B3.2 Endocrine System

Question 1

Tropism

Answer 1

Growth response made by a plant in response to a particular stimuli in their environment
Groups of responses that can be split into phototropisms (response to light) and gravitropisms (response to gravity)
Controlled by auxins

Question 2

Difference between positive and negative tropism

Answer 2

Positive = growing towards direction of stimulus
Negative = growing away from direction of stimulus

Question 3

Phototropism

Answer 3

Plant growth towards/away from a light source
Stems = positively phototropic
Roots = negatively phototropic

Question 4

Gravitotropism

Answer 4

Growth of the parts of plants in response to the force of gravity
Stems = negatively gravitrophic
Roots = positively gravitrophic

Question 5

Another term used for gravitropism

Answer 5

Geotropism

Question 6

Auxin

Answer 6

Plant hormone that enables a plant to grow towards or away from a stimulus

Produced in roots and shoots

Question 7

How does auxin cause a response to a stimulus

Answer 7

Stimulus causes an uneven distribution of auxin,
which causes cell elongation on side with auxin resulting in an unequal growth rate,
causing the root or shoot to bend

Question 8

How plants respond to light

Answer 8

When light hits one side of a shoot the auxin on that side both moves away from the light, and is denatured by the light
This lead to a build up of auxin on shaded side
The cells on the shaded side elongate
Shoot bends towards light

Question 9

How plants respond to gravity

Answer 9

Gravity causes auxins to gather on the lower side of the root and shoot
In roots auxins collect on lowest side of roots, causing the cells to elongate and grows down towards the force of gravity
In shoots auxins stimulates growth so side with the most auxins elongates and grows down away from the force of gravity

Question 10

3 plant hormones commonly used in agriculture and horticulture

Answer 10

Auxins

Gibberellins

Ethene

Question 11

Why is ethene unique to the other two hormones

Answer 11

It is a gas

Question 12

Hormone is used to help to regulate fruit development, without it fruit is often small.

Answer 12

Auxins

Question 13

ethene

Answer 13

Ethene is a hormone that stimulates the conversion of starch into sugar which causes fruit to ripen – this is why unripe fruit is not as sweet as ripe fruit.
This hormone is the only plant hormone that is a gas

Question 14

How is ethene used commercially

Answer 14

To ripen fruit
Stimulate the conversion of starch into sugar which causes fruit to ripen – this is why unripe fruit is not as sweet as ripe fruit.

Question 15

Gibberellins

Answer 15

Plant hormone that ends dormancy period for seeds and buds causing shoots and flowers to open
Gibberellins cause stem elongations

Question 16

List the common agricultural and horticultural uses of plant hormones.

Answer 16

Growing cuttings
Tissue culture
Ripening fruit
Killing weeds
Kromoting flowering
Producing seedless fruit

Question 17

How can plant hormones be used to kill weeds?

Answer 17

Most weeds have broad leaves
Auxin in herbicides causes the broad-leafed weeds to grow too quickly.
They are unable to sustain the high growth rate, causing them to die

Question 18

how a cutting can be grown.

Answer 18

A cutting is a part of plant removed from the main shoot, so it does not have roots, so it is unable to absorb water or minerals.
Rooting powder containing auxin can be used to stimulate root growth in cuttings.

Question 19

Tissue culture

Answer 19

Horticulture method using auxin to grow whole plants from a plant tissue sample

Growth of tissues or cells in an artificial medium separate from the parent organism

Question 20

How have gibberellins made farming more productive?

Answer 20

Gibberellins can be used to end seed dormancy by promoting germination
Enables farmers to control when crops begin to grow - can trigger winter germination in a greenhouse
Enables farmers that plants all grow at the same time - all ready to harvest at same time
Can use to extend growing season/have two growing seasons

Question 21

How can seedless fruit be produced?

Answer 21

Gibberellins can be sprayed on flowers to stimulate fruit growth, even though there are no seeds.

Question 22

How can ripening in fruit be delayed

Answer 22

By spraying plants with auxins.
Allows harvesting at the same time
Prevents fruit from dropping from trees to early

Question 23

Why do horticulturists and gardeners take cuttings and develop them with auxins?

Answer 23

Why do horticulturists and gardeners take cuttings and develop them with auxins?

Question 24

More cards to be made for b 3.2

Question 25

Agriculture

Answer 25

farming, including cultivation of the soil for the growing of crops and the rearing of animals to provide food, wool, and other products.

Question 26

Cutting

Answer 26

A sample of a plant

Question 27

Dormant

Answer 27

When seeds cannot germinate, due to a lack of optimum conditions

Question 28

Herbicide

Answer 28

Chemicals in weed killers, that only kill wide leaf plants, such as weeds

Question 29

Horticulture

Answer 29

Garden cultivation and management

Question 30

Parthenocarpic fruit development

Answer 30

Fruit without seeds

Question 31

Stimulus

Answer 31

Conditions around the plant

Question 32

Thyroxine

Answer 32

Regulates metabolism
Involved in digestion, how heart and muscles work, brain development and bone health
When thyroid gland does not make enough thyroxine (hypothyroidism), many of the body’s functions slow down

Question 33

Adrenaline

Answer 33

Released at times of stress
Prepares the body for fight or flight responses

Question 34

Ovulation

Answer 34

Process of releasing a mature ovum into the fallopian tube each month

Question 35

FSH (pituitary gland)

Answer 35

Causes egg to mature and stimulates ovaries to start producing oestrogen

Question 36

Oestrogen (Ovaries)

Answer 36

Stimulates build up of uterus lining,
inhibits FSH production,
stimulates LH production

Question 37

LH (pituitary gland)

Answer 37

Triggers ovulation at peak

Question 38

Progesterone

Answer 38

Maintains uterus lining