Transport In Plants

Question 0

In what vessel does water travel through to reach the top of the plant

Answer 0

The Xylem vessel

Question 1

What properties of water make it useful for transport in plants (5)

Answer 1

A good solvent
Polar so bonds or sticks to itself - cohesive
Adhesive - sticks to other things
High specific heat capacity
Water densest at 4 degrees so ice floats on top

Question 2

What is the job if the cambium

Answer 2

The cambium is responsible for making new xylem and phloem and is found between existing ones.

Question 3

What is the structure of vascular bundle

Answer 3

Found in outer edge of stems and are seperate in woody plants but become continuos in older stems.
This means there is a ring of vascular tissue under the bark of a tree. This offers support and flexibility.

Question 4

What is the structure of young roots

Answer 4

At the centre is the vascular bundle and the central core is made of xylem. Phloem is between the arms and offers strength. Surrounding the vascular bundle is the endodermis. Meristem then forms layer called pericycle inside the epidermis.

Question 5

What is the name of cells that can still divide

Answer 5

Meristem cells

Question 6

What is the job of lignin

Answer 6

Waterproofs the cell causing it to die. The walls and contents then begin to decay. Strengthens walls to prevent it from collapsing.

Question 7

What is the structure of xylem vessels.

Answer 7

Xylem vessels are long tube of dead cells with no end walks ( due to lignin )

Question 8

What are 4 patterns in cell walls

Answer 8

Spiral
Anular
Peticulate
Pitted

Question 9

What are the useful adaptions of xylem vessels that make it good for transporting water

Answer 9

Dead cells allighn to make continuos collumn
Pits allow movement of water
Lignin in walls allows xylem to grow and stretch and bend.
Flow of water not impeded as no end walls, nucleoles, cytoplasm.

Question 10

What are the 3 paths water can take through cells

Answer 10

Symplast
Apoplast
Vacuolar

Question 11

What is the apoplast pathway

Answer 11

Water moves between spaces between cells. Never enters cell as travels between cells

Question 12

What is the symplast pathway

Answer 12

Water enters cytoplasm through plasma membrane. Then passes through holes (plasdodesmata) from one cell to the next. Cytoplasm in plasmodesmata ensures that it is continuos between cells.

Question 13

What is the vacuolar pathway

Answer 13

Similar to symplast but water not confined to cytoplasm and can pass through vacuole as well.

Question 14

What prevents water from entering xylem through apoplast pathway.

Answer 14

The casparian strip

Question 15

How do nitrate ions pass into xylem

Answer 15

They are actively transported from the cytoplasm of cortex cell to the xylem.

Question 16

By what process does water enter the xylem

Answer 16

Osmosis

Water potential in xylem low

Question 17

What surrounds the xylem and phloem and has the casparian strip

Answer 17

The endodermis

Question 18

What are plants that are adapted to living in very dry or arid conditions called

Answer 18

Xerophytes

Question 19

What is translocation - brief description

Answer 19

Movement of assimilates (sugers and other chemicals made by plant cells).

Question 20

What is a source in terms of sucrose

Answer 20

Part of plant that releases sucrose into the phloem

Question 21

What is a sink in terms of sucrose

Answer 21

Part if plants that removes sucrose from phloem

Question 22

What form do sugers take when being transported in phloem

Answer 22

Sucrose

Question 23

What are companion cells

Answer 23

Thin cells to the side of sieve tube elements

Question 24

How do companion cells use hydrogen ions to bring in sucrose molecules from surrounding tissues

Answer 24

Actively transport H ions out of there cytoplasm and into surrounding tissue. This means diffusion gradient set up. So H ions diffuse back into cell through cotransporter protein which means they can bring back sucrose molecules. When concentration of surcose high enough they diffuse into sieve tubes through plasmodesmata.

Question 25

What protein allows surcose molecules to transport with H ions back into companion cells

Answer 25

Cotransporter proteins