Question 1

What are tropic responses in plants?

Accepted Answer

Tropic responses are growth movements in plants that occur in response to environmental stimuli. These responses ensure that the plant grows towards or away from the stimulus. Common types of tropic responses include phototropism, geotropism, and hydrotropism. These responses are crucial for plant survival and adaptation.

Question 2

How does phototropism work in plants?

Accepted Answer

Phototropism is the growth of a plant in response to light. In this process, plant hormones called auxins accumulate on the side of the plant that is away from the light source, causing the cells on that side to elongate more than those on the light-facing side. This differential growth causes the plant to bend towards the light, optimizing light absorption for photosynthesis.

Question 3

What is the difference between positive and negative tropic responses?

Accepted Answer

Positive tropic responses occur when a plant grows towards a stimulus, such as roots growing towards water (positive hydrotropism) or shoots growing towards light (positive phototropism). Negative tropic responses occur when a plant grows away from a stimulus, such as roots growing away from light (negative phototropism). These responses help plants adapt to their environment by directing growth towards favorable conditions.

Question 4

Why is geotropism important for plant growth?

Accepted Answer

Geotropism, also known as gravitropism, is the growth response of a plant to gravity. Roots exhibit positive geotropism by growing downward into the soil, anchoring the plant and seeking nutrients and water. Shoots exhibit negative geotropism by growing upward, allowing the plant to reach sunlight for photosynthesis. This coordinated growth ensures the plant's stability and access to essential resources.

Question 5

How do tropic responses relate to the Cambridge IGCSE Biology curriculum?

Accepted Answer

Tropic responses are a key concept in the Cambridge IGCSE Biology curriculum under the topic of Coordination and Response. Understanding how plants respond to environmental stimuli through tropic movements helps students grasp the mechanisms of plant adaptation and survival. This knowledge is fundamental for exploring broader biological principles and the interdependence of organisms and their environments.

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