molecular building blocks

Question 1

macromolecules

Answer 1

simple molecules can form complex, large molecules. They can have osmotic, structural, optic, enzymatic and other complex functions. They are very heterogeneous. E.g. Haemoglobin, DNA

Question 2

water

Answer 2

universal solvent, polarity, hydrogen bonding, liquid over a range of 0-100◦C, achieves maximum density at 4◦C. Excellent at dissolving ionic and polar compounds.
Water doesn’t interact with non-polar substances, lipids, aromatic groups and hydrophobic compounds

Question 3

hydrogen bond

Answer 3

electronegative atoms such as oxygen, nitrogen can attract hydrogen atoms from other molecules, partial sharing of proton leads to an attraction, weak, responsible for unusual properties of H2O.

Question 4

carbohydrates

Answer 4

• Cn(H2O)n
• Monosaccharide, disaccharides ect.
• Monosaccharide – chain of carbons, hydroxyl groups, one carbonyl group
• Cyclized (ring) structures- by the reaction of the aldehyde or ketone group with a hydroxyl group of the same molecule
• Sugar derivative – aminosugars (contain amino group), alcohol-sugars, phosphorylated, sulphated
• Glycosidic bond- hydroxyl group of a monosaccharide can react with an OH or an NH group to form glycosides (O-glycosidic bonds form disaccharides, N-glycosidic bonds are found in nucleotides and DNA)
• polysaccharides – starch, glycogen, proteoglycans (long, unbranched PS radiating from a core protein)
• Sulphated (glycosaminoglycans): sulphate groups e.g. heparin

Question 5

lipids

Answer 5

• Straight C chains with a methyl group and a carboxyl group at the ends
• Melting point decreases with a degree of unsaturation (fluidity)
• Can be saturated or unsaturated
• Phosphoacylglycerols: derived from phosphatidic acid. Formed from fatty acids esterified to glycerol and phosphorylated
• Sphingolipids: derive from ceramide

Question 6

nucleotides

Answer 6

• Nitrogenous base + sugar + phosphate
• Ester bond
• Nucleotide polymers can form using phosphodiester bonds

Question 7

Eicosanoids

Answer 7

synthesised from 20 C atoms (cause inflammation)

Question 8

amino acids

Answer 8

• Building blocks of proteins (20)
• Carbon with amino group, carboxyl group and side chain (R)
• Charge is determined by all three components
• Changes with the pH of the environment
• Side chain often determines polarity (hydrophilicity) or nonpolarity (hydrophobicity)
• Dissociation of amino groups – at different pH carboxyl and amino groups are ionised, some amino acids also have ionisable side chains
• Can be charged, neutral, aromatic
• Peptide bond – proteins are formed by aa linked by peptide bonds. Linear chains fold into different shapes to form 3D structures. Folding is determined by charged interactions, flexibility, and physical dimensions
• Proteins have structure-function relationship