Reproduction

• The two types of reproduction are asexual and sexual
• Asexual reproduction has no genetic variation. It is cloning
• Sexual reproduction has 2 sets of different chromosomes from the mum and dad. This means there is variation
• Variation helps animals adapt to their surroundings which can prevent them from going extinct
• Mitosis is cloning of cells. where as meiosis is the production of 4 different gametes
• Stage 1 of the cell cycle is an increase in mitochondria and ribosomes and the replication of chromosomes
• Stage 2 of the cell cycle is where mitosis occurs. the chromosomes are pulled to either end of the cell and the nucleus divides
• The final stage of mitosis is where the cell membrane and cytoplasm divide to form two identical daughter cells
• In meiosis the mitochondria and ribosomes increase and the chromosomes replicate
• stage 2 of meiosis the spindal Fibres are formed and the chromosomes line up at the equator. They are then pulled to opposite ends of the cell then the nucleus divides
• Stage 3 of meiosis the cell membrane and cytoplasm divides to form 2 separate cells. The spindal fibres then pull the chromosomes again and the nucleus and cell divides again to form 4 cells of 23 chromosomes pairs. these are called gametes
• Gametes are haploid (n) as they have only one set of chromosomes
• Fertilisation is when sperm from male meets egg from female, this creates a zygote which has 23 chromosome pairs
• During fertilisation the genetic material from both parents combines to create a unique individual with its own genotype
• The genome is the entire set of genetic material in an organism, including all the genes and the DNA
• The genome of a person is decided by if they dominant or recessive alleles
• A persons phoneme is decided by there characteristics. examples include eye colour, hair colour if they have freckles and how tall they are
• heterozygote is when they have 2 different alleles for a particular gene such as dominant and recessive
• Homozygote is if a person has 2 of the same alleles for a particular gene such as 2 dominant or 2 recessive
• An Allele is a different version of a gene that codes for a different amino acid.