1.24 - Proteins Flashcards
What are proteins made up from?
Amino acids
What is the basic structure of amino acids?
- Amino group(-NH2)
- Carboxyl group(-COOH)
- R group(variable)
What effects can the R group have?
The way the amino acid bonds with others and if the acid is polar or not
What groups of an amino acid react to form a bond?
The amino group(-NH2) and carboxyl group(-COOH)
What type of bond is formed between amino acids?
Peptide bonds
What is a molecule of two amino acids called?
Dipeptide
What is a polymer of amino acids called?
A polypeptide
What bonds can form within a protein?
Hydrogen bonds, disulfide bonds and ionic bonds
Where do disulfide bonds form?
Between two sulfur containing R groups
How many protein structures are there?
4
What is the primary structure?
The sequence of amino acids that make up the polypeptide chain, held together by peptide bonds
What is the secondary structure?
The arrangement of the polypeptide chain into a regular repeating pattern
What to forms can the secondary structure take?
Alpha helix or Beta sheet
What is the tertiary structure?
Further folding of the secondary structure into more complicated shapes
What is the quaternary structure?
The fitting together of several chains of the tertiary structure into a complex 3D shape
What are the two types of protein?
Fibrous(strands) and globular(spherical)
What is collagen?
A fibrous protein that gives strength to tendons, muscles, bones and skin
What shape does collagen make?
Triple helix
What is the test for proteins?
Biuret test
Explain the Biuret test
- Test solution must be alkaline
- Add sodium hydroxide solution
- Add dilute copper(II) solution
- Positive test shows a change of colour from blue to purple
