Free NEET Biology multiple-choice questions on Biomolecules. Attempt each question and reveal the answer with a full explanation.
In a protein's primary structure, the first amino acid is typically referred to as the: N-terminal amino acid C-terminal amino acid Alpha-carbon amino acid R-group amino acid Which of the following bonds is found between the hydroxyl group of the 3' carbon of one sugar and the phosphate group of the 5' carbon of the next sugar in a DNA chain? Phosphodiester bond Glycosidic bond Hydrogen bond Peptide bond Thalassemia and sickle cell anemia are caused due to a problem in globin molecule synthesis. Select the correct statement. Thalassemia is a quantitative problem, while sickle cell anemia is a qualitative problem. Thalassemia is a qualitative problem, while sickle cell anemia is a quantitative problem. Both are qualitative problems. Both are quantitative problems. Who among the following used the frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes? Alfred Sturtevant Thomas Hunt Morgan Gregor Mendel Henking Which of the following is an example of pleiotropy where a single gene controls two traits, one of which shows incomplete dominance? Starch grain size and seed shape in Pea Flower color in Snapdragon ABO blood grouping in humans Skin color in humans In a test cross involving an F 1 dihybrid fly, more parental-type offspring were produced than recombinant-type offspring. This indicates: The two genes are linked and present on the same chromosome The two genes are located on different chromosomes The two genes are segregating independently The fly is aneuploid The mutation causing Sickle Cell Anemia results in a change in the mRNA codon at the 6th position from: GAG to GUG GUG to GAG GAA to GUA UAA to UGA Phenylketonuria (PKU) is caused by the deficiency of which enzyme? Phenylalanine hydroxylase Tyrosinase Homogentisic acid oxidase Hexosaminidase In eukaryotes, structural genes are 'monocistronic'. This means: A single structural gene codes for one polypeptide A single structural gene codes for multiple polypeptides Multiple structural genes are controlled by one promoter The gene contains only introns A person with blood group 'AB' has which of the following characteristics? Presence of both A and B antigens on RBCs and absence of antibodies in plasma Absence of antigens on RBCs and presence of both antibodies in plasma Presence of antigen A and antibody b Presence of antigen B and antibody a In prokaryotes, several structural genes are often regulated by a single promoter and transcribed together as a single mRNA. This unit is called: Polycistronic Monocistronic Exon Split gene Which of the following statements about the 'Coding Strand' of a transcription unit is CORRECT? It has the same sequence as mRNA except for Thymine instead of Uracil It acts as a template for RNA synthesis It is read in the 3' 5' direction by RNA polymerase It is translated directly into proteins Which nitrogenous base is present in RNA but absent in DNA ? Uracil Thymine Cytosine Guanine Thymine is also chemically known as: 5-methyl uracil 2-oxy-4-amino pyrimidine 6-amino purine 1-methyl uracil Interactions between alleles of different genes located at different loci on the same or different chromosomes are called: Non-allelic interactions Intra-allelic interactions Multiple allelism Incomplete dominance According to the 'Central Dogma' proposed by Francis Crick, the flow of genetic information is: DNA RNA Protein RNA DNA Protein Protein RNA DNA DNA Protein RNA Which of the following nitrogenous bases is NOT found in the early 'RNA World' according to evolutionary theories, but appeared later in DNA? Thymine Uracil Adenine Guanine The phenomenon where the interaction between two non-allelic genes results in one gene masking the expression of another is called: Epistasis Codominance Incomplete Dominance Polygenic inheritance If a double-stranded DNA molecule contains 30 % Guanine, what is the percentage of Thymine in the molecule? 