O Level / IGCSE Biology chapter 15: Coordination and response in plants MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
11 exam-style questions on Coordination and response in plants, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Ten Coordination and response in plants questions with answers
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. A shoot is laid horizontally in the dark. After a day its tip has curved upwards. What is the explanation?
A
auxin collects on the upper side, where cells elongate more
B
auxin collects on the lower side, where cells stop growing
C
auxin is made by the lower side only, so it grows faster
D
auxin collects on the lower side, where cells elongate more
Show answer
Answer: D. Gravity causes auxin to gather on the lower side of a horizontal shoot. More elongation there turns the shoot upwards: negative gravitropism.
2. A shoot is lit from one side. How does auxin cause it to bend towards the light?
A
auxin makes cells on the lit side divide faster, so that side grows longer
B
auxin moves to the shaded side, where cells elongate more
C
auxin moves to the lit side, where cells elongate more
D
auxin is destroyed on the shaded side, so cells there stop growing
Show answer
Answer: B. Auxin gathers on the shaded side and stimulates cell elongation there, so that side grows longer and the shoot curves towards the light.
3. A student removes the tip from a shoot and places a small block of jelly containing auxin on one side of the cut end. Which result is most likely after two days?
A
the shoot bends away from the side with the block
B
the shoot bends towards the side with the block
C
the shoot stops growing because its tip is missing
D
the shoot grows straight up without bending
Show answer
Answer: A. Auxin makes shoot cells elongate. Cells on the side with the auxin elongate more, so that side grows longer and the shoot curves away from it, just as it does when auxin gathers on the shaded side of a shoot lit from one side.
4. The tip of a shoot is covered with a small opaque cap and the shoot is lit from one side. What happens?
A
it grows straight up without bending, because the covered tip cannot detect the direction of the light
B
it bends strongly towards the light, as auxin still reaches the shaded side
C
it stops growing, as the cap prevents auxin from being made
D
it bends away from the light, as auxin collects on the lit side
Show answer
Answer: A. The covered tip cannot detect the direction of the light, so auxin is spread evenly and the shoot grows straight.
5. A seedling is laid horizontally on a clinostat that rotates slowly. After some days, how have the shoot and root grown?
A
the shoot has grown up and the root down
B
the shoot has grown down and the root up
C
both have grown straight out horizontally
D
neither has grown at all
Show answer
Answer: C. Rotation means gravity acts equally on all sides, so auxin is not redistributed and there is no bending.
6. A root placed horizontally grows downwards. Which response is this?
A
positive gravitropism
B
negative gravitropism
C
positive phototropism
D
negative phototropism
Show answer
Answer: A. Growing towards the pull of gravity is positive gravitropism. Shoots show negative gravitropism.
7. Ten seedlings have their shoot tips removed and ten do not. After three days the seedlings without tips have grown 1 mm and those with tips 12 mm. What does this show?
A
the tip makes a substance that stops the shoot from growing
B
the tip makes a substance that stimulates the shoot to grow
C
the tip makes food for the shoot by photosynthesis
D
the tip absorbs the water that the shoot needs to grow
Show answer
Answer: B. Auxin is made in the shoot tip and stimulates cells to elongate. With the tip removed there is no auxin, so there is little growth.
8. What is gravitropism?
A
movement of sucrose from the leaves to the roots in the phloem
B
growth of a plant part towards or away from a source of light
C
loss of water vapour from the leaves through the stomata
D
growth of a plant part towards or away from gravity
Show answer
Answer: D. Gravitropism is a growth response to gravity; phototropism is a growth response to light.
9. The tip is cut off a shoot, which is then lit from one side. What happens?
A
the shoot grows faster than before, as there is nothing to slow it
B
the shoot bends towards the light, as the leaves also make auxin
C
the shoot does not bend, because auxin is made in the tip and the tip has been removed
D
the shoot bends away from the light, as the shaded side grows faster
Show answer
Answer: C. Auxin is made in the tip; without the tip there is no auxin to cause unequal growth.
10. What is the advantage to a plant of its shoots showing positive phototropism?
A
the plant loses less water because the stomata close in the light
B
the flowers are hidden from insects, so they are not eaten
C
the roots can absorb more water from the soil as the shoot grows
D
the leaves receive more light for photosynthesis
Show answer
Answer: D. Growing towards light lets the leaves absorb more light energy for photosynthesis.
Coordination and response in plants: questions students ask
How many Coordination and response in plants MCQs are there?
11, each with the answer and a short explanation, across 1 topics: Coordination and response in plants. Every chapter test draws ten of them, so you can take it many times.
Is the O Level / IGCSE Biology chapter 15 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
