Multicellular Organisms - Transport Systems in Plants

Question 1

layers of the leaf

Answer 1

• waxy cuticle
• upper epidermis
• palisade mesophyll
• spongy mesophyll
• lower epidermis
• stomata and guard cells

Question 2

waxy cuticle

layers of the leaf

Answer 2

waterproof layer which prevents evapouration of water vapour from the upper leaf surface

Question 3

epidermis

layers of the leaf

Answer 3

layer of protective tissue on upper and lower surfaces of a leaf

Question 4

mesophyll

layers of the leaf

Answer 4

tissues composed of green cells which make up the main site of photosynthesis

Question 5

why is it important

moist air space

layers of the leaf

Answer 5

large internal surface area of moisture allows for quick diffusion of materials between cells

Question 6

stoma

layers of the leaf

Answer 6

one of many tiny pores found on the surfaces of the leaf

allows for movement of CO2 and oxygen in and out of the leaf

Question 7

guard cell

layers of the leaf

Answer 7

one of the pair of cells which change shape and control gaseous exchange by opening and closing stomata

Question 8

phloem

Answer 8

live tissue responsible for sugar transport in a plant

composed of sieve tubes and companion cells

Question 9

sieve plate

phloem

Answer 9

end wall of a seive tube perforated with holes that allow continuity of cytoplasm from tube to tube

Question 10

sieve tube

phloem

Answer 10

live componant of phloem controlled by companion cell

Question 11

companion cell

phloem

Answer 11

live componant of phloem tissue possessing a nucleus which controls the workings of the sieve tube

Question 12

xylem

Answer 12

non-living tissue containing hollow, lignified vessels responsible for support and water transport in plants

Question 13

lignin

Answer 13

tough supporting material present as rings or spirals in xylem vessel walls

Question 14

transpiration

Answer 14

The continuous passage of water through a plant from root to leaf

Question 15

transpiration process

Answer 15

• root hairs spread out from roots and greatly increase surface area for absorption of water
• water in the soil enters the cells of the root hairs by osmosis, and diffuses through permeable cell walls
• water moves from cell to cell by osmosis until it enters the xylem
• water is being used by cells for photosynthesis and is also being lost from the leaves by evaporation, this causes water to be drawn up the xylem.
• The transpiration pull causes continuous columns of water to be pulled up the xylem

Question 16

rate of transpiration

how to measure

Answer 16

use either a bubble potometer or a weight potometer

Question 17

factors effecting transpiration rates

Answer 17

• temperature up, transpiration up
• wind speed up, transpiration up
• humidity up, transpiration down