Biomolecules

Question 1

List the four classes of macromolecules.

Answer 1

Carbohydrates
Lipids (phospholipids, glycolipids, cholesterol & steroids)
Proteins
Nucleic acids

Question 2

Condensation

Answer 2

Glycosidic bond formed between 2 monosaccharides in a condensation reaction
2 hydroxyl groups;
1 contribute OH other contribute H
loss of H2O molecule

Question 3

Hydrolysis

Answer 3

Polymers disassembled to monomers, glycosidic bond broken by addition of H2O molecule

Question 4

Disaccharide

Answer 4

Formed by 2 monosaccharides joined by glycosidic bond

Question 5

Glucose structure & properties

Answer 5

Hexose sugar, C6H12O6
α-glucose OH above right most C1, no alternating

β-glucose OH below right most C1, ALTERNATES

Soluble in water
- Small molecular size
- polar OH grps, form H bond w. H2O
Reducing sugar -> aldehyde grp

Question 6

How is starch & glycogen designed for energy storage

Answer 6

1. LARGE in size
- insoluble in water
-> Stored in large qty, w/o affecting H2O potential of cells, do not diffuse out of cell

2. Highly folded & COMPACT
- >Many glucose residues stored in a small vol.

3. Highly branched,
- increases no. of terminal ends for enzymes to bind to (glycogen)
-> faster hydrolysis at each branch end
-> Allows glucose to be released at a fast rate for oxidation during respiration

Question 7

What is starch made up of

Answer 7

mixture of amylose (α1,4) & amylopectin (α1,4 & α1,6)

Question 8

Amylose VS Amylopectin

Answer 8

Amylose VS amylopectin
300α monomers| 1200-1500
109° between C-O bonds forming helices|
Branched chain polymer, coils into helix, branch points α1,6 every 24-30 residues

Question 9

What is the structure of glycogen?

Answer 9

Linked by α-1,4-glycosidic bonds and α-1,6-
- More extensive branching as compared to amylopectin, resulting in a more compact structure.
- Coils into a helical, compact structure stabilised by H bonds

Question 10

Structure of cellulose?

Answer 10

Long straight chains
β-1,4 glycosidic bonds
Adj. molq rotated 180°
Straight chain run parallel w. numerous H bonds forming crosslinks
- cellulose chains -> microfibrils -> (bundle tgt) macrofibril -> lattice (parallel each layer, angled in others)
- Results in high tensile strength

Question 11

property, function of cellulose

Answer 11

High tensile strength
- Provides mechanical strength to cell wall
- prevents cell lysis, due to osmosis

Large hence insoluble