Bio 104 2002 Test 2 Answers Stark

1. A pair of sister chromatids might be X-shaped in the microscope
(a) only for the X chromosome.
(b) during the G2 of interphase.
(c) because of the centriole pair.
(d) in anaphase.
*(e) when they are joined at the centromere.

2. Occasional unequal crossing over, over the course of evolutionary time, would lead to
*(a) the evolution of related but different proteins like the many G protein coupled receptors.
(b) is the explanation for the famous 9:3:3:1 ratio.
(c) has the same effect as nondisjunction.
(d) the origin of diploidy.
(e) the inactivation of all but one X chromosome.

3. When does crossing over occur?
(a) during G2
(b) during fertilization
(c) during mitosis
*(d) when the tetrad is present
(e) during interphase

4. Mendel's laws of segregation and independent assortment apply to
(a) mitosis.
(b) non-disjunction.
*(c) meiosis.
(d) linkage.
(e) mapping.

5. Which is a mutation?
(a) Klinefelter's syndrome
*(b) Tay Sach's disease.
(c) Down's syndrome
(d) XYY
(e) Turner's syndrome

6. Making haploid cells from diploid cells is called
(a) nondisjunction.
*(b) meiosis.
(c) mitosis.
(d) mapping.
(e) fertilization.

7. Hemophelia is a sex-linked recessive allele. If a mother and father have a daughter with hemophelia, which of the following statements is the only one which MUST be correct on the basis of this information?
*(a) The father has hemophelia.
(b) The mother has hemophelia.
(c) Both father and mother have hemophelia.
(d) The daughter inherited all hemophelia alleles from the mother.
(e) Half of the mother's sons would have hemophelia.

8. Karyotypes are produced from
(a) gametes.
*(b) cells arrested in metaphase.
(c) nuclei of myocardial dells.
(d) haploid cells.
(e) cells in meiosis.

9. Nondisjunction of chromosome #21 in humans leads to
(a) Tay-Sachs disease.
(b) Crossing over.
(c) Klinefelter's syndrome.
(d) Turner's syndrome.
*(e) Down's syndrome.

10. Most people are not born with fatal genetic diseases. Why not?
(a) Most parents do not have detrimental mutations.
(b) The only mutations that can possibly be detrimental are autosomal dominant.
(c) Mutations only occur on extra chromosomes produced by nondisjunction.
(d) Mutations only occur on the Y chromosome.
*(e) Detrimental mutations are usually heterozygous recessive.

11. What blocks the UV light that damages proteins and DNA?
(a) P700.
(b) cyclin.
(c) cAMP.
*(d) ozone.
(e) NADPH.

12. A person has 44 autosomes plus one X chromosome plus one Y chromosome. Which statement is true for this person?
*(a) The Y chromosome came from the father.
(b) The X chromosome becomes a Barr body.
(c) The X chromosome could have come from either the father or the mother.
(d) The Y chromosome's inactivation is described by the Mary Lyon hypothesis.
(e) This person has Klinefelter's syndrome.

13. The kinetochore is most closely associated with
(a) interphase chromatin.
(b) the stamen.
(c) the G protein linked signal transduction cascade.
(d) the part of the gene to which steroid hormone receptors bind.
*(e) the centromere.

14.What is cytokinesis?
(a) the way useful energy is obtained after light excites an electron
(b) the arrest of neurons in adult human central nervous system in G1
*(c) the final processes of cell division
(d) how cAMP becomes inactivated
(e) a way to test for genetic or chromosomal abnormalities

15. Which statement applies to the Siamese cat having white fur with black extremities?
*(a) A mutation makes an enzyme for melanin synthesis temperature-sensitive.
(b) Black vs. white depends on which X chromosome is active.
(c) There is incomplete dominance like for snapdragon flower color.
(d) The cat is heterozygous for the body color gene.
(e) Sons of such a female cat will be either black or white.

16. What is one reason that type O individuals would be especially useful in a blood drive?
*(a) They are universal donors.
(b) They are universal recipients.
(c) They have A and B antigens as well as antibodies against A and B.
(d) They are homozygous dominant.
(e) They are the only people that are not mutant.

17. Disregarding crossing over, in meiosis, [A] separate in the first division, while [B] separate in the second division.
(a) A-single DNA strands, B-centrioles.
(b) A-alleles, B-genes.
(c) A-homozygotes, B-heterozygotes.
(d) A-chromatin, B-tetrads.
*(e) A-homologous chromosomes, B-sister chromatids.

