BIO 169 Chapter 27 Exam
A child born with an XXY chromosome pattern will have
Klinefelter's syndrome
Non-sex chromosomes are called
autosomal
The individual cells produced by cleavage are called
blastomeres
The oval, three-layered sheet produced by gastrulation is called the
embryonic disc
The stage of labor during which the fetus emerges from the vagina is called the ________ stage.
expulsion
The period of gestation when the rudiments of all major organ systems are established is the ________ trimester.
first
The neonatal period extends
for the first month of life
In pregnancy, expansion of the uterus results from
hypertrophy of smooth muscle cells
Attachment to and penetration of the endometrium by the blastocyst is referred to as
implantation
The region known as the primitive streak is the site of
migration of ectodermal cells to form the mesoderm
After 3 days, a pre-embryo becomes a solid ball of cells known as a
morula
The mesoderm forms
muscle
The ectoderm forms
neural tissues
Which hormone stimulates the milk let-down reflex?
oxytocin
The traits of an individual controlled by his or her genotype are his or her
phenotype
The hormone that increases the flexibility of the pubic symphysis during pregnancy is
relaxin
The prostaglandins produced in the endometrium
stimulate smooth muscle contractions
Deoxygenated blood is carried to the placenta by the
umbilical arteries
A person's original chromosomes and their component genes constitute that person's
genotype
Which of the following traits is a sex-linked inheritance?
hemophilia
If an individual carries two different alleles for the same trait, the individual is ________ for the trait.
heterozygous
A blastocyst is a
hollow ball of cells
If an individual carries a pair of alleles that are the same, the individual is ________ for the trait.
homozygous
A zygote whose genotype is XY will develop as a
male
After fertilization, the first cell division is completed
more than a day later
The placenta is expelled from the uterus during the ________ stage of labor.
placental
The "P" in the abbreviation SNP stands for
polymorphism
During gestation, contraction of the myometrium is inhibited by ________, produced by the placenta.
progesterone
The clinical term for "growing old" is
senescence
At fertilization, the "moment of conception" occurs in
step 5, amphimixis and cleavage
During implantation, the
syncytial trophoblast erodes a path through the endometrium
Each of the following statements concerning development is true except
the first trimester is when the fetus looks distinctively human
During amphimixis,
the male and female pronuclei fuse
The endoderm forms
the urinary bladder
The period of gestation that is characterized by the largest fetal weight gain and fat deposition is the ________ trimester.
third
During gastrulation,
three germ layers are formed
The ________ is formed by the allantois, blood vessels, and yolk sac.
umbilical cord
Which of the following is not one of the extraembryonic membranes?
umbilical cord
Oxygenated blood is carried away from the placenta by the
umbilical vein
The embryonic heart starts beating as blood begins to flow through chorionic vessels at approximately ________ of development.
week 2
Which of the following descriptors regarding the trophoblast is false?
is derived from the inner cell mass
All of the following are true of the allantois except
it acts as the fetal bone marrow
The various forms of any one gene are called
alleles
The extraembryonic membrane that forms a fluid-filled sac is the
amnion
A space opens within the inner cell mass that will form the
amniotic cavity
The almost identical cells produced by cleavage divisions are called
blastomeres
Endoderm + mesoderm = which extraembryonic membrane?
both yolk sac and allantois
Under the influence of the trophoblast, maternal blood vessels in the endometrium
break down and form lacunae
The trophoblast has many of the characteristics of ________ cells.
cancer
The extraembryonic membrane that forms the fetal portion of the placenta is the
chorion
The mesoderm and the trophoblast combine to form the
chorion
The process of cell division that divides the cytoplasm of the zygote among blastomeres is called
cleavage
Which of the following is not part of fertilization?
completion of meiosis I
In polygenic inheritance, phenotypic characters are
determined by interactions among several genes
The first stage of labor is the ________ stage.
dilation
Which of the following hormones is the cause of most puberty-related changes in a female?
estrogen
A zygote whose genotype is XX will develop as a
female
Embryonic and early fetal development occurs in the ________ trimester.
first
The inner cell mass of the blastocyst will
form the embryo
By day 12 of embryonic development, mesoderm begins to form through
gastrulation
If a color-blind (X-linked recessive trait) man marries a woman who is heterozygous for the trait, what proportion of their male offspring can be expected to be color blind?
1/2
How many chromosomes do human somatic cells contain?
46
Trisomy 21 is the clinical term for
Down syndrome
Molly is homozygous for the dominant black hair trait. Therefore,
Molly has black hair
In simple autosomal inheritance, phenotypic characters are determined, or controlled, by
a single pair of alleles
In simple autosomal inheritance, phenotypic characters are determined, or controlled, by Select one:
a single pair of alleles
All of the following occur during pregnancy except
a woman's bladder capacity increases
Which of the following is a puberty-related change caused by increased testosterone levels?
accelerated bone deposition and skeletal growth
The developmental period heralded by the onset of puberty is known as
adolescence
The infancy stage of life is considered to be over when the baby reaches ________ of age.
2 years
By the end of gestation, maternal blood volume normally increases by almost ________ percent.
50
Completion of cytokinesis leads to
All of the answers are correct
Contact of a sperm with the oocyte membrane causes
All of the answers are correct
Progesterone calms the myometrium and prevents contraction. What factors antagonize progesterone and trigger labor and delivery?
All of the answers are correct
The placenta is a source of which of the following hormones?
All of the answers are correct
Which of the following is one of the critical events of the first trimester?
All of the answers are correct
________ is the time spent in growing within the uterus.
Gestation
All of the following occur at puberty except
GnRH levels decline