L4: Protein Chemistry Flashcards
(20 cards)
What are the main components of Amino acid structure?
R-side chain, alpha-carbon, amino group (N-terminus), carboxyl group (C-terminus)
The R side chain varies between amino acids.
What are protein polymers made of?
Amino acids monomers
There are around 20 types of amino acids.
Name the 4 main types of amino acids.
- Non-polar, hydrophobic
- Polar, hydrophilic
- Acidic (negatively charged at neutral pH)
- Basic (positively charged at neutral pH)
How are proteins made?
Dehydration synthesis/condensation reaction of two amino acid, with the formation of a peptide bond and a release of 1 water molecule.
The primary structure is the specific sequence of amino acids.
What main types of bonds holding proteins together?
- Hydrogen bonds
- Ionic interactions
- Hydrophobic interactions
- Disulphide bridges
- Van der Waals interactions
What is a peptide bond?
A strong covalent bond formed between the NH2 group of one amino acid and the COOH group of another
Peptide bonds are formed through condensation reactions.
What is the pattern of the polypeptide backbone?
N—C—C—N—C—C
What are the strengths of different bonds in proteins?
- Covalent (peptide bond): 350 kJ/mol
- Disulphide: 60-80 kJ/mol
- Electrostatic attraction: 15 kJ/mol
- Van der Waals forces: 10 kJ/mol
- Hydrogen bonding: 21 kJ/mol
What is the primary structure of proteins?
A chain polypeptide of amino acids, online linked by covalent peptide bonds.
Known as amino acid residues.
What happens to the secondary structure during denaturation?
Hydrogen bonding in the secondary structure is broken due to the breaking of hydrogen bonds between amino acids/groups.
What is protein folding?
Protein folding is a process by which a polypeptide chain folds to become a biologically active protein in its native 3D structure.
Proper folding is essential for protein function.
What are the levels of protein folding?
- Primary structure
- Secondary structure
- Tertiary structure
- Quaternary structure
What factors affect protein folding?
- High temperatures
- Extreme pH
What is denaturation?
The process where proteins lose their secondary, tertiary, and quaternary structures, resulting in loss of function.
Bonds in primary protein structure
*Peptide bonding
These fibres are tough and insoluble in water.
Bonds in Secondary protein structure
- Peptide bonding
Bonds in tertiary protein structure
*Hydrophobic interactions
*Hydrogen interactions
* Van der Waals forces
*disulfide bridges
*electrostatic/ionic interactions
True or False: Hydrophobic side chains attract water.
False
Globular proteins: Solubility, resistance, example, structure, order
soluble, not resistant, hemoglobin, spherical, irregular amino acid sequence.
Fibrous protein: solubility, resistance, example, structure, order
non-soluble, resistant, fibrin, long and narrow, repetitive amino sequence
