Orginisation In Plants

Question 1

Tissues in leaves: waxy cuticle (1)

Answer 1

Makes leaf waterproof

Question 2

Tissue in leaves: Upper epidermis (2)

Answer 2

Single layer of cells
Protects against water loss
Transparent to allow light to pass through

Question 3

Tissues in leaves: palisade mesophyll (3)

Answer 3

Tightly packed cells
Lots of chloroplast to absorb light for photosynthesis

Question 4

Tissues in leaves: spongy mesophyll (4)

Answer 4

Spherical cells
Lots of air space to allow gases to diffuse quickly
Large surface area to volume ratio to increase gas exchange

Question 5

Tissue in leaves: stomata (5)

Answer 5

Tiny openings on undersides of leaves
Control gas exchange and water loss from leaves by:
allowing diffusion of carbon dioxide into the plant for photosynthesis
Allowing diffusion for oxygen out of the plant

Question 6

Tissues in leaves: guard cells (6)

Answer 6

Control the opening and closing of the stomata

Question 7

How guard cells work

Answer 7

When plant has plenty of water guard cells become turgid
Cell wall on inner surface is very thick so can’t stretch as much as outer surface
So as guard cells swell up they curve away from each other opening stomata

Question 8

Transpiration description

Answer 8

Water lost through stomata by evaporation
This pulls water up from roots through xylem- transpiration
Constant movement of water up the plant is called transpiration stream

Question 9

Transpiration importance

Answer 9

Provided water to cells to keep them turgid
Provided water to cells for photosynthesis
Transports mineral ions to leaves

Question 10

Transpiration importance

Answer 10

Provided water to cells to keep them turgid
Provided water to cells for photosynthesis
Transports mineral ions to leaves

Question 11

Transpiration specialised tissues

Answer 11

Xylem vessel:
Thick walls stiffened with lignin
Made of dead cells joined together with no end walls between them
One way transport only of water and minerals

Question 12

Translocation description

Answer 12

Movement of dissolved sugars from leave to rest of plant through phloem

Question 13

Translocation importance

Answer 13

Moves dissolved sugars made in other leaves during photosynthesis to other parts of plant
Allows for respiration growth and glucose storage

Question 14

Translocation specialised tissue

Answer 14

Phloem vessel:
Cells have end walls with small holes to allow substances to flow through
Water and dissolved sugars transported in both directions

Question 15

Factors effecting rate of transpiration: temperature

Answer 15

Higher temp increases rate of transpiration because water evaporates in higher temperatures

Question 16

Factors effecting rate of transpiration: humidity

Answer 16

Lower humidity increases rate of transpiration because the drier the air the steeper the conc gradient of water molecules between air and leaf

Question 17

Factors effecting rate of transpiration: wind speed

Answer 17

More wind increases rate of transpiration because wind removes water vapour quickly maintaining a steeper conc gradient

Question 18

Factors effecting rate of transpiration: light intensity

Answer 18

Higher light intensity increases rate of transpiration because stomata open wider to let more carbon dioxide into leaf for photosynthesis

Question 19

Root hair cells

Answer 19

Increases absorption of water and mineral ions into root by increasing root hair surface area
Contains lots of mitochondria to transfer energy which is used to take in mineral ions by active transport