Final Exam Book and Mastering questions Bio 191
How does internal fertilization facilitate life on land? ANSWER>>>>Internal fertilization allows
the sperm to reach the egg without either gametes drying out
If a hermaphrodite self-fertilizes will the offspring by identical to the parent? Explain?
ANSWER>>>>No. Owing to random assortment of chromosomes during meiosis the
offspring may receive the same copy or different copies of a particular parental
chromosome from the sperm and the egg. Furthermore, genetic recombination
during meiosis will result in reassortment of genes between pairs of parental
chromosomes.
In what ways are a second polar body and an early spermatid similar? In what ways are they dissimilar?
ANSWER>>>>Both have a haploid DNA content and very little cytoplasm. However
the early spermatid will develop into a functional gamete, whereas a polar body
is a by-product of oocyte production
Why might using a hot tub frequently make it harder for a couple to conceive a child?
ANSWER>>>>Spermatogenesis occurs normally only when the testicles are cooler
than the rest of the body. Extensive use of a hot tub can cause a decrease in
sperm quality and number
How are the uterus of an insect and the ovary of a flowering plant similar in function? How are they
different? ANSWER>>>>Like the uterus of an insect the ovary of a plant is the site of
fertilization. Unlike the plant ovary the uterus is not the site of egg production
which occurs in the insect ovary. In addition, the fertilization insect egg is
expelled from the uterus, whereas the plant embryo develops within a seed in
the ovary
If each vas deferens in a male was surgically sealed off, what changes would you expect in sexual
response and ejaculate composition? ANSWER>>>>The only effect of sealing of each vas
deferens is an absence of sperm in the ejaculate. Sexual response and ejaculate
volume are unchanged. The cutting and sealing off of these ducts, a vasectomy, is
a common surgical procedure for med who do not wish to produce any (more)
offspring
,FSH and LH get their names from events of the female reproductive cycle but they also functions in
males. How are their functions in females and males similar? ANSWER>>>>In both females and
males, FSH encourages the growth of cells that support and nourish developing
gametes (follicle cells in females and Sertoli cells in males), and LH stimulates the
production of sex hormones that promote gametogenesis ( estrogens, prima rily
estradiol, in females and androgens, especially testosterone, in males)
How does an estrous cycle differ from a menstrual cycle and in what animals are the two types of cycles
found? ANSWER>>>>In estrous cycles, which occur in most female mammals, the
endometrium is reabsorbed (rather than shed) if fertilization does not occur.
Estrous cycles often occur just once or a few times a year, and the female is
usually receptive to copulation only duri ng the period around ovulation.
Menstrual cycles are about four weeks in length, do not restrict receptivity to
copulation to a particular interval, and are found only in humans and some other
primates.
If a human female were to take estradiol and progesterone immediately after the start of a new
menstrual cycle, how would ovulation be affected? Explain. ANSWER>>>>The combination of
estradiol and progesterone would have a negative -feedback effect on the
hypothalamus, blocking release of GnRH. This would interfere with LH secretion
by the pituitary, thus preventing ovulation. This is in fact one basis of action of
the most common hormonal contraceptives.
Where does fertilization occur in the human female? ANSWER>>>>Fertilization occurs in one of
the two oviducts
What role does gastrulation play in the specialization of cell types common to most multicellular
animals? ANSWER>>>>Gastrulation places layers of cells with specific functions in
particular locations in the developing embryo. Therefore, the process is essential
for development of an organism in which specialized cells, tissues, and organs
have shapes and connections that enable basic physiological functions, such as
circulation, gas exchange, and reproduction.
If an STD led to complete blockage of both oviducts, what effect would you expect on the menstrual
cycle and on fertility? ANSWER>>>>The menstrual cycle would be unaffected because it
is controlled by hormones, which circulate in the bloodstream. However, the
, woman could not become pregnant naturally because the oviduct blockage would
prevent sperm from reaching her eggs.
Would a pair of haploid offspring produced by pathogenesis be genetically identical? Explain
ANSWER>>>>No. Because parthenogenesis involves meiosis, the mother would pass
on to each offspring a random and therefore typically distinct combination of the
chromosomes she inherited from her mother and father.
How does the difference in size and cellular contents between sperm and eggs relate to their specific
functions? ANSWER>>>>The small size and lack of cytoplasm characteristic of a sperm
are adaptations well suited to its function as a delivery vehicle for DNA. The large
size and rich cytoplasmic contents of eggs support the growth and development
of the embryo.
Why do anabolic steroids lead to reduced sperm count? ANSWER>>>>Circulating anabolic
steroids mimic the feedback regulation of testosterone, turning off pituitary
signaling to the testes and thereby blocking the release of signals required for
spermatogenesis.
How does the fertilization envelope form in sea urchins? What is its function? ANSWER>>>>The
fertilization envelope forms after cortical granules release their contents outside
the egg, causing the vitelline membrane to rise and harden. The fertilization
envelope serves as a barrier to fertilization by more than one sperm.
Which of these refers to parthenogenesis?
A. an individual may change its sex
B. groups of cells grow into new individuals
C. an organism is first a male and then a female
D. An egg develops without being fertilized ANSWER>>>>D. An egg develops without being
fertilized
The cortical reaction of sea urchin eggs functions directly in
A. the formation of a fertilization envelope
How does internal fertilization facilitate life on land? ANSWER>>>>Internal fertilization allows
the sperm to reach the egg without either gametes drying out
If a hermaphrodite self-fertilizes will the offspring by identical to the parent? Explain?
