Amino Acids Flashcards
What are the components of an Amino Acid?
Amino group, carboxyl group, hydrogen, side chain, and a R group.
Why are amino acids non-superimposable?
They also exist as mirror images. AKA enantiomer/optical isomer.
What is a zwitter ion and how are amino acids zwitter ions?
Zwitter ions are molecules that act as both base and acid at different pH’s. For amino acids- amino group gains a proton becoming a base and the carboxyl group loses a proton becoming an acid.
What is a buffer?
A chemical which can absorb H+ and/or OH- without affecting pH too much.
How do amino and carboxyl groups act as buffers?
At a low pH, amino group gains a proton.
At a medium pH, amino group gains proton and carboxyl group loses proton.
At a high pH, carboxyl group loses a proton.
What are hydrophobic amino acids?
Non-polar. Share electrons equally. Doesn’t mix well with water.
What are hydrophilic amino acids?
Polar. Electron further from carbon atom. Positive and/or negative charged.
What is acetylation?
Add an acetyl group to N-terminus of a protein or at lysine residue.
What is lipidation?
Add lipid like fatty acid to protein chain.
What is methylation?
Add methyl group to lysine or arginine residue.
What is hydroxylation?
Add hydroxyl group to side chain of a protein.
What is Phosphorlation?
Add phosphate to serine, threonine, or tyrosine.
What is glycosylation?
Add sugar like N or O onto side chain.
How do amino acids make proteins?
Amino acids are covalently bonded to form a polypeptide chain. Via condensation. Peptide/amide bond formed.
How do polypeptide chains form disulphide bonds?
An amino acid like cystine contains two Thiol groups (sh), which undergoes oxidation with another thiol group to form disulphide bond. Formed on same chain or on another.
Where can disulphide linked protein be found and not found?
Usually secreted in to extracellular fluid, not in intracellular environment as its highly reducing and bonds would not survive.
Describe the arrangement of amino acids.
Instructions come from DNA. Ribosomes read coded instructions on mRNA and determine order of amino acids.
What is a gene?
Length of DNA which orders for one polypeptide.
Function of tryptophan.
Used in cells to produce hormones like serotonin and melatonin.
Function of tyrosine.
Make other biomolecules like melanin and thyroid hormone.
Function of glutamic acid.
Make neurotransmitters like GABA.
Function of arginine.
Make nitric acid, smooth muscle relaxant which enhances blood flow.
Function of histidine.
Used to make histamine used for immune system.
Function of glutathione.
Potent anti-oxidant which protects cells.
