1.4 Proteins Flashcards
(19 cards)
What are proteins made up from?
Monomers called amino acids
What elements do proteins contain?
C,H,O,N and S
What is the structure of an amino acid?
R
|
H2N— C —-COOH
|
H
What is the COOH group called?
Carboxyl group
What is the H2N group called?
Amino group
What does the R mean in an amino acid?
-Any possible number of chains
- it’s a side chain
What is the simplest amino acid and what is its structure?
Glycine
H H O
| | || H—N—C—C—OH
|
H
What forms a peptide bond?
A condensation reaction between two amino acids
What forms from a condensation reaction between two amino acids?
A peptide bond
How are dipeptides formed?
Formed by the condensation of two amino acids.
How are polypeptides formed?
Formed by the condensation of many amino acids.
What may a functional protein contain?
One or more polypeptides.
What 4 levels does protein structure occur at?
-Primary Structure
-Secondary structure
-Tertiary structure
-Quaternary structure
What is primary structure?
The number and sequence of amino acids in a polypeptide chain
What is secondary structure?
The secondary structure is made when hydrogen bonds form between some of the atoms in the polypeptide chain, this pulls the chain into a shape, there are two shapes that are generally made - alpha helix or beta pleated sheets
What is tertiary structure?
The folding of the polypeptide chain into a 3D shape, this is held in place by hydrogen bonds and disulfide bridges
What is quaternary structure?
One or more polypeptide chains joined together to make a fully functional protein. Often there are prosthetic groups with quaternary structure. In haemoglobin the prosthetic group is iron
What is the test for proteins?
The Biuret Test - Which detects peptide bonds
What is the methods of the Biuret test?
-Place a sample of the solution to be tested in a test tube and add an equal volume of sodium hydroxide solution at room temperature
-Add a few drops of very dilute copper sulfate solution and mix gently
-A purple colouration indicates the presence of peptide bonds and hence a protein. If no protein is present, the solution remains blue
