Topic 6

Question 1

What is meristem tissue and where is it found?

Answer 1

It is made up of plant stem cells

It is found in the growing parts of the plants such as the tips of shoots and roots

Question 2

What happens when the guard cells become turgid

Answer 2

they open the stomata

this allows carbon dioxide to enter the leaf and

allows water to escape

Question 2

If there is plenty of water in the leaf, what happens to the guard cells

Answer 2

they become turgid

Question 3

Which structures of a plant help to minimise water loss

Answer 3

Waxy cuticle

Guard cells which can close stomata

Question 4

What is the adaptation of the upper epidermis

Answer 4

It is transparent, so that light can pass through

This means that as much light as possible can reach the palisade mesophyll cells below and used in photosynthesis

Question 5

Describe and explain how the rate of photosynthesis varies with temperature

Answer 5

The rate initially increases with temperature

because the particles have more kinetic energy, so move faster and react more frequently

The highest rate is at optimum temperature for the rate of photosynthesis

At higher temperatures the rate decreases as bonds holding the enzymes together start to break and so the enzyme changes shape

The rate of photosynthesis falls to zero as the enzyme denatures

Question 6

There are three environmental factors that affect the rate of photosynthesis. List them

Answer 6

-Temperature

-Light intensity

-Volume of carbon dioxide

Question 7

What is the inverse square law?

Answer 7

States that the intensity of light decreases proportionally to the square of the distance from its source

I = 1/d^2

Question 8

What are the main uses of glucose in plants?

Answer 8

Cellular respiration - breaks down glucose to release energy

Make starch - which is used to store glucose for a later time

Make amino acids - which are used to make proteins

Make lipids - these store the energy as fats

Make cellulose - which is used to make strong cell walls

Question 9

One use of glucose is to make amino acids.

Whatelsedo plants need to make amino acids

Answer 9

Nitrate ions

Question 10

Explain how nitrate ions are absorbed?

Answer 10

by the roots
through diffusion
from a high concentration to a low concentration

Question 11

Explain how a root hair cell adaptations increases the absorption of water and mineral ions

Answer 11

The root hair cells are long,
this increases surface area
and increases the rate of absorption

Question 12

Explain how water in the root is transported to the leaves of the plant

Answer 12

Through the roots by osmosis
then up through the xylem
by transpiration

Question 13

Describe a method which could be used to show that hormones are found in the tip of a plant shoot?

Answer 13

Remove the tip from one of the plant shoots, leave the other

Measure the changes in growth and direction of movement

Question 14

Explain how plant hormones can work as weed killers?

Answer 14

Auxin can be used as weed killers

This acts on specifically broad leafed plants

Causing them to overgrow

Question 15

Explain how phototropism is controlled in plant shoots?

Answer 15

It is controlled by the hormones auxin

Auxins move towards the shaded side of the shoot

This causes cell elongatation and causes the shoot to bend towards the light

Phototropism is the growth towards light

Question 16

What are the three plant hormones

Answer 16

-Ethene
-Auxin
-Gibberellin

Question 17

What did ethene do?

Answer 17

speeds up ripening

Question 18

What does gibberellin do

Answer 18

seed germination

Question 19

What does auxin do

Answer 19

cell growth and elongation

Question 20

How do guard cells change on a warm day to help the plant survive

Answer 20

They change shape to close the stomata
this reduces water loss by transpiration

Question 21

How does carbon dioxide enter the plant

Answer 21

By diffusion
From an area of high concentration to an area of low concentration
by diffusion

Question 22

How does reducing water content of strawberries help to preserve them

Answer 22

Reducing water content reduces the number of microorganisms that can reproduce
reducing the microorganism reduces the decay process

Question 23

What are the uses of plant hormones for crop production

Answer 23

• Fruit ripening
• Selective weedkillers
• Rooting powders
• Seedless fruit production

Question 24

How are selective weedkillers used in crop production

Answer 24

• allows broad leafed plants to grow uncontrollably then die
• narrow leafed crops and plants are left unaffected
• auxin or gibberellin is used

Question 25

How is rooting powder used in crop production

Answer 25

• plant cuttings are dipped into rooting powder
• roots develop rapidly
• large number of plants can be produced by the same plant
• no need to wait for plants to grow from seeds
• auxins are used

Question 26

How is seedless fruit production used in crop production

Answer 26

• the fruits will develop but the seeds inside will not
• the fruits are able to grow larger
• gibberellins are used

Question 27

Why is a waxy cuticle important for a pine leaf

Answer 27

• It surrounds the pine leaf
• and reduces the water lost from the pine leaf

Question 28

An advantage of using auxins in the roots of a plant

Answer 28

Helps to anchor the plant and make it stable
Roots can reach deeper water, mineral ions

Question 29

Why does oxygen diffuse into plant

Answer 29

For respiration

Question 30

How are mineral ions brought into the plant

Answer 30

By active transport

Question 31

How is water transported through a plant

Answer 31

• Through the xylem
• Osmosis into cells in the leaves
• evaporation from leaves
• diffusion into atmosphere through the stomata

Question 32

How is glucose transported through a plant

Answer 32

• converted to sucrose
• dissolved in water
• through the phloem which is bidirectional

Question 33

How are mineral salts transported through a plant

Answer 33

• dissolved in water
• through the xylem
• root to tip

Question 34

What can the glucose made during photosynthesis be used for after

Answer 34

• Stored as starch for later
• Respiration

Question 35

What are the main uses for glucose in a plant

Answer 35

• Cellular respiration
• Make starch
• Make amino acids
• Make lipids

Question 36

What is the inverse square law

Answer 36

light intensity = 1 / (distance between light source and object)^2

Question 37

Three environmental factors which affect photosynthesis

Answer 37

• Light intensity
• Temperature
• CO2 concentration

Question 38

Why do farmers in cooler climates use greenhouses

Answer 38

They help trap the heat energy from the sunlight and so increase the temperature
They also help keep out pests

Question 39

Why is the upper epidermis transparent

Answer 39

So that light can pass through, and as much as possible can reach the palisade mesophyll cells below and be used in photosynthesis

Question 40

If there is plenty of water in the leaf, what happens to the guard cell

Answer 40

It becomes turgid, opening the stomata, this allows carbon dioxide to enter and water to escape

Question 41

Where is meristem found

Answer 41

shoots and roots

Question 42

Where is glucose produced

Answer 42

In the leaf

Question 43

How can auxin be used as a weedkiller

Answer 43

stimulates too much growth
disrupts growth process and kills the plant

Question 44

How is ethene used in the transport of food

Answer 44

• ethene stimulates fruit to ripen
• fruit is picked unripen so that it is still hard so it isn’t damaged during transport
• Ethene can be used to ripen the fruit so it is soft for customers