#neet
- Which of the following is not a feature of the plasmids ? Answer: 4. Single - stranded Key idea: Plasmids are double-stranded, circular, extra-chromosomal DNA. They replicate independently of the ch... 1
- Which of the following features is not present in *Periplaneta americana* ? Answer: 2. Indeterminate and radial cleavage during embryonic development Key idea: Cockroach (Periplaneta) is a protostome arthropod, so it... 1
- In higher vertebrates, the immune system can distinguish self-cells and non-self. If this property is lost due to genetic abnormality and it attacks self-cells, then it leads to : Answer: 3. Auto-immune disease Key idea: When the immune system attacks the body's own cells, it is an auto-immune disease. Examples are rhe... 1
- Match the terms in Column I with their description in Column II and choose the correct option :Column I: (a) Dominance; (b) Codominance; (c) Pleiotropy; (d) Polygenic inheritanceColumn II: (i) Many genes govern a single character; (ii) In a heterozyg… Answer: 2. (ii) (iii) (iv) (i) Key idea: Match each term with its meaning. Dominance: in a heterozygote only one allele expresses: (ii) Codo... 1
- Joint Forest Management Concept was introduced in India during : Answer: 3. 1980s Key idea: Joint Forest Management (JFM) was introduced in India in 1980s. It involves local communities in protecting and m... 1
- Pick out the correct statements :(a) Haemophilia is a sex-linked recessive disease.(b) Down's syndrome is due to aneuploidy.(c) Phenylketonuria is an autosomal recessive gene disorder.(d) Sickle cell anaemia is an X - linked recessive gene disorder. Answer: 4. (a), (b) and (c) are correct. Key idea: Check each statement. (a) Haemophilia is X-linked recessive: correct. (b) Down syndrome i... 1
- Which one of the following statements is wrong ? Answer: 3. Eubacteria are also called false bacteria. Key idea: Eubacteria are the true bacteria, not 'false' bacteria. Cyanobacteria are bl... 1
- Proximal end of the filament of stamen is attached to the : Answer: 4. