25.9–25.11: Sex can lead to fertilization, but it can also spread sexually transmitted diseases.

Sex can lead to fertilization (the fusing of a sperm and egg, forming a diploid zygote) and pregnancy (which can be prevented by numerous methods), but also to the transmission of STDs.

Question 25.22

The corpus luteum:

  • a) secretes chorionic gonadotropin.
  • b) is reabsorbed when fertilization occurs.
  • c) is the only source of the hormones that maintain pregnancy.
  • d) secretes progesterone but not estrogen.
  • e) is the initial sourceof progesterone during pregnancy.

Question 25.23

In mammalian fertilization, the extracellular layer of the egg that functions, in part, as a sperm receptor is called the:

  • a) endoderm.
  • b) jelly coat.
  • c) acrosome.
  • d) egg plasma membrane.
  • e) zonap ellucida.

Question 25.24

The hormones present in birth control pills typically prevent pregnancy by:

  • a) preventing formation of the endometrial lining of the uterus.
  • b) preventing maturation of ovarian follicles.
  • c) preventing sperm from fertilizing the ovulated egg.
  • d) causing the endometrium to be shed once a fertilized egg has implanted.
  • e) preventing implantation of fertilized eggs in the endometrium.

Question 25.25

Tying off the vas deferens leading from each test is will:

  • a) prevent formation of sperm.
  • b) decrease testosterone secretion.
  • c) reduce secretions from the seminal vesicles.
  • d) reduce secretions from the prostate gland.
  • e) None of the above.