Auxin

Auxins are produced at apical meristem only in the presence of light.

• True

• False

After auxins are produced, they move to region of elongation and stimulate growth there.

• True

• False

The diagram below shows the experiment used to study the growth of oat coleoptile. What is the hypothesis being tested in this experiment?

• The coleoptile is positively phototropic 

• The tip of the coleoptile is sensitive to light 

• Auxins are produced by the tip of the coleoptile 

• Growth occurs mainly in the region of elongation

The diagram below shows a set-up to study the effect of light on the growth of oat coleoptiles. Which coleoptile(s) will bend towards the light source?

• coleoptile 3 only 

• 
  coleoptiles 1 and 3 only

• coleoptiles 3 and 4 only

• coleoptiles 1, 2 and 4 only

If the hole of the black box is covered up at the beginning of this study, 

• coleoptiles 3 and 4 will bend.

• coleoptiles 1 and 2 will stop growing.

• coleoptile 3 will grow faster than coleoptile 1.

• coleoptiles 1, 3 and 4 will grow vertically upwards.

Tags

NGSS.HS-LS1-5

NGSS.HS-LS2-5

The diagram below shows an experiment that collects auxins from the tip of coleoptiles under different conditions. After that, the agar blocks are placed on decapitated coleoptiles of the same height:

• 
• 
• 
• 

Which of the following can be used as a control set-up for the above experiment?

• 
• 
• 
• 

Which of the following conclusions can be drawn from the above results?

(1) Transport of auxins in the stem is not affected by gravity.

(2) Transport of auxins in the stem involves an active process.

(3) Transport of auxins in the stem mainly takes place from a to b.

• (1) and (2) only

• (1) and (3) only

• (2) and (3) only

• (1), (2) and (3)