, and T = tall plants and t = dwarf. What combinations of gametes could be produced by a heterozygote for both the traits a. PpTt only b. Pp, Tt c. P, p, T, t d. PT, Pt, pT, pt correct answer: d. PT, Pt, pT, pt In dogs, erect ears and barking while following a scent are due to dominant alleles; droopy ears and silence while following a scent are due to recessive alleles. A dog homozygous dominant for both traits is mated to a droopy-eared, silent follower. The expected F1 phenotypic ratios should be a. 9:3:3: b. 8:8 or 1: c. 16: d. 4:8:4 or 1:2:1 correct answer: c. 16: In white tigers, the absence of fur pigmentation is caused by a recessive allele. This allele also causes the tigers to be cross-eyed. If two tigers heterozygous for this allele mate and produce offspring, what percentage can be expected to be white and/or cross-eyed a. 25% will be white and the same 25% will be cross-eyed b. 25% will be white and 25% will be cross-eyed, but not necessarily the same 25% due to independent assortment c. 50% will be both white and cross-eyed d. Because it is a recessive allele, none of the offspring in the F1 generation will be white or cross-eyed correct answer: a. 25% will be white and the same 25% will be cross-eyed In cocker spaniels, black color (B) is dominant over red (b), and solid color (S) is dominant over spotted (s). If the offspring between BBss and bbss individuals are mated with each other, what fraction of their offspring will be expected to be black and spotted?

a. 1⁄ b. 9⁄ c. 1⁄ d. 3⁄ e. 3⁄4 correct answer: e. 3⁄ Which of the following statements about Mendelian genetics is false? a. Alternative forms of genes are called alleles b. A locus is a gene's location on its chromosome c. Only two alleles can exist for a given gene d. A genotype is a description of the alleles that represent an individual's genes e. Individuals with the same phenotype can have different genotypes correct answer: c. Only two alleles can exist for a given gene In pea plants, the gene for yellow seeds, Y, is dominant to the allele for green seeds, y. A plant with green seeds must have the genotype a. YY b. Yy c. yy d. XY C correct answer: c. yy Which statement about an individual that is homozygous for an allele is false? a. Each of its cells possesses two copies of that allele b. Each of its gametes contains one copy of that allele c. It is true-breeding with respect to that allele d. Its parents were necessarily homozygous for that allele e. It can pass that allele to its offspring correct answer: d. Its parents were necessarily homozygous for that allele Let P = purple flowers and p = white, and T = tall plants and t = dwarf. Of the 16 possible gamete combinations in the dihybrid cross, how many would be the phenotype white, tall a. none b. 1 c. 3 d. 9 correct answer: c. 3 In a simple Mendelian monohybrid cross, true-breeding tall plants are crossed with short plants, and the F1 plants, which are all tall, are allowed to self-pollinate. What fraction of the F generation are both tall and heterozygous? a. 1/ b. 1/ c. 2/ d. 1/2 correct answer: d. 1/

Unattached earlobes are a dominant trait. Finn and Maggie both have unattached earlobes but their daughter, Celia, does not. If Finn and Maggie have a second child, what is the probability that it will have attached earlobes? a. 1/ b. 1/ c. 3/ d. 1/8 correct answer: a. 1/ What fraction of offspring of the cross AaBb × AaBb is homozygous for all the dominant alleles, assuming that they are on different chromosomes? a. 1⁄ b. 1⁄ c. 1⁄ d. 1⁄32 correct answer: c. 1⁄ Classical albinism results from a recessive allele. Which of the following is the expected ratio for the progeny when a normally pigmented male with an albino father has children with an albino woman? a. 3⁄4 normal; 1⁄4 albino b. 3⁄4 albino; 1⁄4 normal c. 1⁄2 normal; 1⁄2 albino d All normal correct answer: c. 1⁄2 normal; 1⁄2 albino In Netherlands dwarf rabbits, a gene showing intermediate inheritance produces three phenotypes. Rabbits that are homozygous for one allele are small rabbits; individuals homozygous for the other allele are deformed and die; heterozygous individuals are dwarf. If two dwarf rabbits are mated, what proportion of their surviving offspring should be dwarf? a. 1/ b. 1/ c. 1/ d. 2/ e. 3/4 correct answer: d. 2/ The ABO blood groups in humans are determined by a multiple allelic system in which A and B are codominant, and are dominant to O. If an infant born to a type O mother also is type O, possible phenotypes for the father are a. O or A b. A or B c. O only d. O, A, or B e. impossible to determine correct answer: d. O, A, or B A gene for a particular trait that is only expressed in the presence of another gene of the same kind is called a(n) a. dominant gene. b. codominant gene.

