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67 Cards in this Set

  • Front
  • Back

The female gamete just before it is fertilized is termed

a secondary oocyte

The major body part(s) derived from ectoderm is/are

1) the nervous system: sensory organs, lens of eye, tooth enamel, pituitary gland

2) skin: hair, nails, glands of the skin

Teratogens are substances that

cause birth defects

A normal oogonium is a(n) _______ cell


The number of sperm cells in an ejaculate averages

200 to 600 million

the union of a sperm and egg is called a


The stem cells from which sperm cells descend are called


The partial twinning that led to the births of conjoined twins Abby and Brittany Hensel must have happened during the first two weeks of gestation, because the girls

share tissues that descend from ectoderm, endoderm, and mesoderm

Cigarette smoking during pregnancy can cause

spontaneous abortion, prematurity, low birth weight, and stillbirth

Which structures are part of the same primary germ layer?

muscle, kidneys, dermis

After the second meiotic division, the number of chromosomes in each daughter cell is _______ that of the original parental cell.


the placenta forms about __________ weeks after fertilization


Body parts derived from endoderm include

the urinary bladder epithelium, pancreas, and digestive tract lining

Centenarians are

people who live past 100 years

Primary spermatocytes develop from the division of


Latika and Jeremiah are thrilled at the ultrasound scan that shows that their fetus appears to be a boy. It is the first time this has shown up on a scan. Latika is likely in her ___ week of pregnancy.


The ovary of a newborn girl houses about ___ primary oocyte


The symptoms of fetal alcohol syndrome include

impaired intellect

The first step in oogenesis is

an oogonium accumulates cytoplasm and DNA replicates

The head of a sperm contains the


__________ prepares sperm for penetration of the oocyte.


The critical period is

the time during development when structures are sensitive to damage from a mutation, toxin, or virus

Meiosis in females

only completes if an oocyte is fertilized

An embryo develops rudiments of all organs by week __ of prenatal development.


During meiosis II in sperm development

secondary spermatocytes divide meiotically to form haploid spermatids

A bulbourethral gland secretes

a mucus-like fluid

mitochondria are found in which part of a sperm cell


Human prenatal development takes ___ weeks.


Connective tissues are part of the primordial embryo's


After meiosis I, the number of chromosomes is _______ that of a somatic cell.


The number of possible chromosome combinations in a human gamete, considering independent assortment but not crossing over, is about

8 million

The placenta

nourishes the fetus and secretes hormones that maintain the pregnancy

Body parts derived from endoderm include

the urinary bladder epithelium, pancreas, and digestive tract lining

Which is a characteristic of seminal fluid?

It consists of sperm and secretions

The hormone measured in a pregnancy test is


Sperm are produced within the

seminiferous tubules

which gland adds secretions to semen

seminal vesicles

The tubular part of the uterus that extends downward into the upper vagina is the


Starvation in the uterus increases the risk in adulthood of developing

heart and blood vessel disease, type 2 diabetes, and obesity

The female gonads are the


Tanisha and Tawanda are twins but do not look at all alike. They are the result of fertilization of

two oocytes by two sperm cells

A single-gene disease that can cause symptoms in a fetus is

osteogenesis imperfecta

A blastomere is a _____ and a blastocyst is _____.

cell produced by cleavage; a hollow ball of cells

The ovary in an adult contains

many oocytes in various stages of maturity

Erica is 8 years old, but looks as if she is 80. She is thin, with a beaked nose, very little hair, and several diseases that are typically seen in the elderly. She most likely has

a segmented progeroid syndrome

The number of sperm cells that form from a primary spermatocyte is


Crossing over occurs during

prophase I

Fertilization usually occurs in the

uterine tube

Monica takes the drug Accutane throughout her pregnancy, and her child has mental retardation and heart problems, due to the exposure. Accutane is a(n)


Thalidomide is

a drug that causes fetal limb defects, but is used to treat leprosy

The reason that starvation during prenatal development raises the risk for cardiovascular and metabolic problems in adulthood is that

metabolism in the fetus shifts to preserve vital organs, accelerating weight gain in childhood

Synapsis occurs during

prophase I

During the first meiotic division

homologous chromosome pairs separate

Two oocytes released from the same ovary at the same time and fertilized by two sperm results in

dizygotic twins

Sperm undergo capacitation

in the woman's body

which gland adds fluid to semen which protects sperm cells from the acidic environment of the vagina

bulbourethal gland

Spermatocytes and oocytes are


Blastocyst cells that give rise to the embryo's body constitute the

inner cell mass

At the end of meiosis, the number of chromosomes in each daughter cell is halved because meiosis consists of

two cell divisions, but one DNA replication

The inner cell mass

gives rise to the embryo

The correct sequence for the steps of meiosis I is


By the end of meiosis I of oogenesis, an oogonium has become

a secondary oocyte and a polar body

Body parts derived from mesoderm are the

muscle tissue, bone tissue, and internal reproductive organs

The male and female reproductive systems of an adult each include

gonads, tubes, gametes, hormones and secretions

Amniotic fluid

protects the embryo against jarring movements

Meiosis is necessary because otherwise

the fertilized ovum will have too much genetic material

Amanda is eating a chicken breast, and wonders how many chromosomes are in each somatic cell of the unfortunate bird. She looks it up, 78. Therefore, a sperm or an unfertilized egg from a chicken would contain __ chromosomes.