Protein Flashcards
What’s the elemental composition of Protein
. Carbon, hydrogen, oxygen & nitrogen
. Some proteins contain small quantities of sulfur, iron & phosphorus
What’s the chemical structure of Proteins
Proteins are large molecules made up of amino acids, that are joined together by peptide links to form long polypeptide chains that make up proteins.
Whats the structure of an amino acid
. An amino group( NH²) (basic)
. A carboxyl group (COOH)(acidic)
. A central carbon (C)
.A single hydrogen(H)
.A variable group( R): changes with each amino acid
What is the amino acid if the variable group is HS-CH²
Cysteine
What is the amino acid if the variable group is H
Glycine
What are essential amino acids and give three examples
. Cannot be manufactured by the body and therefore must be obtained by food
E.g- Valine, leucine, lysine
(Histidine- (children)
What are non essential amino acids and give three examples
.Can be manufactured by the body and therefore do not need to be obtained by food
E.g- Aspartic acid, cysteine, glutamic acid
How are peptide links formed and what are the stages ?
.formed when two amino acids join togther resulting in a loss of a H²0 molecule called a condensation reaction
Stage1 : the COOH of one A.A reacts with the NH² of another
Stage 2: COOH group loses an OH group & NH² group loses a H atom which both join togther to form a H²0 molecule that is lost.
Stage 3: result is a CO-NH bond
Whats the reverse reaction of a condensation reaction?
Hydrolysis
