Macromolecules: Chemicals of Life

Question 1

Macromolecules

Answer 1

relatively large organic molecules (organic = complex, associated/produced by living things, contain C)
four main macromolecules:
carbohydrates
lipids
proteins 
nucleic acids

Question 2

Carbohydrates/Polysaccharides

Answer 2

subunit = monosaccharides (soluble) eg. glucose, fructose, disaccharides (soluble), polysaccharides (insoluble)
contain C, H, O
common polysaccharides:
- energy storage:
…in plants = starch
…in animals = glycogen
- structural unit of cell walls
…in plant cell walls = cellulose
…in some fungi, arthropod exoskeleton = chitin
…fungal phyla cell wall (C,H,O,N) = chitosan

Question 3

Lipids (fats & oils)

Answer 3

subunit = three fatty acids + one glycerol backbone
contain C, H, O (different proportions)
phospholipids = modified lipids, structural component of cells (2 fatty acids, glycerol, phosphate, ethanolamine)
fats & oils contribute to energy storage (2x energy density as carbs), insulation, protection of some body tissues

Question 4

Proteins

Answer 4

1+polypeptide chain, subunit = amino acids (20 types)
contain C, H, O, N, sometimes S
sequence of amino acids determines shape, therefore function of protein
Primary structure = number and sequence of amino acids
Secondary = coiling/folding of chain due to H-bonds (alpha helical/beta sheet)
Tertiary = 3D structure (important for binding)
Quarternary = 3D shape of 2+ chains, one protein

Question 5

Functions of Proteins (SSCCTED)

Answer 5

SSCCTED

1. Structural: hair skin, nails, cell membrane (channel proteins, receptor molecules)
2. Enzymes: 3D shape important
3. Contraction: fibres in muscles
4. Transport: haemoglobin carrying O
5. Defence: antibodies
6. Coordination: hormones/receptors to hormones
7. Storage: albumin in eggs

Question 6

Nucleic Acids

Answer 6

contain C,H,O,N,P
subunit = nucleotides (sugar, phosphate group, nitrogen base)
RNA (ribonucleic acid) - single strand A-U, G-C
DNA (deoxyribonucleic acid) - double strand helix (complementary base pairing) A-T, G-C