Biochemistry-I MCQs | BIO202 MCQs | Set 4

MCQs (Multiple Choice Questions)

1)    Which of the following shows the greatest tendency to form α helices in most experimental model systems?

    a)        Glycine 

    b)       Alanine 

    c)        Proline 

    d)       Serine 

Correct Answer: 

The correct answer is  'b'.

Explanation:

In most experimental model systems, alanine has the greatest tendency to form α-helices among the options listed. This is because alanine's relatively small and non-bulky side chain allows for a more stable and regular α-helix structure. Proline, on the other hand, is known to disrupt α-helical structures due to the constraints imposed by its cyclic side chain.

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2)    Immunoglobulin G (IgG) consists of __________.

    a)        Two heavy chains and two light chains

    b)        Four heavy chains

    c)        Four light chains 

    d)        None of these

Correct Answer: 

The correct answer is  'a'.

Explanation:

Immunoglobulin G (IgG) is a type of antibody and belongs to a class of proteins known as immunoglobulins. Its structure consists of two identical heavy chains and two identical light chains connected by disulfide bonds. This arrangement gives IgG its characteristic Y-shaped structure. The heavy chains provide the structural framework and antigen-binding site, while the light chains are responsible for antigen recognition and binding. This is why IgG is composed of two heavy chains and two light chains.

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3)    The free energy of a protein molecule is influenced by _________.

    a)       Hydrophobicity  

    b)       hydrogen bonds  

    c)       electrostatic interactions  

    d)       All of these 

Correct Answer: 

The correct answer is  'd'.

Explanation:

The free energy of a protein is affected by factors such as hydrophobicity, hydrogen bonds, and electrostatic interactions, among others. These interactions and properties play a significant role in determining the stability and folding of protein structures, and they influence the protein's free energy.

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4)    Proteins are denatured by ____________.

    a)        Temperature Ph

    b)        organic solvents 

    c)        temperature, pH, organic solvents

    d)       None

Correct Answer: 

The correct answer is  'c'.

Explanation:

Proteins can be denatured by changes in temperature, pH, and exposure to organic solvents. These factors can disrupt the native three-dimensional structure of proteins, leading to denaturation.

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5)    About ________ of amino acid residues in the myoglobin are found in alpha helices.

    a)        98%

    b)        78% 

    c)         27% 

    d)        10%  

Correct Answer:

The correct answer is  'b'.

Explanation:

Myoglobin is a globular protein found in muscle cells. It stores oxygen and releases it to the muscle cells during exercise. Myoglobin has a very high alpha helical content, with about 78% of its amino acid residues in alpha helices.

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6)     Hemoglobin is found exclusively in ______________. 

    a)       white blood cells

    b)       red blood cells

    c)       platelets 

    d)       platelets and white blood cells 

Correct Answer: 

The correct answer is  'b'.

Explanation:

Hemoglobin is found exclusively in red blood cells (erythrocytes). It is a protein that is responsible for binding to and transporting oxygen in the bloodstream. Hemoglobin gives red blood cells their characteristic red color.

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7)    Starch is an example of 

    a)        Polysaccharides

    b)        Monosaccharides

    c)        Disaccharides

    d)       Oligosaccharides

Correct Answer: 

The correct answer is  'a'.

Explanation:

Starch is a polysaccharide. It is composed of multiple glucose molecules linked together and serves as a storage form of energy in plants.

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8)    Which one of the following is not a property of carbohydrates?

    a)        Raw material for glycolysis

    b)        Major source of energy

    c)        Glucose is important monomer

    d)       Contain many amino acids

Correct Answer: 

The correct answer is  'd'.

Explanation:

Carbohydrates do not typically contain amino acids as a part of their structure. Carbohydrates are primarily composed of carbon, hydrogen, and oxygen atoms and are an important source of energy for living organisms. Glucose is indeed an important monomer in carbohydrate structures, and they can serve as a raw material for glycolysis and a major source of energy. However, they are distinct from proteins, which are composed of amino acids. 

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9)     Starch is found in _________.

    a)        Viruses

    b)        Bacteria

    c)         Plants

    d)        Animals

Correct Answer: 

The correct answer is  'c'.

Explanation:

Starch is primarily found in plants. It serves as a storage form of energy in plant cells, much like glycogen serves as an energy storage molecule in animals.

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10)   C6H12O6 is th formula of ________.  

    a)        Maltose

    b)        Lactose

    c)        Sucrose

    d)       Glucose

Correct Answer: 

The correct answer is  'd'.

Explanation:

The chemical formula C6H12O6 corresponds to glucose, which is a monosaccharide and one of the most important simple sugars in biology.

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