Carbon atoms bond strongly to each other forming chains and rings
Carbohydrates include monosaccharides, disaccharides and polysaccharides
Monosaccharides include glucose, fructose and galactose (have same chemical formula but different chemical structures - isomers)
Monosaccharides can become linked together by a glycosidic bond to form disaccharides e.g. maltose, sucrose, lactose and polysaccharides e.g. starch, cellulose
Polysaccharides can perform structural roles e.g. cellulose in plant cells and energy storage roles e.g. starch in plants and animals
Lipids are composed of carbon, hydrogen and oxygen (non-polar and insoluble in water)
Lipids used as energystores, insulation and protection e.g. cell-membrane structure inc. fats oils, phospholipids, waxes and steroids
1 of 6
Biological Molecules pt.2
Fats and oils are condensation products of fattyacids and glycerol
Fatty acids have varying length hydrocarbon tails (also unsaturated or saturated)
Phospholipids similar to triglycerides but a phosphate replaces a fatty acid
Proteins are condensation polymers of up to 20 different amino acids, have many functions e.g. enzymes, hormones, antibodies, transport, structural
Amino acids have amino group, carboxyl group and a differing R group
Amino acids linked by peptidebonds as a result of condensation reactions
2 of 6
Biological Molecules pt.3
PRIMARY STRUCTURE = sequence of amino acids
SECONDARY STRUCTURE = arrangement of polypeptide chain into a helix orpleated sheet
TERTIARY STRUCTURE = folding of secondary structure to give 3D shape
QUATERNERARY STRUCTURE = association of 2 or more polypeptide chains to give protein
Fibrous proteins e.g. collagen, kertatin, elastin form tough fibres that give support
Globular proteins e.g. enzymes, antibodies, hormones are involved in cellular reactions
Water is a fundamental biological molecule - is an important slovent, involved in biochemical reactions and temperature regulation
3 of 6
Enzymes
Globular proteins, properties relates to tertiary strucutre
Speed up the rate of eactions by lowering activation energy
Combines complementary substrate to form an ENZYME-SUBSTRATE COMPLEX
Specific because they only act on a particular substrate
Unchanged after reaction so can be re-used
Temp, pH and conc of reactants affect rate of enzyme-catalysed reaction
Can be prevented from working by competitive and non-competitive inhibitors
4 of 6
Enzymes
Globular proteins, properties relates to tertiary strucutre
Speed up the rate of eactions by lowering activation energy
Combines complementary substrate to form an ENZYME-SUBSTRATE COMPLEX
Specific because they only act on a particular substrate
Unchanged after reaction so can be re-used
Temp, pH and conc of reactants affect rate of enzyme-catalysed reaction
Can be prevented from working by competitive and non-competitive inhibitors
5 of 6
Nucleic Acids and Protein Synthesis
Chromosomes made of long, super-coiled strand of DNA
Gene codes for the production of a particular protein
DNA molecule is a double helix with COMPLEMETARY BASE PAIRING
Sequence of bases = genetic code read off in base triplets (codons)
Each codon codes for particular amino acid
Able to make new DNA by semi-conservative replication
DNA can make mRNA by transcription (carries coded info from DNA to ribosomes)
tRNA carries specific amino acids to the ribosomes to be assembled into protein
Comments
No comments have yet been made