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MCQOPTIONS
This section includes 14620 Mcqs, each offering curated multiple-choice questions to sharpen your NEET knowledge and support exam preparation. Choose a topic below to get started.
| 1051. |
Chargaff's rule is applicable to: |
| A. | Single stranded RNA |
| B. | Single stranded DNA and RNA |
| C. | Single stranded DNA |
| D. | Double stranded DNA |
| Answer» E. | |
| 1052. |
Satellite DNA: |
| A. | Is classified in many categories such as micro-satellites, mini satellites, etc. on the basis of base composition length of segments and number of repetitive units. |
| B. | Normally does not code for any protein. |
| C. | Shows polymorphism. |
| D. | All of the above |
| Answer» E. | |
| 1053. |
DNA fingerprinting using Variable Number Tandem Repeats (VNTRs) is based on the observation that: |
| A. | Every individual has unique alleles at each VNTR locus. |
| B. | The DNA of VNTR loci is more stable than that of loci which code for proteins. |
| C. | VNTR sequences show little variability. |
| D. | VNTR loci are highly polymorphic. |
| Answer» E. | |
| 1054. |
In an eukaryote, a repressor protein may block gene expression by binding to a DNA site called : |
| A. | Operon |
| B. | Histone |
| C. | Enhancer |
| D. | Promoter |
| Answer» D. Promoter | |
| 1055. |
The following ratio is generally constant for a given species: |
| A. | \[\frac{A+G}{C+T}\] |
| B. | \[\frac{T+C}{G+A}\] |
| C. | \[\frac{A+T}{G+C}\] |
| D. | \[\frac{A+C}{T+G}\] |
| Answer» D. \[\frac{A+C}{T+G}\] | |
| 1056. |
In a mutational event, when adenine is replaced by guanine, it is a case of: |
| A. | Frame shift mutation |
| B. | Transcription |
| C. | Transition |
| D. | Transversion |
| Answer» D. Transversion | |
| 1057. |
Number of ammo acids in a polypeptide chain is 150. The number of mRNA bases required is: given species: |
| A. | 150 |
| B. | 450 |
| C. | 100 |
| D. | 50 |
| Answer» C. 100 | |
| 1058. |
Which of the following characters is not associated with a leading strand? |
| A. | Its replication proceeds away from the fork. |
| B. | Its replication takes place in continuous manner. |
| C. | Its replication takes place in along 3'-5' direction of template strand. |
| D. | All of the above. |
| Answer» B. Its replication takes place in continuous manner. | |
| 1059. |
Antibiotic inhibiting interaction between t RNA and mRNA during protein synthesis in bacteria is: |
| A. | Tetracycline |
| B. | Neomycin |
| C. | Erythromycin |
| D. | Streptomycin |
| Answer» C. Erythromycin | |
| 1060. |
Which of the following is the first thing that happens when a signal molecule acts on a target cell? |
| A. | A transcription factor acts on the DNA. |
| B. | The signal molecule binds to RNA. |
| C. | A new protein is made in the target cell. |
| D. | The signal molecule binds to a receptor. |
| Answer» E. | |
| 1061. |
In negative operon: |
| A. | Co-repressor binds with repressor |
| B. | Co-repressor does not bind with repressor |
| C. | Co-repressor binds with inducer |
| D. | cAMP have negative effect on lac operon |
| Answer» B. Co-repressor does not bind with repressor | |
| 1062. |
Lactose operon produces enzymes: |
| A. | \[\beta \]-galactosidase, permease and glycogen synthetase. |
| B. | \[\beta \]-galactosidase, permease and transacetylase. |
| C. | Permease, glycogen synthetase and transacetylase. |
| D. | \[\beta \]-galactosidase, permease and phosphoglucose isomerase. |
| Answer» C. Permease, glycogen synthetase and transacetylase. | |
| 1063. |
The most common way of gene expression is regulated in both prokaryotes and eukaryotes is through the: |
