Bio Lab 8 - Mitosis and Meiosis

interphase - mitosis

when the cell performs it normal functions and prepares for cell division

G1, S, G2

chromosomes not visible

prophase - mitosis

chromosomes are visible

nuclear membrane breaks down

spindle fibers being to form

Metaphase - mitosis

sister chromatids line up at the center of the cell

anaphase - mitosis

sister chromatids are pulled apart and move to opposite sides of the cell

telophase - mitosis

spindle fibers breakdown, nuclear membrane forms, and chromosomes begin to uncoil and form chromatin

cytokinesis

cytoplasm splits in two and the cell divides

G1

4 chromosomes. 2 long, 2 short

2 centrioles

S phase

4 chromosomes that have replicated

G2

separate centrioles

synapsis

the precise pairing of homologous chromosomes that takes place during prophase I of meiosis

allows for cross over to happen

crossing over

the process where homologous chromosomes pair up and exchange segments of their genetic material

chiasma

the point of contact and physical link between non-sister chromatids of homologous chromosomes

allleles

a specific alternative version of a gene

Prophase I - Meiosis 1

Chromosomes condense and pair up with their matches homologous partner

where cross over occurs (only place it happens)

Metaphase I - Meiosis 1

paired homologous chromosomes line up in the middle of the cell

align in pairs allowing for indpenedent assortment

Anaphase 1 - Meiosis 1

the paired chromosomes are pulled apart toward opposite ends of the cell by spindle fibers

sister chromatids remain attached at their centers only the homologous pairs separate

Telophase 1 - Meiosis 1

Chromosomes arrive at opposite poles and the cell splits into 2 new daughter cells

Prophase II - Meiosis 2

the nuclear envelope breaks down and chromosomes re-condense

there are no duplicated homologous pairs, just simple X-shaped chromosomes

Metaphase II - Meiosis 2

individual chromosomes line up in a single file along the middle of the cell

Telophase Ii - Meiosis 2

nuclear membranes reform around the separated chromosomes at each pole the cells physically divide into 4 genetically unique haploid daughter cells