c. incompletely dominant gene. d. recessive gene. e. multiple allele. correct answer: d. recessive gene. If a trait not expressed in the F1 generation reappears in the F2 generation, the inheritance of the trait in question is a(n) example of a. codominance b. dominance and recessiveness c. incomplete dominance d. epistasis e. a sex linked trait correct answer: b. dominance and recessiveness In the ABO blood type system, a. A, B, and O are codominant b. A, B, and O are incompletely dominant c. A and B are codominant d. O is incompletely dominant to A and B f. A is dominant to B, and B is dominant to O correct answer: c. A and B are codominant In Mendel's experiments, if the allele for tall (T) plants was incompletely dominant over the allele for short (t) plants, what offspring would have resulted from crossing two Tt plants? a. 1/4 tall; 1/2 intermediate height; 1/4 short b. 1/2 tall; 1/4 intermediate height; 1/4 short c. All the offspring would have been tall d. All the offspring would have been of intermediate height correct answer: a. 1/4 tall; 1/ intermediate height; 1/4 short A dominant allele K is necessary for normal hearing. A dominant allele M on a different locus results in deafness no matter which other alleles are present. If a kkMm individual is crossed with a Kkmm individual, _______ percent of the offspring will be deaf. a. 0 b. 25 c. 50 d. 75 e. none of the above correct answer: d. 75 Y-linked genes include a gene that produces hairy pinnae (the external ear). A male with hairy pinnae will pass this trait a. usually to his sons, but rarely also to a daughter b. only to his sons c. only to his daughters d. only to his grandsons e. to all his children if the mother is a carrier correct answer: a. usually to his sons, but rarely also to a daughter b. only to his sons

Cleft chin is a sex-linked dominant trait. A man with a cleft chin marries a woman with a round chin. What percent of their female progeny will show the cleft chin trait? a. 0 b. 25 c. 50 d. 75 e. 100 correct answer: e. 100 Organisms generally have many more genes that assort independently than the number of chromosomes. This phenomenon is due to a. independent assortment. b. segregation. c. crossing over. d. epistasis. e. pleiotropy. correct answer: c. crossing over. In guppies, fan tail is dominant to flesh tail, and rainbow color is dominant to pink. F1 female guppies are crossed with flesh-tailed, pink-colored males, and the following progeny are observed: 401 fan-tailed, pink-colored; 399 flesh-tailed, rainbow-colored; 98 flesh-tailed, pink- colored; and 102 fan-tailed, rainbow-colored guppies. Assuming that the F1 female guppies have both dominant alleles on one chromosome, the map distance between these two genes is a. 80 cM b. 25 cM c. 0.8 cM d. 20 cM e. None of the above correct answer: a. 80 cM It is predictable that half of the human babies born will be male and half will be female because a. of the segregation of the X and Y chromosomes during male meiosis b. of the segregation of the X chromosomes during female meiosis c. all eggs contain an X chromosome d. Both 1 and 2 correct answer: a. of the segregation of the X and Y chromosomes during male meiosis Linked genes are genes that a. assort independently b. segregate equally in the gametes during meiosis c. always contribute the same trait to the zygote d. are found on the same chromosome correct answer: d. are found on the same chromosome How is genetic linkage related to the principle of independent assortment? a. If two alleles assort independently than they are linked b. If two loci are linked then they do not assort independently c. Linked loci are present on homologous chromosomes d. Linked loci are present on sister chromatids correct answer: b. If two loci are linked then they do not assort independently

White eyes is a recessive sex-linked trait in fruit flies. If a white-eyed female fruit fly is mated to a red-eyed male, their offspring should be a. 50 percent red-eyed, 50 percent white-eyed for both sexes b. all white-eyed for both sexes c. all white-eyed males, all red-eyed females d. all white-eyed females, all red-eyed males correct answer: c. all white-eyed males, all red- eyed females In tomatoes, tall is dominant to short, and smooth fruits are dominant to hairy fruits. A plant homozygous for both dominant traits is crossed with a plant homozygous for both recessive traits. The F1 progeny are tested and crossed with the following results: 78 tall, smooth fruits; 82 dwarf, hairy fruits; 22 tall, hairy fruits; and 18 dwarf, smooth fruits. These data indicate that the genes are a. linked, but do not cross over b. linked and show 10 percent recombination c. linked and show 20 percent recombination d. linked and show 40 percent recombination correct answer: c. linked and show 20 percent recombination Huntington's disease is caused by an autosomal dominant allele. It is a lethal disease, but it persists in the human population. Which of the following statements best describes why? a. Huntington's disease can present symptoms so mild that they appear to lack dominant expression of the allele in some individuals; in those cases, the allele is passed on to the offspring. b. While lethal to a parent, Huntington's disease will not be lethal to the offspring since it can skip a generation. c. Huntington's disease presents symptoms in humans after many have already reproduced; therefore, they are unaware that they passed on Huntington's disease. correct answer: c. Huntington's disease presents symptoms in humans after many have already reproduced; therefore, they are unaware that they passed on Huntington's disease. In sickle cell anemia, the defective hemoglobin differs from the normal hemoglobin by a. the color of the pigment. b. the size of the molecule. c. a single amino acid substitution. d. the total number of amino acids. e. the type of blood cell it is found in correct answer: c. a single amino acid substitution. Which of the following accurately describes the leading strand and an Okazaki fragment during DNA replication? a. The leading strand is synthesized in a 5' to 3' direction, while the Okazaki fragment is synthesized in a 3' to 5' direction.

