3.1.4.1 Proteins Flashcards
What represents an amine group?
NH2
What represents a carboxyl group?
COOH
What represents a side chain/ variable group?
R
Condensation between two amino acids forms…
a peptide bond
Dipeptides are formed by…
condensation of two amino acids
Polypeptides are formed by…
condensation of many amino acids
How can you break apart a polypeptide?
-hydrolysis reaction
-requires water
Primary structure: what bonds does it contain?
peptide bonds
Primary structure: what varies?
-length of chain
-sequence of amino acids
Primary structure: what odes it control?
protein shape
Secondary structure: folding of parts of chain to form…
beta-pleated sheets or alpha helices
Secondary structure: what bonds does it contain?
hydrogen bonding (between carboxyl and amino residues)
Tertiary structure: what causes the folding of a tertiary strcuture?
intermolecular forces between R groups
Tertiary structure: Hydrogen bonds
between polar R groups
Tertiary structure: Ionic forces
between positive and negative R groups
Tertiary structure: disulphide bridges
covalent bond between cysteine R groups
Tertiary structure: London forces
between non-polar R groups
Quaternary structure: how does it hold polypeptide chains together?
due to intermolecular forces between R groups
How do you test for proteins?
-Biuret test
-colour change from blue —-> purple
Why do weak Hydrogen bons form in the secondary structure?
-H in NH has a slightly positive charge
-O in C–O has a slightly negative charge
Globular proteins are…
compact
Fibrous proteins are…
long and can form fibres
