exam 3 2019

15. Tiffany and Kenny each have a sibling with sickle-cell disease. Neither Tiffany or Kenny nor any of their parents have the disease. No one in the two families was tested for sickle cell trait until Tiffany who was going to South Africa to study oxpeckers in Kruger National Park where there is malaria decided to get tested. She tested positive for sickle cell trait. Based on this incomplete information, calculate the probability that if this couple has a child, the child will be a boy with sickle-cell disease.

1/12

3. Using the information in question 2 what is the probability of Karen and Steve having two sons with the disease

1/16?

8. 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)?

1/2; (b) no

l. In a diploid set of chromosomes, one member of each pair of homologous chromosomes is derived from the father(paternal)' and the other comes from the mother(maternal).lf 2n = 10, what is the probability that a particular gamete will contain only paternal chromosomes

1/8

2.Karen and Steve each have a sibling with sickle-cell disease. Neither Karen nor Steven or any of their parents have the disease, and none of them have been tested to see if they have the sickle-cell trait. Based on this incomplete information, what is the probability that if this couple has two children both will have the disease?

1/9

10. The litter resulting from the mating of two short-tailed cats contained three kittens without tails, two with long tails, and six with short tails. By accident a female with no tail was mated with a male with a long tail from the litter as adults. What are the expected phenotypes from this cross?

100%, short tails

if the haploid number for a species is 3, each dividing cell will have how many chromatids at metaphase?

12

36. What is the total number of different kinds of gametes that can be produced by an individual with the genotype AaBbccDdEeFF?

16

18. Tom's brother suffers from phenylketonuria (PKU). The brothers' parents do not have PKU. What are the chances that Tom, who is normal for this trait, is a carrier of PKU?

2/3

Given the parents AABBCc × AabbCc, assume simple dominance for each trait and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?

3/4

16. A cell has 16 chromosomes at metaphase of mitosis, how many centromeres will it have during anaphase?

32

A cell has a diploid chromosome number of 2n=4. We will designate these four as chromosomes A, B, C, and D. If meiosis occured with the formation of homologous pair AC and BD, and the chromosomes were then distributed randomly between the resulting cells, how many gametes could be formed?

4(AB,AD,BC, and CD)

21. The minimum graded depolarization needed to operate the voltage-gated sodium and potassium channels is indicated by the label _____.

A

What is a karyotype?

A method of organizing the chromosomes of a cell in relation to number, size, and type.

19. Which of the following contributes to the life cycle called alternation of generations?

A,B, and C

7. In sexually reproducing organisms what leads to genetic variation

A,B, and C

45. When can nondisjunction occurs?

A,BandC

50. Which of the following cells can engulf a pathogen?

A,BandC

44. In a Drosophila experiment, a cross was made between homozygous wild-type females and yellow-bodied males. All of the resulting F1s were phenotypically wild type. However, adult flies of the F2 generation (resulting from mating of the F1s) had the characteristics shown in the table above:(a) Is the mutant allele for yellow body recessive or dominant? (b) Is the yellow locus autosomal (not X-linked) or X-linked?

A. (a) recessive; (b) X-linked

25. How is a viral antigen, like Epstein-Barr Virus (EBV) that causes mononucleosis recognized by T cells?

An antigen fragment is presented within class I MHC to cytotoxic T cell receptor.

23. The membrane's permeability to sodium ions is greatest at label .

B

46. Clonal selection is the division of _____ that have been stimulated by binding to an antigen, which results in the production of cloned _____.

B cells ... plasma cells and memory cells

38. Which of the following statements about oogenesis in humans is true?

Beginning at puberty, a primary oocyte completes its first meiotic division to form a secondary oocyte and a polar body approximately every month.

28. The product of the p53 gene _____.

Both A and B are correct

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

Both A and B are correct

40. What happens if twice as many inhibitory postsynaptic potentials (IPSPs) as excitatory postsynaptic potentials (EPSPs) arrive at a postsynaptic neuron in close proximity?

Both A and B results

22. The cell is not hyperpolarized; however, repolarization is in progress, as the sodium channels are closing or closed, and many potassium channels have opened at label _____

C

12. Imagine that a newly discovered, recessively inherited disease is expressed only in individuals with type O blood, although the disease and blood group are independently inherited. A normal man with type A blood and a normal woman with type B blood have already had one child with the disease. The woman is now pregnant for a second time. What is the probability that the second child will also have the disease?

C. 1/16

4. Which of the following directors of embryonic development can be found in the unfertilized egg?

C. cytoplasmic determinants

1. From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

Cleavage → gastrulation → organogenesis

3. Imagine a human disorder that is inherited as a dominant, X-linked trait. Which of the following would be true?

Females would display this disorder with greater frequency than males.

34. Under what conditions can an unaffected male have a red green color-blind daughter?

He can't

20. Why was the cloning of "Dolly" considered a major scientific breakthrough?

It showed that differentiated adult cells of mammals can dedifferentiate.

55. If AabbCcDDEe X AaBbccDdEe, what is the expected proportion of offspring that will have the same phenotype as the first parent?

None of the above

31. What is the greatest benefit of having used a testcross for this experiment?

Progeny can be scored by their phenotypes alone.

26. All your cells contain proto-oncogenes, which can change into cancer-causing oncogenes. Why might cells possess such potential time bombs?

Proto-oncogenes are necessary for the normal control of cell growth and division.

35. Which of the following is a correct element of alternation of generations?

The sporophyte is diploid and produces haploid spores by meiosis.

