3.3

Question 1

What is the need for transport systems in multicellular plants

Answer 1

• larger Plants have a smaller surface area to volume ratio

* high metabolic rate

Question 2

Herbaceous dicotyledonous plants

Answer 2

Plants with 2 seed leaves and a branching pattern of veins in the leaf

Question 3

Xylem tissue

Answer 3

Water + soluble mineral ions travel upwards in xylem tissue

Question 4

Phloem tissue

Answer 4

Assimilates such as sugars travel up or down in the phloem tissue

Question 5

Xylem + Phloem in root

Answer 5

Xylem in centre surrounded by phloem to provide support for the the root as it pushes through the soil

Question 6

Xylem + Phloem in stems

Answer 6

Are near the outside to provide a sort of ‘scaffolding’ that reduces bending

Question 7

Xylem + Phloem in leaf

Answer 7

Make up a network of veins which support the thin leaves

Question 8

Cells in phloem used for transport

Answer 8

• Sieve tube elements

* Companion cells

Question 9

What is sieve tube elements

Answer 9

Make up the tubes in phloem tissue that carry sap up and down the plants. The sieve tube elements are separated by sieve plants

Question 10

What is companion cells

Answer 10

The cells that help to load sucrose into the sieve tubes

Question 11

How does water travel through a plant

Answer 11

•enters through root hair cells
-water moves from areas of higher water potential to areas of lower water potential
•moves through root into xylem
•up xylem out at leaves
-cohesion and tension and adhesion help water move up plants

Question 12

transpiration

Answer 12

The loss of water vapour from the aerial parts of a plant, mostly through the stomata in the leaves

Question 13

Process of transpiration

Answer 13

• water enters leaf thru xylem
• moves by osmosis
• water evaporates from cell walls
• water vapour moves thru diffusion out of the leaf through the open stomata

Question 14

What is transpiration a consequence of

Answer 14

Gas exchange

Question 15

Environmental factors that affect transpiration rate

Answer 15

• Light intensity
• temperature
• relative humidity
• air movement (wind)
• water availability

Question 16

Potometer

Answer 16

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

Question 17

Adaptations of plants to the availability of water in their environment (in water)

Answer 17

Plants adapted to living in water:
Hydrophytes (Water Lilies)
•many large air spaces in leaf to keep afloat + absorb sunlight
•stomata exposed to air to allow gaseous exchange
•leaf stem has many large air spaces-buoyancy + oxygen diffusion

Question 18

Adaptations of plants to the availability of water in their environment (on land)

Answer 18

Xerophyte (plant adapted to living in dry conditions) (Cacti + Marram grass):
Cacti:
• succulents (store water)
•surface area of leaves reduces to reduced water lost by transpiration
•stem green photosynthesis
•roots widespread

Marram grass:
•leaf rolled longitudinally so Air Trapped inside
•thick waxy cuticle to reduce evaporation
•stomata adapted to avoid loss of water vapour

Question 19

Translocation

Answer 19

The transport of assimilated throughout a plant
•energy-requiring process transporting assimilates especially sucrose, in the phloem between sources (e.g leaves), and sinks (e.g roots meristem)

Question 20

Details of active loading and removal at the sink TRANSLOCATION

Answer 20

Active loading: used to move substances into companion cells then sieve tubes against concentration grad
•in companion cell ATP transports H+ out of cell
•more h+ tissue that cell
•h+ binds 2 co-transport protein reenters cells
•sucrose molecules binds 2 protein at same time
•movement of H+ used 2 move sucrose into cell
•sucrose out of companion into sieve same process

Question 21

What translocation do (sink)

Answer 21

Translocation moves substances from ‘sources’ to ‘sinks’. The source of a substance is where its made (high concentration) the sink is the area where it’s used up (lower concentration)

Question 22

symplast pathway

Answer 22

the route taken by water as it goes from cell to cell via the cell cytoplasm

Question 23

apoplast pathway

Answer 23

route by which water travels through the cell walls and in spaces between cells of plant tissue when travelling from roots to xylem and from xylem to leaves