Plant defences Flashcards
What is a pest?
an organism that causes damage to a crop plant (e.g. plant eating insects)
Explain 4 chemical defences
some plants produce chemicals that deter pests from eating/killing them
some plants produce chemicals that attract the predators of their pests, killing the pests and stopping the plant from being eaten
some plants have poisons in their cells to deter pests from eating them
some plants have chemicals which kill pathogens such as bacteria and fungi
What do plant defences protect against?
pests and pathogens
Explain 4 physical defences
Many plants have an outer layer of bark.
This protects the cells underneath and is difficult for pests to get through, stopping pathogens from infecting cells/predators from eating it
Plants also have thick, waxy cuticles that are difficult to get through, stopping pathogens effecting the cell
Some plants have adaptations like spikes or thorns to stop pests from eating them
Cellulose cell walls are difficult for pathogens to break down unless they produce a specific enzyme
Name 4 physical defences
Bark
Cuticles
Spikes, thorns
Cellulose cell walls
What are some of the defence chemicals in plants used as?
medicines
Name 3 uses of medicines made from plants
treating diseases such as malaria
treating diseases such as heart disease
relieving symptoms such as pain and fever (aspirin)
Explain how a nettle protects itself from predators.
it has hairs that contain chemicals that sting skin
this prevents animals from eating/killing the plant, protecting it from predators
Give two ways that medicines made from plants can be used to treat people who are ill
To treat diseases by killing pathogens in people, or to relive symptoms such as pain or fever.
Explain how physical barriers can protect a plant from pests and pathogens
thick bark/cuticles which make it hard for pests/pathogens to penetrate
thick cellulose cell walls that are difficult for pathogens to break down
spikes/thorns to deter pests from eating them
Explain the advantage to plants of producing chemicals that deter pests or kill pathogens
pests and pathogens damage plants
if the plant produces chemicals that protect it against attack, then the plants will be able to produce more food and grow more rapidly
Which of the following is not useful in protecting a plant against damage by pests?
A) thorns and spikes
B) thick waxy cuticle
C) sunken stomata
D) poisons in their cells
C
