Plant organisation

Question 1

what is the purpose of the ‘Large surface area’ leaf adaptation? feature or structural of leaf?

Answer 1

To absorb more light
-feature

Question 2

what is the purpose of the ‘Thin’ leaf adaptation? feature or structural of leaf?

Answer 2

Short distance for carbon dioxide to diffuse into leaf cells
-feature

Question 3

what is the purpose of the ‘Chlorophyll’ adaptation? feature or structural of leaf?

Answer 3

Absorbs sunlight to transfer energy into chemicals
-feature

Question 4

what is the purpose of the ‘Network of veins’ leaf adaptation? feature or structural of leaf?

Answer 4

To support the leaf and transport water and sugar
-feature

Question 5

what is the purpose of the ‘stomata’ leaf adaptation? feature or structural of leaf?

Answer 5

Allows carbon dioxide to diffuse into the leaf and oxygen to diffuse out
-feature

Question 6

state the layers of the internal structure of a leaf? (7)

Answer 6

-waxy cuticle
-upper epidermis
-palisade mesophyll
-spongy mesophyll
-air space
-lower epidermis
-guard cells (with stomata in between)

Question 7

what is the internal structure of a leaf adapted to do?

Answer 7

to promote efficient photosynthesis

Question 8

why is the Epidermis thin and transparent ?

Answer 8

To allow more light to reach the palisade cells

Question 9

why is the Thin cuticle made of wax?

Answer 9

To protect the leaf from infection and prevent water loss without blocking out light

Question 10

why is the Palisade cell layer at top of leaf?

Answer 10

To absorb more light and increase the rate of photosynthesis

Question 11

what is the purpose of the spongy layer?

Answer 11

Air spaces allow carbon dioxide to diffuse through the leaf

Question 12

why does the Palisade cells contain many chloroplasts

Answer 12

To absorb all the available light

Question 13

what are the two types of transport tissue within a plant?

Answer 13

xylem and phloem

Question 14

what are leaves also involved in?
-state how this process works out (what is going on)

Answer 14

gas exchange
- carbon dioxide enters the leaf and oxygen and water vapour leave the plant through the stomata

Question 15

what are the stomata surrounded by?
-what do they do?

Answer 15

guard cells, which control their opening and closing.

Question 16

why are palisade mesophyll cells arranged closely together?

Answer 16

so that a lot of light energy can be absorbed.

Question 17

explain what the xylem and phloem transport within a cell: (2)

Answer 17

xylem transports water and mineral ions
phloem transports substances (such as sucrose and amino acids)

Question 18

what process do plants absorb water and mineral ions by? (2)

Answer 18

water = osmosis
mineral ions = active transport

Question 19

how are root hair cells adapted for taking up water and mineral ions?

Answer 19

by having a large surface area to increase the rate of absorption.

Question 20

how are root hair cells adapted for active transport? (2)

Answer 20

-contain lots of mitochondria, which release energy from glucose during respiration
-in order to provide the energy needed for active transport.

Question 21

what are the stomata and what do they do?
what do they allow in and out of the leaf?

Answer 21

tiny holes found in the underside of leaves.
-control water loss and gas exchange by opening and closing.
-allow water vapour and oxygen out of the leaf and carbon dioxide into the leaf.

Question 22

what do plants growing in drier conditions tend to have a small number of? where?
-why?

Answer 22

stomata and only on their lower leaf surface,
-to reduce water loss.

Question 23

describe what happens to guard cells in bright light and low light conditions

Answer 23

-In bright light the guard cells take in water by osmosis and become plump and turgid.
-In low light the guard cells lose water and become flaccid, causing the stomata to close.

Question 24

when do the guard cells only normal close in? why?

Answer 24

the dark when no carbon dioxide is needed for photosynthesis.

Question 25

what is the size of the stomatal opening is used by the plant to do? + therefore limit what?

Answer 25

control the rate of transpiration
-limit the levels of water loss from the leaf

Question 26

what does the xylem consist of?

Answer 26

dead cells

Question 27

describe how the dead cells making up the xylem are adapted for their function. (2)

Answer 27

-lose their end walls so the xylem forms a continuous, hollow tube.
-become strengthened by a substance called lignin.

Question 28

what does lignin do?

Answer 28

gives strength and support to the plant.

Question 29

what is the difference between the xylem and phloem in terms of direction?

Answer 29

xylem = upwards only
phloem= upwards and downwards

Question 30

describe transpiration and translocation?

Answer 30

transpiration: movement of water and mineral ions via the xylem
translocation: movement of substances (e.g sucrose) via the phloem