Question 1

In mammals, the rise in cytosolic calcium caused by sperm entry into the egg

Accepted Answer

A)  signals the egg to initiate a fast block to polyspermy. 
B)  causes cortical granules to release their contents into the egg cytoplasm. 
C)  prompts formation of the fertilization envelope. 
D)  results in destruction of sperm-binding molecules in the zona pellucida. 
E)  dissolves the bonds between the vitelline envelope and egg cell membrane.

Question 2

Which statement regarding reproduction is true?

Accepted Answer

A)  All members of a population that reproduce sexually can convert resources to offspring. 
B)  Asexual reproduction is an inefficient way for an organism to perpetuate its genome. 
C)  Asexual reproduction generates more genetic diversity than does sexual reproduction. 
D)  Some animals reproduce both sexually and asexually. 
E)  Sexual reproduction preserves successful genotypes in a particular environment.

Question 3

An intrauterine device is a means of birth control that prevents

Accepted Answer

A)  ovulation. 
B)  fertilization. 
C)  implantation. 
D)  ejaculation. 
E)  sperm from reaching the egg.

Question 4

In some female mammals, the corpus luteum does not degenerate completely, but turns into a small spot of scar tissue.If researchers were to count these scar tissue spots, they would be able to determine a female's total number of

Accepted Answer

A)  offspring. 
B)  reproductive cycles. 
C)  pregnancies. 
D)  follicles. 
E)  eggs ovulated.

Question 5

If you examined histological sections of adult human gonads under the microscope, you would conclude that

Accepted Answer

A)  a single germ cell entering meiosis produces four cells by the end of meiosis in the testis but only one cell by the end of meiosis in the ovary. 
B)  the gonad contains germ cells that undergo numerous mitoses in males but few if any mitoses in females. 
C)  a secondary spermatocyte is larger than any primary spermatocyte. 
D)  an ootid is smaller than an oogonium. 
E)  a mature ootid is larger than a primary oocyte.

Question 6

Of the contraceptive methods listed, which has a success rate greater than 95 percent?

Accepted Answer

A)  Spermicidal jelly 
B)  Condom 
C)  Diaphragm 
D)  Oral hormones ("the pill") 
E)  Progestin-only pill ("Plan B")

Question 7

Choose the correct pairing between organ(s) and classification.

Accepted Answer

A)  Penis: primary sex organ 
B)  Ovaries: primary sex organs 
C)  Testes: accessory sex organs 
D)  Vagina: primary sex organ 
E)  Internal and external sex organs: genitalia

Question 8

Which statement characterizes the slow block to polyspermy in sea urchins?

Accepted Answer

A)  It makes the vitelline envelope penetrable to sperm. 
B)  It involves enzymes from cortical granules dissolving the bonds between the vitelline envelope and plasma membrane. 
C)  It includes a transient change in membrane potential. 
D)  It is initiated by the loss of calcium ions from the egg's cytoplasm. 
E)  It involves enzymes from lysosomes degrading sperm-binding molecules on the inner surface of the egg cell membrane.

Question 9

In a mammalian ovary, a _______ consists of one primary oocyte surrounded by ovarian cells.

Accepted Answer

The answer of In a mammalian ovary, a _______ consists...

Question 10

Which event occurs during the process of fertilization in sea urchins?

Accepted Answer

A)  Activation of spermatids 
B)  Species-specific binding of sperm to egg 
C)  Contribution by sperm of nutrients, mitochondria, and mitochondrial genes 
D)  Fusion of egg and sperm diploid nuclei 
E)  Fusion of sperm with cortical granules of the egg

Question 11

You observe two species of amphibians mating in a stream.Species A is engaging in external fertilization and species B is engaging in internal fertilization.In which species would recognition molecules on gametes be more critical?

Accepted Answer

A)  Species A 
B)  Species B 
C)  Recognition molecules would be equally critical in both species A and species B. 
D)  Neither, because vertebrates do not need recognition molecules on their gametes. 
E)  There is insufficient information to make a determination.

Question 12

Which event occurs before all the others, leading to the delivery of a human baby?

Accepted Answer

A)  An increase in the ratio of estrogen to progesterone 
B)  Pressure of the fetal head on the cervix communicated to the hypothalamus 
C)  An increase in secretion of oxytocin by fetal and maternal posterior pituitaries 
D)  Dilation of the cervix 
E)  A positive feedback loop involving oxytocin and uterine contractions

Question 13

When a female Komodo dragon in the London Zoo laid a clutch of eggs after many years in captivity, caretakers were surprised.Even more surprising was that some of the eggs produced baby dragons.Researchers verified that there had been no males around, and the babies were diploid.What is a likely explanation for how this Komodo dragon was able to create a viable embryo?

Accepted Answer

A)  The mature egg activated spontaneously, starting embryonic development. 
B)  Two eggs fused prior to ovulation, starting embryonic development. 
C)  A polar body fused with the haploid egg, restoring the diploid number of chromosomes. 
D)  An ovum fused with a cell in the uterus prior to being laid, "activating" the egg. 
E)  The male of an unrelated species of organism mated with the female Komodo dragon.

Question 14

Ovaries produce estrogen and progesterone.Removal of the ovaries in the parthenogenetic whiptail lizard Cnemidophorus uniparens would result in

Accepted Answer

A)  the absence of male sexual behavior. 
B)  the presence of female sexual behavior. 
C)  repeated ovulations. 
D)  a switch to sexual reproduction. 
E)  the growth of testes.

Question 15

Which statement about gametogenesis in mammals is true?

Accepted Answer

A)  Spermatogenesis and oogenesis have periods of meiotic arrest. 
B)  Oogonia experience developmental arrest in prophase I of mitosis. 
C)  Spermatogenesis produces four gametes from a single spermatogonium, while oogenesis produces one gamete from a single oogonium. 
D)  Cytoplasm is apportioned equally in spermatogenesis and oogenesis. 
E)  The second meiotic divisions of oogenesis and spermatogenesis are completed at fertilization.

Question 16

In mammals, the egg is propelled through the oviduct by means of

Accepted Answer

A)  cilia on the surface of the egg. 
B)  the egg's flagellum. 
C)  uterine contractions. 
D)  cilia lining the oviduct. 
E)  amoeboid motion.

Question 17

Which product of oogenesis acquires the energy, raw materials, and RNA needed for the first cell divisions after fertilization?

Accepted Answer

A)  Second polar body 
B)  Primary oocyte 
C)  Secondary oocyte 
D)  First polar body 
E)  Ootid

Question 18

At birth, a female has about one million primary oocytes in each ovary.During a woman's fertile years, about _______ of these oocytes will mature and be released at ovulation.

Accepted Answer

A)  100 
B)  450 
C)  900 
D)  2,000 
E)  4,500

Question 19

Refer to the figure showing the male reproductive tract.  If a man elects to have a vasectomy as a form of contraception, which duct(s) will be cut and tied off in the procedure?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 20

A woman has learned that her fetus has a major birth defect that will lead to death shortly after birth.Medical termination of her pregnancy is called

Accepted Answer

A)  a miscarriage. 
B)  assisted reproductive technology. 
C)  a therapeutic abortion. 
D)  an abortion for fertility control. 
E)  a spontaneous abortion.

Exam 42: Animal Reproduction