Biological molecules-proteins Flashcards
What are 2 types of proteins?
Globular and Fibrous
What are globular proteins?
soluble proteins with a specific 3D shape e.g. enzymes, hormones,
antibodies, haemoglobin
What are fibrous proteins?
strong/insoluble/inflexible material e.g. collagen and keratin
What are the building blocks for proteins?
amino acids
Structure of amino acid?
central carbon, carboxyl group (COOH), amine group t (NH2), hydrogen and R group
How do amino acids differ?
have different R groups e.g. glycine has a hydrogen in its R group –
simplest amino acid
How are amino acids joined together?
by condensation reaction between the carboxyl group of one and amine group of another, leaves a bond between carbon & nitrogen (called a peptide bond) forming a
dipeptide
Define primary, secondary, tertiary, quaternary structure?
Primary = sequence of AA, polypeptide chain (held by peptide bonds)
Secondary = the primary structure (polypeptide chain) coils to form a helix, held by hydrogen bonds
Tertiary = secondary structure folds again to form final 3d shape, held together by hydrogen/ionic/disulfide bonds
Quaternary = made of more then one polypeptide chain
Examples of quaternary structure proteins?
collagen (3 chains), antibodies (3 chains),
haemoglobin (4 chains)
Structure of collagen?
strong material, used to build tendons/ligaments/connective tissues
primary structure mainly made up of glycine (simplest amino acid)
secondary structure forms a tight coil (not much branching due to glycine)
tertiary structure coils again
quaternary structure made from 3 tertiary structures wrapped around each other like rope
= a collagen molecule
many of these collagen molecules make the tendons/ligaments/connective tissues
Test for protein?
add biuret, turns purple
