B5.11 Plant Defence Responses (Finished)

Question 1

What are three physical barriers to pathogens used by plants?

Answer 1

• A waxy cuticle providing a physical barrier
• Cell walls made of cellulose forming a physical barrier against pathogens
• Layers of dead cells around stems (e.g. outer bark) acting as a barrier

Question 2

How do falling leaves in autumn protect plants against pathogens?

Answer 2

Any pathogens infecting the leaves will fall off with them e.g. rose black spot

Question 3

Give two chemical barriers used by plants to protect against pathogens?

Answer 3

• Some plants produce antibacterial chemicals that kill bacteria
• Some plants produce poisons that can deter herbivores

Question 4

How do thorns and hairs defend plants?

Answer 4

Thorns and hairs stop animals from touching and eating plants

Question 5

How does drooping and curling help plants defend themselves?

Answer 5

• some plants droop or curl when touched, which knocks insects from them , frightening larger animals to prevent being eaten.

Question 6

Give an example of how plant mimicry helps them defend themselves?

Answer 6

Plants can mimic other organisms such as the passion flower that has bright yellow spots looking like butterfly eggs stopping other butterflys from laying eggs there