20% 30% 40% 70% In Beta-Thalassemia ( -thalassemia), the production of the -globin chain is controlled by a single gene located on which chromosome? Chromosome 11 Chromosome 16 Chromosome 21 Chromosome X In the Hershey-Chase experiment, why was radioactive Phosphorus ( 32 P ) used specifically to label DNA? Phosphorus is present in DNA but not in proteins Phosphorus is present in the sulfur-containing amino acids Phosphorus forms the peptide bond in proteins DNA contains a sulfur-phosphate backbone During the transcription of DNA, which strand acts as the 'coding strand'? The strand with 5' to 3' polarity that does not code for RNA The strand with 3' to 5' polarity that acts as a template The newly synthesized RNA strand The strand that contains only introns Thalassemia is an autosomal linked recessive blood disorder. In -Thalassemia, the production of -globin chain is affected by genes located on which chromosome? Chromosome 16 Chromosome 11 Chromosome 21 X Chromosome Which of the following is an example of a secondary metabolite? Vinblastin Glucose Glycine Adenine A phosphoglyceride is always made up of Only a saturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached Only an unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached A saturated or unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached A saturated or unsaturated fatty acid esterified to a phosphate group which is also attached to a glycerol molecule Match the following (a) Inhibitor of catalytic activity (b) Possess peptide bonds (c) Cell wall material in fungi (d) Secondary metabolite Choose the correct option from the following (1) (iii) (i) (iv) (ii) (2) (iii) (iv) (i) (ii) (3) (ii) (iii) (i) (iv) (4) (ii) (iv) (iii) (i) Identify the substances having glycosidic bond and peptide bond, respectively in their structure Glycerol, trypsin Cellulose, lecithin Inulin, insulin Chitin, cholesterol Which of the following statements is not correct? The proinsulin has an extra peptide called C-peptide. The functional insulin has A and B chains linked together by hydrogen bonds. Genetically engineered insulin is produced in E.Coli. In man insulin is synthesised as a proinsulin Match List-I with List-II. array llll ; & List-I & ; & List-II (a) & Protein & (i) & C = C double bonds (b) & Unsaturated fatty acid & (ii) & Phosphodiester bonds (c) & Nucleic acid & (iii) & Glycosidic bonds (d) & Polysaccharide & (iv) & Peptide bonds array Choose the correct answer from the options given below. a-i, b-iv, c-iii, d-ii a-ii, b-i, c-iv, d-iii a-iv, b-iii, c-i, d-ii a-iv, b-i, c-ii, d-iii Following are the statements with reference to 'lipids'. (a) Lipids having only single bonds are called unsaturated fatty acids (b) Lecithin is a phospholipid. (c) Trihydroxy propane is glycerol. (d) Palmitic acid has 20 carbon atoms including carboxyl carbon. (e) Arachidoonic acid has 16 carbon atoms. Choose the correct answer from the options given below. (c) and (d) only (b) and (c) only (b) and (e) only (a) and (b) only Read the following statements on lipids and find out correct set of statements: (a) Lecithin found in the plasma membrane is a glycolipid (b) Saturated fatty acids possess one or more c = c bonds (c) Gingely oil has lower melting point, hence remains as oil in winter (d) Lipids are generally insoluble in water but soluble in some organic solvents (e) When fatty acid is esterified with glycerol, monoglycerides are formed Choose the correct answer from the option given below: (a), (d) and (e) only (c), (d) and (e) only (a), (b) and (d) only (a), (b) and (c) only Given below are two statements: Statement I: A protein is imagined as a line, the left end represented by first amino acid (C-terminal) and the right end represented by last amino acid (N-terminal). Statement II: Adult human haemoglobin, consists of 4 subunits (two subunits of α type and two subunits of β type.) 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. Arrange the following elements in descending order of their contribution to percentage weight of the human body. (a) Oxygen (b) Carbon (c) Hydrogen (d) Nitrogen Choose the correct answer from the options given below : (a), (b), (c), (d) (c), (a), (b), (d) (b), (c), (d), (a) (b), (a), (c), (d) Which of the following is a neutral amino acid? Valine Glutamic acid Lysine Arginine Glycerol, a common component of many lipids, is chemically known as: Trihydroxypropane Dihydroxyacetone Trihydroxymethane Dihydroxypropane In a DNA double helix, the number of hydrogen bonds between Adenine and Thymine is , and between Guanine and Cytosine is . 