11: Meiosis and Sexual Reproduction

Question 1

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

Answer 1

alternation of generations

Question 2

the structure that forms at the crossover points after genetic material is exchanged

Answer 2

chiasma (pl. chiasmata)

Question 3

proteins that form a complex that seals sister chromatids together at their centromeres until anaphase II of meiosis

Answer 3

cohesin

Question 4

exchange of genetic material between nonsister chromatids resulting in chromosomes that incorporate genes from both parents of the organism

Answer 4

crossover

Question 5

union of two haploid cells from two individual organisms

Answer 5

fertilization

Question 6

a multicellular haploid life-cycle stage that produces gametes

Answer 6

gametophyte

Question 7

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

Answer 7

germ cells

Question 8

(also, interphase II) brief period of rest between meiosis I and meiosis II

Answer 8

interkinesis

Question 9

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

Answer 9

life cycle

Question 10

a nuclear division process that results in four haploid cells

Answer 10

meiosis

Question 11

first round of meiotic cell division; referred to as reduction division because the ploidy level is reduced from diploid to haploid

Answer 11

meiosis I

Question 12

second round of meiotic cell division following meiosis I; sister chromatids are separated into individual chromosomes, and the result is four unique haploid cells

Answer 12

meiosis II

Question 13

protein assemblies formed on the synaptonemal complex that mark the points of crossover events and mediate the multistep process of genetic recombination between nonsister chromatids

Answer 13

recombination nodules

Question 14

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

Answer 14

reduction division

Question 15

all the cells of a multicellular organism except the gametes or reproductive cells

Answer 15

somatic cell

Question 16

haploid cell that can produce a haploid multicellular organism or can fuse with another spore to form a diploid cell

Answer 16

spore

Question 17

a multicellular diploid life-cycle stage that produces haploid spores by meiosis

Answer 17

sporophyte

Question 18

formation of a close association between homologous chromosomes during prophase I

Answer 18

synapsis

Question 19

protein lattice that forms between homologous chromosomes during prophase I, supporting crossover

Answer 19

synaptonemal complex

Question 20

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

Answer 20

tetrad