Biochemistry: Proteins Flashcards
What are proteins?
biopolymers
- composed of amino acids
- connected by peptide bonds
What are the functions of proteins?
- structural tissue
- transport molecules
- catalysts
How are proteins classified?
- primary
- secondary
- tertiary
- quartenary
What is the primary structure of proteins?
- particular sequence of amino acids
- backbone of a peptide chain or protein
What are amino acids connected by?
peptide bonds
What is the secondary structure of proteins?
- hydrogen bonding
the structures have well defined shapes. hydrogen bonding is responsibel for the define shapes.
Where is hydrogen bonding located in peptides?
amino group and carbonyl group of antiparallel polypeptide chains
What are the two possible secondary structures of amino acids?
- alpha helix (spiral shape)
- beta pleated sheet (parallel lines)
What proteins is the beta pleated sheet typical for?
beta pleated sheet is typical for fibrous proteins.
What proteins is the alpha helix typical for?
alpha helix is typical for globular proteins
What is an additional secondary structure?
the triple helix
Where is the triple helix usually found?
collagen, connective tissue, skin, tendons, and cartilage.
What is the tertiary structure of proteins?
formed due to interactions between R-groups (side groups), giving a protein its specific three dimentional structure.
What is the tertiary structure of polypeptides stabilised by?
- hydrophobic and hydrophyllic interactions
- salt bridges
- hydrogen bonds
- disulfide bonds
What is the quartanary structure of polypeptides stabilised by?
the same interactions found in tertiary structures
What is the quaternary structure of proteins?
- combination of two or more tertiary structure proteins
How is a peptide name formed?
the end -yl,
which is joint to the name of amino acid starting from the amino-end in sequence and the full amino acid name of the amino acids in the carboxyl-end.
Where is the amino and carboxy group located in proteins?
amino group- beggining of chain
carboxy- end of chain
Describe the insulin protein.
- primary structure of two polypeptide chains linked by disulfide bonds.
What are the bonds in the different interactions of proteins? summary
primary- peptide
secondary- hydrogen
tertiary- interactions of amino acid side groups
quartenary- two or more tertiary structures
What is the function of proteins related to?
its structure
Explain the structure- function relationships of proteins.
ENZYMES:
- active site of enzymes
TRANSPORT PROTEINS:
- bind of oxygen to heam
STRUCTURAL:
- fibrous (eg. collagen), super-helical cable (very strong)