2.81 - Phototropism

1. Phototropism is the growth response to the changes in light

2. When light is shone on the side of the root, the plant bends in its growth towards the lateral light source

3. This is called positive phototropism

4. A plan hormone called auxin grows more, causing the plant to bend

2.80

1. The geotropic response is the growth response to the change in gravity

2. The roots grow downwards, this is described as positive geotropism

3. The embryonic shoot grows upwards towards the surface, called negative geotropism

4. When the seed is rotated, the shoot adjusts and grows upwards

5. when turned, the root changes and grown downwards

2.79

1. Stimuli are changes in the environment, eg. Temperature changes and light changes

2. The receptors detect stimuli and turn them into a response through plant hormones

3. Responses often take the form of growth, called tropisms

4. If it involves light, it is called phototropism

5. When it involves gravity, it is called, geotropsm

2.54 Transpiration

- Transpiration is the evaporation of water from the surface of the plant

- The light energy is transferred into heat, which evaporates the water

- The water is brought to the leaf by the xylem tube

- The water transferres from liquid to gas just before the stomatal pores

- The vapor then diffuses into the outside atmosphere

2.53

1. Root hair cells branch out to absorb more water

2. They are adapted to this by having a large surface area, maximizing the intake of water

3. There are already minerals present (due to active transport) in the root hair cells which attracts the water

4. The water moves into the root hair cell from the soil, via diffusion.