BIOLOGY 1305 FINAL Questions & Answers

Which statement about a dihybrid cross is true? - ANSWERSIt is a cross between identical double heterozygotes When a dihybrid black, normal winged fly is crossed with a double recessive gray, vestigial winged fly, the frequency with which black, vestigial winged and gray, normal winged flies are seen in the progeny is called ______ frequency. - ANSWERSRecombination Epistasis refers to - ANSWERSthe expression of one gene masking the expression of another The major drawback of asexual reproduction is that it - ANSWERSProduces less variation among offspring compared to sexual reproduction Bacteria typically have _______ where is eukaryotes have _______ - ANSWERSOne chromosome that is usually circular; several chromosomes that are linear Cytokinesis occurs during - ANSWERSM phase Condensation of chromosomes occurs during - ANSWERSProphase Cells that do not divide are usually arrested in - ANSWERSG1 phase Late in mitotic anaphase a cell with 28 daughter chromosomes has _______ centromeres in the dividing cell - ANSWERS28 At the milestone that defines telophase, the chromosomes - ANSWERSare at opposite poles Which event is not part of sexual reproduction - ANSWERSThe fusion of sister chromatids during fertilization In an organism with a haploid number of nine, skin cell has ______ chromosomes, a sperm cell at meiotic anaphase II has _____ chromosomes, and a newly formed zygote has _____ chromosomes. - ANSWERS18;9;9 During meiosis the sister chromatids separate during - ANSWERSAnaphase II Bacteria engage in genetic transfers after a thin projection called a _____ extends from one cell to another - ANSWERSSex pilus A deoxyribosenucleoside is a - ANSWERSDeoxyribose plus a nitrogenous base Which molecular model best describes the structure of the DNA molecule - ANSWERSHelical, double-stranded, and anti-parallel What accounts for the uniform diameter of the DNA molecule - ANSWERSA purine always bonds with a pyrimidine In DNA replication each newly made strand is - ANSWERSComplementary in sequence to the strand from which it was copied Mutations are - ANSWERSChanges in the nucleotide sequence of DNA that is passed on from one organism to another Which statement concerning somatic mutations or germline mutation is true - ANSWERSGermline mutation's are passed on to gametes Which molecule functions to transfer information from one generation to the next in eukaryotes - ANSWERSDNA Early transformation experiment demonstrated that adding DNA from bacterium strain B to bacterium strain A could - ANSWERSProduce bacterium strain B Purines include - ANSWERSadenine and guanine A number of characteristics of the common garden pea made it suitable for Mendels breeding experiments. Which of the following is not one of those characteristics - ANSWERSIt can reproduce asexually Mandel's crossing of rounded pea plants with wrinkled seeded pea plants resulted in progeny that have all round seeds. This indicates that the wrinkled seed trait is - ANSWERSRecessive Some organisms can reproduce by cloning themselves, an asexual process. Which type of organism is least able to naturally reproduce through cloning - ANSWERSMammals And a growing DNA strand each monomer is added to which carbon of the deoxyribose - ANSWERS3' The molecules that function to replicate DNA in the cell are - ANSWERSDNA polymerases The primer used for DNA replication - ANSWERSis needed only once on a leading strand The polymerase chain reaction - ANSWERSamplifies specific DNA sequences The first repair of mistakes during DNA replication is made by - ANSWERSDNA polymerase The products of mitosis are - ANSWERStwo genetically identical nuclei Despite the law of independent when two loci are on the same chromosome the phenotypes of the progeny sometimes do not fit the predicted phenotypes this outcome can be explained by the phenomenon of - ANSWERSLinkage The structure of DNA explains which three major properties of genes - ANSWERSThey contain information, replicate exactly, and can change to produce a mutation If a double-stranded DNA molecule contains 60% T, it must contain _____ percent G - ANSWERS40 Fission yeast can reproduce asexually following mitosis by - ANSWERSCytokinesis The members of a homologous pair of chromosomes in a sexually reproducing organisms - ANSWERSAre identical in size and appearance How does a nucleus in G2 differ from a nucleus in G1 - ANSWERSThe G2 nucleus has twice the amount of DNA has the G1 nucleus Centrosomes - ANSWERSDetermine the plane of cell division The mitotic spindle is composed of - ANSWERSmicrotubules After the centromere's separate during mitosis the chromatids now called ______ move toward opposite poles of the spindle - ANSWERSDaughter chromosomes In mitotic metaphase, a cell with eight sister chromatids has ____ centromeres - ANSWERSFour The processes of synapsis and the formation of chiasmata does not - ANSWERSOccur for all of the sister chromatids Down syndrome can be diagnosed by means of an examination of the individuals - ANSWERSKaryotype A triploid Nucleus cannot undergo meiosis because - ANSWERSNot all of the chromosomes can form homologous pairs The particular allele of a gene that is present in most individuals in nature is referred to as - ANSWERSWild type Despite the law of independent assortment went to Loci are on the same chromosome the phenotypes of the progeny sometimes do not that fit the predicted phenotypes. this outcome can be explained by the phenomenon of - ANSWERSLinkage Which statement about sexual and asexual reproduction is true? a. Haplontic organisms reproduce asexually. b. Sexual reproduction always involves the fertilization of eggs by sperm. c. An organism can only reproduce either sexually or asexually. d. Diplontic organisms are haploid in the gamete stage. e. Diplontic organisms are diploid in the gamete stage. - ANSWERSDiplontic organisms are haploid in the gamete stage. In organisms that display alternation of generations, - ANSWERSgametophytes are haploid and zygotes are diploid. Bacteria typically have _______, whereas eukaryotes have _______. a. one chromosome that is usually circular; several chromosomes that are linear b. several chromosomes that are circular; several chromosomes that are linear c. one chromosome that is linear; several chromosomes that are circular d. two chromosomes that are usually circular; eight chromosomes that are linear e. one chromosome that is linear; several chromosomes that are linear - ANSWERSone chromosome that is usually circular; several chromosomes that are linear During prokaryotic cell division, duplicated chromosomes separate from each other and are distributed into the daughter cells by - ANSWERSthe attaching of adjacent regions of ori to a protein filament. Mature nerve cells, which are incapable of cell division, are most likely in - ANSWERSG1 phase Which of the following is not involved in the separation of paired chromatids and their movement to opposite poles? a. ATP is hydrolyzed by cytoplasmic dynein. b. Kinetochore microtubules shorten. c. Kinetochore microtubules pull the chromatids away from the equatorial plate. d. Polar microtubules push the chromatids to the poles. e. Astral microtubules help keep poles apart. - ANSWERSPolar microtubules push the chromatids to the poles Which statement correctly distinguishes kinetochore microtubules from polar microtubules? a. Kinetochore microtubules are replaced by polar microtubules when the chromatids move toward the poles. b. Only polar microtubules contain cytoplasmic dynein, which acts as a "molecular motor." c. Kinetochore microtubules attach to the chromosomes, whereas polar microtubules extend from one pole to the other. d. Kinetochore microtubules form before polar microtubules. e. There is no difference; they are both names for the same structure. - ANSWERSKinetochore microtubules attach to the chromosomes, whereas polar microtubules extend from one pole to the other. Which statement about meiosis and mitosis is true? a. DNA replication occurs only in mitosis. b. DNA replication occurs only in meiosis. c. The products of meiosis can be different from one another, while the products of mitosis are all the same (except for rare mutations). d. The products of mitosis can be different from one another, while the products of meiosis are all the same (except for rare mutations). e. Mitosis and meiosis are the same process. - ANSWERSThe products of meiosis can be different from one another, while the products of mitosis are all the same (except for rare mutations). 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. - ANSWERShomologous chromosome pairs synapse during meiosis but not during mitosis. After DNA replication, each chromosome has _______ molecules of DNA called _______, that after separation are known as _______ chromosomes. a. two; sister chromatids; daughter b. four; sister chromatids; daughter c. two; daughter chromatids; sister d. four; sister chromosomes; daughter e. two; daughter chromosomes; sister - ANSWERStwo; sister chromatids; daughter If two strains of true-breeding plants that have different alleles for a certain character are crossed, their progeny are called - ANSWERSthe F1 generation. 