Biology · Chemistry

Biomolecules and Enzymes

1,432 Questions

This topic focuses on biomolecules, specifically proteins, enzymes, and amino acids. It includes questions on enzyme structures, protein folding, and catalysis. These concepts are crucial for medical and biology competitive exams.

Enzyme catalysisProtein structuresAmino acid synthesisPolypeptide chainsBiomolecule properties

Biomolecules and Enzymes Questions

Multiple choice bio-chemistry cell-the basic unit of life introduction to cell discovery and cell theory cell discovery cell discovery and cell theory cell as structural and functional unit

Which of the following gives a possible sequence of organic chemicals prior to the proto -cell?

  1. Water, salts, protein, oxygen

  2. Inorganic gases, amino acids, polypeptide, microsphere

  3. Inorganic gases, nucleotides, nucleic acids, genes

  4. Both (b) and (c)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The photocell was not considered a cell until it contained the genes. According to the first RNA hypothesis, the first genes and enzymes were RNA molecules. The first protein hypothesis suggested that protein enzymes were needed before nucleic acids could form. So, the correct option is "both (b) and (c)".

Multiple choice biology digestion and absorption digestion in small intestine digestive glands and their secretions alimentary canal

Match the enzymes with their respective substrates and choose the right one among options given.

Column I Column II
A. Lipase  (i) Dipeptides 
B. Nuclease  (ii) Fats
C. Carboxypeptidase  (iii) Nucleic acids
D. Dipeptidases  (iv) Proteins, peptones and proteoses 

  1. A-(ii), B-(iii), C-(i), D-(iv)

  2. A-(iii), B-(iv), C-(ii), D-(i)

  3. A-(iii), B-(i), C-(iv), D-(ii)

  4. A-(ii), B-(iii), C-(iv), D-(i)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

(A) Lipase - Fats

(B) Nuclease - Nucleic acids
(C) Carboxypeptidase - Proteins, peptones and proteoses
(D) Dipeptidases - Dipeptides
So, the correct answer is (d).

Multiple choice bio-chemistry minerals minerals and vitamins nutrition and diet role of various nutrients

Which one is wrong combination?

  1. $N _2$-Amino acid

  2. Fe-cytochrome

  3. Na-Protein

  4. Mg-Chlorophyll

  5. P-DNA
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Na- Protein is wrong combination as Nitrogen (N) is needed for the protein formation. Nitrogen is the main constituent of the amino acid that helps in the formation of protein

Thus, the correct answer is option C.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Basically how many types of enzymes have been recognised by International Union of Biochemistry?

  1. 4

  2. 5

  3. 6

  4. 8
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

According to the modern classification system given by International Union of Biochemistry, enzymes have been classified into six classes as follows :
Class First is Oxidoreductase.
Class Second is Transferase.
Class Third is Hydrolase.
Class Fourth is Lyase.
Class Fifth is Isomerase.
Class Sixth is Ligase.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Which one is not an example for hydrolases?

  1. Dehydrogenase

  2. Protease

  3. Amylase

  4. Esterase

  5. Sucrase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Dehydrogenases catalyze dehydrogenation reactions which involve addition or removal of electrons. The addition or removal of electrons will lead to reduction or oxidation of substrates. Dehydrogenases are a type of oxidoreductases. Some of the important hydrolases includes amylases, sucrase, lactase, maltase, protease, esterase etc.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Which is false about prosthetic groups?

  1. Proteins

  2. Non-proteins

  3. Metal compounds

  4. Tightly bound to enzymes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Many enzymes show enzymatic activity only in association with certain non protein substances. Such substances are known as cofactors. Cofactors may be simple ions such as magnesium or potassium ions or complex organic compounds. An organic non-protein cofactor which is easily separable from the enzyme is called coenzyme and the non-protein organic cofactor which is tightly bound to and non-dissociable from the enzyme is termed as prosthetic group. The organic cofactors directly reduce the activation energy and thus form a functional part of active site of enzyme. They act as carriers of chemical groups, atoms or electrons removed from the substrates during reactions.

Thus, the correct answer is option A.  

