Module 2 - Biological molecules

Question 1

Carbohydrates

Answer 1

store energy and provide structural support for plants, they are classified into 3 groups, they all contain carbon, hydrogen and oxygen

Question 2

Monosaccharides

Answer 2

large carbs like sucrose and starch are made of monosaccharides like glucose, galactose and fructose. Thye are water soluble and can be energy sources or building blocks for other molecules

Question 3

Disaccharides and polysaccharides

Answer 3

D: maltose, sucrose and lactose
P: starch, glycogen and cellulose

Question 4

Glucose (C6H12O6)

Answer 4

provides energy, forms cellulose, energy storage

Question 5

Isomers of glucose

Answer 5

Alpha and beta, they have the same formula but different atom arrangements, this impacts bonding and final structures they form

Question 6

Monomers

Answer 6

small, single units that act as building blocks to create larger molecules. They bond via condensation reactions

Question 7

Polymers

Answer 7

composed of many monomers

Question 8

Disaccharides

Answer 8

formed from 2 monosaccharides by a glycosidic bond formed during condensation reactions. They can be broken down back to monomers via hydrolysis

Question 9

Reducing sugar test

Answer 9

Benedict’s solution is added which has Cu2+ that sugars can reduce (reducing sugar), forms copper oxide which leaves a brick red precipitate

Question 10

Non-reducing sugar test

Answer 10

Like sucrose which cannot reduce Cu2+, they glycosidic bond must be hydrolysed to expose reducing group (complete reducing sugar test after)

Question 11

Polysaccharides

Answer 11

polymers made of monomers, created in a condensation reaction

Question 12

Starch

Answer 12

found in plants only, carbs store, made from excess glucose in photosynthesis. Its presence can be confirmed using iodine.
Structure: made of alpha glucose via condensation reactions help by 1-4 and 1-6 glycosidic bonds

Question 13

Amylose and amylopectin

Answer 13

Amylose: structure in glucose joined by 1-4 glycosidic bonds, spiral shaped. Allows for efficient compaction, large amounts can fit into small spaces
Amylopectin: mixed with 1-4 and 1-6 glycosidic bonds, branched shape. Large SA for enzymes to attach to so starch is readily hyrdolysed to glucose when plant cells are running low on glucose

Question 14

Properties of starch

Answer 14

insoluble due to large molecule size so can be stored in cells without dissolving so WP is not affected

Question 15

Glycogen (what’s it for, structure and properties)

Answer 15

found mainly in liver and muscle cells, created from excess glucose, used in respiration, reserve of energy
Structure: alpha glucose similar to amylopectin, joined by condensation reactions forming glycosidic bonds, highly branched
Properties: insoluble, large SA because it’s highly branched, hydrolysed quickly to glucose for energy, crucial for animals with high metabolic rate