structure of xylem and phloem

Question 1

what are the structural similarities between xylem and phloem

Answer 1

both tube shaped
hollow

Question 2

What 2 types of cells are xylem made up of

Answer 2

1.vessel elements
2. Tracheids

Question 3

Similarities between vessel elements and tracheids

Answer 3

1. Hollow cells
2. lignified cells

Question 4

Differences between vessel elements and tracheids

Answer 4

vessel elements are much larger than tracheids

vessel elements join from end to end to allow water to flow vertically, whereas tracheids have tapered ends which make water flow horizantally

Question 4

why are vessel cells and tracheids hollow

Answer 4

to allow water and minerals to flow

Question 5

what direction does water flow in xylem

what direction does water flow in phloem

Answer 5

xylem: water flows vertically

phloem: water flows horizontally and vert

Question 6

why does water flow horizantally in the tracheids

Answer 6

tracheids have tapered ends

Question 7

what are sink cells

Answer 7

fruit and root cells

Question 8

what regulates transpiration

Answer 8

guard cells

Question 9

how does water flow in phloem cells

Answer 9

The Sieve plates allow water to flow vertically, whilst the pores between the sieve cells allow water to flow horizontally.

Question 10

Companion cells function

Answer 10

egulates the movement of nutrients to allow itself and the sieve cells to survive

Question 11

Key characteristics of phloem:

Answer 11

Hollow cells
Tube like structure
Sieve plates for vertical transport of water
Pits between the sieve cells for horizontal transport of water
Companion cells

Question 12

Transpiration

Answer 12

passive net movement of water through the xylem and evaporation through the stomata

Question 13

how much water is used in phtoyhensis and what happens to the water that is not used in photosytehnsis

Answer 13

Only 1% of the water from the xylem is used for photosynthesis

the rest of the water evaporates into the stomata because there is a higher concentration of water vapour inside than outside the leaf

Question 14

Function of the stomata

Answer 14

gas and exchange and is the stie where carbon dixodie enters the cell

Question 15

ALL FUNCTIONS OF TRANSPIRATION:

Answer 15

Assists photosynthesis
Helps plants regulate heat and water balance
Distributes nutrients throughout the plant
Prevents wilting and cell damage

Question 16

Why does evaporation cause water to move up the xylem

Answer 16

Water evaporates through the stomata causing the air pressure in the leaf to be lower than in the roots. This low pressure causes a force to draw water up the xylem.

Question 17

Why does more water get drawed up the xylem than expected?

Answer 17

Water sticks together(cohesion)

Question 18

Function of capillary action: How is it caused?

Answer 18

Capillary actions help water flow in the xylem

caused by the adhesion of water molecules to the surface of the xylem.

Question 19

the 2 mechanisms of transpiration/ways water moves up the xylem

Answer 19

evaporation in the stomata and capillary action

Question 20

TRANSLOCATION:

Answer 20

Is the movement of nutrients created in the leaves to other areas of the plant

Question 21

How is the translocation of glucose happen

Answer 21

1.Glucose is produced during photosynthesis as it moves into the companion cells and sieve cells of the phloem.

2.As glucose moves into the sieve cells, the water also follows into the sieve cells, creating a higher turgor pressure

3. The turgor pressure causes the liquid in the phloem to move across the plant, therefore glucose is actively transported from source cells into sink cells(root and fruit cells)

4.Once glucose is unloaded into the sink cells, the concentration in the phloem is reduced and water will diffuse back into the xylem.

5.Other solutes, such as amino acids or important minerals, travel through the phloem in a similar manner to glucose

Question 22

Factors affecting transpiration rate

Answer 22

Water loss as leads to high solute concentrations and a reduction in turgidity, which in turn can damage the plant or cause it to wilt

Question 23

Environmental conditions that affect transpiration rates

Answer 23

temperature – at higher temperatures, more water evaporates from the leaves
* water availability – when water availability is high the roots absorb more water.

