Openstax Biology - Chapter 11 - Meiosis & Sexual Reproduction

Front 1

alternation of generations

Back 1

life-cycle type in which the diploid and haploid stages alternate chiasmata (singular, chiasma) the structure that forms at the crossover points after genetic material is exchanged

Front 2

cohesin

Back 2

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

Front 3

crossover

Back 3

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

Front 4

diploid-dominant

Back 4

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

Front 5

fertilization

Back 5

union of two haploid cells from two individual organisms

Front 6

gametophyte

Back 6

a multicellular haploid life-cycle stage that produces gametes

Front 7

germ cells

Back 7

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

Front 8

haploid-dominant

Back 8

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

Front 9

interkinesis

Back 9

brief period of rest between meiosis I and meiosis II; also known as interphase II

Front 10

life cycle

Back 10

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

Front 11

meiosis

Back 11

a nuclear division process that results in four haploid cells

Front 12

meiosis I

Back 12

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

Front 13

meiosis II

Back 13

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

Front 14

recombination nodules

Back 14

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

Front 15

reduction division

Back 15

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

Front 16

somatic cell

Back 16

all the cells of a multicellular organism except the gametes or reproductive cells spore haploid cell that can produce a haploid multicellular organism or can fuse with another spore to form a diploid cell

Front 17

sporophyte

Back 17

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

Front 18

synapsis

Back 18

formation of a close association between homologous chromosomes during prophase I

Front 19

synaptonemal complex

Back 19

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

Front 20

tetrad

Back 20

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