Biochemistry Questions and Answers – Protein Secondary Structure

This set of Biochemistry Multiple Choice Questions & Answers (MCQs) focuses on “Protein Secondary Structure”.

1. Which of the following does not affect the stability of an α-helix?
a) Electrostatic repulsion
b) Bulkiness
c) Interaction between R groups spaced three residues apart
d) Occurrence of alanine and glycine residues
View Answer

Answer: d
Explanation: The occurrence of Proline and Glycine residues affect the stability of an α-helix.

2. Which of the following is not true about secondary protein structure?
a) The hydrophilic/hydrophobic character of amino acid residues is important to secondary structure
b) The ability of peptide bonds to form intramolecular hydrogen bonds is important to secondary structure
c) The alpha helix, beta pleated sheet and beta turns are examples of protein secondary structure
d) The steric influence of amino acid residues is important to secondary structure
View Answer

Answer: a
Explanation: The hydrophilic/hydrophobic character of amino acid residues is important to protein tertiary structure rather than to secondary structure. In secondary structure, it is the steric size of the residues that is important and residues are positioned to minimize interactions between each other and the peptide chain.

3. β-pleated sheets are the examples of _________
a) Primary structure
b) Secondary structure
c) Tertiary structure
d) Quaternary structure
View Answer

Answer: b
Explanation: Secondary structure of proteins is of two forms α-helix and β-pleated structures.
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4. A coiled peptide chain held in place by hydrogen bonding between peptide bonds in the same chain is?
a) Primary structure
b) α-helix
c) β-pleated sheets
d) Tertiary structure
View Answer

Answer: b
Explanation: A coiled peptide chain held in place by hydrogen bonding between peptide bonds in the same chain is α helix.

5. A structure that has hydrogen bonds between polypeptide chains arranged side by side is?
a) Primary structure
b) α-helix
c) β-pleated sheets
d) Tertiary structure
View Answer

Answer: c
Explanation: A structure that has hydrogen bonds between polypeptide chains arranged side by side is β-pleated sheets.
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6. Which of the following are known as helix breakers?
a) Proline and glycine
b) Isoleucine and leucine
c) Valine
d) Threonine
View Answer

Answer: a
Explanation: Proline and glycine are known as helix breakers as they disrupt the regularity of the alpha helical backbone conformation.

7. Which of the following is false about NMR spectroscopy?
a) NMR is an abbreviated form of Nuclear Magnetic Resonance
b) The intramolecular magnetic field around an atom in a molecule changes the resonance frequency giving structural information about the atom
c) The intermolecular magnetic field around an atom in a molecule changes the resonance frequency giving structural information about the atom
d) It is a technique that exploits magnetic properties of atomic nuclei
View Answer

Answer: c
Explanation: The intramolecular magnetic field around an atom in a molecule changes the resonance frequency giving structural information about the atom.
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8. Which of the statements is false about multiple sequence alignment?
a) Both protein and nucleic acid secondary structures can be used
b) More useful in RNA
c) These alignments can be made more accurate by the inclusion of secondary structure information
d) A significant increase in accuracy
View Answer

Answer: b
Explanation: Less useful in RNA. This is because base pairing is highly conserved than sequence.

9. Secondary structure is defined by _________
a) Hydrogen bonding
b) Vander Waals forces
c) Covalent bonding
d) Ionic bonding
View Answer

Answer: a
Explanation: Hydrogen bonding is present between the amine hydrogen and carbonyl oxygen atoms in the peptide backbone.
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10. Which of the following is a false statement?
a) α-Keratin is α helical
b) Collagen is α helical
c) Hemoglobin has a quaternary structure
d) α-Keratin is β pleated structure
View Answer

Answer: d
Explanation: Fibrous structural protein, α-Keratin is α helical.

Sanfoundry Global Education & Learning Series – Biochemistry.

To practice all areas of Biochemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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