Transport in Plants, 3.3

Question 1

How does a plant get water and minerals?

Answer 1

Through the roots

Question 2

How does a plant get sugars?

Answer 2

Photosynthesis

Question 3

What are vascular bundles?

Answer 3

Groups of vascular tissues

Question 4

What is the role of the xylem?

Answer 4

Transports water and dissolve minerals. Move upwards.

Question 5

What is the role of the phloem?

Answer 5

Transports products of photosynthesis all over the plant.

Question 6

What are the structures found in the roots? Draw a diagram.

Answer 6

Endodermis. Epidermis. Phloem. Xylem. Root hair.

Question 7

What are the structures found in the stem? Draw a diagram.

Answer 7

Epidermis. Phloem. Xylem. Layer of cambium between xylem and phloem.

Question 8

What are the structures in the leaf? Draw a diagram..

Answer 8

Cuticle. Upper epidermis. Spongy mesophyll layer. Phloem. Xylem. Guard Cell. Stomata.

Question 9

How does lignin affect the xylem?

Answer 9

Lignin impregnates the walls - waterproof and strong. Lignification kills the cells.

Question 10

How are bordered pits formed?

Answer 10

In some places lignification is not complete leaves gaps. Allow water to leave.

Question 11

How does the killing of the cells help the structure of the xylem?

Answer 11

Decay leaves long columns with no content - continuous

Question 12

Why are xylem vessels able to carry water?

Answer 12

1. Cell walls overlap - continuous
2. Tubes are narrow - water column doesn’t break
3. Bordered pits allow water to ‘leak’ through

Question 13

What are the two components of the phloem?

Answer 13

Sieve tube elements and companion cells..

Question 14

Describe the structure of sieve tube elements.

Answer 14

Elongated. Line up forming sieve tubes. No nucleus. Ends are perforated (sieve plates) allow movement.

Question 15

Describe the structure of companion cells.

Answer 15

Between sieve tube elements. Large nucleus. Dense cytoplasm. Numerous mitochondria.

Question 16

What is the function of a companion cell?

Answer 16

Carries out metabolic processes - needs lots of ATP

Question 17

What is a gap in the cell wall where the cytoplasm joined called?

Answer 17

Plasmodesmata

Question 18

How permeable is cellulose?

Answer 18

Fully permeable

Question 19

Describe the Apoplast pathway

Answer 19

Water passes through space in or between cells. Doesn’t pass through the membrane. Stops at endodermis - casparian strip

Question 20

Describe the process of the symplast pathway.

Answer 20

Water enters the cell through the plasma membrane. Passes through plasmodesmata.

Question 21

Describe the Vacuolar Pathway

Answer 21

Not confined to cytoplasm - move through vacuole

Question 22

Why is the water potential in plant cells always negative?

Answer 22

Has dissolved solutes in it

Question 23

How does water move into the roots from the soil?

Answer 23

Roots take in ions by active transport - lowers water potential. Water moves by osmosis into cells - until its turgid..

Question 24

How does water leave?

Answer 24

Evaporates through the leaves

Question 25

What is transpiration?

Answer 25

The loss of water vapour through stomata

Question 26

What are the stages of water moving through a plant?

Answer 26

1. Water enters the leaf from the xylem 2. Water evaporates 3. Water vapour moves by diffusion through stomata

Question 27

How does light intensity affect transpiration?

Answer 27

Light causes. Stomata to open. Let’s water vapour diffuse out. Increases rate.

Question 28

How does temperature affect transpiration?

Answer 28

High temperature increases kinetic energy. Decrease in vapour water potential near stomata. Rate increases.

Question 29

How does humidity affect transpiration?

Answer 29

More water vapour in the air around the stomata. Smaller gradient. Decreases rate.

Question 30

How does wind affect the rate transpiration?

Answer 30

Moves humid air away from the plant so a bigger water vapour potential. Increases rate.

Question 31

How does water water availability affect transpiration?

Answer 31

Insufficient water causes stomata to close. Cells not turgid..

Question 32

How do we use a potometer to measure transpiration?

Answer 32

Water drawn through a straw wads to a leafy shoot. Distance an air bubble tracks in the capillary tube over a set time. Place apparatus in different conditions.

Question 33

What is the role of root hair cells?

Answer 33

Absorb mineral ions and water from the soil.

Question 34

What is the role of the Casparian strip?

Answer 34

Block the apoplast pathway. Forces water through the symplast pathway.

Question 35

How does root pressure cause transpiration?

Answer 35

Pressure in root medulla builds up. Forces water up the xylem.

Question 36

How does the transpiration pull help move water up the xylem?

Answer 36

Loss of water drags water up the xylem. Whole column gets pulled up. Cohesion and adhesion.

Question 37

What is cohesion?

Answer 37

Water molecules attract to each other

Question 38

What is adhesion?

Answer 38

Water molecules attracted to the walls of the xylem.

Question 39

What is the source?

Answer 39

Part of the plant that loads materials eg leaves (sucrose)

Question 40

What is the sink?

Answer 40

Part of the plant that removes materials eg meristem or roots (sucrose)

Question 41

Describe the stages of active loading?

Answer 41

1. Companion cell actively pumps H+ out - produces conc. gradient 2. H+ ions diffuse back if they’re carrying sucrose 3. Creates a high sucrose conc. in the cells 4. Sucrose then diffuses into sieve tube

Question 42

How do assimilates move through the phloem?

Answer 42

Through sap. Caused by hydrostatic pressure.

Question 43

What happens when sucrose concentration is high?

Answer 43

Water enters via osmosis increasingly hydrostatic pressure

Question 44

What is an xerophyte?

Answer 44

Plants adapted to liv in arid conditions (cacti and marram grass)

Question 45

Name some adaptations of a xerophyte

Answer 45

Hairy leaves. ‘Sunken’ stomata. Rolled up leaves. Widespread roots. Succulent plants. Waxy cuticle. Spikes.

Question 46

What is an hydrophyte?

Answer 46

Plants that live in water/wet conditions (water lilies)

Question 47

What are some adaptations of a hydrophyte?

Answer 47

Large air spaces so it floats. Stomata on the upper side.