2: Biochemistry of Molecules

Question 1

molecular formula

Answer 1

tells us type and number of atoms
shows molecular weight

Question 2

polar molecules

Answer 2

carbon hydrogen bonds not soluble so long carbon chains not soluble
polar bonds don’t always equal solubility, its overall balance of molecule

Question 3

drawing molecules

Answer 3

method 1 = remove showing CH bonds
method 2 = shows only skeleton of carbon chains, no letters implies carbon is bonded to 4 hydrogen

Question 4

drawing 3D molecules

Answer 4

straight line = normal bond
wedged line = anterior
dashed line = posterior

Question 5

isomerism

Answer 5

isomers = compounds with same molecular formula but different molecular structures

Question 6

structural isomers

Answer 6

have same component atoms but arranged differently

chain isomers = chain of carbon atoms is arranged differently

position isomers = location of functional groups is different

function group isomers = different functional groups present

Question 7

stereoisomers

Answer 7

differ in spatial configuration

geometric isomers = differ in spatial arrangement of atoms or groups on either side of a fixed chemical bond, typical across carbon-carbon double bond, cis or trans formation

optical isomers = compounds with same chemical structure but are non-superimposable mirror images of each other

Question 8

carbohydrates

Answer 8

carbon hydrogen and oxygen bonded
monosaccharides = 1 molecule of carbohydrate e.g. glucose, fructose, and galactose
condensation reaction occurs (loss of H2O) to form disaccharide
oligosaccharides = 3-10 molecules
polysaccharides = >10 molecules e.g. glycogen

Question 9

lipids

Answer 9

simplest forms are made up of fatty acids compounds
triglycerides = glycerol with 3 fatty acids bonded
bond via condensation reaction
saturated = single carbon-carbon bonds
unsaturated = double carbon-carbon bonds = harder to break down

Question 10

amino acids

Answer 10

20 genetically encoded amino acids encoded in our DNA which has 3 letter codes
peptide bond = condensation reaction between carboxyl and amine groups on the end of amino acid chains
dipeptide = two amino acids
polypeptide = more than two

Question 11

proteins

Answer 11

proteins = long chains of amino acids known as polypeptides

primary structure = determined by the amino acid sequence

secondary structure = formed by alpha helix (left or right hand turn) or beta sheet (parallel or anti-parallel)

tertiary structure = formed by the presence of intermolecular forces

quaternary structure = influenced by the interaction of multiple polypeptide/protein units