Topic 4

Question 1

Chloroplast

Answer 1

Where the process of photosynthesis takes place

Question 2

Amyloplast

Answer 2

Stores starch grains

Question 3

Tonoplast (vacuolar membrane)

Answer 3

Separates the contents of the cytoplasm from the contents of the vacuole

Question 4

Plasmodesma

Answer 4

Strands of cytoplasm going from one cell to another for transfer of substances between two adjacent cells

Question 5

Cell wall

Answer 5

Strength and support

Question 6

Differences between animal cell and plant cell

Answer 6

-plant cells contain chloroplasts, animals do not
-plant cells contain a cell wall, animals do not
-animal cells contain centrioles, plant cells do not

Question 7

Function of cellulose

Answer 7

Structural component of plant cell walls to provide strength and support

Question 8

Is cellulose made of alpha or beta glucose

Answer 8

Beta

Question 9

Type of bond that joins two beta glucose molecules

Answer 9

beta 1,4 glycosidic bond

Question 10

Type of reaction that joins two beta glucose molecules

Answer 10

Condensation reaction

Question 11

Every alternate beta glucose is…

Answer 11

inverted

Question 12

Is cellulose branched or unbranched

Answer 12

Unbranched

Question 13

Describe the structure of a cellulose microfibril

Answer 13

Many beta glucoses joined by beta 1,4 glycosidic bonds in condensation reaction with every alternate glucose molecule inverted forming a straight chain cellulose molecule
60-70 cellulose molecules lie parallel to each other and are cross linked and held together by hydrogen bonds between adjacent cellulose molecules

Question 14

What else besides cellulose molecules forms the primary plant cell wall

Answer 14

Hemicelluloses and pectins (short branched polysaccharides)

Question 15

What is added to form the secondary plant cell wall

Answer 15

Lignin

Question 16

Difference between alpha glucose and beta glucose

Answer 16

In beta glucose the hydroxyl groups on the first carbon atoms are on opposite sides

Question 17

Xylem vessels structure

Answer 17

Cellulose microfibrils in cell walls
Walls thickened with lignin
Continuous column made of hollow, dead cells, with no end walls and no cell contents
Have pits in their walls
Vessels have open ends

Question 18

Phloem structure

Answer 18

Has cellulose cell wall
Sieve tube elements have thin peripheral cytoplasm and very few organelles
Have sieve plates with sieve pores
A companion cell is linked to each sieve tube element by plasmodesmata
Living tissue

Question 19

Sclerenchyma fibres structure

Answer 19

Fibres have cellulose cell walls which are thickly lignified
Dead and hollow cells when mature
Often have lignin in their walls
Long narrow and usually pointed at both ends

Question 20

Xylem vessels function

Answer 20

Transport of water and dissolved mineral ions from roots to leaves
Structural support

Question 21

Phloem function

Answer 21

Transport of organic solutes (sucrose and amino acids from source to sink via translocation)

Question 22

Sclerenchyma fibres function

Answer 22

Structural support

Question 23

Function of lignin

Answer 23

Provides strength to prevent vessel from collapsing also makes the vessel waterproof

Question 24

Cohesion

Answer 24

Hydrogen bonding between n polar water molecules

Question 25

Adhesion

Answer 25

Hydrogen bonding between water and cellulose in xylem walls