Meiosis

Meiosis one - first phase - prophase 1

Chromosomes pair and become visible, crossing-over occurs

Haploid

a cell has half the number of chromosomes as the original or the parent cell - only one set of chromosomes.

During Meiosis, when is the chromosome haploid?

at the end- the last phase of meiosis 2 (telophase 2)

Meiosis two - third phase - anaphase 2

centromeres split and the chromatids separate - single chromatids move to the opposite ends of the cell

Meiosis one - second phase - metaphase 1

chromosome pairs line up in center of cell

Meiosis two - second phase - metaphase 2

chromosomes (each with 2 chromatids) move to the center of the cell

Genes

control traits (ex: hair color, eye color, etc.)

2n

diploid - when two chromosomes are present

During Meiosis, when is the chromosome number diploid?

during meiosis 1 - metaphase 1

What is Meiosis 2

each of the two cells produced from Meiosis 1 divides into two more cells- resulting in four different haploid cells

What is Meiosis 1

first half of the two divisions of the cell during meiosis - where one cell splits into two

Meiosis two - fourth phase - telophase 2

four sex cells have been produced - each cell has only half the number of chromsomes that the parent cell had at the beginning of meiosis - each cell has only one chromosome for each oiginal pair

Gamete

haploid cell that fuses with another cell during fertilization

Understand why crossing-over is important in helping to create genetic variability

helps promote genetic diversity or mix up the genes - helps the process of evolution

N

number of chromosomes in a gamete - 1 - haploid

Crossing-over

occurs in prophase one, by which the two chromosomes of a homologous pair exchange equal segments with each other. occurs in the first division of meiosis.

Homologous Chromosomes

one chromosome from each parent contains the same information and forms a pair ... They are the chromosomes which pair during meiosis

Meiosis one - third phase - anaphase 1

pairs of chromosomes separate and move to opposite ends of the cell

Meiosis

process where the number of chromosomes is reduced by half to form sex cells sperm, egg (both are gametes)

When does crossing-over occur?

prophase one

Meiosis two - first phase - prophase 2

the nuclear envelope breaks down and the spindleforms

Chromosomes

threadlike structures of nucleic acids and protein found in the nucleus of most living cells

Meiosis one - fourth phase - telophase 1

two cells form - each with half the number of chromosomes - each chromosome still has two chromatids

Diploid

two sets of chromosomes (double the haploid number) - one of each chromosome pair comes from each parent cell

What happens to the chromosomes number when two sex cells join?

you have a full set of chromosomes just like the parent cell