Quiz 4 HCCS biology 1406 PDF

Preview

Summary

Practice questions on genetics material and some questions...

Description

Bi ol ogy1 4 06Qui z4HCCS

Multiple-Choice Questions 1) If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants? A) Backtrack through her previous experiments to obtain another plant with the same traits. B) Breed this plant with another plant with much weaker traits. C) Clone the plant asexually to produce an identical one. D) Force the plant to self-pollinate to obtain an identical one. E) Add nitrogen to the soil of the offspring of this plant so the desired traits continue. 2) In the human species, all somatic cells have 46 chromosomes. Which of the following can also be true? A) A plant species (privet shrubs) has 46 chromosomes per cell. B) Some adult humans have 69 chromosomes per cell. C) Some adult humans have 23 chromosomes per cell. D) A certain fungal species has only one chromosome per cell. E) A certain bacterial species has 23 chromosomes. 3) Which of the following is a true statement about sexual vs. asexual reproduction? A) Asexual reproduction, but not sexual reproduction, is characteristic of plants and fungi. B) In sexual reproduction, individuals transmit 50% of their genes to each of their offspring. C) In asexual reproduction, offspring are produced by fertilization without meiosis. D) Sexual reproduction requires that parents be diploid. E) Asexual reproduction produces only haploid offspring. 4) Which of the following defines a genome? A) representation of a complete set of a cell's polypeptides B) the complete set of an organism's polypeptides C) the complete set of a species' polypeptides D) a karyotype E) the complete set of an organism's genes 5) The human X and Y chromosomes A) are both present in every somatic cell of males and females alike. B) are of approximately equal size and number of genes. C) are almost entirely homologous, despite their different names. D) include genes that determine an individual's sex. E) include only genes that govern sex determination. 6) Referring to a plant's sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes? A) sporophyte meiosis B) gametophyte mitosis C) gametophyte meiosis D) sporophyte mitosis E) alternation of generations 1

7) The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following? A) mitosis in her ovary B) metaphase I of one meiotic event C) telophase II of one meiotic event D) telophase I of one meiotic event E) either anaphase I or II 8) A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following? A) 63 chromosomes in 31 1/2 pairs B) 63 chromosomes in 21 sets of 3 C) 63 chromosomes, each with three chromatids D) 21 chromosome pairs and 21 unique chromosomes 9) After telophase I of meiosis, the chromosomal makeup of each daughter cell is A) diploid, and the chromosomes are each composed of a single chromatid. B) diploid, and the chromosomes are each composed of two chromatids. C) haploid, and the chromosomes are each composed of a single chromatid. D) haploid, and the chromosomes are each composed of two chromatids. E) tetraploid, and the chromosomes are each composed of two chromatids. 10) When does the synaptonemal complex disappear? A) late prophase of meiosis I B) during fertilization or fusion of gametes C) early anaphase of meiosis I D) mid-prophase of meiosis II E) late metaphase of meiosis II 11) When we see chiasmata under a microscope, that lets us know which of the following has occurred? A) asexual reproduction B) meiosis II C) anaphase II D) prophase I E) separation of homologs 12) Assuming that the eggs are diploid, tetraploid, or partially tetraploid, what mechanism may still occur without fertilization? A) meiosis in each generation B) meiosis in every second generation C) independent assortment of maternal and paternal chromosomes D) meiosis in times of adverse environmental conditions E) crossing over of homologs 13) How is natural selection related to sexual reproduction as opposed to asexual reproduction? A) Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction. B) Sexual reproduction results in the most appropriate and healthiest balance of two sexes in the population. 2

C) Sexual reproduction results in the greatest number of new mutations. D) Sexual reproduction allows the greatest number of offspring to be produced. E) Sexual reproduction utilizes far less energy than asexual reproduction. 14) What do we mean when we use the terms monohybrid cross and dihybrid cross? A) A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents. B) A monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny. C) A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid cross involves only one. D) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. E) A monohybrid cross results in a 9:3:3:1 ratio whereas a dihybrid cross gives a 3:1 ratio. 15) What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants? A) There is considerable genetic variation in garden peas. B) Traits are inherited in discrete units, and are not the results of "blending." C) Recessive genes occur more frequently in the F1 generation than do dominant ones. D) Genes are composed of DNA. E) An organism that is homozygous for many recessive traits is at a disadvantage. 16) The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason? A) segregation of maternal and paternal alleles B) recurrent mutations forming new alleles C) crossing over during prophase I D) different possible alignments of chromosomes E) the tendency for dominant alleles to segregate together 17) Which of the following differentiates between independent assortment and segregation? A) The law of independent assortment requires describing two or more genes relative to one another. B) The law of segregation requires describing two or more genes relative to one another. C) The law of segregation requires having two or more generations to describe. D) The law of independent assortment is accounted for by observations of prophase I. E) The law of segregation is accounted for by anaphase of mitosis. 18) A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism? A) tt B) Hh C) HhTt D) T E) HT 19) Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that A) new mutations were frequently generated in the F2 progeny, "reinventing" traits that had been lost in the F1. 3

