Free NEET Chemistry multiple-choice questions on Nucleic Acids & Vitamins. Attempt each question and reveal the answer with a full explanation.
Vitamin B 12 is unique among vitamins because it contains which of the following? A coordinate covalent bond with a metal ion A long hydrocarbon tail like chlorophyll Multiple carboxylic acid groups Only carbon, hydrogen, and oxygen Which metal ion is present in Vitamin B 12 ? Cobalt Magnesium Iron Zinc A nucleoside differs from a nucleotide in that it lacks a: Phosphate group Nitrogenous base Pentose sugar Hydroxyl group The sugar moiety present in RNA is: -D-ribose -D-2-deoxyribose -D-fructose -D-ribose Which of the following is NOT an enzyme? Insulin Pepsin Trypsin Amylase The helical structure of DNA is held together by hydrogen bonds between: Nitrogenous bases Sugar and phosphate groups Phosphate groups Amino acids Which vitamin deficiency leads to increased blood clotting time? Vitamin K Vitamin E Vitamin D Vitamin A Which of the following chemical names is correctly matched with Vitamin B 6 ? Pyridoxine Riboflavin Thiamine Cyanocobalamin The number of hydrogen bonds between Guanine ( G ) and Cytosine ( C ) in a DNA double helix is: 3 2 1 4 Which vitamin deficiency causes 'Ariboflavinosis', characterized by inflammation of the tongue and sores at the corners of the mouth? Vitamin B 2 Vitamin B 1 Vitamin B 12 Vitamin C Which vitamin is also known as Vitamin H ? Biotin Pantothenic acid Folic acid Pyridoxine Which vitamin is destroyed when food is cooked for a long duration, especially in open vessels? Vitamin C Vitamin A Vitamin D Vitamin K Xerophthalmia, a condition of dry eyes that can lead to blindness, is caused by the deficiency of: Vitamin A Vitamin D Vitamin E Vitamin K Which of the following nitrogenous bases is found in RNA but not in DNA? Uracil Thymine Adenine Guanine Vitamin E is also known for its 'antisterility' properties. What is its chemical name? Tocopherol Retinol Calciferol Phylloquinone The deficiency of which vitamin causes the disease 'Pellagra', characterized by dermatitis, diarrhea, and dementia? Vitamin B 3 (Niacin) Vitamin B 1 (Thiamine) Vitamin B 6 (Pyridoxine) Vitamin B 12 (Cobalamin) Which of the following bases is NOT present in DNA? Uracil Adenine Guanine Cytosine Which vitamin is chemically known as Phylloquinone and is essential for the synthesis of prothrombin? Vitamin K Vitamin E Vitamin D Vitamin A Which vitamin is chemically known as Riboflavin and serves as a precursor for the coenzymes FMN and FAD? Vitamin B 2 Vitamin B 1 Vitamin B 6 Vitamin B 12 Among the different types of RNA present in a cell, which one is found in the highest percentage (about 80 % )? rRNA (Ribosomal RNA) tRNA (Transfer RNA) mRNA (Messenger RNA) snRNA (Small nuclear RNA) Which of the following nitrogenous bases contains two heterocyclic rings in its structure? Adenine Uracil Cytosine Thymine Which one of the following is a fat-soluble vitamin? Vitamin A Vitamin B Vitamin C Vitamin H The sugar phosphate backbone of DNA is formed by: Phosphodiester bonds Hydrogen bonds Peptide bonds Glycosidic bonds The deficiency of Vitamin K leads to 'Hypoprothrombinemia'. This condition results in: Delayed blood clotting Night blindness Scurvy Rickets In the DNA double helix, how many hydrogen bonds form between Adenine and Thymine? Two Three One Four Which vitamin is necessary for the absorption of calcium and phosphorus from the intestine? Vitamin D Vitamin C Vitamin A Vitamin K The difference between a nucleoside and a nucleotide is the presence of: Phosphate group Pentose sugar Nitrogenous base Hydrogen bonds In the DNA double helix, the two strands are held together by hydrogen bonds. How many hydrogen bonds are present between a Guanine-Cytosine ( G-C ) pair? 3 2 1 4 Which