54. In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

Tortoiseshell females; black males

52. Which of the following is circled in this electron micrograph?

Two double-stranded DNA molecules

Male calico cats which are extremely rare and are always sterile. Calico males must have which one of the following combinations of sex chromosomes?

XXY

What is a generic cross called between an individual of unknown genotype and a homozygous recessive?

a testcross

11. You are a doctor examining a patient's blood test reports. You are looking at the ratio of helper T cells and cytotoxic T cells. Helper T cells ____________; cytotoxic T cells ____________. You can tell them apart by the type of protein they ____________.

activate other immune system cells; kill altered host cells; express on their plasma membrane

49. Which of the following components of the mammalian gas exchange system has a surface covered by a thin film of mucus (surfactant) without cilia?

alveoli

47. A situation in which chromosome number can be represented as either 2n+1 or 2n-1 is called_____.

aneuploidy

13. The most common dental anesthetic used is lidocaine. Lidocaine blocks voltage-gated Na+ channels. Where along the myelinated facial nerve would you expect lidocaine to be active?

at the nodes of Ranvier

Which of the following is not classified as a chromosomal mutation?

base substitution

37. During Drosophila development, there is a regulatory cascade of gene activation. The proper sequence for thiscascade is ________.

bicoid, gap genes, pair-rule genes, segment polarity genes, and hox genes

24. In 2019, the highest incidence of cancer in U.S. women is _______ and the highest cancer mortality is due to_____-

breast cancer, lung cancer

30. Chemicals produced by lymphocytes that alert neighboring cells to prepare a defense are called _____.

cytokines

17. Which of the following cells are involved in cell-mediated immunity and also respond to class I MHC molecule- antigen complexes?

cytotoxic T cells

9. The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following?

either anaphase I or II

33. Developing ovarian follicles primarily secrete _____.

estrogen

The following pair of hormones is secreted by the ovary

estrogen and progesterone

5. During the menstrual cycle, ________ peaks first, ________ peak next, and finally ________ surges.

estrogen; LH and FSH; progesterone

53. A dominant gene, A, causes yellow color in rats. The dominant allele of another independent gene, R, produces black coat color. When the two dominants occur together (A_ R_), they interact to produce gray. Rats of the genotype aarr are cream-colored. If a gray male and a yellow female, when mated, produce offspring approximately 3/8 of which are yellow, 3/8 gray, 1/8 cream, and 1/8 black, what are the genotypes of the two parents?

father: AaRr; mother: Aarr

2. Acidity in human sweat is an example of

innate immunity.

51. Cell differentiation is first observable when _____.

mRNAs for tissue-specific proteins appear in a cell

32. Which one of the following processes does NOT occur in dividing bacteria?

mitosis

6. A procedure used in treating cancer patients is peripheral blood stem cell transplantation (PBSCT). (Note: My son Nathan had this treatment for his brain cancer done at Duke University.) Stem cells are removed from patients' blood before they receive high-dose chemotherapy or radiation treatments. The stem cells used in PBSCT come from the bloodstream using a process called apheresis. Blood is removed through a large vein in the arm and goes through a machine that removes the stem cells. The stem cells are then frozen until they are given to the recipient. These stem cells produce a variety of different types of blood cells to restore those that have been destroyed by intense chemotherapy or radiation. Thus, the stem cells in this "rescue" transplant are

multipotent

any genetic differences in a clone are due to which process?

mutation

56. In chickens, bar eyes are a sex-linked trait that is caused by a dominant allele. Normal eyes are recessive. What cross(es) would ALWAYS produce all bar-eye males and all normal-eye females

normal-eye male crossed with a bar-eye female

43. An immunoglobulin (Ig) molecule, of whatever class, has regions symbolized as C or V, H or L. A light chain has which of these regions?

one C and one V region

In vertebrate animals, spermatogenesis and oogenesis differ, in that

oogenesis produces one functional gamete, whereas spermatogenesis produces four functional spermatozoan

Fertilization of human eggs usually takes place in the

oviduct

If the release of LH were inhibited in a human female, which of the following events would not occur?

ovulation of a secondary oocyte

39. A pregnant woman comes into the hospital past her due date. The doctor decides it is time for the baby to be delivered. Before performing a cesarean section, the doctor wants to try to induce labor. Which of the following would she most likely inject

oxytocin

48. Naturally acquired passive immunity would involve the

placental transfer of antibodies.

all of the following are functions of meiosis in plants except

production of identical daughter cells

crossing over occurs during which phase of meiosis?

prophase 1

Which of the following terms least related to the others?

seminiferous tubules

41. Meiosis II is similar to mitosis in that

sister chromatids separate during anaphase.

4. Cyclic GMP is an intracellular second messenger. how does cyclic GMP cause an erection of the penis?

smooth muscle relaxation so that arterioles can dilate

The one concept that Darwin did not recognize in his origin of species was the

source of variation in organisms

Which of the following events occurs during prophase I of meiosis?

synapsis and crossing over

27. Human pregnancy is indicated by the presence of human chorionic gonadotropin metabolites in the urine until _____.

the placenta takes over producing estrogen and progesterone

RFLP analysis is being used as evidence to link suspects with blood and tissues found at crime scenes. DNA fingerprints look something like supermarket bar codes. The pattern of bars in a DNA fingerprint shows

the presence of certain DNA fragments

transfusion of type A blood to a person who has type O blood would result in

the recipient's anti-A antibodies clumping the donated red blood cells independent of helper T cells