B) the mechanism controlling the appearance of traits was different between the F1 and the F2 plants. C) traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1. D) the traits were lost in the F1 due to dominance of the parental traits. E) members of the F1 generation had only one allele for each trait, but members of the F2 had two alleles for each trait. 20) Mendel was able to draw his ideas of segregation and independent assortment because of the influence of which of the following? A) His reading and discussion of Darwin's Origin of Species. B) The understanding of particulate inheritance he learned from renowned scientists of his time. C) His discussions of heredity with his colleagues at major universities. D) His experiments with the breeding of plants such as peas and fuchsia. E) His reading of the scientific literature current in the field. 21) In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short? A) 1 B) 1/2 C) 1/4 D) 1/6 E) 0 22) Given the parents AABBCc × AabbCc, assume simple dominance for each trait and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent? A) 1/4 B) 1/8 C) 3/4 D) 3/8 E) 1 23) Which of the following calculations require that you utilize the addition rule? A) Calculate the probability of black offspring from the cross AaBb × AaBb, when B is the symbol for black. B) Calculate the probability of children with both cystic fibrosis and polydactyly when parents are each heterozygous for both genes. C) Calculate the probability of each of four children having cystic fibrosis if the parents are both heterozygous. D) Calculate the probability of a child having either sickle-cell anemia or cystic fibrosis if parents are each heterozygous for both. E) Calculate the probability of purple flower color in a plot of 50 plants seeded from a self-fertilizing heterozygous parent plant. 24) Which of the following is an example of polygenic inheritance? A) pink flowers in snapdragons B) the ABO blood group in humans C) Huntington's disease in humans D) white and purple flower color in peas E) skin pigmentation in humans 4

25) How could you best predict the maximum number of alleles for a single gene whose polypeptide product is known? A) Search the population for all phenotypic variants of this polypeptide. B) Count the number of amino acids in the polypeptide. C) Mate all known genotypes and collect all possible offspring different from the parents. D) Measure the rate of new mutations in the species and estimate the number since it first evolved. E) Count the number of DNA nucleotides that are in the code for the polypeptides. 26) When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result? A) The gene involved is on the Y chromosome. B) The gene involved is on the X chromosome. C) The gene involved is on an autosome, but only in males. D) Other male-specific factors influence eye color in flies. E) Other female-specific factors influence eye color in flies. 27) Which of the following is the meaning of the chromosome theory of inheritance as expressed in the early 20th century? A) Individuals inherit particular chromosomes attached to genes. B) Mendelian genes are at specific loci on the chromosome and in turn segregate during meiosis. C) Homologous chromosomes give rise to some genes and crossover chromosomes to other genes. D) No more than a single pair of chromosomes can be found in a healthy normal cell. E) Natural selection acts on certain chromosome arrays rather than on genes. 28) A woman is found to have 47 chromosomes, including three X chromosomes. Which of the following describes her expected phenotype? A) masculine characteristics such as facial hair B) enlarged genital structures C) excessive emotional instability D) normal female E) sterile female 29) SRY is best described in which of the following ways? A) a gene present on the X chromosome that triggers female development B) an autosomal gene that is required for the expression of genes on the Y chromosome C) a gene region present on the Y chromosome that triggers male development D) an autosomal gene that is required for the expression of genes on the X chromosome E) a gene required for development, and males or females lacking the gene do not survive past early childhood 30) Duchenne muscular dystrophy (DMD) is caused by a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their 20s. How likely is it for a woman to have this condition? A) Women can never have this condition. B) One-half of the daughters of an affected man could have this condition. C) One-fourth of the children of an affected father and a carrier mother could have this condition. D) Very rarely would a woman have this condition; the condition would be due to a chromosome error. E) Only if a woman is XXX could she have this condition. 5

