Mitosis and meiosis

MITOSIS AND MEIOSIS

Cell Replication

IT’S ALL ABOUT THE DNA...

GENETIC STORAGE Humans are a diploid (2n) species; 46

chromosomes Humans gametes are haploid (n); 23

chromosomes

CELL REPLICATION: 2 OPTIONS 1) MITOSIS: division of a nucleus into two

genetically identical nuclei (IPMAT)Somatic cells

2) MEIOSIS: division of nucleus that involves two divisions and one duplication of chromosomes; results in haploid (n) gametes with one chromosome from each homogolous pairGametes (sex cells)

CYTOKINESIS: division of a cells cytoplasm into two distinct cells

MITOSIS

1. Interphase2. Prophase3. Metaphase4. Anaphase5. Telophase6. Cytokinesis

MEIOSIS

1. Interphase2. Prophase 13. Metaphase 14. Anaphase 15. Telophase 16. Cytokinesis 1

7. Prophase 28. Metaphase 29. Anaphase 210. Telophase 211. Cytokinesis 2

THE CELL CYCLE (MITOSIS)

INTERPHASE Growth and DNA

replication

PROPHASE Chromosomes

condense Nuclear

membrane begins to dissolve

Spindle fibers attach to the centromeres

Centrioles move to opposite poles

METAPHASE Chromosomes line up

at the equatorial plate

Nuclear membrane completely dissolves

ANAPHASE Centromeres

divide and the resulting chromosomes move to opposite poles of the cell

Identical chromosomes at each pole

TELOPHASE Chromosomes lengthen

again Spindle fibres dissolve Nuclear membrane forms

Cytokinesis: Cytoplasm begins to

divide A furrow develops

pinching of the cell intotwo parts

Resulting in two separate daughter cells

IF THAT SEEMS LIKE A LOT... Ana and the pro wrestlers might be up

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X X

MITOSIS VS. MEIOSIS http://www.pbs.org/wgbh/nova/body/ho

w-cells-divide.html

INTERPHASE DNA has already

duplicated

Paternal and Maternal Chromosomes duplicated

Chromosomes condense

Homologous chromosomes come together (Tetrad)

Crossing over occurs Spindle fibers attach

to homologous pairs

PROPHASE 1Synapsis

CROSSING OVER

Chromosomes line up at the equatorial plate

METAPHASE 1

Homologous chromosomes separate to opposite poles

ANAPHASE 1

TELOPHASE Nucleus

completes its division.

Results in two cells that are haploid (x2)

Cytoplasm divides during cytokinesis

Centrioles move to opposite poles

Chromosomes become attached to spindle fibres

PROPHASE 2

Chromosomes line up at equatorial plate

METAPHASE 2

Sister Chromatids of each chromosome separate and move to opposite poles

ANAPHASE 2

Spindle fibres detach

Cytoplasm separates (Cytokinesis)

Left with four haploid cells

TELOPHASE 2

GAMETOGENESIS