Meiosis and Gametogenesis
You can now identify the main components, explain the mechanism step by step, interpret an observation and distinguish related ideas.
Big idea
A diploid cell contains homologous pairs carrying the same gene loci but possibly different alleles. Homologues pair, exchange segments and separate, reducing chromosome number from diploid to haploid.
Learning goals
- Homologous chromosomes: A diploid cell contains homologous pairs carrying the same gene loci but possibly different alleles.
- Meiosis I: Homologues pair, exchange segments and separate, reducing chromosome number from diploid to haploid.
- Meiosis II: Sister chromatids separate in a second division without another round of DNA replication.
- Independent assortment: Random orientation of homologous pairs produces many chromosome combinations in gametes.
- Gametogenesis: Meiotic products mature into gametes through specialized developmental processes.
Core concepts
1. Homologous chromosomes
A diploid cell contains homologous pairs carrying the same gene loci but possibly different alleles.
Observation: One homologue in each pair was inherited from each parent.
2. Meiosis I
Homologues pair, exchange segments and separate, reducing chromosome number from diploid to haploid.
Observation: Crossing over in prophase I creates new allele combinations.
3. Meiosis II
Sister chromatids separate in a second division without another round of DNA replication.
Observation: Two haploid cells divide to produce four haploid products.