GCSE A* REVISION NOTES


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B2.7: Cell division and inheritance

B2.7.1: Cell division

Mitosis

Meiosis

  1. DNA doubles and forms chromatids
  2. The chromatids pair up with their sister chromatids to form homologous chromosomes and swap genetic material (crossing over)
  3. Nuclear envelopes disappear and chromatids move to the equator of the cell
  4. Spindle fibres attach to the chromatids and pull them to both sides of the cell
  5. The cell splits and two daughter cells are produced
  6. Chromatids align in the middle and are pulled apart
  7. The cells split again to form 4 haploid genetically different daughter cells

 

Stem Cells

Animals
Plant Growth
Differentiation
Types of Stem Cells

Totipotent – Can differentiate into every cell type in the body

Pluripotent - Can turn into a wide range of cell types but are less useful

Multipotent/Unipotent – Can develop into one or two types only

Therapeutic uses of Stem cells

 

 

 

B2.7.2 & 3: Genetic Variation and Genetic Disorders

Embryo screening

Against

 

For

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