2, 3 3, 2 2, 2 3, 3 The B-DNA model proposed by Watson and Crick is a: Right-handed helix Left-handed helix Triple helix Parallel-stranded helix The secondary structure of proteins, such as the -helix, is stabilized primarily by which type of interaction? Hydrogen bonds Disulfide bridges Ionic bonds Peptide bonds The enzymatic reaction of 'Sucrase' on sucrose results in Glucose + Fructose Glucose + Glucose Glucose + Galactose Fructose + Galactose A nucleoside differs from a nucleotide in that the nucleoside lacks a: Phosphate group Nitrogenous base Pentose sugar Hydroxyl group The formation of a peptide bond between two amino acids is a/an reaction. Dehydration Hydrolysis Oxidation Reduction The primary structure of a protein refers to: The linear sequence of amino acids The folding of the polypeptide into a 3D shape The arrangement of multiple polypeptide subunits The presence of alpha-helices and beta-sheets In a double-stranded DNA molecule, how many hydrogen bonds are formed between a Guanine (G) and a Cytosine (C) base pair? 3 2 1 4 The fact that some amino acids are coded by more than one codon is referred to as: Degeneracy of the genetic code Universality of the genetic code Non-overlapping nature Ambiguity of the genetic code Which of the following is a 'Stop Codon' also known as Amber? UAG UAA UGA AUG Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these - Are exclusively synthesized in the body of a living organism as at present enhance oxidative metabolism Are conjugated proteins Help in regulating metabolism Carbohydrates, the most abundant biomolecules on earth, are produced by - Some bacteria, algae and green plant cells All bacteria, fungi and algae Fungi, algae and green plants cells Viruses, fungi and bacteria Biological organisation starts with cellular level organismic level atomic level submicroscopic molecular level About 98 percent of the mass of every living organism is composed of just six element including carbon, hydrogen, nitrogen, oxygen and sulphur and magnesium magnesium and sodium calcium and phosphorus phosphorus and sulphur. Macro molecule chitin is Nitrogen containing polysaccharide Phosphorus containing polysaccharide Sulphur containing polysaccharide Simple polysaccharide The essential chemical components of many coenzymes are Proteins Nucleic acids Carbohydrates Vitamins A peptide bond is formed between the Carboxyl group of one amino acid and amino group of the next Carboxyl groups of two amino acids Amino groups of two amino acids Hydroxyl group and carboxyl group of amino acids Which one of the following is a non - reducing carbohydrate ? Maltose Sucrose Lactose Ribose 5 - phosphate Which of the following statements is false ? Mg 2+ ions form a complex with ATP Ca 2+ ions are important in blood clotting Ca 2+ ions are not important in maintaining the regular beating of the heart. Mg 2+ ions are important in the green parts of plants. Which one of the following statements is wrong ? (1) Sucrose is a disaccharide. (2) Cellulose is a polysaccharide. (3) Uracil is a pyrimidine. (4) Glycine is a sulphur containing amino acid. A typical fat molecule is made up of :- Three glycerol molecules and one fatty acid molecule One glycerol and three fatty acid molecules One glycerol and one fatty acid molecule Three glycerol and three fatty acid molecules A fat molecule is formed from: Three glycerol molecules and one fatty acid molecule One glycerol molecule and one fatty acid molecule Three glycerol molecules and three fatty acid molecules. One glycerol molecule and three fatty acid molecules Concanavalin A is a pigment an alkaloid an essential oil a lectin Secondary metabolites such as nicotine, strychnine and caffeine are produced by plants for their (1) Growth response (2) Defence action (3) Effect on reproduction (4) Nutritive value Identify the basic amino acid from the following. Glutamic Acid Lysine Valine Tyrosine Which of the following are