NEET UG
- When gene targetting involving gene amplification is attempted in an individual’s tissue to treat disease, it is known as : Answer: 2. Gene therapy Treating a disease by correcting a defective gene, by delivering a normal gene into a person's cells and tissues, is... 1
- Which of the following is not an application of PCR (Polymerase Chain Reaction) ? Answer: 3. Purification of isolated protein PCR amplifies a chosen DNA segment from small amounts of DNA. It is used for gene amplification,... 1
- During the purification process for recombinant DNA technology, addition of chilled ethanol precipitates out : Answer: 2. DNA DNA is insoluble in ethanol. When chilled ethanol is added to the purified lysate, DNA precipitates and appears as fine threa... 1
- Which of the following is a correct sequence of steps in a PCR (Polymerase Chain Reaction) ? Answer: 1. Denaturation, Annealing, Extension Each PCR cycle has three steps in order: denaturation (double strand separated at about 94 °C)... 1
- The factor that leads to Founder effect in a population is : Answer: 4. Genetic drift The founder effect occurs when a small group of individuals starts a new population. Their allele frequencies diffe... 1
- Gemmae are present in : Answer: 4. Some Liverworts Gemmae are small green multicellular buds that form in gemma cups on the thallus. They are a means of asexual rep... 1
- Inspite of interspecific competition in nature, which mechanism the competing species might have evolved for their survival ? Answer: 1. Resource partitioning When two species compete for the same resource, they may evolve ways to share it. This is resource partitio... 1
- Amensalism can be represented as : Answer: 1. Species A ( - ) ; Species B (0) Amensalism is an interaction in which one species is harmed and the other is unaffected. So it is... 1
- In the equation GPP-R=NPPR represents : Answer: 4. Respiration losses Net primary productivity is gross primary productivity minus the energy used by plants in respiration. So NPP... 1
- DNA strands on a gel stained with ethidium bromide when viewed under UV radiation, appear as : Answer: 2. Bright orange bands Ethidium bromide intercalates between DNA bases. Under UV light, the stained DNA fragments in an agarose gel... 1
- The production of gametes by the parents, formation of zygotes, the F1 and F2 plants, can be understood from a diagram called : Answer: 3. Punnett square The diagram used to show gametes of the parents, the zygotes, and the F1 and F2 genotypes is the Punnett square, d... 1
- Match List - I with List - II.List - I | List - II(a) Cells with active cell division capacity | (i) Vascular tissues(b) Tissue having all cells similar in structure and function | (ii) Meristematic tissue(c) Tissue having different types of cells |… Answer: 1. (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii) Match by definition: Actively dividing cells: meristematic tissue, (a)-(ii). All cells ali... 1
- The RBC deficiency is deficiency disease of : Answer: 1. Vitamin B₁₂ Key idea: vitamin mathrmB₁₂ is needed for red blood cell formation. Its deficiency causes pernicious anaemia (reduced... 1
- Which of the following molecules is non-polar in nature ? Answer: 3. SbCl₅ Key idea: a molecule is non-polar if its bond dipoles cancel by symmetry. SbCl₅ is a symmetric trigonal bipyramid with no l... 1
- The slope of Arrhenius Plot ( k v/s 1/T) of first order reaction is -5×10^3 K. The value of E_a of the reaction is. Choose the correct option for your answer.[Given R=8.314 J K^-1mol^-1] Answer: 1. 41.5 kJ mol ⁻¹ Key idea: Arrhenius equation ln k=ln A-E_a/RT ; slope of ln k vs 1/T is -E_a/R . E_a=-slope× R=5×10³×8.314=41570\... 1
- For irreversible expansion of an ideal gas under isothermal condition, the correct option is : Answer: 3. Δ U=0, Δ S_total≠0 Key idea: for an ideal gas, internal energy depends only on temperature. Isothermal means Δ U=0 . An irreversi... 1
- From the following pairs of ions which one is not an iso-electronic pair ? Answer: 4. Fe²⁺, Mn²⁺ Key idea: iso-electronic species have the same number of electrons. mathrmO²⁻ (10) and F^- (10): yes Na^+ (10) and mat... 1
- In which one of the following arrangements the given sequence is not strictly according to the properties indicated against it ? Answer: 2. H₂O < H₂S < H₂Se < H₂Te : Increasing pK_a values Key idea: check each trend. 1: acidic strength HF < HCl < HBr < HI is correct (w... 1
- Match List - I with List - II.List - I : (a) [Fe(CN)_6]^3- (b) [Fe(H_2O)_6]^3+ (c) [Fe(CN)_6]^4- (d) [Fe(H_2O)_6]^2+List - II : (i) 5.92 BM (ii) 0 BM (iii) 4.90 BM (iv) 1.73 BMChoose the correct answer from the options given below. Answer: 4. (a)-(iv), (b)-(i), (c)-(ii), (d)-(iii) Key idea: find unpaired electrons n and use μ=√(n(n+2)) BM. (a) mathrm[Fe(CN)₆]³⁻ : mathrm... 1
- The incorrect statement among the following is : Answer: 2. Most of the trivalent Lanthanoid ions are colorless in the solid state. Key idea: compare f-block properties. Actinoid contractio... 1
- CH_3CH_2COO^-Na^+ [Heat]NaOH,\ +\ ? CH_3CH_3 + Na_2CO_3.Consider the above reaction and identify the missing reagent/chemical. Answer: 3. CaO Key idea: decarboxylation of a sodium carboxylate with soda lime. mathrmCH₃CH₂COONa+NaOHxrightarrowCaO,\ ΔCH₃CH₃+Na₂CO₃ . The... 1
- The reagent 'R' in the given sequence of chemical reaction is :2,4,6-tribromoaniline NaNO_2, HCl,\ 0-5^° C 2,4,6-tribromobenzenediazonium chloride R 1,3,5-tribromobenzene Answer: 2. CH₃CH₂OH Key idea: replacing the diazonium group by hydrogen (hydro-de-diazoniation) needs a mild reducing agent. Ethanol (or H₃P... 1
- The intermediate compound 'X' in the following chemical reaction is :toluene + CrO_2Cl_2 CS_2 X H_3O^+ benzaldehyde Answer: 1. C₆H₅-CH(OCrOHCl₂)₂ Key idea: this is the Etard reaction: toluene is partially oxidised to benzaldehyde by chromyl chloride. Tolue... 1
- The product formed in the following chemical reaction is :2-(methyl-substituted) cyclohexanone bearing CH_2-C(=O)-OCH_3 and CH_3 groups [C_2H_5OH]NaBH_4 ? Answer: 4. Cyclohexane ring with OH, CH₃ and CH₂-C(=O)-OCH₃ substituents Key idea: NaBH₄ is a mild reducing agent. It reduces aldehydes and... 1