Coordination and Response in Plants IGCSE Afl Quiz

A tropism is...

• the growth of a plant towards sunlight only

• the wilting of a plant that occurs when it has received insufficient water

• the growth of a plant in response to any directional stimuli

• the elongation of cells in a plant caused by electrical impulses

Describe the response of a sunflower that bends towards the sun throughout the day.

• positive geotropism

• positive phototropism

• positive hydrotropism

• negative phototropism

Which part of the plant shows a negatively geotropic response?

• root

• xylem

• shoot

• leaves

Auxins stimulate the growth response in plants. What group of chemicals is it most closely related to?

• sugars

• hormones

• lipids

• pigments

In which part of the plant does auxin accumulate in high concentrations?

• xylem

• leaves

• shoot tip

• phloem

Auxins cause a plant to bend towards the light because...

• the increased concentration allows more light to be absorbed into the chloroplast

• the decreased concentration allows more light to be absorbed into the chloroplast

• it stimulates the elongation of cells on the lit side of the shoot

• it stimulates the elongation of cells on the shaded side of the shoot

Which of these shoots is demonstrating positive phototropism?

• A. A

• B. B

• C. C

This plant is attached to a clinostat, which slowly turns the pot in an anti-clockwise direction. Why does this plant continue to grow horizontally?

• As the clinostat turns, gravity is acting on all sides of the plant

• The plant is confused, and therefore grows in a straight line

• The plant is demonstrating a negative geotropism

• The plant has wilted due to a loss of water in the stem

Explain what is happening in Experiment B.

• negative geotropism

• positive phototropism

• positive geotropism

• negative phototropism

Auxins travel up and down the stem by the process of...

• diffusion

• osmosis

• transpiration

• active transport