Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. How are inherited diseases passed on?
   • These disorders are caused by the inheritance of certain alleles.
2. What causes polydactyly?
   • Polydactyly (having extra fingers or toes) is caused by a dominant allele.
3. What causes cystic fibrosis?
   • Cystic fibrosis (a respitory disease) is caused by a recessive allele, so both parents must carry the gene in order for the offspring to have the disease.
4. What are the economical, social and ethical issues concerning embryo screening?
   • Embyro screening is expensive, can damage/kill the embryo, can prevent suffering, some people believe all life is valueable despite disease
5. How many chromosomes are found in an ordinary human body cell?
   • Ordinary human body Cells contain 23 pairs of chromosomes.
6. What does the 23rd choromsome determine?
   • sex (male or female)
7. What is combination of sex chorosomes for a male and female?
   • ? In females the sex chromosomes are the same (XX). ? In males the chromosomes are different (XY).
8. Draw a genetic cross to show sex inheritance
9. What is the probability of having a male or female offpsring?
   • 1:1 / 50%