Problem Set 4 BILD10 / Winter 2014

Transcription

1 1) The DNA in linear eukaryotic chromosomes is wrapped around proteins called, which keep the DNA from getting tangled and enable an orderly, tight, and efficient packing of the DNA inside the cell. A) centromeres B) histamines C) histones D) ribosomes E) telomeres 2) A chicken has 78 chromosomes in its somatic cells. How many chromosomes did the chicken inherit from each parent? How many chromosomes are in each of the chicken s gametes? How many chromosomes will be in each somatic cell of the chicken s offspring? How many chromosomes are in a set? 78 total chromosomes means that the chicken received 39 from each parent s gamete. Likewise, it will also have 39 in its own gametes. 78 total chromosomes in the somatic cells of its offspring. There are 39 chromosomes in one set. 3) What is the name for the special region on a duplicated chromosome that holds the sister chromatids together? A) centrosome B) centromere C) kinetochore D) desmosome E) microtubule organizer region 4) Animal cells have counters that keep track of how many times a cell has divided. These counters are called: A) odometers. B) telomeres. C) chromosomes. D) nuclei. E) centromeres. The questions below refer to the following terms. Each term may be used once, more than once, or not at all. A. telophase B. anaphase C. cytokinesis D. metaphase E. prophase 5) Duplicated cells physically separate from each other at the end of this phase. C. cytokinesis 1

2 6) Centrioles begin to move apart in animal cells. E. prophase 7) This is the longest of the mitotic stages. E. prophase 8) Centromeres uncouple, sister chromatids are separated, and the two new chromosomes move to opposite poles of the cell. B. anaphase 9) The eukaryotic chromosome: A) condenses only during anaphase of mitosis. B) contains no centromeres. C) consists of two joined linear strands of double-stranded DNA during the Gap 2 phase. D) is usually circular. E) consists of a single linear strand of double-stranded DNA during the Gap 2 phase. 10) A human skin cell contains 46 chromosomes (23 paternally inherited and 23 maternally inherited). Before mitosis begins, this cell must duplicate its genetic material. What are the products of this duplication? A) 92 sister chromatids, in 46 pairs that are connected by a centromere B) 92 chromosomes, each consisting of two homologous chromatids connected by a centromere C) 92 chromatids, each consisting of two sister chromosomes connected by a kinetochore D) 23 chromosomes, each consisting of a maternal and a paternal chromatid connected by a centromere E) None of the above is correct. 11) marks the break in the cell cycle between the end of mitosis and the beginning of the synthesis stage. A) Gap 2 B) DNA synthesis phase C) Mitotic phase D) Gap 1 E) None of the above is correct. 12) The planned process of cell suicide is called: A) apoptosis. B) mitosis. C) meiosis. D) metastasis. E) malignancy. 2

3 13) This figure depicts: A) mitotic anaphase. B) mitotic prophase. C) mitotic metaphase. D) mitotic telophase. E) meiotic anaphase I. 14) In order for a eukaryotic cell to undergo reproduction and divide, certain steps must be successfully completed. Which of the following choices is NOT one of these necessary steps? A) There must be proper packaging and segregation of the replicated DNA. B) There must be proper reshuffling of the genetic material in order to provide diversity within the gametes. C) There must be replication of the DNA within the nucleus. D) There must be proper division of the cytoplasm. E) All of the choices above are necessary steps in eukaryotic cellular replication. 15) Which of the following are features that distinguish cancer cells from normal cells? A) Normal cells undergo cytokinesis; cancer cells do not undergo cytokinesis. B) Normal cells have contact inhibition; cancer cells have no contact inhibition. C) Normal cells metastasize; cancer cells do not metastasize. D) Normal cells can divide a finite number of times; cancer cells can divide indefinitely. E) Both b) and d) are correct. 16) A diploid cell undergoes meiosis. What are the products of this division? A) one polyploid gamete B) four haploid cells C) four diploid cells D) two haploid cells E) two diploid cells 17) The egg cells of a horse contain 32 chromosomes. How many chromosomes are in the horse s liver cells? A) 32 B) 16 C) 128 D) 64 E) 8 18) What is the definition of female? A) producing the smaller, more motile gamete B) producing the smaller, less motile gamete C) producing the larger, more motile gamete D) producing the larger, less motile gamete 3

