meiosis + mitosis

Prophase I

Homologous chromosomes pair up and crossover, nuclear membrane dissolves, centrioles migrate to opposite poles

Metaphase I

Homologous chromosome pairs align at the cell's equator, spindle fibers attach to centromeres

Anaphase I

Homologous chromosomes are pulled to opposite poles of the cell, sister chromatids remain attached

Telophase I

Chromosomes arrive at opposite poles, nuclear membranes may reform

interphase

cell growth and preparation of division

prophase II

[chromatin condenses into chromosomes] nuclear envelope disappears, spindle fibers start to form

G1

growth and functioning

Synthesis

DNA replicates

G2

organelles replicate in preparation for division

metaphase II

chromosomes line up in the middle of the cell

anaphase II

the sister chromatids seperated by spindle fibres into individual chromosomes

telophase II

chromosomes return to chromatin, spindle fibres disappear, nuclear membranes form, cleavage furrow begins

cytokinesis II

cytoplasm divides

mitosis

single cell divides to produce two genetically identical daughter cells. for growth, repair, and asexual reproduction.

sister chromatids

Replicated forms of a chromosome joined together by the centromere and eventually separated

centromere

area connecting sister chromatids

spindle fibers

microtubules that extend from the centrioles and guide chromosome movement

somatic cell

all human body cells; not the gametes

diploid

having two sets of chromosomes; all somatic cells

haploid

having one set of chromosomes; the gametes

gamete

sex cell; egg or sperm

zygote

fertilized egg

sexual

reproduction combining genetic info from two parents

asexual

reproduction by one parent

meiosis

cell division producing gametes

variation

differences in members of a population

Chromosome

A chain of DNA in the nucleus and condensed pair of sister chromatids

tetrad

homologous chromosomes; made up of four sister chromatids

crossing over

exchange of genetic material between homologous chromosomes

homologous chromosomes

Pairs of chromosomes that are similar in size and in gene order

“n” number of chromosomes in humans

n=23 chromosomes; one set

synapsis

tetrads come together to form homologous pairs

independent assortment

the random alignment of homologous chromosomes along equatorial plate during cell division

# of divisions in mitosis

1 division

# of divisions in meiosis

2 divisions

cytokinesis I

Cytoplasm divides, forming two haploid daughter cells

Order of mitosis

interphase, prophase, metaphase, anaphase, telophase, cytokinesis

order of meiosis

interphase, prophase I, metaphase I, anaphase I, telophase I, cytokinesis I, prophase II, metaphase II, anaphase II, telophase II, cytokinesis II