Meiosis is the process by which sex cells (gametes) are made in the reproductive organs.
- It involves the reduction division of a diploid germ line cell into four genetically distinct haploid nuclei
- The first meiotic division separates pairs of homologous chromosomes to halve the chromosome number (diploid → haploid)
- The second meiotic division separates sister chromatids (created by the replication of DNA during interphase)
Meiosis I
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Meiosis II
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3.3 meiosis
Understanding:
3.3.U2 The halving of the chromosomes number allows a sexual life cycle with fusion of gametes.
3.3.U2 The halving of the chromosomes number allows a sexual life cycle with fusion of gametes.
Objectives:
- Compare sexual and asexual life cycles.
- Explain why meiosis must occur as part of a sexual life cycle.
Sexual vs Asexual Reproduction
The lifecycle is the period of time that an organism passes through until producing offspring of its own. The lifecycle can involve sexual or asexual reproduction.
The sexual lifecycle combines genetic information from two parents. In order to maintain the correct number of chromosomes in the offspring, the parents must undergo meiosis to create gametes with half of the genetic information.
The lifecycle is the period of time that an organism passes through until producing offspring of its own. The lifecycle can involve sexual or asexual reproduction.
- Sexual
- Two parents
- Meiosis
- Results in genetic variation
- Asexual
- One parent
- Fission, mitosis or budding
- Requires less energy
The sexual lifecycle combines genetic information from two parents. In order to maintain the correct number of chromosomes in the offspring, the parents must undergo meiosis to create gametes with half of the genetic information.