Chapter 27 pre test
Completion of cytokinesis leads to
All are correct
A child born with an XXY chromosome patter will have
Klinefelter's syndrome
Non-sex chromosomes are called
autosomal
The almost identical cells produced by cleavage divisions are called
blastomeres
Endoderm + mesoderm = which extra embryonic membrane?
both yolk sac and allantois
In polygenic inheritance, phenotypic characters are:
determined by interaction among several genes
The first stage of labor is the _____ stage.
dilation
Trisomy 21 is the clinical term for
down syndrome
The oval, three-layered sheet produced by gastrulation is called the
embryonic disc
Which of the following hormones is the cause of most puberty-related changes in a female?
estrogen
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
By day 12 of embryonic development, mesoderm begins to form through
gastrulation
The extra embryonic membrane that forms the fetal portion of the placenta is the
chorion
In pregnancy, expansion of the uterus results from
hypertrophy of smooth muscle cells
Attatchment to and penetration of the endometrium by the blastocyst is referred to as
implantation
Which of the following descriptions regarding the trophoblast is false?
is derived from the inner cell mass
A zygote whose genotype is XY will develop as a
male
After fertilization, the first cell division is completed
more than a day later
After 3 days, a pre-embryo becomes a solid ball of cells known as a
morula
The mesoderm forms
muscle
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 the smooth muscle contractions
During implantation, the
syncytial trophoblast erodes a path through the endometrium
A person't original chromosomes and their component genes constitute that person's
genotype
______ is the time spent in growing within the uterus.
gestation
Which of the following trait is a sex linked inheritance?
hemophillia
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
The region known as the primitive streak is the site of
migration of ectodermal cells to form the mesoderm
The region known as the primitive streak is the site of:
migration of ectodermal cells to form the mesoderm
After fertilization, the first cell division is completed:
more than a day later
The ectoderm forms
neural tissues
Stretching of the cervix cases an increase in the blood levels of
oxytocin
Which hormone stimulates the milk let-down reflex?
oxytocin
The placenta is expelled from the uterus during the ________ state 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 placenta is a source of which of the following hormones?
progesterone placental lactogen hCG relaxin ALL ARE CORRECT
A _____ is used to show all possible combinations of genes that can results from a given
punnett square
The hormone that increases the flexibility of the pubic symphysis during pregnancy is:
relaxin
The clinical term for "growing old" is
senescence
At fertilization, the "moment of conception" occurs in
step 5, amphimixis and cleavage
Completion of cytokinesis leads to
the all are correct
Each of the following statements concerning development is true except
the first trimester is when the fetus looks distintly human
During amphimixis,
the male and female pronuclei fuse
The endoderm forms
the urinary bladder
The period of gestation that is characterized by rapid fetal growth and fat deposition is the ________ trimester.
third
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
Deoxygenated blood is carried to the placenta by the
umbilical arteries
The __________ is formed by allantois, blood vessels, and yolk sac.
umbilical cord
Which of the following is not one of the extra embryonic 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 are true of the allantois except
it acts as the fetal bone marrow
Molly is homozygous for the dominant black hair trait. Therefore,
Molly has black hair.
Completion of cytokinesis leads to:
all are correct
Contact of a sperm with the oocyte membrane causes
all are correct
Progesterone calms the myometrium and prevents contraction. What factors antagonize progesterone and trigger labor and delivery?
all are correct
The various forms of any one gene are called
alleles
The extra embryonic membrane that forms a fluid-filled sac is the
amnion
A space opens within the inner cell mass that will form the
amniotic cavity
A space opens within the inner cell mass that will form the:
amniotic cavity
The individual cells produced by cleavage are called
blastomeres
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 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 gradual modification of anatomical structures during the period from conception to maturity is
development
The stage of labor during which the fetus emerges from the vagina is called the ______ stage.
expulsion
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 old embryonic development, mesoderm begins to form through:
gastrulation
Identify what process is occurring at the structure labeled "13".
gastrulation
How many chromosomes do human somatic cells contain?
46
In simple autosomal inheritance, phenotypic characters are determined, or controlled, by
a single pair of alleles
All of the following occur during pregnancy except
a womans 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
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 expected to be color blind?
1/2
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
All of the following occur at puberty except
GnRH levels decline