4 Levels Of Protein Structure

Question 1

What are the four levels of protein structure?

Answer 1

Primary structure, secondary structure, tertiary structure, and quaternary structure

Individual protein molecules have up to four levels of structure

Question 2

What does primary structure describe?

Answer 2

The linear sequence of amino acid residues in a protein

Primary structure describes the linear sequence of amino acid residues in a protein

Question 3

What does secondary structure refer to?

Answer 3

Regularities in local conformations maintained by hydrogen bonds between amide hydrogens and carbonyl oxygens of the peptide backbone

Secondary structure refers to regularities in local conformations maintained by hydrogen bonds between amide hydrogens and carbonyl oxygens of the peptide backbone

Question 4

What are the major secondary structures?

Answer 4

a helices, B strands, and turns

The major secondary structures are a helices, B strands, and turns

Question 5

What does tertiary structure describe?

Answer 5

The completely folded and compacted polypeptide chain

Tertiary structure describes the completely folded and compacted polypeptide chain

Question 6

What are tertiary structures stabilized by?

Answer 6

The interactions of amino acid side chains in non-neighboring regions of the polypeptide chain

Tertiary structures are stabilized by the interactions of amino acid side chains in non-neighboring regions of the polypeptide chain

Question 7

What are distinct globular units linked by a short stretch of amino acid residues called?

Answer 7

Domains

Many folded polypeptides consist of several distinct globular units linked by a short stretch of amino acid residues, which are called domains

Question 8

What does quaternary structure refer to?

Answer 8

The arrangement of two or more polypeptide chains into a multisubunit molecule

Quaternary structure refers to the arrangement of two or more polypeptide chains into a multisubunit molecule