| Define homologous chromosomes | Homologous chromosomes are chromosome pairs (one from each parent) that have the same genes in the same order but may have different alleles of those genes. Their role is to carry and transmit genetic information from one generation to the next during sexual reproduction. |
| Define an allele | An allele is a variant form of a gene that occurs at a specific location on a chromosome. |
| Define 'crossing over' | Crossing over is a process that occurs during meiosis where homologous chromosomes exchange genetic material, resulting in new combinations of alleles and increasing genetic diversity. |
| Define 'recombination' | Recombination is a process in which genetic material is exchanged between homologous chromosomes during meiosis, resulting in the creation of new combinations of alleles and genetic diversity. |
| Difference between recombination and crossing over | Recombination is a broader term that encompasses all forms of genetic exchange, including crossing over, but also other mechanisms such as independent assortment, random fertilization, and mutations.
Crossing over specifically refers to the physical exchange of genetic material between homologous chromosomes at specific points (chiasmata) during meiosis, which results in the creation of new combinations of alleles and genetic diversity. |
| Define spermatogensis | Spermatogenesis is the process by which haploid sperm cells are produced from diploid cells. During spermatogenesis, diploid cells called spermatogonia undergo mitosis to produce two daughter cells, one of which remains a spermatogonium and the other differentiates into a haploid cell called a primary spermatocyte. The primary spermatocyte undergoes meiosis I and II to produce four haploid cells called spermatids, which then mature into sperm cells. |
| Define oogenesis | Oogenesis is the process of formation and development of mature eggs (ova) in females. It involves meiosis, a specialized type of cell division that reduces the chromosome number from diploid (2n) to haploid (n), resulting in the production of four genetically distinct daughter cells (ovum and three polar bodies) that have half the number of chromosomes as the original cell. |
