Proteins Flashcards
What is an amino acid?
The monomer that makes up polypeptides.
Give the structural formula of an amino acid.
NH2CRHCOOH
What is a variable R group?
A carbon chain that varies in length.
Describe how 2 amino acids join together.
What are the end products?
A condensation reaction occurs, forming the peptide bond and eliminating a water molecule. This means a dipeptide has formed.
What is a polypeptide?
Several amino acids held together by many peptide bonds.
Give the atoms involved in a peptide bond.
C=O N-H
Describe the primary structure of a polypeptide.
What bonds are present?
A simple chain of amino acids.
Held by peptide bonds.
Name both types of secondary protein structure.
What bonds are present, and in between which atoms?
Alpha helix.
Beta pleated sheet.
Hydrogen bonding between carbonyl O in one amino acid, to the H in another amino acid.
Describe the tertiary structure of a protein.
The overall, fully folded 3D structure of a polypeptide.
Name the 3 bonds found in the tertiary protein structure.
Ionic bonds
Disulfide bridges
Hydrogen bonds
How is the tertiary protein structure held together?
By interactions between the amino acid side chains.
Describe the quaternary protein structure.
Several polypeptide chains joined together.
Name the 3 bonds found in the quaternary protein structure.
Ionic bonds
Hydrogen bonds
Disulfide bridges
Describe how to test for proteins.
Add biuret solution.
Presence of a protein causes colour change from blue to purple.
What does biuret solution detect?
Peptide bonds ,meaning that it will not show a positive result if amino acids are present.