Question 24

what gases are exchanged in the stomata

Answer 24

oxygne & carbon dioxde

Question 25

what happens when the stomato closes

Answer 25

, gases cannot freely leave or enter a leaf, thereby reducing the rate of photosynthesis, transpiration, and water loss.

Question 26

whathappesn when the stomato opens

Answer 26

-water vapour can freely leave the leaf as part of transpiration -CO2 can freely enter the leaf as an input of photosynthesis -O2 can exit the leaf after it is produced during photosynthesis.

Question 27

To increase the rate of transpiration, plants:

Answer 27

actively pump potassium ions into guard cells as this will increase the concentration of solutes. Then water will diffuse into the guard cells via osmosis. This causes the vacuoles to increase in size, and each guard cell becomes turgid. Turgid guard cells are shaped like beans, which leaves the stomata open.

Question 28

To reduce the rate of transpiration, plants:

Answer 28

actively pump potassium ions out of guard cells as this will cause water to diffuse out of the vacuoles. This causes guard cells to becomes flaccid, closing the stomata

Question 29

In order for guard cells to open the stomata

Answer 29

active transport must pump potassium ions against the concentration gradient.

Question 30

If there is not enough active transport in the stomata,

Answer 30

, guard cells will lose their turgidity, hence stomata pores will be closed.

Question 31

what are the 4 main forces that cause water to move up The xylem and how

Answer 31

osmosis adhesion- TrANSPIRATION- cohension

Question 32

adhesion

Answer 32

tendency of water and other surfaces to stick together

Question 33

cohension

Answer 33

the bonding of water molecules

Question 34

how does the stomata close

Answer 34

the guard cells become flaccid

Question 35

how does capillary aciton cause water to move up the xylem

Answer 35

s it is caused by the adhesion of water molecules to the surface of the xylem. In small enough tubes, this force of adhesion is large enough to pull the water up the xylem.

Question 36

how does osmosis cause water to move up the xylem

Answer 36

water moves up the xylem underpressure caused by osmosis as the roots require active transport because there is a high concentration of ions inside the root than outside the root

Question 37

Why is the rate of transpiration high on a windy day?

Question 38

wher eis majority of the plant

Answer 38

ground tisuse

Question 39

chracteriistcs of xylem

Answer 39

dead hollow lignified pits between vessle elments for vertical transport of water

Question 40

why does the stomata need to open

Answer 40

gas exchange

Question 41

how does transpiration cause water to move up the xylem

Answer 41

the negative pressure produced in the leaf pulls water up the xylem

Question 42

how does adhesion cause water to move up the xylem

Answer 42

water is attracted to the sides of the walls of the xylem

Question 43

why does cohension cause water to move up the xylem

Answer 43

water is polar therefore water molecuels bond to other water moleucels

Question 44

the amount of water lost in plants depends on

Answer 44

humdiity and wind

Question 45

Water loss via transpiration increases under the following conditions

Answer 45

Higher temperatures Stronger winds Low humidity Large number of open stomata

Question 46

Water loss via transpiration decreases under

Answer 46

Lower temperatures Weak or no winds High humidity Few open stomata

Question 47

Glucose moves from the leaf cells to the phloem by

Answer 47

facilcaited diffusion

Question 48

Why does the cytoplasmic pathway contain active transport? 3 marks

Answer 48

The nutrients, minerals and water in the soil will diffuse from an area of high concentration into an area of low concentration of the plants through the cytoplasmic pathway. cytoplasmic pathay requires active tranpsort so that substnaces can be transported against the concentration against from the soil even when the cocnentration in the soil is low and the concentration in the cytoplasm is high

Question 49

Why does the cytoplasmic pathway contain active transport? 1 or 2 marks

Answer 49

the cytoplasmic pathway contains active transport in order to transport more nutrients, minerals and water from the soil into the cytoplasm even against the concentration gradient depending on the requirements of the plants

Question 50

Does cohesion help in the process of transpiration or translocation and how?

Answer 50

Cohesion is the tendency of the water molecules to stick together and therefore it helps with transpiration as it allows the water to move up the xylem