Biomolecules Chapter-Wise Test 13

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which of the following statements about coenzymes is incorrect?

Coenzymes are organic molecules that assist enzyme function.
NAD+ and FAD are examples of coenzymes.
Coenzymes are always permanently bound to enzymes.
Some vitamins function as coenzymes.
3

Coenzymes are often loosely bound to enzymes and can be reused; they are not always permanently attached.

Which of the following is a saturated fatty acid?

Oleic acid
Linoleic acid
Palmitic acid
Arachidonic acid
3

Palmitic acid is a saturated fatty acid with no double bonds in its hydrocarbon chain.

Which of the following statements is incorrect about cofactors?

Cofactors are non-protein components that assist enzymes.
Some cofactors are metal ions like zinc and magnesium.
All enzymes require cofactors to function.
Coenzymes are organic cofactors.
3

Not all enzymes require cofactors to function; some enzymes work independently.

Which enzyme catalyzes the breakdown of hydrogen peroxide into water and oxygen?

Amylase
Peroxidase
Lipase
Hexokinase
2

Peroxidase is an enzyme that catalyzes the decomposition of hydrogen peroxide into water and oxygen.

Which biomolecule is responsible for the catalytic activity of ribozymes?

Protein
DNA
RNA
Carbohydrate
3

Ribozymes are RNA molecules that have enzymatic activity.

What is the role of competitive inhibitors in enzyme activity?

They increase enzyme activity
They bind to the active site of the enzyme
They permanently disable the enzyme
They bind to a site other than the active site
2

Competitive inhibitors compete with the substrate for the enzyme’s active site, reducing enzyme activity.

Which of the following statements about DNA is correct?

DNA contains ribose sugar.
DNA contains uracil instead of thymine.
DNA is double-stranded in most organisms.
DNA is made of amino acids.
3

DNA is double-stranded and contains deoxyribose sugar and thymine instead of uracil.

Which of the following statements about enzymes is incorrect?

Enzymes are highly specific in their action.
Enzymes are not affected by temperature and pH.
Some enzymes require cofactors for activity.
Enzymes speed up chemical reactions by lowering activation energy.
2

Enzyme activity is affected by temperature and pH, and extreme conditions can denature them.

Which enzyme class catalyzes oxidation-reduction reactions?

Hydrolases
Transferases
Oxidoreductases
Ligases
3

Oxidoreductases catalyze oxidation-reduction reactions by transferring electrons between molecules.

Which property of enzymes allows them to function as biological catalysts?

They decrease the activation energy of reactions
They are consumed in reactions
They provide energy for reactions
They increase the activation energy of reactions
1

Enzymes function by lowering the activation energy required for a chemical reaction to occur, thus speeding up the reaction.

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