| A. | Control of mRNA translation. |
| B. | Breakdown of proteins formed by translation. |
| C. | Prevention of DNA uncoiling prior to transcription. |
| D. | Control of gene transcription. |
| Answer» E. | |
| 1064. |
Which of the following would you expect to find in an inducible system |
| A. | A repressor protein, which is bound to DNA in absence of any other factor. |
| B. | A repressor protein, which is bound to DNA in the presence of a co-repressor. |
| C. | An activator protein, which is bound to D in absence of any other factor. |
| D. | An activator protein, which is bound to DNA only in the absence of an inhibitor. |
| Answer» C. An activator protein, which is bound to D in absence of any other factor. | |
| 1065. |
Chargaff's rules of base pairing states that: |
| A. | The ratio of purines to pyrimidines is roughly equal in all tested organisms. |
| B. | The ratio of A to T is roughly equal in all tested organisms. |
| C. | The ratio of A + T and G + C is roughly equal in all tested organisms. |
| D. | Both [a] and [b] |
| Answer» E. | |
| 1066. |
If a double stranded DNA has 20% of cytosine, what will be the percentage of adenine in it? |
| A. | 20% |
| B. | 0.4 |
| C. | 30% |
| D. | 0.6 |
| Answer» D. 0.6 | |
| 1067. |
A bacterium grown over medium having radioactive \[^{35}S\] incorporates radioactivity in: |
| A. | Carbohydrates |
| B. | Proteins |
| C. | DNA |
| D. | RNA |
| Answer» C. DNA | |
| 1068. |
Match column-I with column-II and select the correct answer using the codes given below. Column-I Column-II A. Operator site I. Binding site for RNA polymerase B. Promoter site II. Binding site for repressor molecule C. Structural gene III. Codes for enzyme protein D. Regulator gene IV. Codes for repressor molecules |
| A. | A-II; B-I; C-III; D-IV |
| B. | A-II; B-I; C-IV; D-II I |
| C. | A-IV; B-III; C-I; D-II |
| D. | A-II; B-III; C-I; D-IV |
| Answer» B. A-II; B-I; C-IV; D-II I | |
| 1069. |
Select the two correct statements out of the four (i - iv) given below about lac operon. (i) Glucose or galactose may bind with the repressor and inactivate it. (ii) In the absence of lactose the repressor binds with the operator region. (iii) The z-gene codes for permease. (iv) This was elucidated by Francois Jacob and Jacque Monod. |
| A. | (ii) and (iii) |
| B. | (i) and (iii) |
| C. | (ii) and (iv) |
| D. | (i) and (ii) |
| Answer» D. (i) and (ii) | |
| 1070. |
The given figure represent one of the step in the process of transcription in bacteria. Identify the step and label A, B & C marked in the figure. |
| A. | Initiation; A - DNA, B - RNA, C - Promoter |
| B. | Termination; A - RNA, B - RNA polymerase, C - Rho factor |
| C. | Elongation; A - RNA, B - RNA polymerase, C - Sigma factor |
| D. | Elongation; A-DNA, B - DNA polymerase, C - RNA |
| Answer» C. Elongation; A - RNA, B - RNA polymerase, C - Sigma factor | |
| 1071. |
Methyl guanosine triphosphate is added at 5' end of hn RNA in a process of: |
| A. | Tailing |
| B. | Splicing |
| C. | Capping |
| D. | None of these |
| Answer» D. None of these | |
| 1072. |
During elongation of polypeptide chain, sigma factor is: |
| A. | Functionless. |
| B. | Retained for specific function. |
| C. | Released for re-use. |
| D. | Required during closing of chain. |
| Answer» B. Retained for specific function. | |
| 1073. |
In ABO system of blood group there are 4-types of: |
| A. | Genotypes |
| B. | phenotypes |
| C. | Antibodies |
| D. | alleles |
| Answer» C. Antibodies | |
| 1074. |
