protein Flashcards
What is an amino acid?
The monomers from which proteins are made
How many different amino acids are there in all living organisms?
20
What are dipeptides?
2 amino acids joined together
What are polypeptides?
many amino acids joined together
What type of bonds are formed by condensation polymerisation in Proteins?
Peptide bonds
Draw the general structure of an amino acid
Amino group (alkali/basic group) NH² [above]
Carboxyll group (acidic group) COOH [below]
Central carbon atom
H [right]
R group [left]
How do peptide bonds form?
H from amino group
OH from carboxyll group
Name the 4 different structural levels of a protein
Primary (1⁰)
Secondary (2⁰)
Tertiary (3⁰)
Quaternary (4⁰)
What is the primary structure of a protein?
A sequence of amino acids in a polypeptide chain joined by peptide bonds
What is the secondary structure of a protein? [2]
- Hydrogen bonds are formed between amino acids at different points in the chain
- Causes polypeptide chain to fold into a-helix or ß-pleated sheet
What is the tertiary structure of a protein?
- 3D structure of polypeptide held together by hydrogen bonds / ionic bonds / disulphide bridges / van der Wall’s forces
Hydrogen Bonds
1 hydrogen bond = weak
many hydrogen bonds = strong
Can be broken by…
- High Temp
- Altered pH
Ionic Bonds
Can be broken by…
- altered pH
Disulphide Bridges
Covalent
Can be broken by…
- reducing agents
van der Wall’s forces
Weak forces of attraction
between non-polar groups
Can be broken by…
- High Temp
What is the quaternary structure of a protein? [2]
- complex molecules containing many polypeptide chains
- soluble in water
What are Fiberouse Proteins
- Triple helix of polypeptide chains
- have 1⁰, 2⁰, 3⁰, 4⁰ structure
- Insoluble in water
