5.1.1 Eukaryotic organisms use sexual/asexual reproduction

Genes are made up of segments of DNA, and Genes form chromosomes

Asexual reproduction无性繁殖: the genetic information is completely identical with its descendent eg. potato

Sexual reproduction: inherits DNA from 2 parents

Compared to asexual, sexual reproduction costs more but have more genetic variation

Vocabulary:

Karyotype核型图

Sex chromosome性染色体

autosome常染色体

homologous chromatids同源染色体

diploid二倍体

hiploid单倍体

5.1.2 Meiosis produces four genetically unique daughter cells that are haploid

Meiosis1: homologous chromosomes seperate

Meiosis2: sister chromatids seperate

synapsis 联会

chiasmata 交叉点

3 mechanisms contribute to genetic variation:

  1. Independent assortment of chromosomes