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Enzymes with heme as prosthetic group are 
(a) Catalase
(b) Carboxypeptidase
(c) Succinic dehydrogenase
(d) Peroxidase

  1. a and d

  2. a ony

  3. a and b

  4. b and c

  5. c and a
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Certain enzymes are made up of two parts - a protein part of enzyme called apoenzyme and a non-protein part called cofactor. Such enzymes are called conjugated enzymes. The working combination of apoenzyme and cofactor together form the holoenzyme. Organic cofactors are of two types- coenzymes and prosthetic groups. Coenzymes are easily separable organic cofactors while prosthetic groups are non-protein organic cofactors firmly associated with protein part of enzyme called apoenzyme. Heme is iron containing prosthetic group in hemoglobin, myoglobin, cytochrome, catalase and peroxidase. Catalase and peroxidase cause the breakdown of hydrogen peroxide to oxygen and water. Carboxypeptidase requires zinc for its activity.

Thus, the correct answer is option A.  

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

A simple enzyme is

  1. Succinate dehydrogenase

  2. Urease

  3. Transaminase

  4. Ribozyme
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Succinate dehydrogenase is a enzyme which is present in the inner mitochondrial membrane. It plays an important role in citric acid cycle and the electron transport chain.
It catalyzes the oxidation of succinate to fumarate. It is a conjugated protein as it has flavo protein which has FMN or FAD molecule as a prosthetic group.
So, the correct answer is option A.
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

In which one of the following enzymes, is copper necessarily associated as an activator? 

  1. Carbonic anhydrase

  2. Tryptophanase

  3. Lactic dehydrogenase

  4. Tyrosinase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Tyrosinase is a copper-containing enzyme present in plant and animal tissues that catalyzes the production of melanin and other pigments from tyrosine by oxidation, as in the blackening of a peeled or sliced potato exposed to air. In animals it is found inside melanosomes which are synthesised in the skin melanocytes.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Carbonic anhydrase is the best known example of 

  1. Hydrolase

  2. Transferase

  3. Lyase

  4. Coagulative
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lyase are the enzymes which catalyze breakdown reactions without hydrolysis. Lyases are classified as EC 4 in the EC number classification of enzymes. Lyases can be further classified into several subclasses : EC 4.1 includes lyases that cleave carbon-carbon bonds, such as decarboxylases (EC 4.1.1), aldehyde lyases (EC 4.1.2), oxo acid lyases (EC 4.1.3) and others (EC 4.1.99).

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

First discovered enzyme was

  1. Isomerase

  2. Transaminase

  3. Zymase

  4. Transferase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Enzymes are biological catalysts, which activate various biochemical reactions of a living cell in a highly specific and precise manner. Enzymology is the study of enzymes. The name enzyme was coined by Kuhne in 1878. Pasteur recognised that some microorganisms like yeasts have got a capacity to cause fermentation in wine. In 1897, Buchner discovered that yeast extract could bring about fermentation of grape juice, like the living yeast cells. He also observed that the extract has lost its catalytic activity on boiling. He coined the word zymase for the active principle involved in the fermentation. The substance on which the enzyme acts is called substrate. Enzymes are essentially proteins but all proteins are not enzymes.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these

  1. Are exclusively synthesized in the body of a living organism as at present.

  2. Enhance oxidative metabolism.

  3. Are conjugated proteins.

  4. Help in regulating metabolism.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
There are more than thousand of biomolecules involve in living organisms in various biological processes. Some are vitamins, hormones, enzymes, ATP, carbohydrates, lipids, nucleic acids and proteins. Out of these main carbohydrates, proteins, lipids and nucleic acid are main biomolecules which play a vital role in living systems and mainly responsible for almost all biochemical processes. The biological molecules or biomolecules are involved in metabolic activities of living bodies such as plants and animals. Most of the biomolecules in the living cell have some broad functions like:
1. They are essential to cellular and body structure.
2. They act as energy-rich fuels during cellular respiration.
3. The molecules are used to carry information of controlling growth and biological characteristics from one generation to another.
4. They are good catalytic agents for the various chemical processes occur in cell and living body.
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Which of the following set of three items are true, as each set belongs to the category mentioned against them?

  1. Lysine, glycine, thiamine - Amino acids

  2. Myosin, oxytocin and gastrin - Hormones

  3. Rennin, helicase and hyaluronidase - Enzyme

  4. Optic nerve, oculomotor, vagus - Sensory nerves
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Rennin is a protease found in rennet. It is produced by newborn ruminant animals in the lining of the fourth stomach to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption. It is widely used in the production of cheese.

Helicases are enzymes that bind and may even remodel nucleic acid or nucleic acid protein complexes. There are DNA and RNA helicases. DNA helicases are essential during DNA replication because they separate double-stranded DNA into single strands allowing each strand to be copied.
Hyaluronidase is a protein enzyme. It works by causing rapid spreading of injected fluid into the body, which increases the absorption of injected fluids.
Therefore, the correct answer is option C.