Here are Structural Biology MCQs (Chapterwise).
1. What is the primary role of X-ray crystallography in structural biology?
a) Determining protein function
b) Visualizing dynamic protein movements
c) Obtaining high-resolution 3D structures
d) Studying protein-protein interactions
View Answer
Explanation: X-ray crystallography is a technique used to determine the three-dimensional structure of a molecule, typically proteins, at atomic resolution.
2. What primarily determines the function of a specific protein?
a) Two-dimensional structure
b) Four-dimensional structure
c) One-dimensional structure
d) Three-dimensional structure
View Answer
Explanation: The three-dimensional structure is stabilized by weak chemical bonds rather than strong covalent bonds like peptide bonds. Hence the three-dimensional structure can easily change its conformation which decides the functionality of that particular protein.
3. Which of the following macromolecules is NOT typically studied in structural biology?
a) Carbohydrates
b) Proteins
c) DNA
d) RNA
View Answer
Explanation: Structural biology primarily focuses on the study of the three-dimensional structures of proteins, nucleic acids (DNA and RNA), and sometimes lipids, but carbohydrates are not as commonly studied using structural biology techniques.
4. Which amino acid can attain a wide range of conformations during protein formation?
a) Leucine
b) Glycine
c) Proline
d) Histidine
View Answer
Explanation: Glycine is the lightest among all of the amino acids having only one hydrogen atom in its side chain. Hence it can easily attain different conformations without any restrictions. Usually, the amino acid with bulk side chains has less possibility of adopting a diverse range of conformations.
5. What is the primary function of the protein collagen in the human body?
a) Structural support in connective tissues
b) Enzyme catalysis
c) Transport of oxygen in the blood
d) Muscle contraction
View Answer
Explanation: Collagen is a fibrous protein that provides structural support in connective tissues such as skin, tendons, and bones.
6. Which one of the following forces will not determine the protein structure?
a) Disulfide bridges
b) H bonds
c) Dispersion forces
d) Spring forces
View Answer
Explanation: The different forces involved in the formation of proteins are hydrophobic/hydrophilic forces, H bonding, Vander Walls/dispersion forces, Electrostatic forces and disulfide bridges. These forces help proteins to attain a specific stable structure which can later perform a certain biological function.
7. What are the mixed beta structures?
a) Combination of anti-parallel beta structures and alpha helix
b) Combination of parallel beta structures and gamma helix
c) Combination of parallel and anti-parallel beta sheets
d) Combination of alpha helix and beta sheets
View Answer
Explanation: In most of the proteins, both parallel, as well as anti-parallel beta sheets, will be present. This combination of parallel and anti-parallel beta sheets are known as mixed beta sheets.
8. What is angle psi in Ramachandran plot?
a) Bond angle of the bond formed between the alpha carbon and carboxyl carbon
b) Bond angle of the bond formed between the amino group and alpha carbon
c) Bond angle of the bond formed between the amino group and carboxyl carbon
d) Bond angle of the bond formed between alpha carbon and beta carbon
View Answer
Explanation: Psi angle is one of the backbone angles used to plot the Ramachandran plot. It represents the bond angle of the bond formed between the alpha carbon and carboxyl carbon of same amino acid. Unlike omega, it can be varied by various factors.
9. What is the common aspect between passive and active proteins?
a) Domains
b) Secondary structure
c) Structure
d) Function
View Answer
Explanation: Even though active and passive are two different types of proteins, they have one thing in common. That is there secondary structures. They have their secondary structures made of either alpha helices or beta sheets or both.
10. Which of the following doesn’t contain collagen fibres?
a) Extracellular space
b) Bone
c) Tendons
d) Hooves
View Answer
Explanation: The collagen can be found in extracellular space of the tissues especially of connective tissue. It is also found in bones, tendons and ligaments. The main reason for the rigidity of the bone even though it’s basic component is collagen, is the mineralisation. Tendons are also connective tissues. Hence, they are made of collagen. But hooves are made of keratins.
11. Which of the following are the basic functions of a fibrous protein?
a) Provide shape, support, external protection
b) Enzymatic, regulatory functions
c) Only provide structural support
d) Fight foreign antigens
View Answer
Explanation: Fibrous proteins are mainly found in systems that provide shape and support like collagen and keratin while regulatory functions are taken care of by globular proteins like myoglobin.
12. What kind of protein is ferritin?
a) Extracellular protein
b) Membrane protein
c) Intercellular protein
d) Intracellular protein
View Answer
Explanation: Ferritin is an intracellular protein that is present in tissues. It regulates the iron levels in the body and stores iron.
13. Which of the following domain does not contain helices?
a) Alpha+beta
b) Alpha/beta domain
c) Beta domain
d) Alpha domain
View Answer
Explanation: As the name suggests, alpha domains contain alpha helices. And alpha/beta domains contain several beta-alpha-beta motifs which also contains alpha helices linking parallel beta sheets. Alpha+beta domains also contain alpha helices but in less number. But the beta domain does not contain alpha helices. Hence, the answer is the beta domain.
14. What are active type of proteins?
a) Structural components
b) Proteins involved in biological function
c) Ribosomal proteins
d) Non-functional protein
View Answer
Explanation: It is one of the two types of protein like passive and active. Active proteins are the one which are involved in biological function of the cell. These components will have specific function like synthesis or metabolism.
15. Which of the following is not a function of globular proteins?
a) Regulate various bio-reactions
b) Transport biomolecules through membranes
c) Catalyze organic reactions
d) Provide structural stability
View Answer
Explanation: Globular proteins mainly participate in regulatory, catalytic and transportation functions whereas fibrous proteins engage in provide structural stability.
Chapterwise Multiple Choice Questions on Structural Biology
- Amino Acid Metabolism
- Covalent Structure of Proteins and Nucleic Acids
- Three Dimensional Structure of Proteins
1. Structural Biology MCQ on Amino Acid Metabolism
The section contains multiple choice questions and answers on composition and primary structure of proteins.
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2. Covalent Structure of Proteins and Nucleic Acids
The section covers Structural Biology questions and answers on conformational analysis of proteins and determinants of protein structure.
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3. Three Dimensional Structure of Proteins
The section contains MCQs on the three-dimensional structure of proteins, protein beta structures, Ramachandran Plot, protein motifs, domain structures, Hill constant, keratin, collagen, potential energy, quaternary structure, immunoglobulin, ferritin, insulin, and globular proteins.
Wish you the best in your endeavor to learn and master Structural Biology!
