Meiosis Learning Objectives Contrast the number of chromosomes

Meiosis

Learning Objectives § Contrast the number of chromosomes in body cells and in gametes. § Summarize the events of meiosis. § Contrast meiosis and mitosis. § Describe how alleles from different genes can be inherited together.

Chromosome Number Homologous: chromosomes with the same genes, one originally from each of the organism’s parents Diploid: containing both sets of homologous chromosomes; 2 N Haploid: containing only a single set of chromosomes; 1 N chromosome number = 4

Reviewing Mitosis Prophase Metaphase Anaphase Telophase

Meiosis

Prophase I Centrioles Spindle forming Chromosomes Nuclear envelope Tetrad Centromere

Metaphase I Pair of homologous chromosomes

Anaphase I Sister chromatids

Telophase I Nuclear envelopes reforming

Prophase II

Metaphase II and Anaphase II Metaphase II Anaphase II

Telophase II and Cytokinesis four The end product of meiosis is daughter cells that half have the normal chromosome number.

Summary of Meiosis

Meiosis Video Let’s review the steps in animation before we model! Video

Comparing Mitosis and Meiosis prophase (I) metaphase (I) anaphase (I) telophase (I) 2 N = 4 N=2

Just remember: Disco Pug!

Gene Linkage Alleles of different genes tend to be inherited together when those genes are located on the same chromosome.

Gene Maps