Biological Molecules - Proteins (2.1.2) Flashcards
Explain the general structure of an amino acid?
A carboxyl group (-COOH) and an amino group (-H2N) attached to a carbon atom.
What differentiates amino acids?
R Group (Variable)
Why do polypeptide chains not remain flat and straight?
The -NH and -CO groups are polar.
Hydrogen bonds form between different amino acids in the chain.
Explain how a disulfide bond is formed.
When two molecules of the amino acid cysteine come close together the sulfur atom in one cysteine bonds to the sulfur atom in the other cysteine.
Explain quaternary structure.
Some proteins are made of different polypeptide chains held together.
The quaternary structure is the way these polypeptide chains are assembled together.
Give three examples of fibrous proteins.
Collagen
Keratin
Elastin
Provide three pieces of information about Haemoglobin.
Carries oxygen around the body.
Conjugated with a prosthetic group called Haem.
Haem contains iron which Oxygen binds to.
What is the role of insulin?
Regulate blood glucose level.
Where is collagen found?
Animal connective tissues (bone, skin and muscle).
Where is keratin found?
External structures of animals (skin, hair, nails, feathers and horns).
Where is Elastin found?
Elastic connective tissue (skin, large blood vessels, some ligaments)
Describe the structure of Hemoglobin.
Protein with a non-protein group attached.
The non-protein group is called a prosthetic group.
A haem group contains iron which oxygen binds to.
Describe the structure of insulin.
Two polypeptide chains held together by disulfide bonds.
When they are in the pancreas, six of the molecules bind together to form a large globular structure.
Describe the structure of amylase
A single chain of amino acids.
Its secondary structure contains both halpha-helix and beta-pleated sheet sections.
Draw the chemical structure of the hydrogen bonds in a protein’s secondary structure.
