Amino Acids Flashcards
What components make up the structure of an amino acid?
An alpha carbon surrounded by a carboxyl group, Hydrogen, R group, amino group
What are the 5 R group classifications?
Non- polar, aliphatic
- long chain of C and H atoms that cannot form hydrogen bonds
Polar, uncharged
- soluble, hydrophilic, can form H bonds
Aromatic
- has a 6 carbon benzene ring, hydrophobic, absorbs UV light
Positively charged
- basic
Negatively charged
- acidic
What are the 4 structural levels of an amino acid?
Primary
- chain
Secondary
- alpha helix, beta sheet
Tertiary
- 3D structure
Quaternary
- one or more subunits joined by H bonds
What are the 4 types of protein mutations?
Silent
- change to DNA sequence, no change to amino acid sequence
Conservative
- change to DNA sequence, change to amino acid within the same classification
Non- conservative
- change to DNA sequence, change to amino acid from one classification
- sickle cell anaemia
Nonsense
- stop codon is inserted into the gene and the protein is shortened resulting in severe impacts on protein function
Define stereoisomer
Two molecules are described as stereoisomers if they are made of the same atoms connected in the same sequence, but the atoms are positioned differently in space.
What is significant about the structure of Glycine?
It has a hydrogen as its R group
How is Maple Syrup Urine Disease characterised?
By the deficiency of certain enzymes that result in the inability to breakdown branched chain amino acids such as Valine, Leucine and Isoleucine
How is PKU characterised?
The inability to breakdown Phenylalanine resulting in a build up and, if left untreated, causingintellectual disability, seizures, behavioral problems, and mental disorders
What is the key thing to remember about aromatic amino acids? What is an example of one?
They are the only amino acids that can absorb UV light,
Example: Phenylalanine
What is the key thing to remember about positively charged, basic amino acids? What is an example?
Basic side chains (that contain nitrogen- NH3+)
High pKa
Examples: lysine, arginine
What is the key thing to remember about negatively charged, acidic amino acids? What is an example?
Side chains have carboxylic acid groups/ are acidic
Low pKa
Examples: aspartate, glutamate
What is the key thing to remember about non-polar, aliphatic amino acids? What is an example?
Long chains of H and C atoms
Cannot form H bonds
Example: Glycine
What is the key thing to remember about polar, uncharged amino acids? What is an example?
Soluble, hydrophilic
Can form H bonds
Example: Serine
Define Chiral
Asymmetric in such a way that the structure and its mirror image are not superimposable.
Where is the L-isomer always found?
In human protein.
L for Life
