MULT10011 Lecture Notes - Lecture 4: Endergonic Reaction, Hydrophile, Peptide
L.E.U – Lecture 4
Proteins and enzymes, tree of life, prokaryotes
Amino acids
• Building blocks of protein (20)
• Each amino acid has four groups bonded to a central carbon atom
o Acid (COOH)
o H2N (amine)
o H proton
o R group – each amino acid has a different R group that differentiates the
amino acids
R Groups
• Some are polar but uncharged (hydrophilic)
• Some are charged (hydrophilic)
• Some are non-polar (hydrophobic)
• Some form rings
Protein
• Formed by joining amino acids – always linear chain
• Peptide bonds between amino acids – polypeptide chain
• Variable length and order of amino acids gives almost infinite possibilities
• Each protein has a unique 3D shape
Ribosomes
• Synthesis of proteins is done by ribosomes using info from the gene
• All cells have them
• Made of several proteins and RNAs
• Site of translation (from mRNA to protein sequence)
• Bacterial ribosomes are small and are different to eukaryotic ribosomes
Enzymes
• Catalysts – speed up reatios ut dot get used up
• Typically proteins
• Do not alter final equilibrium of reaction
• Recyclable
• Regulated
Coupling of reactions
• Cell chemistry largely achieved by coupling endergonic (requires energy) reactions
with exergonic (releases energy)
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