not secondary metabolites in plants? Amino acids, glucose Vinblastin, curcumin Rubber, gums Morphine, codeine Identify the incorrect pair Toxin – Abrin Lectins – Concanavalin A Drugs – Ricin Alkaloids – Codeine Non-reducing sugar among the following is Sucrose Glucose Fructose Lactose Match List-I with List-II array llll ; & List-I; (Biological Molecules) & ; & List-II; (Biological functions) (a) & Glycogen & (i) & Hormone (b) & Globulin & (ii) & Biocatalyst (c) & Steroids & (iii) & Antibody (d) & Thrombin & (iv) & Storage product array Choose the correct answer from the options given below: (a) - (iv), (b) - (ii), (c) - (i), (d) - (iii) (a) - (ii), (b) - (iv), (c) - (iii), (d) - (i) (a) - (iv), (b) - (iii), (c) - (i), (d) - (ii) (a) - (iii), (b) - (ii), (c) - (iv), (d) - (i) Cellulose does not form blue colour with Iodine because It is a disaccharide It is a helical molecule It does not contain complex helices and hence cannot hold iodine molecules It breaks down when iodine reacts with it Lecithin, a small molecular weight organic compound found in living tissues, is an example of: Amino acids Phospholipids Glycerides Carbohydrates Match List-I with List-II array ll List-I & List-II A. GLUT-4 & I. Hormone B. Insulin & II. Enzyme C. Trypsin & III. Intercellular ground substance D. Collagen & IV. Enables glucose transport into cells array Choose the correct answer from the options given below. (1) A-IV, B-I, C-II, D-III (2) A-I, B-II, C-III, D-IV (3) A-II, B-III, C-IV, D-I (4) A-III, B-IV, C-I, D-II Match List I with List II: array llll ; & List-I & ; & List-II A. & Adenosine & I. & Nitrogen base B. & Adenylic acid & II. & Nucleotide C. & Adenine & III. & Nucleoside D. & Alanine & IV. & Amino acid array Choose the option with all correct matches. A-II, B-III, C-I, D-IV A-III, B-IV, C-II, D-I A-III, B-II, C-IV, D-I A-III, B-II, C-I, D-IV Alpha-helix is found in which level of protein structure? Secondary structure Primary structure Tertiary structure Quaternary structure Which of the following statements are correct regarding amino acids? A. They are substituted methanes. B. Serine is an aromatic amino acid. C. Valine is a neutral amino acid. D. Lysine is an acidic amino acid. Choose the correct answer from the options given below: A and B only C and D only B and C only A and C only Match List I with List II : array llll ; & List I & ; & List II A. & Trypsin & I. & Intercellular ground substance B. & Morphine & II. & Lectin C. & Concanavalin A & III. & Enzyme D. & Collagen & IV. & Alkaloid array A-III, B-IV, C-II, D-I A-IV, B-III, C-II, D-I A-I, B-II, C-III, D-IV A-III, B-II, C-IV, D-I Identify the correct statements about biomolecules. A. Lipids are generally water soluble. B. Proteins are polypeptides. C. Polysaccharides are long chains of sugars. D. Adenine and guanine are substituted pyrimidines. E. Almost all enzymes are proteins. Choose the correct answer from the options given below : A, B and C only B, D and E only B, C and E only C, D and E only Secondary metabolites like Vinblastine and Curcumin are categorized as Drugs Alkaloids Toxins Lectins The bond formed between the phosphate group and the sugar molecule in the backbone of DNA is a/an Phosphodiester bond Glycosidic bond Hydrogen bond Peptide bond A protein with four polypeptide chains ( 2 and 2 ) such as human hemoglobin represents which level of protein structure? Quaternary structure Tertiary structure Secondary structure Primary structure The most abundant protein in the animal world is , and the most abundant protein in the whole of the biosphere is . Collagen; RuBisCO Insulin; Hemoglobin Collagen; Pepsin Keratin; RuBisCO Fatty acids are found esterified with glycerol to form monoglycerides, diglycerides, and triglycerides. How many carbon atoms are present in Palmitic acid, including the carboxyl carbon? 