TOPIC 2 - INHERITANCE

Question 1

Describe the process of DNA replication (4)

Answer 1

1. helicase unwinds DNA double helix breaking H bonds
2. 2 template strands formed
3. free nucleotides attach to template strands
4. DNA polymerase joins nucleotides forming phosphodiester bonds
5. new DNA contains half the original DNA

Question 2

how does Rhythmical tapping of the chest wall ease CF symptoms (2)

Answer 2

• loosens mucus
• mucus can be expelled more easily
• airways become clearer

Question 3

Explain why people with cystic fibrosis can have breathing difficulties.

Answer 3

• Thicker mucus is produced
• cilia unable to waft mucus out of lungs
• loss of SA of airways
• reduced gaseous exchange
• ucus can trap bacteria causing respiritory infections