SB5g Plant Defences

Question 1

physical barriers in plants? 3

Answer 1

~cuticle - covers the surfaces of leaves and stems, making it difficult for pathogens to enter
~woody plants have a layer of bark
~cells are surrounded by tough cell walls

Question 2

how do cell walls protect cells from pathogens?

Answer 2

prevent pathogens from entering the cell

Question 3

how does the waxy epidermal cuticle help the plant cell?

Answer 3

prevent water loss and micro bacterial from entering epidermal

Question 4

physical barrier issues in plants 3

Answer 4

~some pathogens release enzymes to soften the cell walls
~some pathogens infect the growing tips of plants where the cell walls are softer
~pests can eat through the physical barriers with their tough mouthparts

Question 5

state the chemical defences in plants? 2

Answer 5

~insect repellents
~some release chemical substances when attacked

Question 6

chemical defences in plants issues? 1

Answer 6

~producing chemical defences takes energy which the plant could use to grow

Question 7

medicines from plants and what they are used for? 2

Answer 7

~Artemisinin (wormwood plant) - treats malaria by killing the plasmodium parasite
~aspirin (willow tree) - treats symptoms of disease such as fever

Question 8

how to prevent contamination of producing medicines and why does this work?

Answer 8

~sterilising equipment and growth medium
~this kills the bacteria on them, preventing contamination

Question 9

explain why cultures of bacteria in Petri dishes and vials must be kept covered. (2 marks)​

Answer 9

Covering the cultures prevents any bacteria from the surrounding environment landing on the dishes which could cause contamination as unwanted organisms could grow instead.