Proteins Flashcards
Are proteins polymers?
Yes, of amino acids.
How many types of amino acids are there?
20
Give examples of proteins.
Enzymes, antibodies, hormones, muscle is made up of protein, haemoglobin has a special type of protein
What determines the function of a protein?
The amino acids in the protein (type, number, order) and how the protein folds.
What is the structure of an amino acid?
R group, amino group (NH2), carboxyl group (COOH)
What type of reaction is needed for a peptide bond to be formed?
Condensation reaction
What is a peptide bond?
A bond formed from the condensation reaction between two amino acids, the NH2 and COOh group.
How is the peptide bond different from the glycosidic linkage?
It has an NH instead of O only.
What is a polypeptide?
Many amino acids joined together by peptide bonds in condensation reactions.
Where do the condensation reactions to form a protein take place?
In ribosomes.
What is the primary structure of a protein?
The order of the amino acids in a polypeptide.
Why is the shape of a protein important?
It determines the function of the protein.
What is the secondary structure of a protein?
The way that the polypeptide is folded: alpha helix or in a beta pleated sheet.
What is the tertiary structure of the protein?
Further folding of the polypeptide into its 3D shape. Intermolecular bonds that hold the shape together.
What is the quaternary structure of a protein?
Some proteins are made up of more than one polypeptide chain which stick together by intermolecular bonds.
What do alpha helix and beta pleated sheets hold their structure?
Because of the hydrogen bonds.
Why does the folding of the polypeptide chain not fall apart?
Because of 4 types of intermolecular bonds.
What are the 4 types of intermolecular bonds in a tertiary structure?
Hydrogen bonds, ionic bonds, hydrophobic interactions and disulfide bonds.
Give examples of proteins that have a quaternary protein structure.
Haemoglobin and collagen.
how many polypeptide chains is haemoglobin made up of?
4
how many polypeptide chains is collagen made up of?
3
How are the polypeptide chains in quaternary structure held together?
By the same intermolecular forces/bonds as in the tertiary structure.
What are globular proteins?
Soluble proteins that are made up of chains which are folded in a compact structure.
What do globular proteins play an important role in?
Metabolic reactions
Give examples of globular proteins
Enzymes and haemoglobin
What are fibrous proteins?
They are proteins made up of long molecules to form fibres. Several helices wound around each other to form strong fibres.
Give an example of a fibrous protein.
Collagen
