mitosis

• a chromosome is a DNA molecule made up of sections called genes.
• a gene is a length of DNA that codes for protein
• chromosomes carry genetic information in the form of genes
• each organism has a fixed number of chromosomes
• chromosomes are always in pairs. the reason is that when the zygote is formed, one of each pair comes from the male and female gamete
• haploid nucleus contains a single set of unpaired chromosomes, e.g sperm and egg cells
• diploid nucleus contains two sets of chromosomes, e.g normal body cells
• haploid nucleus is formed by meiosis
• diploid nucleus is formed by mitosis
• an allele is an alternative form of a gene
• alleles are genes that control the same characteristics