Biology · Chemistry

Biomolecules and Enzymes

1,501 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 biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans
Feed back inhibition of an enzyme is influenced by

  1. Enzyme itself

  2. External factors

  3. End product

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

In feed back inhibition product of a reaction inhibits the enzyme catalysing that reaction. It is a type of control mechanism at the enzyme level. If the product is produced in sufficient amount, it inhibits the enzyme to stop the further production. So, the correct answer is 'End product'.

Multiple choice botany plant breeding common modes of vegetative propagation plant breeding for food production tissue culture

To obtain seedless watermelon, which among the following method is followed?

  1. Apomixis

  2. Somatic hybridization

  3. Organogenesis

  4. Micropropagation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Isolated protoplasts from two different varieties of plants – each having a desirable character – can be fused to get hybrid protoplasts, which can be further grown to form a new plant. These hybrids are called somatic hybrids while the process is called somatic hybridization.
  • Protoplasts are used to produce variations in the morphology of leaves and flowers, ability/potential of the growth of the embryo, and enhancement of disease resistance in plants.
  • To obtain seedless watermelon, somatic hybridization methods are followed.
  • So, the correct answer is 'Somatic hybridization'.
Multiple choice biology kingdom monera, protista and fungi mycorrhiza classification of fungi useful and harmful microbes

Which of the following fungi consists chitosan in its cell wall?

  1. Penicillium

  2. Aspergillus

  3. Mucor

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mucor is a saprotrophic fungus. The cell wall of the fungus contains considerable amounts of chitosan. Chitosan is a linear polysaccharide composed of randomly distributed β-(1→4)linked D glucosamine and N-acetyl glucosamine. It has commercial application in agriculture, biopesticide, and winemaking. Thus the correct answer is option C.

Multiple choice biology food and it's constituents energy giving food carbohydrate and its test biological molecules

A biological molecule made up of only carbon, hydrogen and oxygen.

  1. Lipids

  2. Proteins

  3. Carbohydrates

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

Carbohydrates (CHO) - These are the principle energy storage molecules. They contain carbon (C), hydrogen (H), and oxygen (0) in a 1:2:1 ratio and are classified according to their size into monosaccharide, disaccharide, polysaccharide.

Monosaccharides are simple sugar having single chain or single ring structure which contains 3-7 carbon atoms. Example is glucose with 6 carbons, 12 hydrogens, and 6 oxygens.

Disaccharides: Double sugars are formed by dehydration reaction between 2 monosaccharides glucose + glucose ------ - > maltose + water. Disaccharides are too large to pass through cell membranes and must be digested to simple sugar units by hydrolysis (add water).

Polysaccharides are long chains of simple sugar molecules. The two major molecules of importance are starch, which is used for storage form for carbohydrate fuel in plants and glycogen, which is used for storage form for carbohydrate fuel in animals.

Function: It is ready source of cellular fuel & cellulose, is used for structural support in plants and carbohydrates help form cell receptors for recognition. Hence, option C is correct.

Multiple choice biology food and it's constituents energy giving food carbohydrate and its test biological molecules

Macro molecule chitin is 

  1. Phosphorus containing polysaccharide

  2. Sulphur containing polysaccharide

  3. Simple polysaccharide

  4. Nitrogen containing polysaccharide
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Macro-molecule chitin is a complex nitrogen-containing polysaccharide containing amino sugars and chemically modified sugar for example -glucosamine, N-acetyl-galactosamine etc.

So, the correct answer is 'Nitrogen containing polysaccharide'

Multiple choice biology food and it's constituents energy giving food carbohydrate and its test biological molecules

The prosthetic group of a conjugated protein classified as a glycoprotein is a

  1. Chromomorphic group

  2. Polysaccharide

  3. Metal ion

  4. Lipid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A conjugated protein is a protein that functions in interaction with other (non-polypeptide) chemical groups attached by covalent bonding or weak interactions.  The non-amino part of a conjugated protein is usually called its prosthetic group. Most prosthetic groups are formed from vitamins. Glycoproteins are proteins that contain various amounts of carbohydrate. A number of very important proteins fall in this class, including many of the blood plasma proteins and a large number of en­zymes and hormones. The carbohydrate bonded at each site of the protein may consist of a sin­gle monosaccharide unit or a linear or branched chain of several mono saccharides (called an oligosaccharide).

So, the correct answer is 'Polysaccharide'.
Multiple choice chemistry chemistry in daily life antimicrobials and antifertility drugs therapeutic action of different classes of drugs drugs and their classification

Lysine is used as:

  1. disinfectant

  2. germ killer

  3. treating eye disease

  4. anti-cancer drug
Reveal answer Fill a bubble to check yourself
B,C,D Correct answer
Explanation

Lysine is used for treating eye disease and as an anti-cancer drug because it is a nutritional supplement containing the biologically active L-isomer of the essential amino acid lysine, with potential anti-mucositis activity.
People use it to make medicine, also used for preventing and treating cold sores. 

Multiple choice biology digestive system of human assimilation of food and egestion assimilation of food components and importance of food

Which of the following is known as the building block of proteins?

  1. Amino acids

  2. Enzymes

  3. Fatty acids

  4. Glycogen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Amino acids are directly absorbed into blood stream. Blood carries these amino acids to the tissues where they become part of the metabolic pool, from which body proteins are synthesized. Hence, it is known as the building block of proteins.

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 carbohydrate metabolism energy output living organisms and energy production respiration in cell

One mole of glucose on metabolism, liberate how many kilo calories of energy ?

  1. 180

  2. 80

  3. 160

  4. 380
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

On complete combustion of glucose (1 mole) to CO$ _{2}$ & H$ _{2}$O, approx. 686 kcal of energy is released. When 1 g of glucose respires aerobically by ETS, Glycolysis and  Krebs cycle, around 38 ATP molecules are generated. The terminal group of a mole of ATP has around 10 kcal. Thus, 38 ATP molecules represent a yield of 380 kcal of energy.  

So the correct option is '380'

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

Complete oxidation of 1 gm mol of glucose gives rise to ................. calories.

  1. 6860000

  2. 686000

  3. 68600

  4. 6860

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At pH 7.0 and temperature 298 K, the standard free energy change of oxidation of glucose is -686 Kilocalories per mole or -2840 Kilojoules per mole. The negative values indicate that oxidation of glucose is an exergonic or energy releasing process.