EXAM 4 CHAPTERS BIOL 1406 GENERAL BIOLOGY I DR. FARNSWORTH

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1 EXAM 4 CHAPTERS BIOL 1406 GENERAL BIOLOGY I DR. FARNSWORTH 1. The centromere is a region in which A. metaphase chromosomes become aligned at the metaphase plate. B. chromosomes are grouped during telophase. C. chromatids remain attached to one another until anaphase. D. the nucleus is located prior to mitosis. E. new spindle microtubules form at either end. 2. Which term describes centromeres uncoupling, sister chromatids separating, and the two new chromosomes moving to opposite poles of the cell? A. telophase B. anaphase C. prophase D. metaphase E. prometaphase 3. If there are 20 chromatids in a cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis? A. 20 B. 10 C. 80 D. 30 E Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants A. sister chromatids are identical, but they differ from one another in animals. B. the spindles contain microfibrils in addition to microtubules, whereas animal spindles do not contain microfibrils. C. chromosomes become attached to the spindle at prophase, whereas in animals chromosomes do not become attached until anaphase. D. a cell plate begins to form at telophase, whereas in animals a cleavage furrow is initiated at that stage. E. spindle poles contain centrioles, whereas spindle poles in animals do not. 5. During which phases of mitosis are chromosomes composed of two chromatids? A. from metaphase through telophase B. from anaphase through telophase C. from G2 of interphase through metaphase D. from G1 of interphase through metaphase E. from interphase through anaphase 6. The somatic cells derived from a single-celled zygote divide by which process? A. meiosis B. replication C. mitosis D. cytokinesis alone E. binary fission 1

2 7. Imagine looking through a microscope at a squashed onion root tip. The chromosomes of many of the cells are plainly visible. In some cells, replicated chromosomes are aligned along the center (equator) of the cell. These particular cells are in which stage of mitosis? A. anaphase B. prophase C. metaphase D. prometaphase E. telophase 8. Cells that are in a nondividing state are in which phase? A. S B. M C. G2 D. G0 E. G1 9. DNA is replicated at this time of the cell cycle: A. S B. M C. G2 D. G0 E. G1 10. In the cells of some organisms, mitosis occurs without cytokinesis. This will result in A. cell cycles lacking an S phase. B. destruction of chromosomes. C. cells with more than one nucleus. D. cells lacking nuclei. E. cells that are unusually small. 11. Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called A. centrioles. B. ATPases. C. kinetochores. D. cyclins. E. proton pumps. 12. Density-dependent inhibition is explained by which of the following? A. As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor. B. As cells become more numerous, the level of waste products increases, eventually slowing down metabolism. C. As cells become more numerous, more and more of them enter the S phase of the cell cycle. D. As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors. E. As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing. 2

3 13. Besides the ability of some cancer cells to overproliferate, what else could logically result in a tumor? A. metastasis B. lack of appropriate cell death C. inability of chromosomes to meet at the metaphase plate D. changes in the order of cell cycle stages E. inability to form spindles 14. What is a genome? A. The complete complement of an organism's genes B. A specific segment of DNA that is found within a prokaryotic chromosome C. A specialized polymer of four different kinds of monomers D. An ordered display of chromosomes arranged from largest to smallest E. A specific set of polypeptides within each cell 15. A gene's location along a chromosome is known as which of the following? A. Sequence B. Allele C. Variant D. Locus E. Trait 16. What is a karyotype? A. The combination of chromosomes found in a gamete B. The collection of all the mutations present within the genome of an individual C. A system of classifying cell nuclei D. The set of unique physical characteristics that define an individual E. A display of every pair of homologous chromosomes within a cell, organized according to size and shape 17. In animals, meiosis results in gametes, and fertilization results in A. sporophytes. B. spores. C. zygotes. D. clones. E. gametophytes. 18. A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? A. It must be a primate. B. It must be sexually reproducing. C. It must be an animal. D. Its gametes must have 23 chromosomes. E. It must be human. 19. How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis? A. They have twice the amount of cytoplasm and half the amount of DNA. B. They have half the amount of cytoplasm and twice the amount of DNA. C. They have half the number of chromosomes and half the amount of DNA. D. They have half the number of chromosomes and one-fourth the amount of DNA. E. They have the same number of chromosomes and half the amount of DNA. 3

4 20. Independent assortment of chromosomes occurs. A. The statement is true for mitosis and meiosis II. B. The statement is true for meiosis II only. C. The statement is true for meiosis I only. D. The statement is true for mitosis only. E. The statement is true for mitosis and meiosis I. 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. Separated sister chromatids at each pole of the cell B. A cleavage furrow C. Tetrads lined up at the center of the cell D. A visible nuclear envelope E. A synaptonemal complex 22. Chiasmata are what we see under a microscope that let us know which of the following has occurred? A. Crossing over B. Anaphase II C. Meiosis II D. Asexual reproduction E. Separation of homologs 23. A human cell containing 22 autosomes and a Y chromosome is A. a sperm. B. an egg. C. a somatic cell of a male. D. a somatic cell of a female. E. a zygote. 24. Independent assortment of chromosomes is a result of A. the random nature of the fertilization of ova by sperm. B. the random distribution of the sister chromatids to the two daughter cells during anaphase II. C. the relatively small degree of homology shared by the X and Y chromosomes. D. the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I. E. All of the above 25. For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes? A. 460 B. 23 C. 46 D. 920 E. About 8 million 26. The F1 offspring of Mendel's classic pea cross always looked like one of the two parental varieties because A. no genes interacted to produce the parental phenotype. B. the traits blended together during fertilization. C. one phenotype was completely dominant over another. D. different genes interacted to produce the parental phenotype. E. each allele affected phenotypic expression. 4