A segment of DNA molecule contains 200 guanine and 200 thymine bases. What will be the total number of nucleotides in this segment of DNA? |
| A. | 400 |
| B. | 200 |
| C. | 800 |
| D. | 100 |
| Answer» D. 100 | |
| 1075. |
From the experiments carried out by Avery, Macleod and McCarty by using various enzymes, which of the following results prominently proved that DNA is the transforming material? |
| A. | DNA of heat killed 'S' + R type + DNAase \[\to \]virulent strain |
| B. | DNA of heat killed 'S'+R type + RNAase \[\to \]virulent strain |
| C. | DNA of heat killed' S' + R type\[\to \]virulent strain |
| D. | DNA of heat killed 'S'+R type + Protease\[\to \]virulent strain |
| Answer» B. DNA of heat killed 'S'+R type + RNAase \[\to \]virulent strain | |
| 1076. |
Phosphodiester linkage is formed between: |
| A. | C-5 of one nucleotide and C-3 of the next |
| B. | C-1 of one nucleotide and C-2 of the next |
| C. | Purines of opposite strands |
| D. | Pyrimidines of opposite strands |
| Answer» B. C-1 of one nucleotide and C-2 of the next | |
| 1077. |
In tertiary structure of DNA, what is a histone octamer? |
| A. | A complex consisting of eight positively charged histone proteins (two of each\[{{H}_{2}}A,{{H}_{2}}B,{{H}_{3}}and{{H}_{4}}\]) that aid in the packaging of DNA. |
| B. | A complex consisting of eight negatively charged histone proteins (two of each\[{{H}_{2}}A,{{H}_{2}}B,{{H}_{3}}and{{H}_{4}}\]) that aid in the packaging of DNA. |
| C. | A complex consisting of nine positively charged histone proteins (\[{{H}_{1}}\]and two of each\[{{H}_{2}}A,{{H}_{2}}B,{{H}_{3}}and{{H}_{4}}\]) that aid in the packaging DNA. |
| D. | A complex consisting of nine negatively charged histone proteins (v\[{{H}_{1}}\] and two of each\[{{H}_{2}}A,{{H}_{2}}B,{{H}_{3}}and{{H}_{4}}\]) that aid in the packaging of DNA. |
| Answer» B. A complex consisting of eight negatively charged histone proteins (two of each\[{{H}_{2}}A,{{H}_{2}}B,{{H}_{3}}and{{H}_{4}}\]) that aid in the packaging of DNA. | |
| 1078. |
What is the main function of tRNA in relation to protein synthesis? |
| A. | Initiates transcription |
| B. | Inhibits protein synthesis. |
| C. | Identifies amino acids and transport them to ribosomes. |
| D. | Proofreading. |
| Answer» D. Proofreading. | |
| 1079. |
Which enzymes will be produced in a cell in which there is a nonsense mutation in the lac Y gene? |
| A. | Lactose Permease |
| B. | Transacetylase |
| C. | Lactose permease and transcetylase |
| D. | \[\beta \]-galactosidase |
| Answer» E. | |
| 1080. |
Given diagram represents the schematic structure of a transcription unit with some parts labeled as A B C and D. Select the option which shows its correct labeling. |
| A. | ABCDTerminatorPromoterTemplate StrandCoding Strand |
| B. | PromoterTerminatorCoding StrandTemplate Strand |
| C. | PromoterTerminatorTemplate StrandCoding Strand |
| D. | TerminatorPromoterCoding StrandTemplate Strand |
| Answer» D. TerminatorPromoterCoding StrandTemplate Strand | |
| 1081. |
If a nucleotide lacking a hydroxyl group at the 3' end is added to a PCR, what would be the outcome? |
| A. | No additional nucleotides would be added to a growing strand containing that nucleotide. |
| B. | Strand elongation would proceed as normal. |
| C. | Nucleotides would only be added at the 5' end. |
| D. | T. aquaticus DNA polymerase would be denatured. |
| Answer» B. Strand elongation would proceed as normal. | |
| 1082. |
DNA polymerisation rate of DNA polymerase is: |
| A. | \[3.9\times {{10}^{7}}bp\] |
| B. | 2000\[bp/s\] |
| C. | \[4.6\times {{10}^{6}}bp\] |
| D. | 5000\[bp/s\] |
| Answer» C. \[4.6\times {{10}^{6}}bp\] | |
