Bennett Biology - Meiosis

asexual reproduction

Has the advantage of producing offspring in greater numbers, with no partner required. (cloning)

sexual reproduction

Reproduction that results from combining genetic material from two individuals.

mitosis

Produces cells almost genetically identical. Cell division for growth, repair or maintenance. Occurs in somatic cells. PMAT

meiosis

Type of cell division that results in 4 daughter cells that each have half the number of chromosomes as the parent cell. Cell division for gamete production (sperm and eggs). PMATPMAT

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.

diploid

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

haploid

A cell containing a single/ half set of chromosomes n=23. (sex cell)

gametes

A haploid male or female 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).

23

Number of paired chromosomes present in humans

chromosome

Coiled up DNA

chromatin

Uncoiled DNA. Present in interphase.

homologous chromosomes

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

somatic

Of the body

cell cycle

1. Interphase (G1, S, G2)

2. Mitosis (PMAT)

3. Cytokinesis (cell division)

prophase

Chromatin coils up into chromosomes. Centrioles move to poles. Spindle fibers form. Nucleus and nucleolus disappear.

metaphase

Chromosomes line up at the equatorial plate.

MIDDLE

anaphase

Centromeres divide. APART

telophase

Cleavage furrow forms.

cytokinesis

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

cancer cells

Cells that reproduce out of control. Can move and grow in another part of the body - metastasis

cloning

Producing identical offspring from a single parent cell; asexual reproduction.

interphase

G1 - growth, protein synthesis

S - DNA replicates

G2 - growth, protein synthesis

fertilization

When a sperm enters an egg. It doubles the chromosome number.

zygote

sperm + egg (2n)

crossing over

homologous chromosomes exchanging genes; creates genetic variation

independent assortment

The way the homologous pairs line up in Metaphase I is random; creates genetic variation

46

Number of chromatids present in a human somatic cell.