BIO 120- Meiosis

Asexual reproduction

A single individual is the only parent and passes copies of all its genes to its offspring without the fusion of gamete

Binary fusion

A type of asexual reproduction used by prokaryotes and single-celled eukaryotes

meiosis; haploid

Sexual reproduction uses _________ because a __________ egg from each parent contains 23 chromosomes which combine to 46 chromosomes when they fuse, thus making a diploid

4

How many haploid cells does meiosis make?

prophase 1

meiosis 1: chromosomes condense, centrioles move to opposite sides, and nuclear envelope breaks down

synapsis

When homologous chromosomes line up next to each other

crossing over

The exchange of part of a chromatid from one chromosome with the equivalent part of a chromatid from a homologous chromosome

meiosis 1

What one and only phase does genetic variation take place in?

metaphase 1

meiosis 1: chromosomes line up at metaphase plate for first time and microtubules of centromeres reach out and touch kinetochore

random alignment

chromosomes from the mother and some from the father line up on each side of the equator randomly and go to different cells

independent assortment

the segregation of one pair of homologous chromosomes independently of the segregation of any other pair of chromosomes

anaphase 1

meiosis 1:Tetrads break apart and homologous chromosomes separate towards the poles 

telophase 1

meiosis 1: One pair of homologous chromosomes at each pole. Nuclear envelope reforms around chromosomes that condense

cytokinesis 1

meiosis 1: Division of two new daughter cells

2; 23; 2

At the end of meiosis 1, there are _____ daughter cells, each containing _______ chromosomes and _____ duplicate chromatids in each chromosome

prophase 2

meiosis 2: chromosomes condense a second time and nuclear envelope breaks down

metaphase 2

meiosis 2: Chromosomes line up at metaphase plate for a second time and microtubules of centromere attach to kinetochore of sister chromatids

anaphase 2

meiosis 2: Sister chromatids are pulled apart 

telophase 2

meiosis 2: Nuclear envelope reforms and chromosomes decondense for a second time

cytokinesis 2

meiosis 2: division of four daughter cells

4; 23; 1

At the end of meiosis 2, there are ______ daughter cells, each with ______ chromosomes but only _____ chromatid in each chromosome

gametogenesis

The process of making sex cells

spermatogenesis

gametogenesis in males is called __________

oogenesis

gametogenesis in females is called __________