Feature Plant shoot and light Human and hot object Speed of response slow fast Response coordinated by ................... nervous system Type of movement g...
Question 1 Report
| Feature | Plant shoot and light | Human and hot object |
|---|---|---|
| Speed of response | slow | fast |
| Response coordinated by | ................... | nervous system |
| Type of movement | growth (tropism) | ................... |
Both plants and animals are able to respond to changes in their environment, known as stimuli. Plants usually respond by slow growth movements called tropisms, whereas animals often respond rapidly using nerves and muscles. Table 5.1 compares the response of a plant shoot to light with the response of a human who touches a hot object.
| Feature | Plant shoot and light | Human and hot object |
|---|---|---|
| Speed of response | slow | fast |
| Response coordinated by | ................... | nervous system |
| Type of movement | growth (tropism) | ................... |
(a) Complete Table 5.1 by filling in the two empty boxes. [2]
(b) State what is meant by the terms stimulus and response. [2]
(c) State the name of the response of a shoot growing towards light. [1]
(d) Explain why a growth response in a plant is usually slower than a response in an animal. [2]
(e) Suggest one advantage to a plant of being able to respond to the direction of light. [2]
(f) Describe how auxin brings about the bending of a shoot towards light. [3]
(g) State one stimulus, other than light, to which plant shoots or roots respond. [1]
Answer Details
This question compares a slow plant growth response (a tropism) with a fast animal nervous response. The completed Table 5.1 is:
| Feature | Plant shoot and light | Human and hot object |
|---|---|---|
| Speed of response | slow | fast |
| Response coordinated by | auxin (a plant hormone) | nervous system |
| Type of movement | growth (tropism) | muscle contraction |
(a) Plant response coordinated by: auxin / a plant hormone [1]; human type of movement: muscle contraction (muscles move a limb) [1]. [2]
(b) A stimulus is a change in the environment that is detected [1]; a response is a change in an organism produced as a result of a stimulus [1]. [2]
(c) A shoot growing towards light shows (positive) phototropism. [1]
(d) A plant response depends on cells growing and dividing, which is a slow process [1], whereas an animal response is carried by fast electrical nerve impulses [1]. [2]
(e) One advantage: the shoot grows towards the light so the leaves face the light [1], allowing it to absorb more light for photosynthesis and making food [1]. [2]
(f) Auxin is made at the shoot tip and collects on the shaded side of the shoot [1]; auxin makes the cells on the shaded side elongate more [1], so the shaded side grows faster than the lit side and the shoot bends towards the light [1]. [3] (max 3)
(g) One other stimulus: gravity (also accept water or touch). [1]
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