31) Which of the following statements is true of linkage? A) The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them. B) The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%. C) All of the traits that Mendel studied–seed color, pod shape, flower color, and others–are due to genes linked on the same chromosome. D) Linked genes are found on different chromosomes. E) Crossing over occurs during prophase II of meiosis. 32) Recombination between linked genes comes about for what reason? A) Mutation on one homolog is different from that on the other homolog. B) Independent assortment sometimes fails because Mendel had not calculated appropriately. C) When genes are linked they always "travel" together at anaphase. D) Crossovers between these genes result in chromosomal exchange. E) Nonrecombinant chromosomes break and then re-join with one another. 33) Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for which of the following reasons? A) The frequency of crossing over varies along the length of the chromosome. B) The relationship between recombination frequency and map units is different in every individual. C) Physical distances between genes change during the course of the cell cycle. D) The gene order on the chromosomes is slightly different in every individual. E) Linkage map distances are identical between males and females. 34) If nondisjunction occurs in meiosis II during gametogenesis, what will be the result at the completion of meiosis? A) All the gametes will be diploid. B) Half of the gametes will be n + 1, and half will be n - 1. C) 1/4 of the gametes will be n + 1, 1/4 will be n - 1, and 1/2 will be n. D) There will be three extra gametes. E) Two of the four gametes will be haploid, and two will be diploid. 35) A nonreciprocal crossover causes which of the following products? A) deletion only B) duplication only C) nondisjunction D) deletion and duplication E) duplication and nondisjunction 36) Abnormal chromosomes are frequently found in malignant tumors. Errors such as translocations may place a gene in close proximity to different control regions. Which of the following might then occur to make the cancer worse? A) an increase in nondisjunction B) expression of inappropriate gene products C) a decrease in mitotic frequency D) death of the cancer cells in the tumor E) sensitivity of the immune system 37) In his transformation experiments, what did Griffith observe? 6

A) Mutant mice were resistant to bacterial infections. B) Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form. C) Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic. D) Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains. 38) After mixing a heat-killed, phosphorescent strain of bacteria with a living nonphosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observations would provide the best evidence that the ability to fluoresce is a heritable trait? A) DNA passed from the heat-killed strain to the living strain. B) Protein passed from the heat-killed strain to the living strain. C) The phosphorescence in the living strain is especially bright. D) Descendants of the living cells are also phosphorescent. E) Both DNA and protein passed from the heat-killed strain to the living strain. 39) Which of the following investigators was/were responsible for the following discovery? In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine. A) Frederick Griffith B) Alfred Hershey and Martha Chase C) Oswald Avery, Maclyn McCarty, and Colin MacLeod D) Erwin Chargaff E) Matthew Meselson and Franklin Stahl 40) Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA? A) the diameter of the helix B) the rate of replication C) the sequence of nucleotides D) the bond angles of the subunits E) the frequency of A vs. T nucleotides 41) In an analysis of the nucleotide composition of DNA, which of the following will be found? A) A = C B) A = G and C = T C) A + C = G + T D) G + C = T + A 42) What is meant by the description "antiparallel" regarding the strands that make up DNA? A) The twisting nature of DNA creates nonparallel strands. B) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. C) Base pairings create unequal spacing between the two DNA strands. D) One strand is positively charged and the other is negatively charged. E) One strand contains only purines and the other contains only pyrimidines. 43) An Okazaki fragment has which of the following arrangements? A) primase, polymerase, ligase B) 3' RNA nucleotides, DNA nucleotides 5' 7

C) 5' RNA nucleotides, DNA nucleotides 3' D) DNA polymerase I, DNA polymerase III E) 5' DNA to 3' 44) Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction? A) primase B) DNA ligase C) DNA polymerase III D) topoisomerase E) helicase 45) The enzyme telomerase solves the problem of replication at the ends of linear chromosomes by which method? A) adding a single 5' cap structure that resists degradation by nucleases B) causing specific double-strand DNA breaks that result in blunt ends on both strands C) causing linear ends of the newly replicated DNA to circularize D) adding numerous short DNA sequences such as TTAGGG, which form a hairpin turn E) adding numerous GC pairs which resist hydrolysis and maintain chromosome integrity 46) At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' C C T A G G C T G C A A T C C 5' An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence? A) 5' G C C T A G G 3' B) 3' G C C T A G G 5' C) 5' A C G T T A G G 3' D) 5' A C G U U A G G 3' E) 5' G C C U A G G 3' 47) To repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act? A) exonuclease, DNA polymerase III, RNA primase B) helicase, DNA polymerase I, DNA ligase C) DNA ligase, nuclease, helicase D) DNA polymerase I, DNA polymerase III, DNA ligase E) endonuclease, DNA polymerase I, DNA ligase 48) The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that A) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose. B) the nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups. C) ATP contains three high-energy bonds; the nucleoside triphosphates have two. D) ATP is found only in human cells; the nucleoside triphosphates are found in all animal and plant cells. E) triphosphate monomers are active in the nucleoside triphosphates, but not in ATP. 49) A new DNA strand elongates only in the 5' to 3' direction because A) DNA polymerase begins adding nucleotides at the 5' end of the template. B) Okazaki fragments prevent elongation in the 3' to 5' direction. 8

C) the polarity of the DNA molecule prevents addition of nucleotides at the 3' end. D) replication must progress toward the replication fork. E) DNA polymerase can only add nucleotides to the free 3' end. 50) What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? A) It synthesizes RNA nucleotides to make a primer. B) It catalyzes the lengthening of telomeres. C) It joins Okazaki fragmen...