Biochemistry of Molcules

Question 1

isomerism

Answer 1

compounds which have the same molecular formula but different molecular structures
structural + sterioisomers

Question 2

structural isomers

Answer 2

same compoment atoms but arranged differently
can be; chain, position and functional group isomers

Question 3

chain isomers

Answer 3

same molecular formula but chain of carbon atoms present is arranged differently between isomers
usually occurs in the presence of 1 or more side chain
eg saturated fatty acid

Question 4

position isomers

Answer 4

same carbon skeleton and fucntional groups
location of functional groups on carbon skeleton differs
could be bonding structure or a group of atoms

Question 5

functional group isomers

Answer 5

different functional groups present between molecules with same molecular formula
changes in functional group will change function of the compound

Question 6

sterioisomers

Answer 6

compounds that differ in spatial configuration
have same formation of bonds but 3D structure is different
can be; geometric or optical

Question 7

geometric isomers

Answer 7

compounds that have same number/type of atoms and fundamental layout
different spatial arrangement of atoms or groups on either side of fixed chemical bond (rotation can occur)
eg across C C bonds- double bonds fixed, free rotation around single

can be in cis or trans formation
cis= r groups on same side of C C bond (below)
trans= r groups on opposite sides of C C bond

Question 8

optical isomers

Answer 8

compounds with same chemical structure that are non superimposable mirror images of eachother
4 unique r groups bonded to carbon atom
chiral compounds
chiral- different groups on either side of plane
achiral- same groups on either side of plane
two compounds that are optical isomers of eachother are called enantiomers
this changes chemical properties

Question 9

monosaccharides

Answer 9

functions in cellular energy production and building nucleic acids
sugars in their smallest form
glucose, fructose, galactose

Question 10

disaccharides

Answer 10

condensation reaction occurs forming a glycosidic bond between monosaccharides
loss of water

Question 11

larger carbohydrates

Answer 11

oligosaccharides- chain of 3-10 monosaccharides
polysaccharides are long chains of monosaccharides

Question 12

lipids

Answer 12

group of chemicals- mostly insoluble in water
can be liquid (oil) or solid (wax) form
essential nutrient for biological function
used in energy production at low to medium intensity exercise (fat oxidation)
main constitutional of cell walls and deposits of fats around organs for protection

Question 13

lipid structure

Answer 13

simplest forms made up as fatty acid compounds
organic chains with carboxyl functional groups

Question 14

triglycerides

Answer 14

glycerol backbone and three bonded fatty acids (triacylglycerols)
fatty acids bond to glycerol by a condensation reaction (carboxyl to hydroxyl group)
make up main constituent of body fat
saturated= c-c or unsaturated- c=c
c=c can be cis or trans

Question 15

amino acids

Answer 15

20 genetically encoded in dna
proteinogenic amino acids
proteins made up of long chain a amino acids joined by peptide bonds (N terminus to C terminus)
amine group- NH2
side chain- R group
carboxyl group- COOH

Question 16

peptide bond

Answer 16

formed via condensation reaction between carboxyl and amine groups
can include two amino acids or more
proteins are complex polypeptide structures

Question 17

primary structure

Answer 17

amino acids sequence
written from N to C terminus

Question 18

secondary structure

Answer 18

local structural features- commonly observed motifs forming regular repeats
alpha helix, beta sheets
formed by interactions between neighbouring molecules (hydrogen bonds)

Question 19

alpha helix

Answer 19

each C=o forms hydorgen bond with amine H (4) between carboxyl and amine groups
helix turns right handed (clockwise)

Question 20

beta sheet

Answer 20

angular conformation of peptide chain causes zig zag shape
backbone can form hydrogen bonds between each segment
can be antiparallel or parallel
sidechains project alternately above and below the sheet

Question 21

tertiary structure

Answer 21

overall protein conformation caused by side chain interactions- folding of poly chain into 3d shapes
many a helix and b sheets twisted around eachother
3d shape is influenced by intermolecular forces and hydrophobicity
ionic bonds, disulphide bridges, hydrogen bonds

Question 22

quaternary structure

Answer 22

made up a number of subunits
two or more chains
structure refers to the way in which four subunits interact with eachother
arrangement due to intermolecular forces

Question 23

interactions in protein structure

Answer 23

combination of many interactions (covalent and non covalent) responsible for different levels of structure
electrostatic, π- π stacking, hydrophobic , disulphide bridges, hydrogen bonding