Transport in plants

Question 1

Suggest two advantages of chloroplast movement within palisade cells

Answer 1

to absorb more light
to avoid damage from high light intensities

Question 2

Xylem function

Answer 2

-Structural support
- Food storage
- Carries dissolved minerals & water up the plant

Question 3

Phloem function

Answer 3

Transport organic compounds (esp. sucrose) from the source (eg leaf) to the sink (eg root)

Question 4

Which way does phloem transport organic compounds

Answer 4

Up and down the plant

Question 5

What complex cells are the phloem made up of?
and state 2 of their role

Answer 5

-Sieve tube elements (main conducting cells)
- Companion cells
- Parenchyma (storage and strengthening of the fibres)

Question 6

What are the structures in xylem elements

Answer 6

• Lignified cell walls
• No end plates
• No protoplasm
• Pits in wall
• Small diameter in vessels

Question 7

Hows does lignified cell walls help xylem

Answer 7

-Adds strength to withstand hyrdostatic pressure
- Impermeable to water

Question 8

How does no end plates help xylem

Answer 8

Allows mass flow of water & dissolved solutes as cohesive and adhesive forces are not impeded

Question 9

How does no end plates help xylem

Answer 9

Allows mass flow of water & dissolved solutes as cohesive and adhesive forces are not impeded

Question 10

how does No protoplasm help xylem

Answer 10

doesnt impede the mass flow of water and dissolved solutes

Question 11

how does pits in walls help xylem

Answer 11

allows continuous flow even if air bubbles formed in vessels

Question 12

how does small diameter of vessels help xylem

Answer 12

-Prevents water column from breaking
-Assists capillary action

Question 13

State the structures of the sieve tube elements in phloem

Answer 13

• Sieve plates with sieve pores
  -Cellulose cell wall
  -No nucleus, vacuole, or ribosome in mature cells
  *Er and mitochondria is present
  -Thin cytoplasm

Question 14

Function of sieve plates and sieve pores in phloem

Answer 14

Allows for continuous movement of the organic compounds

Question 15

Function of cellulose cell wall in phloem

Answer 15

Strengthens the wall to withstand hyrdostatic pressure that moves the assimilates

Question 16

Function of having no nucleus, vacuole or ribosomes in phloem

Answer 16

Maximizes space for translocation

Question 17

Function of thin cytoplasm in phloem

Answer 17

Reduces friction to help movement of assimilates

Question 18

What does companion cells do in plhoem?

Answer 18

• They control the metabolism of their associated sieve tube member
• They help in unloading and loading sugars into the phloem

Question 19

Function of nucleus and other organelles in companion cells?

Answer 19

-Provides metabolic support to sieve tube elements
-Helps in the loading and unloading of assimilates

Question 20

Function of transport proteins in plasma membrane located in the companion cells?

Answer 20

Moves assimilates in and out of the sieve tube elements

Question 21

Function of large no. of mitochondria in companion cells?

Answer 21

Provides ATP for the active transport of assimilated in and out of the companion cells

Question 22

Function of plasmodesmata in companion cells?

Answer 22

It links the sieve tube elements, allowing organic compounds to move from the companion cells into the sieve tube elements

Question 23

What is the liquid transported in phloem sieve tubes called?

Answer 23

Phloem sap

Question 24

Outline the role of ATP in leaf cell

Answer 24

It provides energy ( don’t write produces)
- for active transport of sucrose from source to sink ( proton pumping H+ ions)
- for endocytosis ( movement of vesicles)

Question 25

Explain how hydrogen bonds occur between water molecules

Answer 25

• weak hydrogen bonds present
• water is dipolar
• oxygen has a SMALL negative charge and hydrogen has a SMALL positive charge

Question 26

Why is water an excellent solvent for ions

Answer 26

• Water is polar
• ions are charged
• therefore there will be an attraction between ions and water molecules