Practice Exam 3

25. Test Cross: In house cats, brown eyes (BB or Bb) are dominant to green eyes (bb). You would like to determine whether your brown-eyed female cat is homozygous dominant OR heterozygous for brown eye by doing a test cross with a green-eyed male cat. If your female cat is homozygous dominant:

a. 100% of the kittens will have brown eyes

33. Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately, what percentage of the nucleotides in this sample will be thymine?

a. 12 %

12. A human cell containing 22 autosomes and a Y chromosome is

a. a sperm.

14. A cell in G2: a. has twice the amount of DNA present in

a. has twice the amount of DNA present in a telophase nucleus.

7. An animal with a diploid number of 36 chromosomes will have ________ chromosomes in its gametes and _________ chromosomes in its somatic cells.

b. 18; 36

18. Which of the following triggers the cell's passage past the G2 checkpoint into mitosis?

b. MPF

40. Which of the following scientists is incorrectly matched with their discoveries?

b. Maurice Wilkins - The bases in DNA follow the role of A=T, G=C

45. Lab9 Strawberry DNA: Which of the following is not correctly matched with its function in the procedure for strawberry DNA isolation? a. EtOH - Precipitates DNA b. NaCl - Allows the cells to swell and burst open c. SDS - Lyses the cells and denature the proteins d. EDTA - Chelates divalent cations like Mg+2 from solution

b. NaCl - Allows the cells to swell and burst open

31. Which of the following DNA replication enzymes is incorrectly described?

b. Primase: Removes RNA and adds the equivalent DNA to the 3' end of the Okasaki fragment

13. Homologous chromosomes move toward opposite poles of

b. anaphase I.

6. The _____ is responsible for the separation of the chromosomes during ____ of mitosis.

b. mitotic spindle; anaphase

15. Homologous chromosomes synapse or pair during:

b. prophase I

23. Halloween Pumpkin Genetics: Pumpkins can be Orange (P-) or yellow (pp), Smooth (S-) or "warty" (ss). If a pumpkin plant heterozygous for orange, smooth pumpkins (PpSs) is crossed with a plant that is Ppss, what is the probability of observing a yellow, warty pumpkin?

d. 1/8

24. Incomplete Dominance: Flower color in snapdragons shows incomplete dominance. If a red-flowered plant is crossed with a white-flowered plant, the F1 generation has pink flowers. If a pink-flowered plant is crossed with a pink-flowered plant, the progeny plants will be

d. 25% red, 50% pink, and 25% white

11. (Figure above) Which of the cells above shows the arrangement of chromosomes that occurs just before the sister chromatids separate?

d. A and C see diagram

26. Blood Type: A women and her baby daughter both have Type O blood. In a paternity suit, who would be immediately disqualified for paternity of this child?

d. A man with blood type AB

19. During which of the following stages of meiosis do the sister centromeres separate?

d. anaphase II

39. Individuals with the disorder XP (xeroderma pigmentosum) are hypersensitive to sunlight because their cells have an impaired ability to

d. correct errors in DNA sequences by excision repair enzymes.

29. Which of the following genetic disorders is incorrectly matched with its type of inheritance?

a. Progeria- autosomal recessive

32. Match the following aspects of DNA replication (A-F) to their correct descriptions

a. Site of action of DNA Ligase = D b. Leading Strand = A c. Okasaki Fragments = E d. Lagging Strand = B e. RNA primers = F f. DNA Template Strand = C see diagram

42. Lab7 Photosynthesis: The solvent front on a chromatogram ran 80 mm from the origin. A green pigment on that chromatogram ran 40 mm from the origin. Based on this,

a. The Rf for the pigment is 0.5 see diagram

10. (Figure above) Which of the cells above shows the arrangement of chromosomes that occurs just before the homologous chromosomes separate?

b Cell B See diagram

27. Epistasis: A black Labrador retriever (BbEe) is crossed with a yellow Lab (Bbee). In a litter of F1 puppies, what are the likely proportions of black, chocolate or yellow Labs?

b. 3 Black, 1 Chocolate, 4 Yellow

34. The strands that make up DNA are antiparallel. This means that

b. the 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

30. Based on your understanding of the sugars, nitrogenous bases, and hydrogen bonding between nucleic acids, what does the diagram below represent?

c. 1 is deoxyribose, 2 is Guanine (G), 3 is Cytosine (C) see diagram

22. Dihybrid Cross: A couple has three children, all of whom have blue eyes (bb) and blonde hair (rr). Both parents are heterozygous for brown eyes (Bb) but one is a blonde (rr) and the other is a redhead (Rr). What is the probability that their next child will be a blue-eyed redhead?

c. 1/8

44. Lab8 Mitosis: The cell cycle in the onion root tip has a duration of 16 hours. The nuclei of 660 cells showed 13 cells in anaphase. What is the approximate duration of anaphase in these cells?

c. 19 minutes

9. Which of the following cells are in Mitotic Metaphase, Metaphase of Meiosis I and Metaphase of Meiosis II, respectively, for a cell with n=3 (2n = 6)?

c. Cell A is in Metaphase II of Meiosis, Cell B is in Metaphase I of Meiosis, and Cell C is in Metaphase of Mitosis (See Diagram)

36. The following nucleotide (at right) used in RNA:

c. Could be either A or G see diagram

35. Which enzyme catalyzes the elongation of a DNA strand in the 5' 3' direction?

c. DNA polymerase

28. The maintenance of the sickle cell allele in human populations in Africa is an example of

c. Heterozygote advantage

41. Lab7 Photosynthesis The figure below shows the absorption spectrum for chlorophyll a (chl a) and the action spectrum for photosynthesis. Why are they different?

c. Other pigments absorb light in addition to chl a.

17. During prophase I, each chiasma represents

c. a site of crossing-over.

21. One difference between a cancer cell and a normal cell is that

c. cancer cells continue to divide even when they are tightly packed together.

38. What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

c. join Okazaki fragments together

37. What is the function of topoisomerase?

c. relieving strain in the DNA ahead of the replication fork

16. Which of the following events does not occur during meiosis I?

c. separation of sister chromatids

8. A cell is in metaphase if:

c. the chromosomes are aligned on the equatorial plane of the cell.

43. Lab7 Photosynthesis: In the Hill Reaction with isolated chloroplasts, the blue reagent DCPIP

e. Both a and d

20. Observations of cancer cells in culture support the hypothesis that cancer cells _____

e. all of the above