b. The leading strand is synthesized in a 3' to 5' direction, while the Okazaki fragment is synthesized in a 5' to 3' direction. c. Both the leading strand and the Okazaki fragment are synthesized in a 5' to 3' direction. d. Both the leading strand and the Okazaki fragment are synthesized in a 3' to 5' direction. correct answer: c. Both the leading strand and the Okazaki fragment are synthesized in a 5' to 3' direction. Why does replication proceed in opposite directions on the leading and lagging strands? a. The polymerase enzyme needs a primer b. DNA polymerase III can only add to the 3´ end of a strand c. The Okazaki fragments are only on the leading strands d. The parent strands are oriented in the same directions e. Helicase only allows for replication of one strand at a time correct answer: b. DNA polymerase III can only add to the 3´ end of a strand The enzyme that removes the RNA primers is called a. DNA ligase b. Primase c. DNA polymerase III d. DNA polymerase I correct answer: d. DNA polymerase I Name the enzyme that links Okazaki fragments a. DNA polymerase I b. RNA primase c. DNA ligase d. Helicase e. ATP synthase correct answer: c. DNA ligase Which of the following is the correct order of events for synthesis of the lagging strand? a. Primase adds primer, DNA polymerase I removes the primer, DNA polymerase III extends the segment, and ligase seals the gap b. Primase adds RNA primer, DNA polymerase III creates a stretch, DNA polymerase I removes the primer, and ligase seals the gaps c. Ligase adds bases to the primase, the primase generates polymerase I, polymerase III adds to the stretch, helicase winds the DNA d. Helicase unwinds the DNA, primase creates a primer, DNA polymerase I elongates the stretch, DNA polymerase III removes the primer, and ligase seals the gaps in the DNA. correct answer: b. Primase adds RNA primer, DNA polymerase III creates a stretch, DNA polymerase I removes the primer, and ligase seals the gaps Genes code for a. Enzymes b. Polypeptides

c. rRNA d. tRNA correct answer: a. Enzymes b. Polypeptides c. rRNA d. tRNA The number of codons that actually specify amino acids is a. 20 b. 23 c. 45 d. 60 e. 61 correct answer: e. 61 Which of the following single base substitutions in the transcribed strand of DNA would result in premature termination of translation? a. CAA to CAG b. CCT to CCC c. ATG to ATT d. GAG to TAG e. CTG to CTT correct answer: c. ATG to ATT mRNA is made by a(n) a. RNA-dependent DNA polymerase b. RNA-dependent RNA polymerase c. DNA-dependent RNA polymerase d. form of RNA correct answer: c. DNA-dependent RNA polymerase Where does eukaryotic transcription take place? a. Nucleus b. Nucleolus c. Cytoplasm d. Ribosome e. Rough ER correct answer: a. Nucleus Eukaryotic mRNA molecules are modified a. in the cytoplasm. b. at the ribosome. c. in the nucleus. d. at the Golgi complex. e.. at the initiation of transcription. correct answer: c. in the nucleus. What is the function of the 5´ cap and the 3´ poly-A-tail? a. Initiates transcription b. Forms bonds between amino acids c. Protects mRNA from degradation d. Splices out the intron sequences

e. Acts as a stop codon in some polypeptides correct answer: c. Protects mRNA from degradation Which of the following statements about the flow of genetic information is true? a. RNA encodes information that is translated into DNA, and DNA encodes information that is translated into proteins b. Proteins encode information that can be translated into RNA, and RNA encodes information that can be transcribed into DNA c. DNA encodes information that is transcribed into RNA, and RNA encodes information that is translated into proteins correct answer: c. DNA encodes information that is transcribed into RNA, and RNA encodes information that is translated into proteins Fewer different tRNA molecules exist than might have been expected for the complexity of its function. This is possible because a. the third position of the codon does not have to pair conventionally b. the second position of the codon does not have to pair conventionally c. the anticodon does not have the conventional bases d. there are fewer amino acids than there are possible codons e. the code is degenerating correct answer: a. the third position of the codon does not have to pair conventionally During translation elongation, the existing polypeptide chain is transferred to a. the tRNA occupying the A site b. the tRNA occupying the P site c. the ribosomal rRNA d. a signal recognition particle e. None of the above correct answer: a. the tRNA occupying the A site A sequence of three RNA bases can function as a a. codon b. anticodon c. gene correct answer: a. codon b. anticodon The stop codons code for a. no amino acid b. methionine c. glycine d. halt enzyme e. DNA binding protein correct answer: a. no amino acid The codons that serve as "stop" signals for the protein synthesis are called a. anticodons. b. release codons. c. nonsense codons. d. amino acid codons.