Biology Test

What is the major characteristic of asexual reproduction?

The offspring are genetically identical to the parent

The fertilization of the egg by a sperm produces the ___

zygote

Which of the following is an accurate statement?

In external fertilization, sperm and egg unite outside the bodies of the parents

Provide a reason that internal fertilization was an important adaptation that allowed organisms to survive terrestrial life

It provided a means to keep sperm moist and prevent them from drying out

What major event within the female is critical to successful internal fertilization?

ovulation

Which of the following is the best definition of parthenogenesis?

eggs from a female developing into offspring without being fertilized

The most important function of sexual reproduction is

creating genetic variability

A fertilized egg usually implants itself and develops in the ___

uterus

A rapid increase in the ___ level stimulates ovulation

luteinizing hormone

After ovulation, high levels of ___ inhibit ___ secretion

estrogen and progesterone… FSH and LH

Developing ovarian follicles primarily secrete ___

estrogens

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

human chorionic gonadotropin

If there is no fertilization, degeneration of the corpus luteum results in a drop in ___ which results in the sloughing off of the uterus’s endometrium

estrogen and progesterone

Ovulation usually occurs on or about day ___ of a 28 day ovarian cycle

14

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

oviduct

Sperm become more capable of movement while in the ___

epididymis

Sperm exit a males body via the ___

urethra

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

negative… hypothalamus… pituitary gland

Which hormones are directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth?

androgens

Which pituitary secretion stimulates sperm production?

FSH

Which pituitary secretion stimulates the testes to secrete androgens?

LH

Sperm develop in the ___

seminiferous tubules

What hormone is released in both sexes by the hypothalamus to initiate puberty?

gonadotropin-releasing hormone

Which of the following correctly matches the anatomy to its function in the human reproductive tract?

the purpose of the epididymis is storage of sperm

Assume that you have chosen to research a topic for your biology class and you have become interested in studying the abuse of performance-enhancing drugs by male athletes. The first thing you learn is that many athletes use anabolic-androgenic steroid hormones. Males produce one called testosterone and an appropriate physiological concentration of testosterone keeps the production of sperm at nearly constant levels. You also learned that a consequence of injection of testosterone is suppression of sperm production. Why do you suppose this is true?

Excess testosterone can feed back and inhibit certain steps in spermatogenesis, resulting in lowered sperm counts

The midpiece just behind the head of a human sperm cell is packed with mitochondria. What is the function of the midpiece?

It provides the energy necessary to move the tail of the sperm to propel it through the female reproductive tract

What is the name of the component of the male reproductive tract that produces an alkaline, nutrient-rich secretion that comprises about 30% of the semen volume?

prostate gland

Why would the seminal vesicles in the male reproductive tract produce a fluid that contains prostaglandins?

to stimulate uterine contractions that help transport sperm up the female reproductive tract

What term is used to describe egg production in the human ovaries?

oogenesis

Which of the following is an accurate statement?

The uterus is a muscular chamber where the embryo develops

Why does the inner lining, or endometrium, of the uterus contain many blood vessels and glands that secrete carbohydrates, lipids, and proteins?

so that it can become part of the placenta

If the cervix is a ring of connective tissue at the outer end of the uterus that holds the developing baby in the uterus, how does the baby get out of the uterus during labor?

the cervix has a tiny opening at its center that expands during labor, permitting passage of the child

What happens to the human egg if it is not fertilized?

The corpus luteum disintegrates, hormone levels fall, the overgrown endometrium disintegrates, and the uterus contracts

What ovarian hormones are involved in the menstrual cycle?

estrogen and progesterone

Given your understanding of oogenesis and hormonal control of the menstrual cycle, answer this question: How does a combination birth control pill (containing estrogen and progesterone) prevent pregnancy?

The pill inhibits GnRH production, reducing the release of FSH and LG, thereby preventing development of more follicles

Which of the following statements is accurate?

Hormone levels produced during the menstrual cycle are under the influence of both positive and negative feedback mechanisms

Very soon after fertilization of the egg, it implants in the endometrium. At this point, it begins to secrete a hormone called chorionic gonadotropin (CG), which is carried in the blood to the corpus luteum to keep it alive to help maintain the pregnancy. Interestingly, some CG is excreted in the mother’s urine. Using this information, suggest a way we could determine without invasive methods and without visiting the doctor whether someone is pregnant or not.

