Read each question carefully and then select the best answer.

1		One human ejaculation delivers about ____ sperm.
			A)	200 thousand
			B)	200 million
			C)	200 billion
			D)	an unknown quantity
2		Male gametes originate in ____ within the ____. They pass through the ____ and ____ where they mature before exiting the body.
			A)	seminiferous tubules, ovaries, epididymis, fallopian tubes
			B)	vas deferentia, seminiferous tubules, testes, penis
			C)	seminiferous tubules, testes, epididymis, vas deferentia
			D)	epididymis, ovaries, vas deferentia, testes
3		The formation of a fertilized ovum usually occurs in the _____.
			A)	cervix
			B)	uterine tube
			C)	ovaries
			D)	placenta
4		Egg and sperm are
			A)	monoploid.
			B)	haploid.
			C)	diploid.
			D)	triploid.
5		A diploid cell containing eight chromosomes undergoes meiosis. How many chromosomes are present in the cell after meiosis I?
			A)	2
			B)	4
			C)	8
			D)	16
6		A diploid cell containing eight chromosomes undergoes meiosis. How many chromosomes are present in the cell after meiosis II?
			A)	2
			B)	4
			C)	8
			D)	16
7		A diploid cell has 40 units of DNA at G1 of interphase. How many units of DNA are present in the cell after meiosis I?
			A)	10
			B)	20
			C)	40
			D)	80
8		Genetic variability arises during meiosis from
			A)	crossing over.
			B)	independent assortment.
			C)	random alignment of chromosomes at metaphase.
			D)	All of the above.
9		Are the sister chromatids of a chromosome necessarily identical at the beginning of metaphase I of meiosis?
			A)	Yes, sister chromatids are always identical structures.
			B)	Yes, only homologous chromosomes differ from each other.
			C)	No, crossing over could generate differences.
			D)	Maybe, it varies from cell division to cell division.
10		A diploid cell has 40 units of DNA at G1 of interphase. How many units of DNA are present in a gamete?
			A)	10
			B)	20
			C)	40
			D)	80
11		Crossing over occurs during ________.
			A)	interphase
			B)	prophase of meiosis I
			C)	prophase of meiosis II
			D)	metaphase of meiosis I
12		During oogenesis,
			A)	a female will always produce three polar bodies.
			B)	the first polar body is diploid, while the others are haploid.
			C)	meiosis will be completed only if fertilization occurs.
			D)	several primary oocytes will complete meiosis I each cycle.
13		A phenotypically normal woman has a polar body biopsy. Upon examination, the polar body is found to carry a disease-causing recessive allele. The woman knows that the associated oocyte
			A)	carries the mutant allele.
			B)	carries the normal allele.
			C)	cannot support the development of an embryo.
			D)	No conclusions can be drawn about the oocyte.
14		Before birth, a female's oocytes are
			A)	not present.
			B)	arrested in prophase I of meiosis.
			C)	arrested in prophase II of meiosis.
			D)	arrested in prophase of mitosis.
15		How many sets of chromosomes are present in a primary oocyte and the polar body derived from it?
			A)	2, 1
			B)	2, 2
			C)	1, 2
			D)	1, 1
16		Which of the following statements about gamete formation is false?
			A)	In females, most of the cytoplasm concentrates in one huge cell.
			B)	In males, meiosis produces four similarly shaped sperm.
			C)	Spermatogenesis takes months.
			D)	Oogenesis is completed prior to birth.
17		Meiosis II proceeds in a female's oocyte_____.
			A)	prior to birth
			B)	monthly after puberty
			C)	upon ovulation
			D)	upon fertilization
18		Around day 6 or 7 of embryonic development, hCG is secreted by
			A)	the blastomere.
			B)	the morula.
			C)	trophoblast cells.
			D)	the sperm.
19		At what week of development is the term fetus applied?
			A)	the first week
			B)	the eighth week
			C)	the ninth week
			D)	the twenty-second week
20		Which of the following terms represents the earliest stage of human development?
			A)	morula
			B)	gastrula
			C)	blastomere
			D)	trophoblast
21		The ____ is a membrane surrounding the embryo that gives rise to the umbilical blood vessels.
			A)	yolk sac
			B)	allantois
			C)	choronic villi
			D)	trophoblast
22		The ____ is composed of specialized ectoderm that develops into the brain and spinal cord.
			A)	notochord
			B)	primitive streak
			C)	allantois
			D)	neural tube
23		The skin forms from cells of what layer in the gastrula?
			A)	endoderm
			B)	ectoderm
			C)	mesoderm
			D)	inner cell mass
24		Muscle and connective tissue is derived from the ________.
			A)	endoderm
			B)	ectoderm
			C)	mesoderm
			D)	inner cell mass
25		Dolly, the sheep, was cloned from
			A)	an embryonic cell.
			B)	a fetal cell.
			C)	a mammary gland cell.
			D)	an artificial cell.
26		Which of the following would contain identical genetic information?
			A)	monozygotic twins
			B)	dizygotic twins
			C)	conjoined twins
			D)	All of the above.
27		Chemicals or other agents that cause birth defects are called
			A)	transformers.
			B)	carcinogens.
			C)	alterations.
			D)	teratogens.
28		The drug ____ was used to treat morning sickness between 1957 and 1961. Unfortunately, babies born to mothers who used this drug were born with incomplete or missing legs and arms.
			A)	lithium
			B)	diethylstilbestrol
			C)	penicillamine
			D)	thalidomide
29		The majority of birth defects can be traced to problems that occur during the
			A)	second trimester.
			B)	third trimester.
			C)	embryonic period.
			D)	entire pregnancy.
30		Which of the following is a rapid-aging disorder?
			A)	porphyria
			B)	pattern baldness
			C)	progeria
			D)	Marfan syndrome