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 F2 generation will be both tall and heterozygous? a. 1/8 b. 1/4 c. 1/3 d. 2/3 e. 1/2 - ANSWERS1/2 In garden peas, the allele for tall plants is dominant over the allele for short plants. A true-breeding tall plant is crossed with a short plant, and one of their offspring is test crossed. Out of 20 offspring resulting from the test cross, about _______ should be tall. a. 0 b. 5 c. 10 d. 15 e. 20 - ANSWERS10 The genotype of an organism that expresses a dominant trait can be determined by - ANSWERScrossing the organism with a homozygous recessive organism Separation of the alleles of a single gene into different gametes is called - ANSWERSsegregation Genetic mutations are not - ANSWERSalways deleterious When a given trait is the result of multigene action, one of the genes may mask the expression of one or all other genes. This phenomenon is termed - ANSWERSepistasis When a dihybrid black, normal-winged fly is crossed with a double-recessive gray, vestigial-winged fly, the frequency with which black vestigial-winged and gray normal-winged flies are seen in the progeny is called the _______ frequency. a. mutation b. mitotic c. meiotic d. allele e. recombination - ANSWERSrecombination Humans have 46 chromosomes and _______ autosomes. a. 23 pairs of b. 22 pairs of c. 1 pair of d. 45 e. 16 - ANSWERS22 pairs of Which statement about the molecular architecture of the standard configuration of DNA is false? a. The two strands run in opposite directions. b. The molecule's twist is left-handed. c. The molecule is a double-stranded helix. d. It has a uniform diameter. e. The helix has major and minor grooves. - ANSWERSThe molecule's twist is left-handed. The antiparallel relationship of the two strands of DNA refers to the - ANSWERSalignment of the strands, such that one strand starts with a 3 carbon and the other starts with a 5 carbon. The structure of DNA explains which three major properties of genes? - ANSWERSThey contain genetic information, can replicate exactly, and are susceptible to stable mutations. Which statement about the semiconservative replication of DNA is true? a. Each of the original strands acts as a template for a new strand. b. Only one of the original strands acts as a template for a new strand. c. It involves the complete separation of the original strands, the synthesis of new strands, and the reassembly of double-stranded molecules. d. The intact double-stranded molecule is used as a template. e. RNA is used as a template for DNA. - ANSWERS. Each of the original strands acts as a template for a new strand. DNA polymerase lengthens a polynucleotide strand by - ANSWERScovalently linking new nucleotides to a previously existing strand. A bacterial cell gives rise to two genetically identical daughter cells by a process known as - ANSWERSbinary fission Some organisms can reproduce by "cloning" themselves, an asexual process. Which type of organism is least able to naturally reproduce through "cloning"? a. Trees b. Bacteria c. Mammals d. Fungi e. Yeast - ANSWERSMammals The molecules that make up a chromosome are _______ and _______. a. nucleotides; nucleosides b. DNA; proteins c. proteins; lipids d. DNA; RNA e. proteins; phospholipids - ANSWERSDNA; proteins In a diploid organism, zygotes are - ANSWERSdiploid A typical eukaryotic cell cycle consists of - ANSWERSinterphase, mitosis, and cytokinesis. A number of characteristics of the common garden pea made it suitable for Mendel's breeding experiments. Which of the following is not one of those characteristics? a. It is "true-breeding." b. Self-fertilization can be controlled. c. It can reproduce asexually. d. It is easily cultivated. e. It can be manually fertilized. - ANSWERSIt can reproduce asexually. The parents of individuals in the F2 generation are members of the _______ generation. a. P b. F1 c. F2 d. F3 e. M - ANSWERSF1 If Mendel had performed experiments on cattle rather than on peas, the patterns of inheritance would not have been easily detectable, because cattle - ANSWERShave small numbers of offspring. Mendel's crossing of round-seeded pea plants with wrinkled-seeded pea plants resulted in progeny that all had round seeds. This indicates that the wrinkled-seed trait is - ANSWERSrecessive. Mendel concluded that each pea has two units for each character, and each gamete contains one unit. Mendel's "unit" is now referred to as a(n) - ANSWERSgene Different forms of a gene are called - ANSWERSalleles Which statement about a dihybrid cross is true? a. It results in a genotypic ratio of 2:1. b. It involves genes located on the sex chromosomes. c. It results in offspring of lower quality than that of the parents. d. It results in two different phenotypes in the F2 generation. e. It is a cross between identical double heterozygotes. - ANSWERSIt is a cross between identical double heterozygotes. Segregation of alleles occurs - ANSWERSduring gamete formation. Epistasis refers to a. a group of genes that are close together. b. the equal interaction of two genes so that a new phenotype is produced. c. the expression of two genes in the same individual. d. the linear order of genes on a chromosome. e. the expression of one gene affecting the expression of another.