Phototropism

High school (ages 12+)
Animals & Nature

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/phototropism

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the primary stimulus?Light, perceived by photoreceptors such as phototropins
2. What is the key hormone?Auxin, mediating differential cell elongation on shaded versus illuminated sides
3. How do plants know where the light is?Plants have special light sensors called phototropins. When light hits one side, the plant moves a hormone called auxin to the shaded side, making that side grow faster and bend toward the light.
4. Why do vines grow toward dark objects?Vines use negative phototropism to grow toward dark walls or trees. This lets them climb up and reach brighter light higher up.

Phototropism: The directional growth of an organism in response to a light stimulus, crucial for optimizing light capture.
Auxin: A pivotal plant hormone that regulates cell elongation, mediating phototropic bending by accumulating on shaded sides.
Phototropins: Blue-light photoreceptors that initiate the phototropic response by sensing light direction and intensity.
Differential Cell Elongation: Unequal growth rates of cells on opposite sides of a plant organ, leading to bending.