Chapter 8

Question 1

somatic cells

Answer 1

23 pairs of homologous chromosomes and

one member of each pair from each parent.

Question 2

Locus

Answer 2

is the position of a gene.

Different versions of a gene may be found at the same locus on maternal and paternal chromosomes.

Question 3

Sexual

Answer 3

Requires Fertilization of egg and sperm

Question 4

Asexual

Answer 4

The creation of genetically Identical offspring by a single parent.

Question 5

Homologous Chromosomes

Answer 5

e matched in
length,
centromere position, and
gene locations.

Question 6

Sister chromotids

Answer 6

contain Identical DNA copies

Question 7

Diploid cells

Answer 7

have two homologous sets of chromosomes

Question 8

Haploid cells

Answer 8

have one set of chromosomes.

Question 9

Gametes

Answer 9

Meiosis occurs in the sex organs, producing—sperm and eggs.

Question 10

Fertilization

Answer 10

is the union of sperm and egg.

Question 11

zygote

Answer 11

has a diploid chromosome number, one set from each parent.

Question 12

Meiosis

Answer 12

s a type of cell division that produces haploid gametes in diploid organisms.
Two haploid gametes combine in fertilization to restore the diploid state in the zygote.

Question 13

Meiosis I – Prophase I –

Answer 13

vents occurring in the nucleus.
Chromosomes coil and become compact.
Homologous chromosomes come together as pairs by synapsis.
Each pair, with four chromatids, is called a tetrad.
Nonsister chromatids exchange genetic material by crossing over.

Question 14

Meiosis I – Metaphase I

Answer 14

Tetrads align at the cell equator.

Question 15

Meiosis I – Anaphase I

Answer 15

Homologous pairs separate and move toward opposite poles of the cell.

Question 16

Meiosis I – Telophase I

Answer 16

Duplicated chromosomes have reached the poles.
A nuclear envelope re-forms around chromosomes in some species.
Each nucleus has the haploid number of chromosomes.

Question 17

Meiosis II – Prophase II

Answer 17

Chromosomes coil and become compact (if uncoiled after telophase I).
Nuclear envelope, if re-formed, breaks up again.

Question 18

Random fertilization

Answer 18

The combination of each unique sperm with each unique egg increases genetic variability

Question 19

Autosomes

Answer 19

not involved in deciding the sex of an organism

Question 20

karyotype

Answer 20

Karyotypes
are often produced from dividing cells arrested at metaphase of mitosis and
allow for the observation of 
homologous chromosome pairs,
chromosome number, and
chromosome structure.

Question 21

Genetic recombination

Answer 21

is the production of new combinations of genes due to crossing over.

Question 22

Crossing over

Answer 22

s an exchange of corresponding segments between separate (nonsister) chromatids on homologous chromosomes.