D3.2 Inheritance & Chromosome Numbers PDF

## D3.2 Inheritance 1. In some cases: - A heritable trait is controlled by a single gene but often is controlled by more than one 2. Some traits appear more often in: - Males than females depending on which chromosome the gene is located 3. Some versions of genes: - Mask others, so some...

## D3.2 Inheritance 1. In some cases: - A heritable trait is controlled by a single gene but often is controlled by more than one 2. Some traits appear more often in: - Males than females depending on which chromosome the gene is located 3. Some versions of genes: - Mask others, so sometimes a characteristic can skip a generation 4. ABO blood type: - There are multiple versions rather than just two - Mix so that: someone can have type AB blood 5. Flowering plants: plants with red flowers crossed with plants with white flowers produce: - Only: red flowers - Only: white flowers - Some produce: pink flowers 6. Genetic variety in humans can be explained by: - Whether or not the gene is found on the first: 22 chromosomes - On the: X or Y chromosome - The nucleotides present in the different alleles - Which alleles code for which proteins ## A3.1.6 Diversity in chromosome numbers and D3.2.1 Haploid gametes and diploid zygotes 1. Diploid and haploid cells: - Diploid= describe a nucleus that has chromosomes organized into homologous pairs. - Most cells in the human body and each nucleus contains 23 chromosomes from the mother and 23 from the father (TOTAL: 46) - Haploid= do not come in pairs - Gametes = sperm/egg - Humans: 23 total chromosomes - Adult forms of animal cells are rarely haploid - Exception: adult male bee, wasp, and ant cells are haploid - Generally: majority of cells in sexually reproducing organisms are diploid, and only the gametes are haploid - n= haploid number - Number of sets of chromosomes that a nucleus can have - Human egg cell: 23 - Human sperm cell: 23