18. Where do the reactions of the Calvin cycle take place?
*(a) in the stroma
(b) in the grana
(c) in the cytoplasm
(d) in the nucleus
(e) in the rough endoplasmic reticulum

19. A pea plant with purple flowers is referred to as Pp. Pp
(a) is the plant's phenotype.
(b) indicates that the plant is homozygous.
(c) are only seen in the F2 of a cross of purple- and white-flowered pea plants.
*(d) is the plant's genotype.
(e) is a gamete.

20. The intracellular signal molecule IP3 binds to an IP3 receptor on a smooth endoplasmic reticulum and causes the release of
(a) kinase.
(b) hormone.
*(c) Ca++ ions.
(d) cAMP.
(e) testosterone.

21. In your genetics coverage, you were introduced to the term "locus." Of the following, which would be the best term to substitute for "locus?"
(a) true-breeding
(b) hybrid
(c) chromosome
*(d) gene
(e) allele

22. Most people have two copies of chromosome 21. These two copies would be called
(a) alleles.
(b) tetrads.
*(c) homologues.
(d) spindles.
(e) centromeres.

23. Name a cell that could have 22 autosomes and one Y chromosome.
*(a) a human sperm cell
(b) a human ovum
(c) a human diploid cell
(d) a body cell from a Klinefelter's syndrome individual
(e) a cell from a Turner's syndrome individual

24. Which wavelength or color of light would be least likely to be absorbed by a leaf?
(a) 450 nm
*(b) 550 nm
(c) 650 nm
(d) blue
(e) red

25. Which is a dominant lethal mutation which probably would not be expressed until after affected men and women have had children?
(a) Down's syndrome
(b) PKU
*(c) Huntington's chorea
(d) Tay Sachs disease
(e) Sickle cell anemia

26. What made the example of the ABO blood groups an interesting contrast with the pea crosses used to exemplify Mendel's first and second laws?
(a) There were more than two loci.
(b) There are no homozygotes.
(c) There are no genotypes, only phenotypes.
(d) The genes are sex-linked.
*(e) There were three alleles.

27. When sperm and egg form the zygote, this is called
(a) nondisjunction.
(b) meiosis.
(c) mitosis.
(d) crossing over.
*(e) fertilization.

28. The tetrad would form
(a) during the preparation of the karyotype.
(b) in the G1 portion of the cell cycle.
*(c) during meiosis.
(d) only during interphase.
(e) after gametes are haploid.

29. Epinephrine would best be described as a
(a) G protein.
*(b) ligand.
(c) second messenger.
(d) enzyme.
(e) kinase.

30. H2O is used in [A] while CO2 is fixed in [B].
(a) A-Calvin cycle; B-Calvin cycle.
(b) A-light reactions; B-light reactions.
(c) A-Calvin cycle; B-light reactions.
*(d) A-light reactions; B-Calvin cycle.
(e) A-P680; B-P700.

31. Haploid is a term that would apply to
(a) interphase.
(b) chromosomes viewed for the karyotype.
(c) daughter cells of a mitotic division
*(d) gametes.
(e) zygotes.

32. In flowering plants, meiosis
(a) makes gametes just as it does in animals.
(b) makes sperm and eggs.
(c) makes zygotes, in contrast with the situation for animals.
*(d) gives rise to a separate gamete-forming organism.
(e) makes all the cells of the plants.

33. How does testosterone signal its target cells.
(a) It is a neurotransmitter that opens channels at the synapse.
(b) It binds the G protein coupled receptor.
*(c) It crosses the plasma membrane, binds a protein, and activates transcription in the nucleus.
(d) It breaks down cAMP.
(e) It binds GTP.

34. Mendel's second law
(a) explains how both yellow or green pea bearing plants would be seen in subsequent generations if homozygous yellow or green pea bearing plants are crossed.
*(b) applies to two alleles of two genes on two different chromosomes.
(c) is the law of segregation.
(d) was used by Darwin to explain some aspects of evolution.
(e) is how linked genes are mapped on one chromosome.

35. What do carotenoids do in photosynthesis?
(a) They are responsible for the electron transport chain.
*(b) They absorb short wavelength light.
(c) They carry the H which was split from H2O over to carbohydrate.
(d) They deliver the captured light energy to the "dark" reactions.
(e) They are the 4-carbon molecules of C4 photosynthesis.

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