Protein Structure and Hydrogen Bonds

What type of hydrogen bonds are formed between peptide chains in a beta-pleated sheet?

Intersheet
Interchain (correct)
Intrachain
Intramolecular

What is the orientation of polypeptide chains in an antiparallel beta-pleated sheet?

Parallel
Diagonal
Perpendicular
Antiparallel (correct)

What is the geometry of a peptide bond?

Linear and s-trans
Bent and s-cis
Non-planar and s-cis
Planar and s-trans (correct)

What type of structure is formed by a series of tight reverse turns connecting stretches of the polypeptide chain?

Beta-meander (C) Signup and view all the answers

What is the function of a beta-barrel motif in a protein?

To provide information about the folding of proteins (B) Signup and view all the answers

What is the characteristic of a reverse turn in a protein?

A change in direction of the polypeptide chain (B) Signup and view all the answers

What is the 3-D arrangement of all atoms in a protein molecule?

Tertiary structure (A) Signup and view all the answers

What is the primary structure of a protein?

Order in which amino acids are covalently linked together (C) Signup and view all the answers

In fibrous proteins, what is the arrangement of the atoms of the side chains?

Not specified by the secondary structure (D) Signup and view all the answers

What type of bonds are responsible for the stability of the alpha-helix?

Hydrogen bonds parallel to the helix axis (A) Signup and view all the answers

What is the characteristic of the peptide bond in an alpha-helix?

It is s-trans and planar (A) Signup and view all the answers

What type of bonds are involved in the interactions between side chains in globular proteins?

Hydrogen bonds (B) Signup and view all the answers

What is the unique feature of collagen triple helix?

Three polypeptide chains wrapped around each other (C) Signup and view all the answers

What is the effect of proline on the alpha-helix structure?

It restricts rotation due to its cyclic structure (B) Signup and view all the answers

What is the role of hydroxyproline in collagen triple helix?

It is involved in hydrogen bonding (A) Signup and view all the answers

What is the consequence of strong electrostatic repulsion caused by the proximity of several side chains of like charges?

It disrupts the alpha-helix structure (C) Signup and view all the answers

What is the purpose of X-ray crystallography in determining protein structure?

To produce a diffraction pattern that reveals the 3-D structure of a protein (A) Signup and view all the answers

What type of arrangement is characterized by hydrogen-bonded polypeptide chains?

β-pleated sheet (C) Signup and view all the answers

What is the advantage of Nuclear Magnetic Resonance (NMR) spectroscopy over X-ray crystallography?

It can be used to study protein dynamics (A) Signup and view all the answers

What is the role of peptide bonds in the secondary structure of proteins?

They form covalent bonds between amino acids (C) Signup and view all the answers

What is the role of hydrogen bonding in the tertiary structure of proteins?

It helps to stabilize the tertiary structure (A) Signup and view all the answers

What is the consequence of steric repulsion caused by the proximity of bulky side chains?

It disrupts the alpha-helix structure (C) Signup and view all the answers

What is the repeating sequence of amino acid residues in collagen triple helix?

X-Pro-Gly (C) Signup and view all the answers

What is the linear distance between corresponding points on successive turns of the alpha-helix?

5.4 Å (D) Signup and view all the answers

How many residues are typically found in each turn of the alpha-helix?

3.6 residues (C) Signup and view all the answers

What is the term for the cross-linking of collagen helices that occurs with age?

Covalent bonding (C) Signup and view all the answers