Biological molecules - Proteins Flashcards
What are proteins made of?
proteins are made up of many amino acids that are bonded together into a polypeptide.
What is an amino acid? (or draw and label one)
Each amino acid has the same fundamental structure, which consists of a central carbon atom, also known as the alpha carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom. Every amino acid also has another atom or group of atoms bonded to the central atom known as the R group. This R group, or side chain, gives each amino acid proteins specific characteristics, including size, polarity, and pH.
How do two amino acids link together to form a dipeptide? Name the reaction type and bonds formed.
A dipeptide is formed when two Amino acids join together by one Peptide bond. This happens via a Condensation Reaction. The bond between the two amino acids forms between the carboxyl group on one and the amino group on another.
What is the primary structure?
The sequence of amino acids in a protein chain is called the primary structure.
What are the bonds involved in the primary structure?
Polypeptide bonds
What is the secondary structure?
The chain of amino acids is twisted into a shape which is the secondary structure. Some chains coil into a alpha helix and other chains fold very slightly into a zig zag called the beta pleated sheet.
What are the bonds involved in the secondary structure?
Hydrogen bonds
What is the tertiary structure?
When the coil pleats itself start to fold, along with areas of straight chains of amino acids.
What bonds are involved in the tertiary structure?
Ionic and hydrogen bonds, disulphide bridges
What is the quaternary structure?
Many proteins are made up of many polypeptide chains. The quaternary structure describes how multiple polypeptide chains are arranged to make the complete protein molecule.
What bonds are involved in the quaternary structure?
Ionic and hydrogen bonds, disulphide bridges
What is the difference between a globular and fibrous protein?
Fibrous proteins are generally composed of long and narrow strands and have a structural role (they are something) whereas globular proteins generally have a more compact and rounded shape and have functional roles (they do something).
Name the fibrous proteins.
Collagen, Keratin and Elastin
Name the globular proteins.
Haemoglobin, Insulin and pepsin.