| 1083. |
The component of nitrogenase and nitrate reductase is: |
| A. | N |
| B. | Mo |
| C. | Co |
| D. | No specific component |
| Answer» C. Co | |
| 1084. |
Plant obtains nitrogen from soil in the form of: |
| A. | Nitrite |
| B. | Nitrate |
| C. | Ammonia |
| D. | Hydroxylamine |
| Answer» C. Ammonia | |
| 1085. |
Which of the following statement(s) is/are correct? (i) Conversion of organic nitrogen to \[N{{H}_{4}}\]by soil microbes is called ammonification. (ii) Ammonia is first oxidised to nitrite by Nitrosomonas and Nitrosococcus. (iii) The nitrite is further oxidised to nitrate with the help of the bacterium Thiobacillus, (iv) In leaves, nitrate is reduced to form ammonia that finally forms the \[-N{{H}_{2}}\] group of amino acids. (v) Nitrosomonas, Nitrosococcus and Nitrobacter are chemoautotrophs. |
| A. | (i), (ii) and (iii) |
| B. | (ii), (iii), (iv) and (v) |
| C. | (i), (ii) and (iv) |
| D. | (i), (ii), (iv) and (v) |
| Answer» E. | |
| 1086. |
Leguminous plants are able to fix atmospheric nitrogen through the process of symbiotic nitrogen fixation. Which one of the following statements is incorrect during this process of nitrogen fixation? |
| A. | Leghaemoglobin scavanges oxygen and is pinkish in colour. |
| B. | Nitrogenase is insensitive to oxygen. |
| C. | Nodules act as sites for nitrogen fixation. |
| D. | The enzyme nitrogenase catalyses the conversion of atmospheric \[{{N}_{2}}\] to\[N{{H}_{3}}\]. |
| Answer» C. Nodules act as sites for nitrogen fixation. | |
| 1087. |
Find the incorrectly matched pair. |
| A. | Rhizobium \[\to \] Alfalfa |
| B. | Frankia \[\to \] Alnus |
| C. | Rhodospirillum \[\to \] Aerobic |
| D. | Bacillus \[\to \] Free ?living |
| Answer» C. Rhodospirillum \[\to \] Aerobic | |
| 1088. |
Match the items given in column-I with their examples given in column-II and choose the correct answer. Column-I Column-II A. Free living aerobic nitrogen I. Anabaena and Nostoc B. Anaerobic nitrogen fixers II. Pseudomonas and Thiobacillus C. Nitrogen fixing cyanobacteria III. Nitrosomonas and Nitrococcus D. Denitrifying bacteria IV. Azotobacter and Beijernickia E. Nitrifying bacteria V. Rhodospirillum |
| A. | A-IV; B-V; C-I; D -II; E-III |
| B. | A-V; B-IV; C-I; D-III; E-II |
| C. | A-IV; B-V; C-II; D-III; E-I |
| D. | A-IV; B-III; C-I; D-II; E-V |
| Answer» B. A-V; B-IV; C-I; D-III; E-II | |
| 1089. |
Which of the following statements about nitrification is correct? |
| A. | Nitrobacter oxidises nitrate to nitrite. |
| B. | Nitrosomonas and Nitrosococcus convert ammonium ions to nitrite. |
| C. | Nitrification reactions are energy consuming reactions. |
| D. | Heterotrophic plants are more directly dependent on the nitrifying bacteria for usable nitrogen than autotrophic plants. |
| Answer» C. Nitrification reactions are energy consuming reactions. | |
| 1090. |
All of the following statements concerning the Actinomycetous filamentous soil bacterium Frankia are correct except, the Frankia |
| A. | Can induce root nodules on many plant species. |
| B. | Cannot fix nitrogen in the free-living state. |
| C. | Like Rhizobium, it usually infects, its host plant through root hair deformation and stimulates cell proliferation in the host's cortex. |
| D. | Forms specialised vesicles in which the nitrogenase is protected from oxygen by a chemical barrier involving triterpene hopanoids. |
| Answer» C. Like Rhizobium, it usually infects, its host plant through root hair deformation and stimulates cell proliferation in the host's cortex. | |
| 1091. |
