Carbohydrates

Question 1

What are monomers?

Answer 1

many identical or similar building blocks (monomers) linked covalently together

Question 2

What is a homopolymer?

Answer 2

identical monomers

Question 3

What is a heteropolymer?

Answer 3

different monomers branched or unbranched (linear)
biological polymers.

Question 4

What are condensation reactions for?

Answer 4

Formation of biomacromolecules

Question 5

What is hydrolysis for?

Answer 5

Degradation (digestion) of biomacromolecules

Question 6

What are the roles of carbohydrates

Answer 6

metabolism-sources of energy and carbon skeleton
structural- used by plants, microorganisms and some animals
cell recognition
protection- anti-freeze and anti-desiccation

Question 7

Formation of disaccharides?

Answer 7

Condensation reaction used to form a glycosidic link

Question 8

Uses of polymers with examples?

Answer 8

glycogen in animals used for storage

structural found in plant cell walls (cellulose)

arthropod exoskeletons (chitin)

Question 9

What does each branched polysaccharide have at the ends?

Answer 9

Each branch has 1 non-reducing end
Entire polymer has 1 reducing end

Question 10

What is Glycogen?

Answer 10

It is a storage polysaccharide that is branched
with a homopolymer of glucose.
(1→4) links
(1→6) links
glycogen granules have >100,000 glucose residues

Question 11

What is Glycogen: helical structure

Answer 11

Alpha-linkage and flexible chains
left-handed (anticlockwise) helix
with hydrogen bonding between adjacent residues stabilising the helix.

Question 12

Structural polysaccharides Chitin

Answer 12

Arthropod exoskeleton, insects, crustacea.
Found in fungal cell walls
(1->4) links.
Chitin is a linear homopolymer of N-acetylglucosamine.
It is a structural polysaccharide with a laminar structure stabilised by hydrogen bonds and hydrophobic interactions.

Question 13

What is the Chitin: laminar structure

Answer 13

Beta-linkage= rigid rod-like molecules
strong hydrogen bonding between adjacent sugar residues
acetamido group

Question 14

Chitin: structural interactions

Answer 14

parallel array
hydrogen bonds between adjacent molecules with a non-reducing end and a reducing end
The chitin stack and row interactions- extensive non-covalent bonding and its insoluble

Question 15

What are polyols?

Answer 15

They contain either an aldehyde or a ketone group and are sugar alcohols.

Question 16

What are reducing sugars?

Answer 16

Disaccharides in which one sugar residue can interconvert between linear and cyclic forms.

Question 17

What are diastereoisomers

Answer 17

stereoisomers not related as mirror images.

Question 18

What has supra-molecular complexes?

Answer 18

lipids (not all bound together just associated together) and these are involved in membranes

Question 19

aldose sugars
ketose sugars

Answer 19

They all have an aldehyde group
They all have a ketone group

Question 20

Glucose, fructose and their hemiacetal and hemiketal formations.

Answer 20

In aqueous solution glucose, fructose, and other sugars of five or six carbons rapidly interconvert between straight-chain and cyclic forms, the cyclic forms are intramolecular hemiacetals and hemiketals.
The cyclic form of glucose is a six-membered ring, with an intramolecular hemiacetal formed by attack of the hydroxl on the fifth carbon on the aldehyde carbon . This carbon is called the anomeric carbon. The cyclic form of glucose is called glucopyranose.
Fructose in solution forms a six-membered cyclic hemiketal called fructopyranose when the hydroxyl on C6 attacks the C2 ketone carbon.
In the formation of fructofuranose from open-chain fructose, the hydroxyl group on the fifth carbon attacks the ketone.