Auxins and Plant Responses

Miss Angler's biology class video covers phototropism, focusing on how plant hormones like auxins influence plant growth in response to light. The video explains the mechanism of cell elongation, the role of unilateral light, and how auxins migrate to the dark side, causing plants to bend towards light. It also discusses common exam questions and experiments related to phototropism, providing insights into how auxins function. The video concludes with a recap of key concepts, including phototropism and geotropism.

What is phototropism?

• The movement of plants in response to gravity

• The movement of plants in response to light

• The movement of plants in response to water

• The movement of plants in response to temperature

Where are auxins primarily found in plants?

• In the leaves and flowers

• In the roots and shoots

• In the stems and branches

• In the fruits and seeds

What happens to auxins when light is applied unilaterally?

• They evaporate

• They move to the dark side

• They remain evenly distributed

• They move towards the light

How do auxins affect cell elongation in shoots?

• They inhibit cell elongation

• They stimulate cell elongation

• They have no effect on cell elongation

• They cause cell division

What is the purpose of covering the tip of a plant with an opaque cap in an experiment?

• To change the color of the plant

• To allow light to reach the tip

• To prevent light from affecting the auxins

• To increase the growth rate

What does a transparent cap demonstrate in phototropism experiments?

• Auxins are not affected by light

• Auxins are sensitive to light

• Auxins are produced in the roots

• Auxins are not necessary for growth

What is the main aim of the more complex phototropism experiment?

• To show that plants grow faster in the dark

• To demonstrate that auxins are responsible for phototropism

• To prove that auxins are ineffective

• To show that light has no effect on growth

What is unilateral light?

• Light that is blocked

• Light that is diffused

• Light coming from one direction

• Light coming from all directions

What is the response of roots to light?

• Positively phototropic

• Negatively phototropic

• Neutral to light

• Positively geotropic

What keeps shoots growing upwards towards the sun?

• Thigmotropism

• Phototropism

• Hydrotropism

• Geotropism