16 18 20 15 Identify the aromatic amino acid from the following options. Tyrosine Valine Alanine Serine Inulin is a polymer of which of the following monosaccharides? Fructose Glucose Galactose Mannose Amino acids exist as Zwitterions at a specific pH . A Zwitterion is characterized by The presence of both positive and negative charges on the same molecule. The presence of only a positive charge. The presence of only a negative charge. The absence of any charge. Which of the following amino acids contains sulfur in its side chain? Cysteine Serine Tyrosine Proline The -helix and -pleated sheet structures of proteins are examples of: Secondary structure Primary structure Tertiary structure Quaternary structure How many carbon atoms are present in Arachidonic acid, including the carboxyl carbon? 20 16 18 22 In B-DNA , what is the distance (rise) between two consecutive base pairs along the helical axis? 3.4 A 34 A 20 A 2 A In a nucleic acid, a nitrogenous base is linked to the pentose sugar through which of the following bonds? N-glycosidic bond Phosphodiester bond Hydrogen bond Peptide bond The bond formed between two monosaccharides in a polysaccharide is a Glycosidic bond Peptide bond Phosphodiester bond Hydrogen bond The linkage between the nitrogenous base and the pentose sugar in a nucleotide is a: N-glycosidic bond Peptide bond Phosphodiester bond Glycosidic bond Which of the following represents a nucleoside? Adenosine Adenylic acid Adenine Guanine In a polypeptide chain, the bonds that stabilize the -helix and -pleated sheet secondary structures are: Hydrogen bonds Disulfide bonds Ionic bonds Hydrophobic interactions Which of the following is a polymer of fructose? Inulin Glycogen Cellulose Starch Which of the following amino acids is considered optically inactive because its R-group is a simple hydrogen atom? Glycine Alanine Serine Valine Which of the following is an example of a polymeric secondary metabolite? Rubber Morphine Ricin Abrin A nucleosome, the fundamental unit of chromatin, consists of DNA wrapped around a core of: Eight histone proteins Four histone proteins Six histone proteins Two histone proteins Which of the following carbohydrates is a reducing sugar because it possesses a free aldehyde or ketone group? Lactose Sucrose Starch Cellulose If the concentration of Adenine in a double-stranded DNA molecule is 30 % , what is the expected percentage of Cytosine based on Chargaff's Rule? 20% 30% 40% 70% In a polypeptide chain, the first amino acid is also called as the: N-terminal amino acid C-terminal amino acid Alpha-terminal amino acid R-terminal amino acid Which of the following statements about the tertiary structure of proteins is TRUE? It is absolutely necessary for the many biological activities of proteins. It represents only the linear sequence of amino acids. It is stabilized only by peptide bonds. It is a two-dimensional structure. In a DNA molecule, the two strands are held together by hydrogen bonds between nitrogenous bases. How many hydrogen bonds are found in a segment of DNA with 5 Cytosine and 3 Adenine bases? 21 15 24 16 The amino acid Glycine is unique because its R-group is a hydrogen atom. This makes Glycine: The only achiral amino acid The most hydrophobic amino acid A basic amino acid An aromatic amino acid Which of the following is a toxin often found in plants, categorized as a secondary metabolite? Ricin Morphine Vinblastine Concanavalin A In a B-DNA molecule, the two strands are described as being 'antiparallel'. This means: One strand runs 5' 3' and the other 3' 5' orientation. The strands run in the same direction but are twisted. One strand contains purines and the other contains pyrimidines. The strands are parallel but face in opposite directions horizontally. When a protein is subjected to high temperature or extreme pH , it loses its biological activity. This process primarily destroys which level of protein structure? Tertiary and Secondary Primary Only Secondary Only Quaternary Chromatin contains DNA , some basic proteins called histones, some non-histone proteins, and: RNA ATP Lipids Glucose Satellite DNA is important because it Shows high degree of polymorphism in population and also the same degree of polymorphism in an individual, which is heritable from parents to children. Does not code for proteins and is same in all members of the population. Codes for enzymes needed for DNA replication. Codes for proteins needed in cell cycle. In a B-DNA molecule, the pitch of the helix is and there are