homeostasis: plant hormones

Question 1

what is the pratical for Aim: To investigate the effect of light or gravity on the growth of newly germinated seedlings?

Answer 1

Question 2

what would the result of the plant practical be?

Answer 2

• In the first petri dish all rootshave grown downwards (positive gravitropic response)
• (shoots) have grown upwards (negative gravitropic response)
• all roots and all shoots have all grown neither up nor down but straight outwards in whichever direction they were placed
• The experiment needs to be done in a lightproof box in order to control the effect of light on the growth of the seedlings

Light is a control variable when investigating gravity

Question 3

what the indpendan, dependant and control variable of this practical?

Answer 3

• control varible= volume of water, type of seed
• independant variable= light intensity
• depednant varibale= height of the seedlings

Question 4

what would the sources of error be?

Answer 4

Question 5

what is a risk in this practical?

Answer 5

Question 6

what is phototropism?

Answer 6

growth of an organism in response to light

Question 7

why do plants produce hormones?

Answer 7

plants produce hormones to coordinate and control growith in phototropism and gravitropism

Question 8

what is gravitopism?

Answer 8

when a plant grows twoards the force of gravity

Question 9

what causes unequal growth in a plant?

Answer 9

Unequal distributions of auxin causes unequal growth in the plants root and shoots

Question 10

why is Gibberellins important?

Answer 10

gibberellins are important in initiating seed germination – the process that occurs when a seed starts to grow

Question 11

why is ethene important?

Answer 11

Ethene is a gas released by plants which controls cell division and ripening of fruits

Question 12

where is auxin produced?

Answer 12

Auxins are produced in the tips of the shoots and the roots;

Question 13

what effect does auxin have in the shoots and roots?

Answer 13

In the shoots auxin promotes cell elongation; more auxin = more cell elongation = more growth

In the roots auxin inhibits cell elongation; more auxin = less cell elongation = less growth

Question 14

how does photropism happen with auxin?

Answer 14

Question 15

what is the use of auxin in agriculture and horitculture?

Answer 15

• as weed killers
• as rooting powders
• for promoting growth in tissue culture.

Question 16

what is the use of ethene in agriculture or horitculture?

Answer 16

Ethene is used in the food industry to control ripening of fruit during storage and transport

Question 17

what is the use of Gibberellins in agriculture and horticulture?

Answer 17

• end seed dormancy
• promote flowering
• increase fruit size.