1. Protein Flashcards
What reaction occurs to form a peptide bond?
Carboxyl group on one amino acid reacts with the amino group on the second
Name 3 types of interactions between amino acids
Electrostatic
van der Waals reaction
Covalent (disulphide, glycosylation)
What is the primary structure of protein?
Amino acids are formed into a polypeptide chain, linked by peptide bonds
Direction is from amino end to carboxyl end
What is the secondary structure of protein?
The regular repetitive folding pattern Alpha helix (collagen, keratin) and beta pleated sheet (silk)
Describe the structure of an alpha helix
Spiral like structure
Stabilised by hydrogen bond formed between every 4th amino acid
Describe the structure of a beta pleated sheet
Stretched out sheet
Hydrogen bonds in side my side polypeptide chains
If chains run in same direction= parallel
Opposite direction= antiparallel
What is tertiary structure?
Folding into globular form
Hydrophobic amino acids go on inside and hydrophilic on outside
What is tertiary structure stabilised by?
Disulphide bonds
Hydrophobic interactions
Hydrogen bonds
Ionic interactions
How are globular proteins formed?
Combination of secondary structural elements connected by loops
Form super secondary structures called domains or motifs
Name 3 super-secondary structures
Greek key
Beta meander
beta barrel
What configuration is porin?
Beta barrel
What is the function of porin?
Forms pores in cell membranes for the passive diffusion of water soluble molecules
How are fibrous proteins formed?
Regular, secondary structural elements of specific amino acids
What configuration is collagen?
3 alpha chains are wound round each other in a triple helix
Which amino acids is collagen rich in?
Proline
Glycine
