Chapter 3 Vocab

Question 1

zygote

Answer 1

A prenatal human from the fertilized ovum stage until formation of the primordial embryo, at about 2 weeks.

Question 2

sperm

Answer 2

The male sex cell (gamete).

Question 3

oocyte

Answer 3

The female gamete (sex cell). An egg.

Question 4

gamete

Answer 4

A sex cell.

Question 5

gonads

Answer 5

Paired structures in the reproductive system where sperm or oocytes are manufactured.

Question 6

testes

Answer 6

The male gonads.

Question 6

ovaries

Answer 6

The female gonads.

Question 7

homologous pair

Answer 7

Two chromosomes with the same gene sequence.

Question 8

polyploid

Answer 8

A cell with one or more extra sets of chromosomes.

Question 9

reduction division

Answer 9

The first meiotic division, which halves the chromosome number.

Question 10

equational division

Answer 10

The second meiotic division, yielding four cells from two.

Question 11

spermatozoon

Answer 11

A mature male reproductive cell (meiotic product).

Question 11

independent assortment

Answer 11

Inheritance of a gene on one chromosome does not influence inheritance of a gene on a different chromosome (Mendel’s second law) because of the random arrangement of homologous chromosome pairs, in terms of maternal and paternal origin, down the center of a cell in metaphase 1.

Question 11

crossing over

Answer 11

An event during prophase I when homologs exchange parts.

Question 12

spermatogonium

Answer 12

An undifferentiated cell in a seminiferous tubule that can give rise to a sperm cell following meiosis and maturation.

Question 13

spermatogenesis

Answer 13

Sperm cell formation and differentiation.

Question 14

oogenesis

Answer 14

Oocyte (egg) formation.

Question 15

oogonium

Answer 15

A cell in the ovary that gives rise to an oocyte, in meiosis.

Question 16

polar body

Answer 16

A product of female meiosis that contains little cytoplasm and does not continue to develop into an oocyte.

Question 17

embryo

Answer 17

In humans, the prenatal organism from fertilization until the end of the eighth week, when all basic structures are present.

Question 18

fetus

Answer 18

The prenatal human after the eighth week of development, when structures grow and specialize.

Question 19

cleavage

Answer 19

A series of rapid mitotic cell divisions after fertilization.

Question 20

blastomere

Answer 20

A cell of a blastocyst.

Question 21

ectoderm

Answer 21

The outermost primary germ layer of the primordial embryo.

Question 21

inner cell mass

Answer 21

A clump of cells on the inside of the blastocyst that will continue developing into an embryo.

Question 21

morula

Answer 21

The very early prenatal stage that resembles a mulberry.

Question 22

blastocyst

Answer 22

A fluid-filled ball of cells descended from a fertilized ovum.

Question 22

endoderm

Answer 22

The innermost primary germ layer of the primordial embryo.

Question 23

mesoderm

Answer 23

The middle primary germ layer.

Question 24

gastrula

Answer 24

A three-layered embryo.

Question 25

primary germ layers

Answer 25

The three layers of an embryo.

Question 26

epigenetic

Answer 26

Any effect that modifies gene expression without changing the DNA sequence, such as methylation.

Question 27

dizygotic twins (DZ)

Answer 27

Twins that originate as two fertilized ova; fraternal twins.

Question 28

monozygotic twins (MZ)

Answer 28

Twins that originate as a single fertilized ovum; identical twins

Question 29

neural tube

Answer 29

A structure in the embryo that develops into the brain and spinal cord.

Question 30

teratogen

Answer 30

A substance that causes a congenital disorder.

Question 30

critical period

Answer 30

The time during prenatal development when a structure is sensitive to damage from a mutation or an environmental intervention.

Question 31

Meiosis I, a __1__, halves the number of chromosomes. Meiosis II, an __2__, produces four cells from the two that result from meiosis I, without another DNA replication

Answer 31

1: reduction division 2: equational division

Question 31

The male and female reproductive systems include paired __1__ and networks of tubes in which __2__ and __3__ are made.

Answer 31

1: Gonads 2: Sperm 3: Oocytes