B2- simple inheritance in animals and plants

cell division and growth

• cell division is important for growth and repair of cells
• mitosis is a-sexual reproduction so does not involve the joining of gametes
• it results in two identical 2 daughter cells which are a copy of the original cell
• mitosis creates clones
• 1)normal body cell has 2 pairs of chromosomes
• 2)the cell divides to create another copy of each chromosome resulting in 4 pairs
• 3)that cell divides to form 2 daughter cells with 4 chromosomes identical to the parent cell
• in early development of plants and animals the cells are unspecialised and called stem cells- these then go through mitosis to form new types of cells

cell division in sexual reproduction

• cells in reproductive organs divide by meiosis to form gametes
• results in variation because it has mixed genetic information
• gametes have one pair of chromosomes and body cells have 2
• 1)a normal body cell contains 2 pairs of chromosomes
• 2)that body cell is copied to create 4 pairs of identical chromosomes
• 3)this cell divides into 2 
• 4)they then divide into 4 all with 2 chromosomes each

stem cells

• theyre unspecialised
• found in human embryo and bone marrow
• they can differitate into different type…