Long questions

Question 1

Selective breeding

Answer 1

1) Breed the desired variant of an organism with another which has the same attributes
2) Not all of the offspring will have the same characteristics
3) Get rid of the ones that don’t
4) Keep the ones that do and nurture them
5) When they turn into adults, breed them again
6) Repeat this process over time

Question 2

Natural selection

Answer 2

1) Organism is variable to mutation and overproduces
2) Live in an environment they are not suited for so get eaten by predators
3) Some will have genetic mutations
4) These will adapt to their environment and survive
5) The ones which don’t will be killed off
6) This is called selection pressure
7) These organisms then reproduce to create offspring with that same mutation
8) This process is repeated over time, causing all of them to have the same survival characteristic

Question 3

Katydids

Answer 3

1) Katydids are herbivores and so chew on the leaves of plants
2) Without the surface area of a leaf which contains chloroplasts, the plants won’t be able to photosynthesize
3) This prevents them from making so they have no glucose for respiration
4) This can affect their rate of growth

Question 4

Explain the simple function of a reflex arc

Answer 4

1) When a limb comes into contact with a stimulus e.g. fire, pain receptor cells found in the skin send electrical impulses through the sensory neurone
2) They then enter grey matter in the spinal cord and are given to the relay neurone (coordinator)
3) This ferries them a short distance to the motor neurone
4) The impulses are then taken to the muscle (effector)
5) The muscle gives off an antagonistic response, causing the muscles to contract and pulling the limb away from the flame

Question 5

How is a plant cell adapted for photosynthesis

Answer 5

1) Have a large surface area so they can absorb a lot of light
2) There is a palisade cell on the upper part which absorbs lots of light for photosynthesis
3) The top has a waxy cuticle surface to block disease and prevent water loss
4) They are thin to give a short diffusion distance for carbon dioxide (stomata)
5) Guard cells open/close the stomata to control what goes in and out of the leaf
6) They have a network of tubes to transport water (xylem) and food (phloem) around the plant