Topic 1 - Year 1 - Biological Molecules - Proteins Flashcards
Proteins are polymers , what is the monomer of a protein?
The monomer of a protein is an amino acid.
What is a dipeptide?
A dipeptide is what is made when two amino acids join together
What is a polypeptide?
A polypeptide is what is created when many amino acids join together.
What are proteins made up of?
Proteins are made up of one or more chains of polypeptides .
How are amino acids linked together?
Amino acids are linked together in condensation reactions, the bonds that are made between the amino acids are known as peptide bonds.
What type of bond forms between two amino acids when a condensation reaction takes place?
A peptide bond.
What molecule is released in the formation of a peptide bond?
A molecule of water is released as peptide bonds form in condensation reactions.
What reaction takes place to break peptide bonds?
Hydrolysis happens to break down peptide bonds , hydrolysis uses a molecule of water to break the bond.
Describe the structure of an amino acid.
Amino acids have the same general structure , a carboxyl group (COOH) , an amine group / amino group (NH^2) and an R group which can also be referred to as a variable side group.
R
|
H2N ------ C --------- COOH
|
H
Could also be displayed as:
H R O \ | // N ---- C ----- C / | \ H H OH
How many amino acids are there ?
20
Which two groups on the amino acid join by peptide bond in the condensation reaction ?
The carboxyl group of one amino acid bonds one of its OH molecules to one of the 2 hydrogen atoms in the amine group of the second amino acid.
H R O H R O
\ | // \ | //
N —- C —– C N —- C —– C
/ | . / | \
H H OH + H H OH
=
H R O H. R. O
\ | // . |. //
N —- C —– C ——— N —– C —– C. + H20
/ | |. \
H H H. OH
What is Primary structure?
Primary structure is the sequence of amino acids that make up a polypeptide chain.
What is Secondary structure?
The secondary structure of a protein is the way in which it is twisted or folded. the poly peptide chain doesn’t remain flat or straight . Hydrogen bonds form between amino acids in the polly peptide chains, these hydrogen bonds make the polypeptide chain twist or fold into an alpha helix or a beta pleated sheet.
What type of bonds cause the polypeptide chain to twist into an alpha helix or cause it to fold into a beta pleated sheet ?
Hydrogen bonds.
What is tertiary structure?
Tertiary structure is a progression from secondary structure the structure occurs as alpha helix or beta pelted sheets are folded and twisted further in consequence of the formation of new bonds. Further hydrogen bonding occurs in this type of structure , ionic bonds also form between negative and positive charges o different parts of the polypeptide chain. In the tertiary structure there also can be disulphide bridges , disulphide bridges form when two amino acids with the R group that makes them cysteine come close together. The sulphur atom in one cysteine bonds to the sulphur atom in another. For many proteins made of a single polypeptide chain the tertiary structure forms the proteins final 3 dimensional structure.
