4A

Question 1

what is the function of the cell wall?

Answer 1

supports plant cell

Question 2

what is the function of plasmodesmata?

Answer 2

allow transport of substances and communication between cells

Question 2

what is the function of the middle lamella?

Answer 2

this layer act as an adhesive, sticking adjacent plant cells together. It gives the plant stability.

Question 2

Plasmodesmata

Answer 2

channels in the cell walls that link adjacent cells together

Question 3

middle lamella

Answer 3

outermost layer of the cell

Question 4

what is the function of pits?

Answer 4

allow transport of substances between cells

Question 5

Pits

Answer 5

regions of the cell wall where the wall is very thin. they’re arranged in pairs - the pit in one cell is lined up with the pit in the adjacent cell

Question 6

Amyloplast

Answer 6

a small organelle enclosed by a membrane, containing starch

Question 7

what is the function of amyloplasts?

Answer 7

stores starch grains and converts starch back to glucose when the plant requires it.

Question 8

which two organelles allow transport of substances between plant cells?

Answer 8

pits and plasmodesmata

Question 9

name the membrane that surrounds the vacuole

Answer 9

tonoplast

Question 10

what is the function of the vacuole?

Answer 10

• contains the cell sap
• keeps the cell turgid
• break down unwanted chemicals

Question 11

what is the function of xylem vessels?

Answer 11

transport water and mineral ions up the plant

Question 12

describe the structure of xylem vessels

Answer 12

long tube-like structures formed from dead cells, joined end to end

Question 13

what are the xylem walls thickened with?

Answer 13

lignin

Question 14

where do water and mineral ions move into and out of the vessels?

Answer 14

through pits in the walls where there is no lignin

Question 15

what is the function of sclerenchyma fibres?

Answer 15

provide support

Question 16

what are sclerenchyma fibres made up of?

Answer 16

dead cells that run vertically up the stem

Question 17

how do sclerenchyma fibres differ from xylem vessels?

Answer 17

• cells have a hollow lumen, but have end walls
• they dont contain pits

Question 18

what is the function of phloem tissue?

Answer 18

transport organic solutes (translocation)

Question 19

what types of cells does phloem tissue contain?

Answer 19

sieve tube elements
companion cells

Question 20

sieve tube elements

Answer 20

living cells, joined end to end forming a sieve tubes

Question 21

what is unusual about sieve tube elements?

Answer 21

no nucleus
very thin layer of cytoplasm
few organelles

Question 22

why does every sieve tube element need a companion cell?

Answer 22

they lack a nucleus and other organelles

Question 23

companion cells

Answer 23

carry out the living functions for both themselves and their sieve cells. e.g. providing energy

Question 24

vascular bundles

Answer 24

xylem vessels grouped together with phloem tissue

Question 25

what is associated with the vascular bundle?

Answer 25

sclerenchyma fibres

Question 26

why are plant fibres strong?

Answer 26

the cell wall contains cellulose microfibrils in a net-like arrangement

Question 27

where is the secondary cell wall?

Answer 27

between the primary cell wall and the cell membrane

Question 27

what plant cells produce a secondary cell wall?

Answer 27

sclerenchyma and xylem

Question 28

what does the secondary cell wall contain?

Answer 28

lignin

Question 28

what is thicker the primary or secondary cell wall?

Answer 28

the secondary cell wall

Question 29

what is the growth of the secondary cell wall called?

Answer 29

secondary thickening

Question 30

what is meant by tensile strength?

Answer 30

the tensile strength of a fibre is the max load it can take before it breaks