5 27. 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. HT C. HhTt D. T E. Hh Use Figure 14.1 and the following description to answer the questions below. In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in Figure 14.1, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Figure Which of the boxes marked 1-4 correspond to plants with dark leaves? A. 4 only B. 2 and 3 C. 1, 2, and 3 D. 1 only E. 1 and Which of the boxes correspond to plants with a heterozygous genotype? A. 2 and 3 B. 1 and 2 C. 2, 3, and 4 D. 1 E. 1, 2, and Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of the cross BbTt BBtt will have black fur and long tails? A. 3/8 B. 9/16 C. 1/2 D. 3/16 E. 1/16 5

6 Use the following information to answer the questions below. Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant characteristic. 31. If true-breeding red long radishes are crossed with true breeding white oval radishes, the F1 will be expected to be which of the following? A. Red and oval B. Purple and oval C. White and long D. Purple and long E. Red and long 32. The flower color trait in radishes is an example of which of the following? A. Sex linkage B. A multiple allelic system C. Codominance D. Epistasis E. Incomplete dominance 33. Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower color is dominant to white (r). The heterozygous condition results in pink (Rr) flower color. A dwarf, red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F1 individuals? A. ttrr dwarf and white B. TtRr tall and red C. TtRr tall and pink D. ttrr dwarf and pink E. TTRR tall and red Use the following information to answer the questions below. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. 34. Which of the following is a possible partial genotype for the son? A. ii B. IBIA C. IBIB D. IBi E. IAIA 35. Which of the following is a possible phenotype for the father? A. AB negative B. O negative C. Impossible to determine D. A negative E. B positive 6

7 36. Which describes the ability of a single gene to have multiple phenotypic effects? A. Epistasis B. Multiple alleles C. Pleiotropy D. Incomplete dominance 37. Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following? A. The alleles being codominant B. The fact that a mutation has occurred C. Acknowledging that multiple alleles are involved D. The allele for blue hydrangea being completely dominant E. Environmental factors such as soil ph 38. Huntington's disease is a dominant condition with late age of onset in humans. If one parent has the disease, what is the probability that his or her child will have the disease? A. 1 B. 1/4 C. 3/4 D. 0 E. 1/2 39. A woman has six sons. The chance that her next child will be a daughter is A. 1. B. 1/6. C. 5/6. D. 1/2. E An ideal procedure for fetal testing in humans would have which of the following features? A. The procedure that can test for the greatest number of traits at once B. A procedure that provides a 3D image of the fetus C. Lowest risk procedure that would provide the most reliable information D. A procedure that could test for the carrier status of the fetus E. The procedure that can be performed at the earliest time in the pregnancy 41. An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable biochemically in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient? A. CVS B. Amniocentesis C. X-ray D. Ultrasound imaging E. Fetoscopy 7

8 42. 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. D. Other female-specific factors influence eye color in flies. E. Other male-specific factors influence eye color in flies. 43. What is the chromosomal system for determining sex in mammals? A. Haploid-diploid B. X-Y C. Z-W D. X-0 E. X-X 44. Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents? A. XCXC and XcY B. XcXc and XcY C. XCXC and XCY D. XcXc and XCY E. XCXc and XCY 45. A Barr body is normally found in the nucleus of which kind of human cell? A. Somatic cells of a female only B. Both male and female somatic cells C. Unfertilized egg cells only D. Somatic cells of a male only E. Sperm cells only 46. Which of the following statements is true? A. Crossing over occurs during prophase II of meiosis. B. The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%. C. Linked genes are found on different chromosomes. D. All of the traits that Mendel studied seed color, pod shape, flower color, and others are due to genes linked on the same chromosome. E. The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them. 8

9 47. The following is a map of four genes on a chromosome: Figure 15.1 Between which two genes would you expect the highest frequency of recombination? A. E and G B. A and W C. W and E D. A and G E. A and E 48. A cell that has 2n + 1 chromosomes is A. euploid. B. monosomic. C. trisomic. D. triploid. E. polyploid. 49. One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this alteration called? A. Deletion B. Translocation C. Duplication D. Disjunction E. Inversion 50. The frequency of Down syndrome in the human population is most closely correlated with which of the following? A. Age of the mother B. Exposure of pregnant women to environmental pollutants C. Average of the ages of mother and father D. Frequency of new meiosis E. Age of the father 9