Specialised plant cells

Question 1

What do phloem sieve tubes transport?

Answer 1

sucrose

Question 2

What is transporting sucrose around a plant called?

Answer 2

translocation

Question 3

Name and explain the adaptations of phloem tubes

Answer 3

-little cytoplasm/no nucleus
more room flr the central channel

-companion cells contain lots of mitochondria to provide energy for active transport of sucrose into and out of the sieve tubes

-holes in the cell walls of the sieve cells
liquids can flow from one cell to the next

-companion cells next to sieve cells
sucrose is pumped into the sieve cells

-holes between companion cells and sieve cells
sucrose solution is pumped through pores

Question 4

What do xylem vessels transport?

Answer 4

water and dissolved mineral ions

Question 5

Name and explain the adaptations of xylem tubes.

Answer 5

-they are made of dead cells with no cytoplasm or cell contents
this means there is more space for the water to move through

• holes called pits/pores in the walls allow water and mineral ions to move out and enter
• the walls are strengthened with lignin rings to make them strong/rigid and prevent them from collapsing
• there are no end walls so they form a long tube that allows water to flow easily through

Question 6

Name 4 types of mineral ions

Answer 6

magnesium (Mg)

nitrates (NO3)

phosphorous (P)

potassium (K)

Question 7

Why do plants need water?

Answer 7

• carrying dissolved mineral ions
• keeping cells rigid
• cooling leaves through evaporation
• photosynthesis

Question 8

What do root hair cells do?

Answer 8

-absorb water/mineral ions

Question 9

How is a root hair cell adapted?

Answer 9

• thin cell wall
• large surface area
• lots of mitochondria for energy

Question 10

How does water enter the root hair cell?

Answer 10

• diffusion
• osmosis
• water diffuses down a concentration gradient into the cell wall of the cell and diffuses through the cell walls to the stem where it enters the xylem vessels
• water enters through osmosis down a concentration gradient across the cell membrane and diffuses through the cytoplasm of the cells. Tiny tubes join the cytoplasm together, allowing water to diffuse.

Question 11

How do mineral ions enter the root cell?

Answer 11

• by active transport up a concentration gradient

- they can’t diffuse because there is a higher concentration in the cell than in the soil

Question 12

Which way does water move in transpiration?

Answer 12

up

Question 13

Which way does sucrose move in translocation?

Answer 13

all directions/up and down