of the following is the correct chemical name for Vitamin B 12 ? Cyanocobalamin Thiamine Pyridoxine Riboflavin The sugar moiety in DNA is 2- deoxy-D-ribose . The term '2-deoxy' means that the oxygen atom is missing at which position? C-2 C-3 C-1 C-5 The hydrolysis of nucleosides yields: A pentose sugar and a nitrogenous base A pentose sugar and a phosphate group A nitrogenous base and a phosphate group Amino acids The functional group that links the sugar and phosphate in the DNA backbone is: Ester Ether Amide Anhydride Which of the following is the major source of Vitamin C ? Citrus fruits Fish liver oil Egg yolk Wheat germ oil Which of the following vitamins is water-soluble and cannot be stored in the body (except B 12 )? Vitamin C Vitamin A Vitamin D Vitamin E In DNA, the complementary bases are held together by: Hydrogen bonds Covalent bonds Phosphodiester bonds Glycosidic bonds Which of the following vitamins is required for the conversion of prothrombin to thrombin during blood clotting? Vitamin K Vitamin E Vitamin D Vitamin A The vitamin whose deficiency causes the disease 'Beriberi' is: Vitamin B 1 Vitamin B 2 Vitamin B 6 Vitamin B 12 In the DNA double helix, the two strands are held together by hydrogen bonds. Which of the following is the correct number of bonds between Adenine and Thymine? 2 3 1 4 Which of the following vitamins is synthesized by the human body when the skin is exposed to sunlight? Vitamin D Vitamin A Vitamin K Vitamin E Which of the following nitrogenous bases is a Purine? Guanine Cytosine Uracil Thymine Which vitamin is essential for maintaining healthy vision and its deficiency causes 'Night Blindness'? Vitamin A Vitamin C Vitamin D Vitamin K Which of the following molecules acts as the 'energy currency' of the cell? Adenosine triphosphate (ATP) Deoxyribonucleic acid (DNA) Cyclic AMP Glucose-6-phosphate Which of the following is a symptom of Vitamin C deficiency? Bleeding gums Brittle bones Poor blood clotting Skin dermatitis The base found in DNA but not in RNA is: Thymine Uracil Adenine Guanine Vitamin E is a fat-soluble vitamin that primarily functions in the human body as a: Chain-breaking antioxidant Hormone precursor Oxygen carrier Blood clotting factor In the B-form of DNA (Watson-Crick model), the number of base pairs per turn of the helix is approximately: 10 12 8 14 Which of the following is the chemical name for Vitamin B 3 , the deficiency of which causes Pellagra? Niacin Pyridoxine Pantothenic acid Folic acid The coenzyme derived from Vitamin B 2 (Riboflavin) is: FMN NAD+ Coenzyme A TPP RNA and DNA are chiral molecules, their chirality is due to chiral bases chiral phosphate ester units D-sugar component L-sugar component. Which of the following is water-soluble? Vitamin E Vitamin K Vitamin A Vitamin B Given below are two statements : Statement I : A unit formed by the attachment of a base to 1' position of sugar is known as nucleoside. Statement II : When nucleoside is linked to phosphorous acid at 5 ' -position of sugar moiety, we get nucleotide. In the light of the above statements, choose the correct answer from the options given below : Both Statement I and Statement II are true Both Statement I and Statement II are false Statement I is true but Statement II is false Statement I is false but Statement II is true The deficiency of which vitamin causes Pernicious anemia? Vitamin B 12 Vitamin B 1 Vitamin B 2 Vitamin B 6 Which of the following statements is true regarding RNA? It contains D-ribose sugar It contains D-2-deoxyribose sugar It has a double-stranded helical structure only It contains thymine In nucleic acids, the sequence of nucleotides is linked by: 3'-5' phosphodiester linkage 1'-4' glycosidic linkage Peptide linkage Hydrogen bonding What is the chemical