UNE BIOCHEM 1005 WEEK 1 QUESTIONS WITH
CORRECT ANSWERS.
What are the four different protein structures?
1. Primary
2. Secondary
3. Tertiary
4. Quaternary
What is the primary structure of a protein?
a linear sequence of amino acids in polypeptide chains which is written from the amino
terminus (N-terminus) to the carboxyl terminus (C-terminus)
What is the secondary structure made of?
a-helix, b-sheets, and bends, turns, or loops
How are alpha helices formed?
They are formed when the carbonyl group of peptide bonds form a hydrogen bond with
the amide hydrogen located 4 residues down the chain.
Approximately how much of all secondary structures are a-helices?
1/3
What is not typically found in secondary structures and why?
Proline, because it forms a non-traditional peptide bond and adds a "kink" in the helix
How are beta sheets formed?
They are formed when beta strands are connected laterally by at least two or three
backbone hydrogen bonds
How are the b-strands connected and and by what?
They are horizontally by hydrogen bonds formed between C=O groups of either strand
and NH groups of either strand
B-sheets can either be _____________ or _________________.
parallel or anti-parallel
Where does the R group always protrude to?
The top or bottom
Depending on the R groups on the sides of the B-sheet, the sheet may have a
________________ and a ________________ side.
hydrophilic and hydrophobic
Where will the hydrophilic side of the sheet be?
on the surface of the protein and be exposed to the polar H2O solvent.
Where will the hydrophobic side of the sheet be?
It will be buried in the protein and will only rarely be exposed to the polar H2O solvent.
What are bends, turns, or loops?
Short stretched areas of the polypeptide chain from these structures that are stabilized
by hydrogen bonds (these are not random)
What is tertiary structure?
The total 3D conformation of an entire polypeptide chain including interactions between
alpha helices, bets sheets, and any other loops, turns, or bends
Give an example of a tertiary structure
Rossman Fold
CORRECT ANSWERS.
What are the four different protein structures?
1. Primary
2. Secondary
3. Tertiary
4. Quaternary
What is the primary structure of a protein?
a linear sequence of amino acids in polypeptide chains which is written from the amino
terminus (N-terminus) to the carboxyl terminus (C-terminus)
What is the secondary structure made of?
a-helix, b-sheets, and bends, turns, or loops
How are alpha helices formed?
They are formed when the carbonyl group of peptide bonds form a hydrogen bond with
the amide hydrogen located 4 residues down the chain.
Approximately how much of all secondary structures are a-helices?
1/3
What is not typically found in secondary structures and why?
Proline, because it forms a non-traditional peptide bond and adds a "kink" in the helix
How are beta sheets formed?
They are formed when beta strands are connected laterally by at least two or three
backbone hydrogen bonds
How are the b-strands connected and and by what?
They are horizontally by hydrogen bonds formed between C=O groups of either strand
and NH groups of either strand
B-sheets can either be _____________ or _________________.
parallel or anti-parallel
Where does the R group always protrude to?
The top or bottom
Depending on the R groups on the sides of the B-sheet, the sheet may have a
________________ and a ________________ side.
hydrophilic and hydrophobic
Where will the hydrophilic side of the sheet be?
on the surface of the protein and be exposed to the polar H2O solvent.
Where will the hydrophobic side of the sheet be?
It will be buried in the protein and will only rarely be exposed to the polar H2O solvent.
What are bends, turns, or loops?
Short stretched areas of the polypeptide chain from these structures that are stabilized
by hydrogen bonds (these are not random)
What is tertiary structure?
The total 3D conformation of an entire polypeptide chain including interactions between
alpha helices, bets sheets, and any other loops, turns, or bends
Give an example of a tertiary structure
Rossman Fold