ANSWER>>>>No. Owing to random assortment of chromosomes during meiosis the
offspring may receive the same copy or different copies of a particular parental
chromosome from the sperm and the egg. Furthermore, genetic recombination
during meiosis will result in reassortment of genes between pairs of parental
chromosomes.
In what ways are a second polar body and an early spermatid similar? In what ways are they dissimilar?
ANSWER>>>>Both have a haploid DNA content and very little cytoplasm. However
the early spermatid will develop into a functional gamete, whereas a polar body
is a by-product of oocyte production
Why might using a hot tub frequently make it harder for a couple to conceive a child?
ANSWER>>>>Spermatogenesis occurs normally only when the testicles are cooler
than the rest of the body. Extensive use of a hot tub can cause a decrease in
sperm quality and number
How are the uterus of an insect and the ovary of a flowering plant similar in function? How are they
different? ANSWER>>>>Like the uterus of an insect the ovary of a plant is the site of
fertilization. Unlike the plant ovary the uterus is not the site of egg production
which occurs in the insect ovary. In addition, the fertilization insect egg is
expelled from the uterus, whereas the plant embryo develops within a seed in
the ovary
If each vas deferens in a male was surgically sealed off, what changes would you expect in sexual
response and ejaculate composition? ANSWER>>>>The only effect of sealing of each vas
deferens is an absence of sperm in the ejaculate. Sexual response and ejaculate
volume are unchanged. The cutting and sealing off of these ducts, a vasectomy, is
a common surgical procedure for med who do not wish to produce any (more)
offspring
,FSH and LH get their names from events of the female reproductive cycle but they also functions in
males. How are their functions in females and males similar? ANSWER>>>>In both females and
males, FSH encourages the growth of cells that support and nourish developing
gametes (follicle cells in females and Sertoli cells in males), and LH stimulates the
production of sex hormones that promote gametogenesis ( estrogens, prima rily
estradiol, in females and androgens, especially testosterone, in males)
How does an estrous cycle differ from a menstrual cycle and in what animals are the two types of cycles
found? ANSWER>>>>In estrous cycles, which occur in most female mammals, the
endometrium is reabsorbed (rather than shed) if fertilization does not occur.
Estrous cycles often occur just once or a few times a year, and the female is
usually receptive to copulation only duri ng the period around ovulation.
Menstrual cycles are about four weeks in length, do not restrict receptivity to
copulation to a particular interval, and are found only in humans and some other
primates.
If a human female were to take estradiol and progesterone immediately after the start of a new
menstrual cycle, how would ovulation be affected? Explain. ANSWER>>>>The combination of
estradiol and progesterone would have a negative -feedback effect on the
hypothalamus, blocking release of GnRH. This would interfere with LH secretion
by the pituitary, thus preventing ovulation. This is in fact one basis of action of
the most common hormonal contraceptives.
Where does fertilization occur in the human female? ANSWER>>>>Fertilization occurs in one of
the two oviducts
What role does gastrulation play in the specialization of cell types common to most multicellular
animals? ANSWER>>>>Gastrulation places layers of cells with specific functions in
particular locations in the developing embryo. Therefore, the process is essential
for development of an organism in which specialized cells, tissues, and organs
have shapes and connections that enable basic physiological functions, such as
circulation, gas exchange, and reproduction.
If an STD led to complete blockage of both oviducts, what effect would you expect on the menstrual
cycle and on fertility? ANSWER>>>>The menstrual cycle would be unaffected because it
is controlled by hormones, which circulate in the bloodstream. However, the
, woman could not become pregnant naturally because the oviduct blockage would
prevent sperm from reaching her eggs.
Would a pair of haploid offspring produced by pathogenesis be genetically identical? Explain
ANSWER>>>>No. Because parthenogenesis involves meiosis, the mother would pass
on to each offspring a random and therefore typically distinct combination of the
chromosomes she inherited from her mother and father.
How does the difference in size and cellular contents between sperm and eggs relate to their specific
functions? ANSWER>>>>The small size and lack of cytoplasm characteristic of a sperm
are adaptations well suited to its function as a delivery vehicle for DNA. The large
size and rich cytoplasmic contents of eggs support the growth and development
of the embryo.
Why do anabolic steroids lead to reduced sperm count? ANSWER>>>>Circulating anabolic
steroids mimic the feedback regulation of testosterone, turning off pituitary
signaling to the testes and thereby blocking the release of signals required for
spermatogenesis.
How does the fertilization envelope form in sea urchins? What is its function? ANSWER>>>>The
fertilization envelope forms after cortical granules release their contents outside
the egg, causing the vitelline membrane to rise and harden. The fertilization
envelope serves as a barrier to fertilization by more than one sperm.
Which of these refers to parthenogenesis?
A. an individual may change its sex
B. groups of cells grow into new individuals
C. an organism is first a male and then a female
D. An egg develops without being fertilized ANSWER>>>>D. An egg develops without being
fertilized
The cortical reaction of sea urchin eggs functions directly in
A. the formation of a fertilization envelope
