plant responses

Question 1

examples of abiotic factors

Answer 1

temperature, light, water and competition

Question 2

How do stomata help prevent overheating in plants?

Answer 2

Stomata open to increase the rate of transpiration, which cools the plant by evaporation.

Question 3

what type of chemicals are nicotine, caffeine morphine and cocaine

Answer 3

an alkaloid

Question 4

what are alkaloids

Answer 4

nitrogenous compounds found in many plants, acts a s drugs and affect the metabolism of the animals eating them and sometimes poison them

Question 5

How do pheromones defend plants against herbivores?

Answer 5

Pheromones trigger nearby plant leaves to produce more callose, which makes leaves harder to eat.

Question 6

What is tropism?

Answer 6

Tropism is when part of a plant has a/an directional growth response to a/an stimulus.

Question 7

what is phototropism

Answer 7

tropism as a result of light

Question 8

what is geotropism

Answer 8

tropism as a result of gravity

Question 9

what hormone in plants controls cell elongation

Answer 9

auxin

Question 10

how do plant shoots grow towards a source of light

Answer 10

auxin accumulates in cells that are not facing the light, and stimulates cell elongation in shoot tips

Question 11

how do plant roots grow in response to gravity

Answer 11

auxin accumulates in the cells that are on the lower side of the root and in root tips auxin inhibits cell elongation

Question 12

Which group of plant hormones have a role in cell elongation, leaf loss and apical dominance?

Answer 12

auxins

Question 13

Which plant hormone has a role in stem elongation, stomatal closure, and seed germination?

Answer 13

gibberellins

Question 14

Which plant hormone causes fruit ripening and leaf loss?

Answer 14

ethene

Question 15

Give three commercial uses of plant hormones.

Answer 15

1. Control of fruit ripening
2. rooting powders
3. weedkillers

Question 16

Describe how auxin can be used to grow more plants.

Answer 16

First, a small piece is cut from a plant’s stem. This small piece is called a cutting.
Then, it is dipped into a rooting powder that contains auxin, before being planted in soil.

Question 17

Describe how auxin can be used as a weedkiller.

Answer 17

Auxin is applied at high concentrations to the weed. This causes uncontrolled shoot growth, causing the weed to die.