Plant transport

Question 1

What are the 6 things that need to be transported by plants

Answer 1

Water,Assimilates, Mineral ions, Oxygen, Carbon dioxide and hormones

Question 2

What does the xylem transport

Answer 2

water and soluble mineral ions up the plant

Question 3

What is the xylems other function

Answer 3

To provide structural support

Question 4

What does the phloem transport

Answer 4

Assimilates and sucrose

Question 5

Whatis the endodermis

Answer 5

Sheath of cells surrounding the vascular bundle and has a key role in getting water into the xylem vessel

Question 6

What is the pericycle

Answer 6

Layer of meristem cells which are undifferentiated so can grown new tissues

Question 7

What is the cambium

Answer 7

Meristem cells that can produce new xylem or phloem cells

Question 8

What is the parenchyma

Answer 8

packing and support tissue capable of cell division

Question 9

What is the collenchyma

Answer 9

cells providing structral support in growning shoots and leaves

Question 10

Is the xylem on the outside or inside of young roots and young stems

Answer 10

inside

Question 11

Describe xylem vessels

Answer 11

columns of fused hollw and dead cells which transport the water and mineral ions up the plant

Question 12

What are fibres

Answer 12

Long dead cells with thick cell walls which provide support

Question 13

What are xylem parenchyma

Answer 13

Living cells that form packing tissue and store food . May contain bitter tasting tannin to protect against insects

Question 14

Describe the structure of xylem vessels

Answer 14

starts as live column of cells that lay waterproof lignin inside cell walls.
Cell contents die
Endplates are removed and lignin increases as cells age. It is arranged into spirals annular or reticulate patterns
Gaps in lignin called pits

Question 15

What are adaptations of xylem vessesls

Answer 15

Continuous column
No contentsb
Lignin prevents walls collapsing under surface tension
Small diameter for flow
Pits for lateral movement if water
Arrangement of lignin allows for growth

Question 16

What does the phloem tissue consist of

Answer 16

Sieve tube elements Companion cells Parenchyma Fibres and sclereids

Question 17

What is water potential

Answer 17

Water potential is the tendency of free water molecules to leave a solution. the more slute in a solution the lower the water potential
Water moves form a higher water potential to a lower one

Question 18

How does water move into the roots

Answer 18

As the root is filled with mineral ions the water potentail in the root is lower than outside the cells therfore water moves in along the water potential gradient by os,osis into the roots

Question 19

Describe the symplast pathway

Answer 19

Water travels through the cytoplasm and vacuoles
The cells are connected by plasmodesmata whcih are thin strands of cytoplasm

Question 20

Describe the apoplast pathway

Answer 20

cellulose cell wall is fully permeable and water moves through gaps by adhesion
Does not pass through the membane
Water moving up xylem with cohesion together meaning there is a continuous flow
Stops at the endodermis

Question 21

What is the casparian strip made of

Answer 21

A waxy waterproof substace called suberin

Question 22

What is root pressure

Answer 22

Mineral ions transported into xylem which lowers water potenial causing water to move in by osmosis and forces water up the stem
Effected by metabolic poisons and oxygen availability

Question 23

Describe transpiration pull

Answer 23

Cohesion causes mollecules to be attracted to each other
This forms a long column of water in the xylem
As water is lost at the top of the plant by transpiration , the column is pulled up through the xylem
The pull of water creates a tension in the column. The lignin prevents the xylem from collapsing inward from tension

Question 24

Describe capillary action

Answer 24

Adhesive forces between molecules and lignin in the narrow walls of the xylem vessels help pull the water up the xylem vessels

Question 25

What is transpiration

Answer 25

The loss of water vapour frop the upper parts of the plant especially the leaves

Question 26

What is the transpiration stream

Answer 26

flow of water through the plant from the roots to the leaves in the xylem vessels

Question 27

What are some adaptations of xerophytes

Answer 27

Leaves reduced to spines, Succulents, hairs, dense spongey mesopyhll rolled leaves sunken stomata reduced leaves thick waxy cuticles reduced no stomata root adaptations

Question 28

What are some adaptations of hydrophytes

Answer 28

Wide flat leaves Aerenchyma Stomata facing upward Thin or no waxy cuticle Reduced plant structure Small roots Large SA of stem and root under water Air sacs

Question 29

What is translocation

Answer 29

The movement of assimilates up and down the plant in the phloem

Question 30

What is a source

Answer 30

An area of the plant that produces sucrose e.gleaves in summer

Question 31

Describe the process of train

Answer 31

An area that takes in sucrose for growth or other processes e.g growing stems

Question 32

Describe the process of translocation (companion cell loading)

Answer 32

Protons are actively pumped out of the companion cell against conc gradient They look to diffuse back across but can only do so through a cotransporter protein This also transports sucrose against the conc gradient into the companion cell