Chapter 27

Front 1

Which of the following is a disadvantage of asexual reproduction?

Back 1

It does not increase genetic variability.

Front 2

Hermaphrodites are animals that

Back 2

possess both male and female reproductive systems.

Front 3

Which of the following statements regarding sexual reproduction is true?

Back 3

Sexual reproduction generates greater genetic variation than asexual reproduction.

Front 4

Reproductive systems with external fertilization are most common in

Back 4

aquatic animals

Front 5

Which of the following is a form of sexual reproduction?

Back 5

formation of a zygote

Front 6

Which reproductive method is used most frequently by mammals?

Back 6

internal fertilization

Front 7

How does a zygote differ from an ovum?

Back 7

A zygote has more chromosomes.

Front 8

The embryo implants in the ________ of the uterus.

Back 8

endometrium

Front 9

The human egg is swept through the oviduct toward the uterus by

Back 9

the beating of cilia in the oviduct.

Front 10

Which of the following statements about the reproductive system of human females is true?

Back 10

The corpus luteum secretes progesterone, which helps maintain the uterine lining during pregnancy.

Front 11

The route that sperm take from formation to ejaculation from the penis is from the testes to _____.

Back 11

the epididymis, vas deferens, ejaculatory duct, and urethra

Front 12

After being produced in the testes, sperm mature further in a structure called the

Back 12

epididymis.

Front 13

Which of the following produces a thick fluid containing fructose, which is used for energy by sperm?

Back 13

seminal vesicles

Front 14

Men who take very long, hot baths are likely to

Back 14

produce fewer sperm

Front 15

Human testes are positioned in an external sac rather than in the abdominal cavity

Back 15

so the testes can be kept cooler than the body's interior.

Front 16

Which of the following statements comparing spermatogenesis and oogenesis is true?

Back 16

Men, but not women, can produce gametes throughout their lives.

Front 17

Which of the following statements regarding spermatogenesis and oogenesis is true?

Back 17

Meiosis in oogenesis produces one mature egg from one primary oocyte.

Front 18

What does an ovum and a sperm have in common?

Back 18

a haploid set of chromosomes

Front 19

A decrease in ________ is followed by the gradual degradation of the corpus luteum.

Back 19

LH

Front 20

Which of the following hormones stimulates the growth of an ovarian follicle?

Back 20

FSH

Front 21

In human females, the ovarian cycle begins when

Back 21

the hypothalamus stimulates the anterior pituitary to increase its output of FSH and LH.

Front 22

Menstruation

Back 22

coincides with the beginning of the pre-ovulatory phase of the ovarian cycle.

Front 23

Menstruation results in the discharge of _____.

Back 23

the endometrium

Front 24

A peak in _____ triggers ovulation around the _____ day of the monthly cycle.

Back 24

LH … 14th

The surge in LH is the trigger for ovulation, occurring usually about midway through the cycle.

Front 25

If a woman wants to become pregnant, what is the optimal day on which to have sexual intercourse?

Back 25

the day of ovulation

Because the egg can survive in the oviduct for 24 to 48 hours, intercourse must be timed to coincide with ovulation.

Front 26

After ovulation occurs, the empty follicle _____.

Back 26

changes into the corpus luteum and makes hormones

Front 27

What is the source of the hormones that, when suddenly absent, are directly responsible for the onset of menstruation?

Back 27

corpus luteum

Front 28

What prevents menstruation when a woman first becomes pregnant?

Back 28

The release of HCG from the implanted embryo acts like LH, stimulating the corpus luteum to continue to secrete progesterone and estrogen.
(Human chorionic gonadotropin is typically the substance tested for in pregnancy tests.)

Front 29

Which of the following STDs is caused by a virus that can also cause cancer?

Back 29

genital warts

Front 30

Which of the following types of pathogens cause sexually transmitted diseases that cannot be treated with antibiotics?

Back 30

viruses

Front 31

Which of the following agents can cause an infection that can ultimately develop into pelvic inflammatory disease in women?

Back 31

Chlamydia trachomatis

Front 32

Which of the following birth control methods also provides the best protection against STDs?

Back 32

condoms

Front 33

Which of the following statements about sexually transmitted diseases (STDs) is false?

Back 33

genital warts are caused by a bacterium

Front 34

Which of the following statements regarding birth control is true?

Back 34

Morning-after pills taken within three days of unprotected intercourse prevent fertilization or implantation about 75% of the time.

Front 35

Morning-after pills taken within three days of unprotected intercourse prevent fertilization or implantation about 75% of the time.

Back 35

tubal ligation or vasectomy.

Front 36

The only totally effective way to prevent the spread of STDs is through

Back 36

abstaining from sexual intercourse.

Front 37

Which of the following is the least effective method of birth control?

Back 37

rhythm method

Front 38

The drug RU-486 was developed in France and is widely used in Europe as a method of birth control. Its introduction to the United States has been controversial, however. The drug is taken after sexual intercourse. It blocks implantation, and in this sense it prevents pregnancy _____.