base pairs in each turn. 34 , ; 10 3.4 , ; 10 34 , ; 12 20 , ; 10 Morphine and Codeine, obtained from the poppy plant, are examples of which type of secondary metabolites? Alkaloids Terpenoids Lectins Drugs A triglyceride is formed by the esterification of: One glycerol molecule with three fatty acid molecules Three glycerol molecules with one fatty acid molecule One glycerol molecule with one fatty acid molecule One fatty acid molecule with three phosphate groups Which of the following is considered an 'Essential' amino acid in the human diet? Valine Glycine Alanine Serine The isoelectric point ( pI ) of an amino acid is the pH at which: The amino acid exists primarily as a Zwitterion with no net charge The amino acid has a maximum positive charge The amino acid has a maximum negative charge The amino acid is most soluble in water Identify the incorrect statement regarding the secondary structure of proteins. The β-pleated sheet is formed by hydrogen bonds between amino acids of the same polypeptide chain only. The α-helix is always right-handed in biological proteins. Hydrogen bonds stabilize both α-helix and β-pleated sheets. The secondary structure arises from regular folding of the polypeptide backbone. Which type of DNA helix is left-handed and has a zigzag backbone? Z-DNA B-DNA A-DNA C-DNA The primary structural difference between cellulose and starch is that cellulose is a polymer of: -D-glucose -D-glucose -D-fructose -D-galactose Identify the acidic amino acid among the following options: Glutamic acid Lysine Valine Tyrosine Many coenzymes contain essential chemical components which are vitamins. Which vitamin is found in the coenzymes Nicotinamide Adenine Dinucleotide ( NAD ) and NADP ? Niacin Riboflavin Thiamine Pyridoxine The diameter of a B-DNA double helix is approximately: 20 34 3.4 10 Unsaturated fatty acids are different from saturated fatty acids because they: Contain one or more double bonds between carbon atoms Contain only single bonds between carbon atoms Are solid at room temperature Do not contain a carboxyl group Unsaturated fatty acids are characterized by the presence of: One or more double bonds between carbon atoms Only single bonds between carbon atoms A high melting point compared to saturated fats Maximum number of hydrogen atoms What is the stoichiometric formula for a typical carbohydrate? (CH 2O) n (C 2HO) n (CHO 2) n (CH 3O) n Which of the following is a Lectin, often categorized as a secondary metabolite in plants? Concanavalin A Vinblastine Ricin Curcumin Which of the following is an example of an 'Essential Oil' categorized as a secondary metabolite in plants? Lemon grass oil Castor oil Peppermint oil Coconut oil Kinetin, a modified form of adenine (a purine), was first isolated from: Autoclaved herring sperm DNA Corn kernels Coconut milk Fungus Which of the following describes the 'redundancy' or 'degeneracy' of the genetic code? One amino acid can be coded by more than one codon. One codon can code for more than one amino acid. The code is read in a continuous fashion without punctuation. The code is nearly universal across all life forms. In the Hershey-Chase experiment, which radioactive isotopes were used to label DNA and proteins, respectively? 32 P and 35 S 35 S and 32 P 14 N and 15 N 3 H and 14 C T.H. Morgan observed that even when two genes were located on the same chromosome, some genes were very tightly linked and showed very low recombination. The frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes was explained by: Alfred Sturtevant Gregor Mendel Sutton and Boveri Henking Sickle cell anemia is caused by the substitution of Glutamic acid by Valine at which position of the beta globin chain? 6th position 1st position 11th position 14th position If a double-stranded DNA has 20% of Cytosine, calculate the percentage of Adenine in the DNA. 30% 20% 40% 60% Which of the following enzymes was used by Avery, MacLeod, and McCarty to prove that DNA is the transforming principle? DNase RNase Protease Lipase If the length of DNA in a human diploid cell is approximately 2.2 meters, how many base pairs are present in it? 6.6 10 9 bp 3.3 10 9 bp 4.6 10 6 bp 2.2 10 9 bp