Proteins Flashcards
What is a protein/polypeptide?
A polymer made up of many amino acids joined together by peptide bonds
What are amino acids made from?
- Amine group (NH2)
- Carboxylic acid group (-COOH)
- R group (carbon containing chain)
How are dipeptides formed?
Through a condensation reaction, a peptide bond is formed between the amine group of an amino acid and the hydroxyl group of another and a water molecule will be released
What are the four different structures of proteins?
- Primary
- Secondary
- Tertiary
- Quaternary
How many bases code for 1 amino acid?
3 bases
Describe the primary structure of proteins.
The sequence of amino acids in a polypeptide chain.
Describe the secondary structure of proteins.
- folding of a polypeptide chain into alpha helices or beta pleated sheets
- due to the sequence of the amino acids in the primary structure
- held in place by hydrogen bonds
Describe the tertiary structure of proteins.
- further folding of the secondary structure
- forms a unique 3D shape due to side chain interactions
- held in place by ionic, hydrogen, disulphide bonds
Describe the quaternary structure of proteins.
A protein made up of more than one polypeptide chain
What are the 4 types of R group?
- Positively charged
- Negatively charged
- Non-polar
- Polar
What are the different type of bonds within tertiary and quaternary proteins?
- Disulphide bonds/bridges (strongest)
- Hydrophobic & hydrophilic interactions (weak)
- Hydrogen bonds (weak)
- Ionic bonds
Where are hydrogen bonds formed?
Hydrogen bonds are formed between the H of the amine group of one amino acid and a O of the carboxyl group of another
Where are ionic bonds found?
Between amino acids with oppositely charged R groups
Where are disulphide bonds/bridges found?
Between R-groups that contain a sulfur
Where are hydrophobic amino acids found?
In the centre of proteins as they repel water
- this means they have non-polar R-groups
