Amino Acids And Proteins Flashcards
(30 cards)
What monomer are proteins made up of?
Different combinations of the 20 naturally occurring amino acids
Which three groups can amino acids be classified in to?
- essential amino acids
- non essential amino acids
- conditional amino acids
What are essential amino acids?
amino acids that cannot be made by the body so must come from food
What are non essential amino acids?
Amino acids that can be made in the body
What are conditional amino acids?
Amino acids in that are only essential in tunes if stress or illness
Give examples of essential amino acids
PHITTL
- Phenylalanine
- Histidine
- Isoleucine
- Trypsin
- Lysine
Give examples of non essential amino acids
AlAs GAsp
- alanine
- Aspartic acid
- Glutamic acid
- Asparagine
Give examples of conditional amino acids
STAGG COP
-serine
-tyrosine
-Argine
- Glycine
cysteine
-omnithine
-proline
What does the amino acid structure consist of?
An r group, a hydrogen, an amino group and a carboxylate group
Why is the carbon in amino acids special?
The carbon in amino acids is attached to four different groups and therefore it is chiral. This means that two optical isomers form. However on l- amino acids are found in the body
At a low ph what is the net charge on an amino acid?
Net positive charge
At a high ph what is the net charge on the amino acid?
The amino acid has a net negative charge
What is an amino acid called when it has no overall net charge, and at what ph does this form?
- a zwitterion
- a zwitterion forms at the isoelectric point (an intermediate ph where charges on the amino acid balance)
What happens to the amino acid’s solubility at the isoelectric point?
At the isoelectric point the amino acid will have minimum solubility and will often precipitate out of solution
How are proteins formed?
By condensation reactions between the amino group and the carboxyl group of two amino acids
Which properties is the separation of proteins based on?
Physico-chemical
Amino acids and proteins contain which elements?
CHON and sometimes S
By which process connects amino acids together to form a protein
Condensation reactions between the amino group of one amino acid and the carboxyl group of another amino acid
What is a polypeptide chain?
Short condensation chains with the amino and carboxyl terminal
What is the primary structure of a protein?
The unique sequence of amino acids that make up the protein
What is the secondary structure?
The secondary structure is determined by the way in which the primary structure folds to maximise the number of hydrogen bonds. This lowers the free energy of the molecule and therefore it’s interaction with water
What are the two main conformations or structures found in the secondary protein structure?
- the alpha helix
- the beta pleated sheet
What influences the type of conformation (aloha held or beta pleated sheet) taken by molecules?
These structures are largely determined by the side groups of individual amino acids
- side groups will sterically hinder or aid certain conformations
What is the alpha helix?
The alpha helix is a right handed helix ( the chain rotaries clockwise) as it is viewed down the peptide chain
- because of limited rotation around either side of the polypeptide bond only a few angles are energetically stable
