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