Develop a test to detect CG in the mothers urine

Cyclic GMP is an intracellular second messenger that causes smooth muscles to relax. How does cyclic GMP cause an erection of the penis?

Cyclic GMP causes smooth muscle relaxation so arterioles can dilate, allowing blood to fill tissue spaces within the penis

Which of the following STD is the most common bacterial STD?

chlamydia

Why can no more than one sperm enter an egg?

As a sperm enters, vesicles near the surface of the egg release chemicals into the zona pellucida that reinforce it and prevent other sperm from entering

MB Chapter 41 Question 1-3 Art

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A couple has been trying unsuccessfully to conceive for several years. An examination reveals that scar tissue blocks the woman’s uterine tubes. The woman has complained about large amounts of vaginal discharge, which coincide with her husband complaining of painful urination and a pus discharge from his penis. Antibiotics clear up the infections. This couple has probably been infected with

gonorrhea

Puberty is triggered when brain maturation causes the hypothalamus to secrete

gonadotropin-releasing hormone (GnRH)

If a child develops an anterior pituitary tumor that reduces LH and FSH production:

the child’s puberty will be delayed or disrupted

The development of secondary sexual characteristics is due to

increased levels of estrogen or testosterone

In men, as testosterone levels increase, LH levels

decrease

The only flagellated cells in the human body are

sperm

Gonadotropin-releasing hormone (GnRH)

stimulated the release of FSH and LH

During an erection, blood flow to the penis is decreased. True or False?

False

What is the function of an acrosome?

It contains enzymes that dissolve the protective layers around the egg

In the male, the primary target of FSH is

sertoli cells

Which of these hormones stimulates the production of testosterone?

LH

Mature sperm are stored in the

epididymis

The epididymis connects the

testis and the vas deferens

Which of the following is the correct path sperm travel on their way out of the male?

seminiferous tubules -> epididymis -> vas deferns -> urethra

What would happen to male hormone levels if the hypothalamus produced GnRH continuously?

LH, FSH, and testosterone levels would be high

Why is it necessary for the testes to be in the scrotum to function properly?

The scrotum keeps the testes at a cool temperature necessary for sperm production

If the prostate gland failed to add its contribution to semen

the semen would not be fluid, due to lack of enzymes

Which of the following is the correct path sperm travel on their way to fertilize and egg?

vagina -> cervix -> uterus -> uterine tube

Most of the fluid in semen is produced by the

seminal vesicles

The interstitial cells of the testes produce

testosterone

In the typical menstrual cycle, day 1 is the day

menstruation begins

In the typical menstrual cycle, day 13 or 14 is when

ovulation occurs

Ovulation occurs due to a surge in ___ concentrations

LH

A surge in the level of LH indicated that ___ is about to occur

ovulation

In which respect do spermatogenesis and oogenesis differ?

number of gametes produced

The corpus luteum is located in the

ovary

Menstruation occurs due to a decrease in

levels of estrogen and progesterone

In humans, fertilization normally occurs in the

uterine tube

After ejaculation, sperm live ___ in the female reproductive tract

2 to 4 days

Why is it necessary for many sperm to be present in order for one to fertilize the egg?

the combined enzymes digest a path through the corona radiata and zona pellucida

Sexually transmitted diseases caused by viruses include herpes, aids, and

human papillomavirus (HPV)

Which of the following STI causes cervical cancer?

HPV

Oozing, painful lesions that reoccur are characteristic of

genital herpes

Which of the following is a bacterial infection that can cause the uterine tubes to be blocked by scar tissue

chlamydia

A sterilization procedure in men that involves severing and clamping the vas deferens leading from each testis is called an ___

vasectomy

Which of the following temporary contraception methods prevent ovulation?

birth control pill

Which of the following is an accurate explanation of birth control devices?

With rare exceptions, birth control methods do not protect against STDs

Vasectomy and tubal ligation result in

an interruption of the path taken by the egg or sperm

In each of the vas deferens of a male human is cut, his semen does not contain

sperm

Contraceptive methods that rely on synthetic hormones

prevent ovulation

Other than sterilization, the most effective method of contraception is the

birth control pill

If taken within 72 hours of unprotected intercourse, the morning after pill should

delay or prevent ovulation

The vaginal ring

releases hormones that prevent ovulation