Biological molecules: Proteins

Describe protein + function

Describe protein + function

contain carbon , hydrogen, nitrogen, sometimes sulfur

polymers of the monomer amino acids

A SEQUENCE OF AMINO ACIDS IN A POLYPEPTIDE CHAIN WITH PEPTIDE BONDS

structural support, biochemical catalysts

hormones

enzymes

building blocks

initiators of cellular death

How many types of amino acid are there

20

Draw the general structure of and label an amino acid

What kind of reaction to form a dipeptide?

Condensation reaction

Draw a dipeptide

Peptide bond

Amide, covalent, chemical bond between consecutive alpha-amino acids

Primary structure of protein

Type, number, and sequence of amino acids in a polypeptide chain, with peptide bonds

Secondary protein structure

coiling and folding of polypeptide chain

forms alpha helix (coil)

or beta pleated sheet: two or more parts run parallel to eachother, linked by hydrogen bonds

tertiary protein structure

twisted and folded further to produce specific 3D shape. either globular or fibrous

Determined by r group

H bond between R groups (not strong, but lots)

Ionic bonds between amino +, - groups. easily broken

Disulphide bridges: amino acids w/ r groups, strong covalent

Quaternary structure

2 or more polypeptide chains bonded together (same bond types as tertiary) to form functional proteins

eg. haemoglobin, antibodies

Describe globular proteins

metabolic functions eg enzymes, hormones

tertiary or quaternary

specific 3D shape

soluble - polar R groups on outside (hydrophilic)

Describe fibrous proteins

Structural function eg keratin in hair, collagen in connective tissue

Maybe quaternary

individual polypeptide chains have secondary protein structure

insoluble - non polar r groups on outside of molecule - hydrophobic