transport in plants

Question 1

what is a dicotyledonous plant?

Answer 1

plants with two seed leaves and a branching pattern of veins in the leaves

Question 2

what is meristem?

Answer 2

a layer of diving cells

Question 3

what is the phloem?

Answer 3

something that transports assimilates

Question 4

what is vascular tissue?

Answer 4

consists of cells that are specialised for transporting fluids by mass flow

Question 5

what is the xylem?

Answer 5

transports water and minerals

Question 6

how is the xylem adapted to its function?

Answer 6

• dead cells form a continuous column

- tubes are narrow

Question 7

how is the phloem adapted for its function?

Answer 7

-contains sieve tube elements –> make sieve plates

Question 8

what are the three pathways that water can take?

Answer 8

• apoplast
• symplast
• vacuolar

Question 9

what is the plasmodesmata?

Answer 9

gaps in the cell wall that contain cytoplasm

Question 10

what is a potometer?

Answer 10

a device that can measure the rate of water uptake as a leafy stem transpires

Question 11

what is transpiration?

Answer 11

• loss of water vapour

- mostly through stomata

Question 12

what factors can effect transpiration?

Answer 12

• light intensity
• temp
• humidity
• air movement
• water availability

Question 13

why is transpiration important?

Answer 13

• transports useful mineral ions up the plant
• maintains cell turgidity
• supplies water for growth, cell elongation and photosynthesis
• keep the plant cool

Question 14

what is adhesion?

Answer 14

the attraction between water molecules and the walls of the xylem vessels

Question 15

what is cohesion?

Answer 15

the attraction between water molecules caused by hydrogen bonds

Question 16

what is the role of the endodermis?

Answer 16

-the Casparian strip blocks the apoplast pathway between the cortex and the medulla

Question 17

what helps move the water up the stem?

Answer 17

• root pressure
• transpiration pull
• capillary action

Question 18

what is a hydrophyte?

Answer 18

a plant adapted to living in water.

Question 19

what is a xerophyte?

Answer 19

a plant adapted to living in dry conditions.

Question 20

what are assimilates?

Answer 20

substances that have become part of the plant

Question 21

what is a sink?

Answer 21

a part of the plant where assimilates are removed from the plant

Question 22

what is the source?

Answer 22

a part of the plant which loads assimilates into the transport system

Question 23

what are the 3 main stages of active loading?

Answer 23

1) H+ ions actively pumped out of the companion cell using ATP
2) high conc of H+ causes facilitated diffusion back into companion cell. Sucrose is carried passively with the H+
3) increased conc of sucrose in companion cell causes diffusion into the sieve tube element