#3: Carbohydrates

Question 1

Function

Answer 1

Short and long term energy, structural support, surface markers (cell communication)

Question 2

Structure

Answer 2

Simple sugar molecules

Contain hydrocarbon chain, hydroxyl group, carbonyl group

Molecules may be linear or ring structure

Question 3

Monosaccharides

Answer 3

Only one simple sugar molecule

Have many polar functional groups, so highly soluble in water

Five or more Carbons - linear in dry state and ring structure when dissolved in water

Quick source of energy

Question 4

Glucose (mono)

Answer 4

Hexose (6 carbon)

Various forms:

1. Linear/ring
2. Alpha helix or beta
3. D or L

Question 5

Alpha helix and beta glucose

Answer 5

Geometrical stereoisomers - atoms bonded in same way but with different arrangement

Have different properties

Question 6

D and L-glucose

Answer 6

Optical stereoisomers - mirror images of each other

All life uses D-glucose

Question 7

Galactose (mono)

Answer 7

Hexose

Geometrical stereoisomers

Question 8

Fructose (mono)

Answer 8

Hexose

Structural isomers -same molecular formula but atoms bonded differently

Question 9

Ribose (mono)

Answer 9

Pentose

Question 10

Disaccharides

Answer 10

2 sugars

Formed via condensation reaction between simple sugar molecules through GLYCOSIDIC LINKAGE

Question 11

Maltose (di)

Answer 11

Formed between two alpha helix D-glucose molecules

Bond between molecules called alpha helix 1-4 glycosidic linkage

Question 12

Sucrose (di)

Answer 12

Formed between alpha helix D-glucose and alpha helix D-fructose molecule

Bond called alpha helix 1-2 glycosidic linkage

Question 13

Oligosaccharides

Answer 13

3-9 sugar molecules

Found on plasma membrane -play role in cell-to-cell recognition/communication

Question 14

Polysaccharides

Answer 14

Many simple sugar molecules

Used in plants and animals for long term energy and structural support

Very polar but too big to dissolve
Less functional groups so less sweet

Question 15

Glycogen (poly)

Answer 15

Used by animals for long term energy

Formed from linked alpha helix D-glucose molecule

Branched

Main chain: alpha helix 1-4 glycosidic linkage
Branches: alpha helix 1-6 glycosidic linkage

Question 16

Starch (poly)

Answer 16

Used by plants for energy

Formed from linked alpha helix D-glucose molecules

Two Types:

1. Amylose (straight)- contain alpha helix 1-4 glycosidic linkage
2. Amylopectin (branched)- contains alpha helix 1-4 and 1-6 glycosidic linkages

Question 17

Cellulose (poly)

Answer 17

Used by plant for structural support

Formed from linked beta D-glucose molecule

Not branched

Consists of beta 1-4 glycosidic linkage
(Cannot be broken by human enzymes)

Held together by H-bonds

Question 18

Chitin (poly)

Answer 18

Used by insects, crustaceans, fungi for structural support

Formed from linked N-acetylglucosamine molecules

Increased H-bonds=stronger molecule

Question 19

Monomer

Answer 19

Small molecules that bing chemically to other molecules

Question 20

Polymer

Answer 20

Large molecule that is formed when monomers link together in a chain