1. What do you know? Meiosis & mitosis? Inheritance? Cystic Fibrosis? Polydactly?

2. B2 REVISION – CHAPTER 5 – Cell Division and Growth Labe l the diagram: A gene is a section of D____. It controls a c____________ of your body. You have ___ chromosomes in the n______ of your b_______ cells. Arranged in _____ pairs. One of each pair is inherited from your m________ and one from your f_________. Your sex cells or g_________ only have _____ chromosomes. Other key terminology: Differentiation: Fertilisation: Variation: Stem cells FeatureMitosisMeiosis Used for growth & repair Used for gamete production Use for asexual reproduction DNA is copied before Cell divides once Cell divides twice 4 new cells formed Two new cells formed New cells contain one set of chromosome New contain two sets of chromosomes New cells show genetic variation New cells genetically identical

3. Key terms in genetics B2 REVISION – CHAPTER 5 – INHERITANCE Who was Mendel? What work did he do? Two men claim to be the father of the same child. Explain how DNA fingerprinting can be used to find out which one is the real father. HomozygousHas two ________________ alleles. HeterozygousHas two of the _____________ alleles. GenotypeThe mixture of ________________ an organism has. PhenotypeCharacteristics of an _______________. AlleleDifferent versions of the same _______________. DominantYou only need _____ copy for it to have an effect. RecessiveYou need _____ copies for it to have an effect. Inheritance of Cystic Fibrosis Type of allele : Symptoms: Draw a genetic diagram to show the inheritance of this condition (two parents carriers) Inheritance of Polydactyly Type of allele : Symptoms: Draw a genetic diagram to show the inheritance of this condition (Pp x pp) Inheritance of Huntington's disease Type of allele : Draw a genetic diagram to show the inheritance of this condition (Hh x hh) What is genetic screening? What are the main ethical issues? The genetic code. What molecule do genes code for and how?

4. Organisation of genetic material Each chromosome in the nucleus contains thousands of genes.

5. Mitosis & Meiosis

6. Becoming specialized Tissue cells continue to divide and differentiate, each time becoming more and more specialized. nerve cells red blood cells stem cell tissue cells cardiac muscle cells

7. Gregor Mendel (1822-1884) He was a Monk He experimented with pea plants He is known as the forefather of genetics He determined there were inheritable factors that controlled traits

8. Proteins

9. Homozygous alleles If the alleles for a characteristic are the same, the organism is said to be homozygous for that characteristic. So the organism has a homozygous genotype. allele for brown eyes allele for blue eyes

10. Heterozygous alleles The phenotype expressed by heterozygous alleles will depend on which allele is dominant and which allele is recessive. If the alleles for a characteristic are different, the organism is said to be heterozygous for that characteristic. So the organism has a heterozygous genotype. allele for brown eyes allele for blue eyes ?

11. What eye colour? The allele for brown eyes is dominant over the allele for blue eyes. The individual will have brown eyes, because the allele for brown eyes is dominant. allele for brown eyes allele for blue eyes

14. DNA Fingerprinting

15. The advantages of embryo screening –Their children will not have CF. Although CF can be treated, people with it have many health problems and may live shorter lives. –Their children will not have the CF allele, so will not be able to pass on the disorder to their own children. –Although IVF is expensive, in the long term, money will be saved by the NHS as the children born will not have to be treated for CF. Also they will not need a heart–lung transplant.