1. Biological Molecules - Proteins Flashcards
What are 2 examples of amino acids?
L-Histidine and L-Isoleucine
Describe the structure of an amino acid?
-Carboxyl group COOH
-Amino group NH2
-Different R groups
How are peptide bonds formed?
Due to a condensation reaction, where the carboxyl group of one amino acid joins to the amino group of another amino acid.
What chemical property does a polar R group have?
Hydrophilic
What chemical property does a non-polar R group have?
Hydrophobic
What chemical property does a positively charged R group have?
Hydrophilic
What chemical property does a negatively charged R group have?
Hydrophilic
What are the typical secondary structures?
α-helices and β-pleated sheets
How do secondary structures form?
As a result of hydrogen bonding between carboxyl and amino residues
How do tertiary structures fold into their complex, specific shapes?
Due to intermolecular forces between different types of bonds in R groups
What are the 4 different kinds of bonds which create intermolecular forces to hold together tertiary structures?
-Hydrogen bonds
-Ionic forces
-Disulfide bridges
-London forces
What do hydrogen bonds form between?
Polar R groups AS WELL AS between the carbonyl oxygen of one amino acid and the amide hydrogen of another in the secondary structure (backbone atoms)
What do ionic forces form between?
Positive and negative R groups
What are disulfide bridges?
Covalent bonds between cysteine R groups
What do London forces form between?
Non-polar R groups
What are the two groups of quaternary structures?
Globular and fibrous.
Give 3 broad examples of globular structured proteins:
-Enzymes
-Signalling molecules
-Transport molecules
Give one broad example of a fibrous structured protein:
Structural molecules
Give one specific example of a globular protein:
Haemoglobin
Give one specific example of a fibrous protein:
Collagen
What structure does haemoglobin have?
A quaternary structure
What structure does collagen have?
Quaternary structure
How many polypeptide chains does haemoglobin have? What do these consist of?
-4 polypeptide chains
-2 α-subunits
-2 β-subunits
How many polypeptide chains does collagen have?
3 polypeptide chains
What additional group do quaternary structures contain?
Non-amino acid derived groups known as prosthetic groups.
How many prosthetic groups does haemoglobin have?
4 heme prosthetic groups
Give 4 examples of what prosthetic groups can be formed from:
-Metal ions
-Methyl groups
-Phosphate groups
-Vitamins
