Topic 6 - Plant Structures and Their Functions

Question 1

Photosynthetic orgnanisms are the main

Answer 1

Producers of food and biomass for nearly all organisms on earth

Question 2

Photosynthesis reaction type

Answer 2

Endothermic

Question 3

Photosynthesis reaction

Answer 3

Carbon dioxide + Water(+Light) —-> Glucose + Oxygen

Question 4

Glucose chemical formula

Answer 4

C6H12O6

Question 5

3 factors affecting photosynthesis

Answer 5

Light intensity
C02 concentration
Temperature

Question 6

Light intensity effect on photosynthesis

Answer 6

Not enough light slows down photosynthesis
Up to a certain point, then after it doesnt affect the rate

Question 7

CO2 effect on photosynthesis

Answer 7

Increasing Co2 increases rate up to a point

Question 8

Temperature effect on photosynthesis

Answer 8

Temp needs to be just right, there is an optimal level
If too hot, the enzymes denature

Question 9

Investigating light intensity on photosynthesis process

Answer 9

Canadian pondweed is used to show oxygen production in proportion to photosynthesis
Source of light placed at specific distance to pondweed in water
Left to photysnthesise and oxygen production measured using a gas syringe
Rate of oxygen production can be compared between distances of light source

Question 10

Photosynthesis is directly proportional to

Answer 10

LIght intensity, up to a point

Question 11

Photosynthesis is inversely proportional to

Answer 11

Distance from light source

Question 12

Light intensity is directly proportional to

Answer 12

1 / Distance^2

Question 13

Root hair cells are

Answer 13

Cells on the end of plant roots shaped like hairs

Question 14

Root hair cells adaptations

Answer 14

Millions on the root
Large surface area to absorb more water and mineral ions
Water absorbed by osmosis, mineral ions by active transport

Question 15

Phioem tubes transport

Answer 15

Food

Question 16

Xylem tubes transport

Answer 16

Water and mineral ions up the plant

Question 17

Phloem adaptations

Answer 17

Elongated living cells with small pores to allow flow
Transport goes both directions(translocation)
Requires energy from respiration

Question 18

Xylem adaptations

Answer 18

Dead cells joined with no walls between them
Strengthened by material called lignin

Question 19

Transpiration is

Answer 19

The loss of water from the plant

Question 20

Transpiration is caused by

Answer 20

The evaporation and diffusion of water from the surface of plants leaves through the stomata

Question 21

Transpiration leads to

Answer 21

A shortage of water in leaves
The xylem vessels transport more water to leaves along with mineral ions

Question 22

Sucrose is transported around the plant by

Answer 22

Translocation in the phloem

Question 23

The sructure of a leaf features

Answer 23

Waxy cuticle
Upper epidermis
Palisade mesophyll tissue
Spongy mesophyll tissue
Lower epidermis
Stomata
Guard cell

Question 24

Waxy cuticle function

Answer 24

Reduces water loss by evaporation

Question 25

Palisade mesophyll function -

Answer 25

Lots of chloroplasts as it is high in the leaf for photosynthesis

Question 26

Upper epidermis function

Answer 26

Transparent to let light through

Question 27

Spongy mesophyll function

Answer 27

Contains air spaces to increase rate of diffusion of gases into and out of leaf cells

Question 28

Lower epidermis function -

Answer 28

Lts of stomata to let CO2 out, bottom of leaf to prevent evaporation

Question 29

Stomata are

Answer 29

Tiny pores on the surface of plant

Question 30

Stomata function

Answer 30

Let CO2 and oxygen diffuse directly into and out of leaf, alos let water vapour out

Question 31

Guard cells function

Answer 31

Chnage shape to control size of stomata

Question 32

Transpiration rate is affected by

Answer 32

Light intensity Temperature Air Flow

Question 33

How to find tranpiration rate

Answer 33

Use potometer Shows how far a bubble moves in relation to the water uptake

Question 34

Transpiration rate in potometer experiment =

Answer 34

Distance moved by bubble / Time taken

Question 35

6 possible ways plants are adapted to extreme environments

Answer 35

Small leaves or spines Curled leaves to reduce air flow Thick waxy cuticles Thick stem that stores water Fewer stomata Stomata sunken in pits to reduce air flow

Question 36

What do hormones do in plantsd

Answer 36

Control growth and development

Question 37

Auxin is an example of

Answer 37

A plant hormone

Question 38

Auxins are

Answer 38

Plant growth hormones which control growth at the tip of shoots and roots

Question 39

Auxins move through the plant in

Answer 39

Solution

Question 40

Auxin causes growth by

Answer 40

Being produced in the tip and diffusing backwards to cause cell elongation just behind the tip

Question 41

Auxin behaviour at tip and root

Answer 41

Promotes growth at tip Inhibits growth in the root

Question 42

Phototropic means

Answer 42

It grows towards light

Question 43

Gravitropic means

Answer 43

It grows towards gravity

Question 44

Shoots phototropism and gravitropism

Answer 44

Positively phototropic(towards light) Negatively gravitropic(away from gravity)

Question 45

Roots phototropism and gravitropism

Answer 45

Negatively phototropic Positively gravitropic

Question 46

Auxin action in shoot phototropism

Answer 46

Auxins accumulates in the side in the shade. This causes this side to grow faster and the shoot bends towards the light

Question 47

Auxin action in shoot gravitropism

Answer 47

When the shoot is grwoing sideways, gravity causes auxins to go to the bottom side. This causes that side to grow and bend the shoot upwards.

Question 48

Auxin action in root gravitropism

Answer 48

A root growing sideways will have more auxin in its lower side, so it inhibits growth in that side and causes downwards growth

Question 49

Auxin action in root phototropism

Answer 49

If a root is exposed to light, auxin is accumulated on the shaded side. That sides growth is inhibited, so the root bends downwards away from the light

Question 50

How are plant hormones used in selective weedkillers

Answer 50

Auxins specific to the broad-leaved weeds are used, which completely inhibit growth and kill them

Question 51

How are plant hormones used in growing from cuttings from rooting powders

Answer 51

Auxins that stimulate root growth allow cuttings to be planted in soil and become plants as their roots grow rapidly.

Question 52

How are plant hormones used in in fruit and flower formation

Answer 52

Giberellins cause plants to flower more earlier, or make them flower less to improve fruit quality

Question 53

Gibberelins are

Answer 53

Plant hormones that stimulate seed germination, stem growth and flowering.

Question 54

How are plant hormones used in producing seedless fruit

Answer 54

When giberrelins are applied to flowers without pollenation, the fruit grow without the seeds

Question 55

How are plant hormones used in controlling fruit ripening

Answer 55

The ripening can be controlled while they are on the plant or during transport. A ripenign hormone called ethene is added and the fruits that have been taken early will ripen during transport