Created @December 6, 2022 1:01 PM
Reviewed
biochemistry 1
, link reaction (decarboxylation) is irreversible which is why you can’t make
glucose from fats
Molecules of life
biochemistry 2
, outline the chemical features and properties of the four main classes of
biological molecules (carbohydrates, lipids, nucleic acids and proteins), and
recognise that complex biological macromolecules are composed of smaller
biomolecules.
carbohydrates
properties = nxCH2O, carbonyl (C=O) and hydroxyl (OH) groups,
hydrophilic, polar, water soluble, can be modified with lipids/proteins
monomer = monosaccharide
bonds = glycosidic > di/oligo/polysaccharides
role = energy source/storage, surface recognition molecules
lipids
properties = water insoluble, hydrophobic, organic soluble, melting point
determined by fatty acids (FAs), amphipathic = bilayer
monomer = FA = hydrophilic carboxyl head and hydrophobic CH tail,
varying length and saturation
bonds = ester bond between FAs and glycerol/phosphate with hydrophilic
head
role = energy storage (triacylglycerol droplets), membrane bilayer
(glycerophospholipids), steroid hormones (fused alkyl rings), cholesterol
(steroid, fluidity of membrane)
nucleic acids
monomer = nucleotides: pentose sugar, nitrogenous base
(pyrimidine/purine), phosphate
bonds = phosphodiester and hydrogen (h) bonds > RNA/DNA
role = info carrier, energy carrier eg. ATP (phosphoanhydride bonds)
proteins
monomer = amino acids (AAs): 20, water soluble, differ in R groups
bonds = peptide bonds > polypeptide/protein
biochemistry 3
, role = mechanical, transport, enzymes
distinguish aldose and ketose sugars and explain the formation of ring
structures of monosaccharides
aldose - aldehyde H-C=O group eg. glyceraldehyde 3C, ribose 5C,
glucose 6C
ketoses - ketone C=O eg. dihydroxyacetone 3C, ribulose 5C, fructose 6C
ring - 5/6C chains spontaneously form rings in aqueous = carbonyl reacts
with hydroxyl
distinguish isomeric forms of glucose: enantiomers, anomers and epimers
enantiomers = optical isomers, complete mirror eg. D/L glucose (natural -
D glucose - dextrose)
anomers = ring stereoisomers, differ around one anomeric carbon C1 (O
on either side, from carbonyl) eg. a-D glucose and b-D glucose, can flip
when free in solution
epimers = different arrangement of one OH group not on anomeric C eg. D
glucose and D galactose
structural isomers eg. glucose and fructose
recognise and name correctly α and β glycosidic bonds in disaccharides and
polysaccharides
alpha glucose - OH on bottom (when writing ‘a ‘pen goes down)
beta glucose - OH on top (when writing ‘’ pen goes up)
glycosidic bond fixes in a/b form
glycogen = a1,4 and a1,6, to branch
draw the chemical structure of a representative amino acid (alanine) and a
peptide bond between two amino acid residues
amino group/n terminus on left, carboxyl/c terminus on right (see
diagrams)
explain how amino acids are grouped according to the characteristics of their
side chains
biochemistry 4