Biological Molecules - Protiens Flashcards
What is the minimum amount amount of amino acids in a polypeptide?
3
What is the primary structure of proteins?
The sequence of amino acids in the polypeptide chain.
What determines the primary structure of a protein?
DNA of a cell.
What can an alteration in the sequence of amino acids result in?
The primary structure is specific for each protein therefore if there is an alteration, the function of the protein will be different.
What is the secondary structure of proteins?
Occurs when the weak negative charged nitrogen and oxygen atoms interact with the weak positively charged hydrogen forming hydrogen bond this further folding twisting either forms and alpha helix or a beta pleated sheet.
What is the secondary structure of proteins?
Occurs when the weak negative charged nitrogen and oxygen atoms interact with the weak positively charged hydrogen forming hydrogen bond this further folding twisting either forms and alpha helix or a beta pleated sheet.
How does an alpha helix occur?
When the hydrogen bonds form between every fourth peptide bond.
How does a beta pleated sheet form?
When protein folds so that two parts of the polypeptide chain are parallel to each other by enabling hydrogen bonds to form between parallel peptide bonds.
What is the tertiary structure of protein?
Further folding of the secondary structure leads to additional bonds forming between the R groups.
The additional bonds are:
Hydrogen (these are between R groups).
Disulphide bridges (occurs between cysteine amino acids).
Ionic (occurs between charged R groups).
What is the quaternary structure of a protein?
Occurs in proteins that have more than one polypeptide chain working together as a functional macromolecule.
What is the biochemical test for proteins?
- The sample is treated with potassium hydroxide to make it alkaline.
- A few jobs of copper sulphate solution is added to the sample.
- If the colour is changed from blue to lilac/purple protein is present.
