4B: resources from plants

Question 1

role of the cell wall

Answer 1

supports the plant cell

Question 1

what is a cell wall

Answer 1

rigid structure that’s surrounds plane cell - made of cellulose

Question 2

what is the middle lamella

Answer 2

the outermost layer of the cell

Question 3

role of the middle lamella

Answer 3

acts like an adhesive, sticking adjacent plant cells together and gives the cell stability

Question 4

what is the plasmodesmata

Answer 4

channels in the cell walls that link adjacent cells together

Question 5

role of the plasmodesmata

Answer 5

allows transport of substances and communication between cells

Question 6

what is pits in a plant cell

Answer 6

regions of the cell wall that are very thin - paired up with adjacent cell so that the pits line up with eachother

Question 7

role of the pits in plant cells

Answer 7

allows transport of substances between cells

Question 8

what are chloroplasts

Answer 8

a small flattened structure with a double membrane which contains membranes inside it aswell. The membranes are stacked to form grana. Filled with a thick fluid called stroma

Question 9

role of chloroplast

Answer 9

the site where photosynthesis takes place - some of the process take place in the grana & some in the stroma

Question 10

what are amyloplasts

Answer 10

a small organelle enclosed by a membrane - contains starch granules

Question 11

role of amyloplasts

Answer 11

storage of starch grains - convert starch back to glucose for release

Question 12

what is the vacuole and tonoplast

Answer 12

the vacuole is a compartment surrounded by the membrane called the tonoplast

Question 13

role of the vacuole and the tonoplast

Answer 13

vacuole: contains cell sap - keeps cell turgid, involved in breakdown and isolation of unwanted chemicals in the cell

tonoplast: controls what enters and leaves the vacuole

Question 14

what is cellulose

Answer 14

a polysaccharide made of beta glucose

Question 15

what is the structure of cellulose

Answer 15

long unbranched chain of beta glucose with 1-4 glycosidic bonds
cellulose chains are linked together with hydrogen bonds to form strong threads called microfibrils which help provide structural support

Question 16

function of cellulose in a plant cell wall

Answer 16

• prove structural support for the cell
• allows substances to pass in and out of cell freely
• gives the cell shape

Question 17

what features makes plant fibres strong

Answer 17

• the arrangement of cellulose microfibrils in the cell walls
• the secondary thickening of a cell wall

Question 18

how does the arrangement of cellulose microfibrils help make strong plant fibres

Answer 18

net like arrangement

Question 19

how does the secondary thickening of the cell wall help make strong plant fibres

Answer 19

between cell walls & cells membrane, a secondary cell wall forms
- has more lignin

Question 20

how can the arrangement of cellulose microfibrils and secondary cell wall thickening be explored by humans

Answer 20

due to being strong, they can be used for ropes and fabrics like hemp

Question 21

how does the arrangement of cellulose microfibrils and secondary wall thickening contribute to the physical properties of xylem & sclerenchyma

Answer 21

creates strong plant fibres due to lignin development - which helps with the strength of the vessels walls

Question 22

what is starch

Answer 22

the main energy source in plants (storage polysaccharide)

Question 23

what is starch made up of

Answer 23

2 alpha glucose polysaccharides
amylose & amylopectin

Question 24

what is the structure of amylose

Answer 24

long, unbranched chain of alpha glucose
- coiled
- compact

Question 25

what is the structure of amylopectin

Answer 25

long, branched chain of alpha glucose
- more compact than amylose

Question 26

what is the role of hydrogen bonds between the beta glucose sheets in the formation of glucose microfibils

Answer 26

link cellulose chains together to form strong threads which can be used practically for humans and to help provide structural support for the plant cell

Question 27

what is the function of the xylem

Answer 27

vessel used to transport water and mineral ions up from the roots to the leaves of a plant (transpiration)

Question 28

what is the function of the phloem

Answer 28

vessel used to bidirectly transfer organic solutes around the plant (translocation)

Question 29

what is the function of the sclerenchyma fibres

Answer 29

fibres that provide support to vessels

Question 30

what is the structure of the xylem

Answer 30

long tube formed from dead cells
- hollow lumen
- no end walls
- walls thickened by lignin

Question 31

what is the structure of the phloem

Answer 31

arranged in tubes

sieve cells
- living cells
- have holes in them to allow transport of solutes
- thin layer of cytoplasm
- no nucleus therefore have companion cells

Question 32

what is the structure of a sclerenchyma fibre

Answer 32

made of dead cells that run vertically up the stem of a plant
- hollow lumen
- have end walls
- have more cellulose
- strengthened w lignin