Back 38

by blocking progesterone receptors in the uterus, thus preventing progesterone from maintaining pregnancy

DOES NOT PREVENT CONCEPTION

Front 39

Immediately after the fusion of sperm and egg plasma membranes, _____.

Back 39

there is a change in the egg membrane that prevents the entry of other sperm

Front 40

After a human sperm penetrates an egg, a fertilization envelope forms. This membrane _____.

Back 40

prevents more than one sperm from entering the egg

Front 41

Fertilization

Back 41

joins two haploid sets of chromosomes and activates development in the egg.

Front 42

Which of the following generates the ATP that is required for movement of the sperm's tail?

Back 42

mitochondria in the neck and middle piece

Front 43

Two important contributions that cleavage makes to development are to

Back 43

create a multicellular embryo and partition the embryo into developmental regions.

Front 44

Which of the following results from cleavage?

Back 44

formation of more cells

Front 45

Which of the following events occurs first during embryonic development?

Back 45

cleavage

Front 46

Which of the following structures develops from mesodermal tissue?

Back 46

notochord

Front 47

What occurs during gastrulation?

Back 47

A hollow blastula is changed into a hollow embryo that has three tissue layers.

Front 48

The ectoderm is one of the embryonic tissue layers produced during gastrulation that forms the

Back 48

outer layer of the gastrula.

Front 49

Which of the following processes dominates the third trimester of human development?

Back 49

RAPID GROWTH

Front 50

At which gestational age does a developing human fetus first look obviously human and not like other vertebrate embryos?

Back 50

9 WEEKS

Front 51

Which of the trimesters primarily involve(s) an increase in size and general refinement of the human features?

Back 51

THE 2ND AND 3RD TRIMESTERS

Front 52

Contractions in uterine smooth muscle during labor are initiated by

Back 52

oxytocin.

Front 53

Which of the following options correctly lists the three stages of labor in the order in which they occur?

Back 53

dilation, expulsion, delivery of the placenta

Front 54

Where does fertilization of an egg cell occur?

Back 54

OVIDUCT

Front 55

Which hormone spikes midway through the menstrual cycle and triggers ovulation?

Back 55

Luteinizing hormone (LH)

Front 56

True or false. The corpus luteum develops from the ruptured follicle during the luteal phase after ovulation and produces hormones that can aid in pregnancy.

Back 56

TRUE

Front 57

Sperm become capable of movement while in the _____.

Back 57

epididymis

Front 58

Sperm exit a male's body via the _____.

Back 58

URETHRA

Front 59

The secretion of androgens is regulated by a _____ feedback mechanism involving the _____ and _____.

Back 59

negative ... hypothalamus ... pituitary gland

Front 60

Which hormone(s) is(are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth?

Back 60

ANDROGENS

Front 61

Which pituitary secretion stimulates sperm production?

Back 61

FSH

Front 62

Which pituitary secretion stimulates the testes to secrete androgens?

Back 62

LH

Front 63

Sperm develop in the _____.

Back 63

seminiferous tubules

Front 64

True or false. During sperm maturation, secondary spermatocytes are the products of meiosis II that go on to form spermatids, which undergo restructuring to form spermatozoa.

Back 64

FALSE

Front 65

Which male reproductive structures are responsible for the transport and delivery of sperm?

Back 65

Vas deferens, urethra, and penis

Front 66

Which of the following events does NOT occur during human fertilization?

Back 66

Enzymes on the outside of the sperm break down the follicle cells surrounding the egg

Front 67

A fertilized egg usually implants itself and develops in the _____.

Back 67

UTERUS

Front 68

A rapid increase in the _____ level stimulates ovulation.

Back 68

luteinizing hormone

Front 69

After ovulation, high levels of _____ inhibit _____ secretion.

Back 69

FSH and LH ... estrogen and progesterone

Front 70

Developing ovarian follicles primarily secrete _____.

Back 70

estrogens

Front 71

If there is fertilization, secretion of _____ by the early embryo maintains the corpus luteum.

Back 71

estrogen and progesterone

Front 72

Ovulation usually occurs on or about day _____ of a 28-day ovarian cycle.

Back 72

14

Front 73

What is the usual site of the fertilization of an egg cell?

Back 73

OVIDUCT

Front 74

If there is fertilization, secretion of _____ by the early embryo maintains the corpus luteum.

Back 74

human chorionic gonadotropin

Front 75

Which of the following terms describes the embryonic cell divisions that occur without cell growth in mammals?

Back 75

Cleavage

Front 76

True or false. Early animal development progresses through distinct stages: first the production of the zygote through fertilization, then cleavage, then the formation of the gastrula, and then the formation of the blastula.

Back 76

FALSE

Front 77

The human heart is functioning by which point in development?

Back 77

4 WEEKS

Front 78

How long does it take for an embryo to begin implantation in the uterus?

Back 78

7 DAYS

Front 79

What cells are responsible for implantation in the uterus?

Back 79

trophoblast

Front 80

The linkage between the _____ and _____ eventually becomes the placenta.

Back 80

trophoblast; uterine wall