Which of the following statement are incorrect? (i) The morphological changes are indicative of certain element deficiencies and are called deficiency symptoms. (ii) The part of plants that show the deficiency symptoms depend on the mobility of the element in the plant. (iii) Deficiency symptoms appear first in the young tissues whenever the element are relatively mobile. (iv) The deficiency symptoms of Cl, Zn, N, O, are visible first in the senescent leaves. |
| A. | (iii) and (iv) |
| B. | (i) and (iii) |
| C. | (i) and (iv) |
| D. | (ii) and (iv) |
| Answer» B. (i) and (iii) | |
| 1092. |
Match column-I with column-II and select the correct answer using the codes given below. Column-I (Element) Column-II (Function) Column-III (Deficiency Symptom) A. Calcium I. Required for ionic balance (i) Grey blot on leaves. B. Boron II. Essential for constitution of nucleic acid (ii) Fruit yield decreases. C. Phosphorus III. Required for absorption of calcium. (iii) Red blots on leaves. D. Chlorine IV. Required to activate respiratory enzyme. (iv) Fruit-size diminishes. E. Manganese V. Required for synthesis of bipolar spindle (v) Young root tip begin to die. |
| A. | A- I-iv; B-II-v; C - III-iii; D - IV-i; E -V-ii |
| B. | A- V-v; B-IV-iv; C - iii-i; D - II-iii; E - I-ii |
| C. | A- IV-iii; B-I-iv; C - V-v; D - III-ii; E - II-i |
| D. | A- V-v; B-III-iv; C - ii-iii; D - I-ii; E - IV-i |
| Answer» E. | |
| 1093. |
Which of the following statement represent hydroponics? (i) Is useful in areas having thin; infertile and dry soils. (ii) Can regulate pH optimum for a particular crop. (iii) Increases labour cost. (iv) Increases problem of weeding. |
| A. | (i),(ii) and (iii) |
| B. | (i) and (ii) |
| C. | (ii) and (iv) |
| D. | (i) and (iii) . |
| Answer» C. (ii) and (iv) | |
| 1094. |
Non-biological nitrogen fixation is: |
| A. | Electrochemical and photochemical |
| B. | Rhizobial |
| C. | Cyanobacterial |
| D. | None of the above |
| Answer» B. Rhizobial | |
| 1095. |
Consider the statements and choose the correct options. (i) The deficiency of any element can cause multiple symptoms. (ii) Same symptoms may be caused by the deficiency of one or several different elements. (iii) The concentration of the essential element below which plant growth is retarded is termed as critical concentration. (iv) Chlorosis is the loss of chlorophyll due to deficiency of N, K, Mg, Fe, S, Mn, Zn, Mo. (v) Different plants respond differently to the deficiency of the same element. |
| A. | All are the above |
| B. | (i) and (iv) |
| C. | (i) and (iii) |
| D. | (iii) and (iv) |
| Answer» B. (i) and (iv) | |
| 1096. |
Azotobacter and Beijerinckia are the examples of: |
| A. | Symbiotic nitrogen-fixers |
| B. | Non-symbiotic nitrogen-fixers |
| C. | Ammonifying bacteria |
| D. | Disease causing bacteria |
| Answer» C. Ammonifying bacteria | |
| 1097. |
Nitrogen gas is reduced to ammonia by: |
| A. | Rhizobium |
| B. | Nitrogenase |
| C. | Nitrification |
| D. | Denitrification |
| Answer» C. Nitrification | |
| 1098. |
Legume's roots have swellings called nodules that: |
| A. | Produce antibiotics that protect the plant from soil bacteria. |
| B. | Provide a steady supply of sugar to the host plant. |
| C. | Increases the surface area for water uptake. |
| D. | Contain nitrogen-fixing bacteria. |
| Answer» E. | |
| 1099. |
Enzyme nitrogenase contains element: |
| A. | Potassium |
| B. | Zinc |
| C. | Molybdenum |
| D. | Manganese |
| Answer» D. Manganese | |
| 1100. |
Which of the following is a bacterium involved in denitrification? |
| A. | Nitrococcus |
| B. | Azotobacter |
| C. | Pseudomonas |
| D. | Nitrosomonas |
| Answer» D. Nitrosomonas | |