7.4 Meiosis Flashcards
meiosis
cell division to create gametes
fertilization
sperm + egg = zygote
homologous chromosomes
two copies of same gene
one from Mom, one from dad
not necessarily identical
sister chromatids
identical copies of same chromosome formed during DNA replication
haploid
cells without homologous chromosomes
1n = 23
diploid
cells with homologous chromosomes
2n = 46
somatic cells
body cells
diploid
gametes
sperm/egg
haploid
crossing over
homologous chromosomes swap pieces randomly each time we do meiosis
independent assortment
chromosomes line up randomly each time we do meiosis
asexual reproduction
genetic clones
mutation is only source of genetic variation
mutations passed down to offspring
mitosis
sexual reproduction
great genetic variation
recombination of DNA, independent assortment, crossing over, and mutation cause genetic variation
mutations don’t affect parent, only offspring
meiosis and fertilization
prophase (mitosis)
diploid
DNA condenses into chromosomes
nuclear membrane dissolves
spindle fibers form
prophase I
diploid
DNA condenses into chromosomes
crossing over
nuclear membrane dissolves
spindle fibers form
prophase II
haploid
DNA condenses into chromosomes
nuclear membrane dissolves
spindle fibers form
metaphase (mitosis)
diploid
sister chromatids line up in middle of cell
metaphase I
diploid
homologous chromosomes line up in middle of cell
metaphase II
haploid
sister chromatids line up in middle of cell
anaphase (mitosis)
diploid
sister chromatids pulled apart to opposite ends of cell
anaphase I
diploid
homologous chromosomes pulled apart to opposite ends of cell
anaphase II
haploid
sister chromatids pulled apart to opposite ends of cell
parent and daughter cells (mitosis)
daughter cells genetic clones of parent cell
daughter cells genetic clones of each other
somatic
diploid