name of the nitrogenous base Thymine found in DNA? 5-Methyluracil 2-Methyluracil 4-Methyluracil 3-Methyluracil The deficiency of Vitamin A can lead to the formation of foamy, triangular spots on the conjunctiva of the eye. These are known as: Bitot's spots Koplik's spots Roth's spots Brushfield spots In DNA and RNA, the nitrogenous base is attached to the sugar moiety at which position of the sugar? C-1' C-2' C-3' C-5' The deficiency of which vitamin leads to 'Megaloblastic anemia' and neural tube defects in newborns? Vitamin B 9 (Folic acid) Vitamin B 2 (Riboflavin) Vitamin B 5 (Pantothenic acid) Vitamin C In the backbone of a nucleic acid (DNA or RNA), the phosphodiester linkage joins which carbon atoms of the adjacent pentose sugars? 3' and 5' 1' and 5' 2' and 3' 1' and 4' Structurally, the difference between the sugar moiety in DNA and RNA lies at which carbon atom? C2' C1' C3' C5' According to Chargaff's rule, in a double-stranded DNA molecule, the ratio of (A+G)/(T+C) is always: Equal to 1 Equal to 0.5 Variable Equal to 2 Which vitamin is a component of Coenzyme A and is involved in the metabolism of fatty acids? Vitamin B 5 (Pantothenic acid) Vitamin B 1 (Thiamine) Vitamin B 2 (Riboflavin) Vitamin B 3 (Niacin) Vitamin D 3 , the form synthesized in human skin upon exposure to UV light, is chemically known as: Cholecalciferol Ergocalciferol Retinol Tocopherol In the Watson-Crick model of DNA, the two strands are antiparallel. This means: One strand runs 5' 3' and the other 3' 5' The strands run in the same direction but have different bases One strand is DNA and the other is RNA The strands are mirror images of each other The nucleoside of RNA consisting of Uracil and Ribose sugar is called: Uridine Uridylic acid Deoxyuridine Uracilate Which of the following nitrogenous bases has a single-ring structure? Uracil Adenine Guanine None of these What is the chemical name of Vitamin B 1 ? Thiamine Riboflavin Pyridoxine Cyanocobalamin Which vitamin is synthesized by bacteria in the human colon and is essential for bone health indirectly through calcium regulation? Vitamin K Vitamin A Vitamin C Vitamin E The distance between two adjacent base pairs in the Watson-Crick model of B-DNA is approximately: 3.4 Å 34 Å 20 Å 2 Å In a DNA molecule, the nitrogenous base is linked to the pentose sugar via which type of bond? N-glycosidic bond Phosphodiester bond Peptide bond Hydrogen bond Which of the following vitamins contains a steroidal nucleus in its structure? Vitamin D Vitamin A Vitamin C Vitamin B1 Which of the following nitrogenous bases has a methyl group at the C-5 position? Thymine Uracil Cytosine Adenine The melting temperature ( T m ) of a DNA double helix is the temperature at which 50 % of the DNA is denatured. Which of the following DNA sequences would have the highest T m ? A sequence with 70 % Guanine-Cytosine content A sequence with 70 % Adenine-Thymine content A sequence with equal amounts of all four bases A sequence consisting only of Adenine and Thymine Which of the following vitamins is a constituent of Coenzyme A and is chemically known as Pantothenic acid? Vitamin B 5 Vitamin B 3 Vitamin B 6 Vitamin B 2 Vitamin H (Biotin) is a sulfur-containing vitamin that acts as a coenzyme for which type of reactions? Carboxylation Decarboxylation Transamination Dehydrogenation In a nucleoside, the nitrogenous base is linked to the C-1' of the pentose sugar via which specific type of bond? N-glycosidic bond O-glycosidic bond Phosphodiester bond Peptide bond Which of the following represents the correct order of abundance (percentage of total RNA) of the three major types of RNA in a typical eukaryotic cell? rRNA > tRNA > mRNA mRNA > tRNA > rRNA rRNA > mRNA > tRNA tRNA > rRNA > mRNA A deficiency of Vitamin A in the human