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3.4 explain the relationship between the structure and behaviour of chromosomes during meiosis and the inheritance of genes
explain the relationship between the structure and behaviour of chromosomes during meiosis and the inheritance of genes
- Chromosomes are made of DNA. Genes are coded within the DNA on the chromosomes. During division each chromosome (which therefore includes the genes) makes a complete copy of itself. The new chromosome is attached to the original chromosome by a centromere. In the initial division of meiosis the homologous chromosomes line up in matching pairs and one of each pair of homologous chromosomes moves into a new cell. Next the duplicated chromosomes separate to single strands resulting in four sex cells that are haploid, (ie contain half the chromosome number of the original cell).
- The genes are located on the chromosomes. They are duplicated during the first stage of meiosis and are then randomly assorted depending on which chromosomes from each pair enters which new haploid cell during the first and second division.