Tutorial - Week 4 - Amino acids, protein structure & function Flashcards
Key concept: describe the structure and properties of amino acids
Key concept: describe the primary structure of proteins
Key concept: Describe polymerisation of amino acids
Key concept: Describe peptide bonds
Key concept: Describe intramolecular bonds
Key concept: Describe secondary structure of proteins
Key concept: Describe tertiary structure of proteins
Key concept: Describe quaternary structure of protein
Key concept: Describe proteins associated with membranes
Key concept: Describe denaturation
Key concept: Describe isoelectric point
How many common amino acids are there and how are the groups they are divided into classified?
20
Classified based on the chemistry of the side chain
What are the different side chain groups?
- Non-polar or hydrophobic (means that their side chain has hydrophobic properties)
- Uncharged Polar (soluble in water because they have groups that can establish hydrogen bonding - e.g: hydroxyl groups, carbonyl groups)
- Charged Polar
3.1 Acidic (-)
3.2 Basic (+)
T/F: Cysteine also has a group that can establish hydrogen bonding? Why is it special and different to others in it’s group?
True (But is a special amino acid and doesn’t have the regular hydroxyl group or carbonyl group like the other amino acids in the uncharged polar category
Aspartate and glutamate are also named what?
Aspartic acid and glutamic acid
Are aromatic amino acids similar to non-polar/hydrophobic AA’s? How do they differ?
Yes, they are also part of the non-polar/hydrophobic group
Differ because they also have their own properties and have the benzine ring/rings within their structure
T/F: Depending on certain properties of amino acids they can be grouped differently and often are grouped slightly differently depending on what the focus is?
True
Aromatic residues (Trp, Tyr and Phe) can be classified in different groups - name the groups they belong to:
- Tyr (aromatic, polar or amphipathic)
- Trp (aromatic, apolar or amphiphatic)
- Phe (aromatic, or apolar)
What is unique about proline (Pro)?
Proline has a cyclic structure where the side chain is fused with the amino group.
The amino group is slightly different because of this and proline has some unique properties because of it
What are the two amino acids that we focused on in this tut that have a cyclic structure?
Proline (Pro) and histidine (His)
T/F: Histidine (His) has a cyclic structure in the side
chain, involving an amino group.
How is histidine different to proline and aromatic AAs?
True
Histidine’s cyclic structure doesn’t attach to it’s side chain. Other aromatic AAs have benzine rings but histidine doesn’t have that, it just has a cyclic structure without the proper benzine ring
T/F: histidine is ALWAYS classified as a basic amino acid
True
Describe two main points about Non-polar, aliphatic amino acids (R-groups and what they participate in)
- R groups are non-polar and are hydrophobic
- Participate in the hydrophobic effect. The side chains
of these amino acids tend to cluster together inside
the protein (i.e. not accessible to the surrounding
aqueous environment)
Aromatic amino acids:
What are their side chains classed as?
Aromatic