Nucleic Acids Flashcards
What is the general structure of an amino acid?
COOH
R-variable
NH2- amine group
How do you test for protein in a sample
Buiret test
- add equal volume of NaOH to sample at room temperature
-add drops of CuSO4 and swirl.
Colour changes from blue to purple
How many amino acids are there and how do they differ from one another
20 amino acids
R changes
How do dipeptides and polypeptide form?
Through condensation reactions forms peptide bonds -CONH- and eliminates water
Name the 4 levels of protein structure
Primary
Second
Tertiary
Quaternary
Define primary structure
Sequence of amino acids found in a polypeptide.
Determined by the Sequence of codons on mRNA
Define secondary structure of a protein
H-bonds form between O attached to -C=O & H attached to -NH
Describe the two types of secondary protein structures
Alpha-helix
-all N-H bonds on the same side of protein chain
-Spiral shape
-H bonds parallel to helical axis
Beta-pleated sheets
•N-H & C=O groups alternate from side to side
Define Tertiary structure of protein
3d structure formed from further folding of polypeptide
- disulphide bridges
- ionic bonds
- hydrogen bonds
Describe each type of bond found in the Tertiary structure of protein
1) Disulfide bridges: strong covalent S-S bonds between molecules of amino acid cysteine
2) ionic bonds: string bonds between charged R Groups
3) hydrogen bonds: numerous and easily broken
Define quaternary structure
●Consists of multiple polypeptide chains
●Precise 3D structure held by same Tertiary structure bonds
● may involve phosphate groups.g metal ions
Describe structure and functions of globular proteins
Spherical
and compact.
-hydrophilic R faces outwards and hydrophobic faces inward=water soluble
-involved on metabolic processes like enzymes and haemoglobin.
