Meiosis and Mitosis, Mitosis and Meiosis

sexual reproduction

reproduction that results from combining genetic material from two individuals.

meiosis

type of cell division that results in 4 daughter cells that each have half the number of chromosomes as the parent cell.

Diploid

A cell containing two full sets of chromosomes 2n=46.

Haploid

A cell containing a single/ half set of chromosomes n=23

Gametes

A haploid male or female germ cell (e.g. sperm and egg)

gene

a section of the DNA (chromosome) that codes for a specific trait (e.g. eye color or hair color)

crossing over

when homologous chromosomes exchange genes during Prophase 1 creating new mixture of parent traits in their offspring

Meiosis I

PMAT I: The first cell division of meiosis when the homologous pairs are split up into two separate cells.

Meiosis II

PMAT II: The second cell division of meiosis. This is when the sister chromatids are split up into two separate cells.

Mitosis

Produces cells almost genetically identical

Asexual reproduction

Has the advantage of producing offspring in greater numbers, with no partner required

23 pairs of chromosomes

How many pairs of chromosomes present in humans

Chromosome

Coiled up DNA

Chromatin

Uncoiled DNA. Present in interphase

Homologous Chromosomes

Carry the same genes at the same locus (location).

Ex. Chromosome 1 and Chromosome 1

Mitosis (Function and location of)

Cell division for growth, repair or maintenance. Occurs in body cells.

PMAT

Meiosis (Function and location of)

Cell division for gamete production (sperm and eggs).

PMATPMAT

Phases of the Cell Cycle

1. Interphase (G1, S, G2)

2. Mitosis (PMAT)

3. Cytokinesis (cell division)

Parts of Interphase

DNA is chromatin

G1- growth/protein synthesis

S- DNA replication

G2- growth/protein synthesis

Prophase (events)

Chromatin coils up into chromosomes.

Centrioles move to poles.

Spindle fibres and asters form. Nucleus and nucleolus

disappear.

Metaphase (events)

Chromosomes line up at the metaphase plate.

MIDDLE

Anaphase

APART! Centromeres divide.

Telophase

Cleavage furrow forms.

Cytokinesis

Cell divides into two. Cell plate forms in plant cells.

Sexual Reproduction

Requires male and female gametes. Variation.

Asexual Reproduction

One parent only. (cloning)

Mitosis.

Crossing over

Homologous chromosomes may exchange genetic material during prophase I.

Occurs more often in genes that are further apart.

Prophase I

Synapsis - homologous chromosomes (tetrads) pair up.

Crossing over may occur - exchange of genetic material.

Metaphase I

Homologous pairs line up in the middle on the metaphase plate.

Anaphase I

Segregation - Homologous pairs separate to opposite poles.

Telophase I

Cleavage furrow. Replicated chromosomes reach the poles.

Prophase II

Chromosomes can be seen.

Cells are haploid (n).

Metaphase II

Chromosomes line up in the middle

Anaphase II

Centromeres split. Single chromosomes move apart.

Telophase II

Cleavage furrow.

Zygote

sperm + egg

2n