body leads to: Xerophthalmia Scurvy Rickets Pellagra RNA is chemically more reactive and genetically less stable than DNA. This is primarily because RNA contains: A free 2'-OH group on the ribose sugar Uracil instead of Thymine A single-stranded structure A phosphate group at the 5' end Which of the following descriptions accurately defines the 3',5'-phosphodiester linkage in DNA? A phosphate group joins the 3' carbon of one sugar to the 5' carbon of the next A phosphate group joins the 1' carbon of one sugar to the 3' carbon of the next A base joins the 3' carbon of one sugar to the 5' carbon of the next A phosphate group joins the 2' carbon of one sugar to the 5' carbon of the next In the B-DNA double helix, the two strands are right-handed. Which alternative form of DNA is characterized by a left-handed helical twist? Z-DNA A-DNA C-DNA D-DNA According to Chargaff's rules, which of the following is NOT necessarily true for single-stranded RNA? The amount of Guanine equals the amount of Cytosine The sum of Purines equals the sum of Pyrimidines The amount of Adenine equals the amount of Uracil All of the above Vitamin B 6 exists in three natural forms. Which of the following is NOT one of these forms? Pyridoxine Pyridoxal Pyridoxamine Pyridoxic acid What is the net charge on a DNA molecule at physiological pH ( 7.4 )? Negative Positive Neutral Variable depending on the base sequence Vitamin D 2 , which is found in plants and fungi, is also known by the chemical name: Ergocalciferol Cholecalciferol Tocopherol Retinol Which of the following statements about Vitamin C (Ascorbic Acid) is NOT correct? It can be stored in large quantities in the human body It acts as a reducing agent in the hydroxylation of Proline Its deficiency causes Scurvy It is a water-soluble vitamin Cheilosis (fissuring at corners of mouth) is caused by the deficiency of: Vitamin B 2 Vitamin B 1 Vitamin B 6 Vitamin B 12 In DNA, if the percentage of Adenine is 30 % , what is the percentage of Guanine? 20 % 30 % 70 % 40 % Which vitamin is also known as Ascorbic acid? Vitamin C Vitamin A Vitamin D Vitamin E Which of the following is used in the synthesis of Vitamin D when the skin is exposed to sunlight? 7-Dehydrocholesterol Ergosterol Cholesterol Tocopherol The 'Corrin' ring system, similar to the porphyrin ring in heme, is found in which vitamin? Vitamin B 12 Vitamin B 2 Vitamin B 6 Vitamin E The deficiency of which of the following vitamins causes 'Burning feet syndrome'? Vitamin B5 Vitamin B1 Vitamin B6 Vitamin B2 Which of the following is the biologically active form of Vitamin D in the human body? 1,25-dihydroxycholecalciferol Ergocalciferol Cholecalciferol 7-dehydrocholesterol Scurvy is a disease characterized by bleeding gums and poor wound healing. It is caused by Vitamin C deficiency because the vitamin is a cofactor for the enzyme that hydroxylates which amino acid in collagen? Proline Glycine Leucine Valine The nitrogenous base Uracil is chemically known as: 2,4-dioxopyrimidine 2-amino-4-hydroxypyrimidine 4-amino-2-oxopyrimidine 5-methyl-2,4-dioxopyrimidine Vitamin B 1 (Thiamine) contains two heterocyclic rings in its structure. These rings are: Pyrimidine and Thiazole Pyridine and Imidazole Pyrimidine and Pyrrole Pyridine and Thiazole The heterocyclic ring system present in the structure of Vitamin B 2 (Riboflavin) is known as: Isoalloxazine Pteridine Corrin Purine The nitrogenous bases in DNA can exist in different tautomeric forms. Under physiological conditions, which forms are predominant for the Keto/Enol and Amino/Imino pairs? Keto and Amino Enol and Imino Keto and Imino Enol and Amino Match the vitamins in List I with their sources in List II A-II, B-III, C-IV, D-I A-IV, B-I, C-II, D-III A-IV, B-II, C-I, D-III A-III, B-I, C-IV, D-II