4 19) Asexual reproduction and sexual reproduction are different in that A) individuals reproducing asexually transmit 100% of their genes to their progeny, whereas individuals reproducing sexually only transmit 50%. B) asexual reproduction produces offspring that are genetically identical to the parents, whereas sexual reproduction gives rise to genetically distinct offspring. C) asexual reproduction involves a single parent, whereas sexual reproduction involves two. D) asexual reproduction only requires mitosis, whereas sexual reproduction always involves meiosis. E) all of the above 20) Independent assortment of chromosomes is a result of: A) the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I. B) the random nature of the fertilization of ova by sperm. C) the random distribution of the sister chromatids to the two daughter cells during anaphase II. D) the relatively small degree of homology shared by the X and Y chromosomes. E) all of the above 21) You have in your possession a microscope slide with meiotic cells on it and a light microscope. What would you look for if you wanted to identify metaphase I cells on the slide? A) a visible nuclear envelope B) separated sister chromatids at each pole of the cell C) tetrads lined up at the center of the cell D) a synaptonemal complex E) a cleavage furrow 22) Which of the following is true of a species that has a chromosome number of 2n = 16? A) The species is diploid with 32 chromosomes. B) The species has 16 sets of chromosomes. C) There are 8 homologous pairs. D) During the S phase of the cell cycle there will be 32 separate chromosomes. E) A gamete from this species has 4 chromosomes. 23) Which of the following is the term for a human cell that contains 22 pairs of autosomes and two X chromosomes? A) an unfertilized egg cell B) a sperm cell C) a male somatic cell D) a female somatic cell 24) Organisms with different genotypes can have the same phenotype! Is this statement true or false? Explain why. TRUE. Dominant alleles carried in individuals with either homozygous or heterozygous genotypes could result in identical phenotypes. 4

5 25) A) In a diploid organism, how many different alleles at a single locus can that organism possess? TWO. B) How many different alleles of a particular gene can be found in a population of organisms? MANY/UNLIMITED. 26) The gene specifying blood group determinants can occur in three alleles: A, B and O. A and B are codominant, while O is recessive. If Luke Skywalker s mother was blood type A and Luke himself were type B, what blood type(s) if any would DarthVader have to be to unequivocally rule him out as Luke s natural father? Darth Vader could not be his father if blood type A (AA or AO) or O (OO). (Mom is AA or AO. Luke must be BO. Darth Vader can only be AB or BO.) 27) Cystic fibrosis is inherited as a simple autosomal recessive in humans. If a woman who is a carrier marries a man who is normal and not carrying the trait, what percent of their children would be expected to have the disease? NONE. 28) Brown eyes (B) are dominant to blue eyes (b). A blue-eyed man, both of whose parents had brown eyes, married a brown-eyed woman whose father was blue-eyed and whose mother was brown-eyed. This man and woman have a blue-eyed child. A) What are the genotypes of all the individuals mentioned? The blue-eyed man s pedigree: Bb x Bb à bb The brown-eyed woman s pedigree: bb x B(B or b) à Bb à bb (blue-eyed child) B) What is the probability that their next child will also have blue eyes? brown eyes? 50% blue-eyed, 50% brown-eyed. 29) Peas (Pisum sativum) were well suited for Mendel s breeding experiments for all of the following reasons except: A) peas exhibit variations in a number of observable characteristics, such as seed color and shape. B) Mendel and his staff could control the pollination between different pea plants. C) it is easy to obtain large numbers of offspring from any given cross. D) many of the characteristics that vary in pea plants are controlled by single genes. E) peas have a particularly long generation time. 30) In pea plants, purple flower color is dominant to white flower color. If two pea plants that are truebreeding for white flowers are crossed, in the offspring: A) all of the flowers will be purple. B) three-quarters of the flowers will be purple and one-quarter will be white. C) half of the flowers will be purple and half will be white. D) one-quarter of the flowers will be purple and three-quarters will be white. E) all of the flowers will be white. 5

6 31) A true-breeding red rose is mated with a true-breeding white rose, and all of their offspring are red. If two of these red offspring are mated, what percentage of their offspring will be red? A) 60% B) 100% C) 25% D) 50% E) 75% 32) The test-cross: A) makes it possible to determine the genotype of an individual of unknown genotype who exhibits the dominant version of a trait. B) is a cross of an individual whose genotype for a trait is not known with an individual homozygous-recessive for the trait. C) sometimes requires the production of multiple offspring in order to reveal the genotype of an individual whose genotype is unknown. D) a) and b) are both correct. E) a), b), and c) are correct. 33) Assuming that a particular disorder is caused by an allele of a single gene, what feature of a pedigree would allow one to conclude that the disorder was caused by a dominant allele? A) Two unaffected parents have an affected child. B) Two affected parents have an unaffected child. C) Two unaffected parents have an unaffected child. D) An affected mother only has affected sons. E) All of the descendants of a particular affected person are also affected. 34) What is a sex-linked trait? A gene located on a sex chromosome (in humans, usually refers to gene on X chromosome) 35) The ABO blood type system in humans is an example of: A) balanced polymorphism and codominance. B) codominance but not multiple alleles. C) multiple alleles and codominance. D) multiple alleles but not codominance. E) balanced polymorphism but not codominance. 36) A woman with type B blood and a man with type A blood could have children with which of the following phenotypes? A) A, B, AB, or O B) A, B, or O C) AB only D) AB or O E) O only 6