Chapter 7: Cellular Basis of Inheritance

Question 1

alternation of generations

Answer 1

a life-cycle type in which the diploid and haploid stages alternate

Question 2

aneuploid

Answer 2

an individual with an error in chromosome number; includes deletions and duplications of chromosome segments

Question 3

autosome

Answer 3

any of the non-sex chromosomes

Question 4

chiasmata

Answer 4

(singular = chiasma) the structure that forms at the crossover points after genetic material is exchanged

Question 5

chromosome inversion

Answer 5

the detachment, 180° rotation, and reinsertion of a chromosome arm

Question 6

crossing over

Answer 6

(also, recombination) the exchange of genetic material between homologous chromosomes resulting in chromosomes that incorporate genes from both parents of the organism forming reproductive cells

Question 7

diploid-dominant

Answer 7

a life-cycle type in which the multicellular diploid stage is prevalent

Question 8

euploid

Answer 8

an individual with the appropriate number of chromosomes for their species

Question 9

fertilization

Answer 9

the union of two haploid cells typically from two individual organisms

Question 10

gametophyte

Answer 10

a multicellular haploid life-cycle stage that produces gametes

Question 11

germ cell

Answer 11

a specialized cell that produces gametes, such as eggs or sperm

Question 12

haploid-dominant

Answer 12

a life-cycle type in which the multicellular haploid stage is prevalent

Question 13

interkinesis

Answer 13

a period of rest that may occur between meiosis I and meiosis II; there is no replication of DNA during interkinesis

Question 14

karyogram

Answer 14

the photographic image of a karyotype

Question 15

karyotype

Answer 15

the number and appearance of an individuals chromosomes, including the size, banding patterns, and centromere position

Question 16

life cycle

Answer 16

the sequence of events in the development of an organism and the production of cells that produce offspring

Question 17

meiosis

Answer 17

a nuclear division process that results in four haploid cells

Question 18

meiosis I

Answer 18

the first round of meiotic cell division; referred to as reduction division because the resulting cells are haploid

Question 19

meiosis II

Answer 19

the second round of meiotic cell division following meiosis I; sister chromatids are separated from each other, and the result is four unique haploid cells

Question 20

monosomy

Answer 20

an otherwise diploid genotype in which one chromosome is missing

Question 21

nondisjunction

Answer 21

the failure of synapsed homologs to completely separate and migrate to separate poles during the first cell division of meiosis

Question 22

polyploid

Answer 22

an individual with an incorrect number of chromosome sets

Question 23

recombinant

Answer 23

describing something composed of genetic material from two sources, such as a chromosome with both maternal and paternal segments of DNA

Question 24

reduction division

Answer 24

a nuclear division that produces daughter nuclei each having one-half as many chromosome sets as the parental nucleus; meiosis 1 is a reduction division

Question 25

somatic cell

Answer 25

all the cells of a multicellular organism except the gamete-forming cells

Question 26

sporophyte

Answer 26

a multicellular diploid life-cycle stage that produces spores

Question 27

synapsis

Answer 27

the formation of a close association between homologous chromosomes during prophase I

Question 28

tetrad

Answer 28

two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase I

Question 29

translocation

Answer 29

the process by which one segment of a chromosome dissociates and reattaches to a different, nonhomologous chromosome

Question 30

trisomy

Answer 30

an otherwise diploid genotype in which one entire chromosome is duplicated

Question 31

X inactivation

Answer 31

the condensation of X chromosomes into Barr bodies during embryonic development in females to compensate for the double genetic dose