Bio 60 Exam 2

1. A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation). Albinism is an autosomal (not sex-linked) recessive trait. What is the probability that their first child will be an albino?

2. A cell that has 2n + 1 chromosomes is

3. A pedigree analysis for a given disorder's occurrence in a family shows that, although both parents of an affected child are normal, each of the parents has had affected relatives with the same condition. The disorder is then which of the following?

4. An individual heterozygous for cystic fibrosis _______.

5. A couple has a child with Down syndrome when the mother is 39 years old at the time of delivery. Which is the most probable cause?

6. Which of the following represents the Klinefelter syndrome in man?

7. Duchene muscular dystrophy is a human disorder that causes gradual deterioration of the muscles. Only boys are affected, and they are always born to phenotypically normal parents. Due to the severity of the disease, the boys die in their teens. Is this disorder likely to be caused by a dominant or recessive allele? Is its inheritance sex-linked or autosomal?

8. Which of the following is true of a species that has a chromosome number of 2n = 32?

9. How is plant cell cytokinesis different from animal cell cytokinesis?

10. Sickle-cell anemia represents the most common genetic disorder among African Americans that is manifested as

11. Nerve cells lose their ability to undergo mitosis. Instead, they are permanently stuck in _____.

12. A man has six fingers on each hand and six toes on each foot. His wife and their daughter have the normal number of digits. Extra digits is a dominant trait. What fraction of this couple's children would be expected to have extra digits?

13. Prior to mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called

14. Which one of the following is false?

15. Interphase is the part of the cell cycle when

16. What it the total number of chromosomes you would expect to find in the karyotype of a female with Turner syndrome?

17. The frequency of crossing over between any two linked genes will be which of the following?

18. A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question in most likely in

19. 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?

20. If a female of this species has one chromosome 12 with a blue allele of a gene and another chromosome 12 with an orange allele, she will produce which of the following egg types?

21. In eukaryotic cells, chromosomes are composed of _____.

22. The observable traits of an organism are its__________

23. One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this alteration called?

24. Cycle of life for humans requires

25. Glucose-6-phosphate dehydrogenase deficiency (G6PD) is inherited as a recessive allele of an X-linked gene in humans. A woman whose father suffered from G6PD marries a normal man. (a) What proportion of their sons is expected to be G6PD? (b) If the husband was not normal but was G6PD deficient, would you change your answer in part (a)?

26. Family pedigree shows

27. What is the genotype of an individual who is heterozygous for dimples?

28. Asexual reproduction takes place by which of the following processes?

29. Sister chromatids are separated from each other

30. The mitotic spindle is a microtubular structure that is involved in _____.

31. Metaphase occurs prior to the splitting of centromeres. It is characterized by _____.

32. Which of the following events occurs during telophase?

33. In birds, sex is determined by a ZW chromosome scheme that is much like the typical XY scheme seen in humans and many other organisms, except that the system is reversed: Males are ZZ (similar to XX in humans) and females are ZW (similar to XY in humans). A lethal recessive allele that causes death of the embryo occurs on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male heterozygous for the lethal allele and a normal female?

34. Siblings of the same biological parents can look very much alike, but they are not identical, because of

35. When the coding sequence ONEREDEYEFLYEATONEREDBUG, changes to ONEREDEEYEFLYEATONEREDBUG, this mutation represents

36. A homozygous tomato plant with red fruit and yellow flowers was crossed with a homozygous tomato plant with golden fruit and white flowers. The F1 all had red fruit and yellow flowers. The following phenotypes were obtained in the F2: Red fruit and yellow flowers—41 Red fruit and white flowers—7 Golden fruit and yellow flowers—8 Golden fruit and white flowers—44 How many map units separate these genes?

37. Scientists isolate cells in various phases of the cell cycle. They isolate a group of cells that have 1 1/2 times more DNA than G1 phase cells. What is the most likely part of the cell cycle from which these cells were isolated?

38. In a diploid cell with 5 chromosome pairs (2n = 10), how many sister chromatids will be found in a nucleus at prophase of mitosis?

39. How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I?

40. The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. In addition to mutations, how might genetic diversity be generated in this species?

41. 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?

42. Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6,022 yellow and 2,001 green (8,023 total). Which of the following statements correctly describes the relationship of the allele for green seeds to the allele for yellow seeds?

43. Which of the following inheritance patterns describes the ability of a single allele to have multiple phenotypic effects?

45. The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. What is the result of this type of mutation?

46. A single base substitution mutation is likely to have a less deleterious effect when the base change exhibits which of the following results?

47. 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?

48. Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cacti have spines. Homozygous recessive nn cacti have no spines at all. The relationship between genes S and N is an example of which of the following inheritance patterns?

49. Sex determination in mammals is due to the SRY gene found on the Y chromosome. Which of the following situations could allow a person with an XX karyotype to develop a male phenotype?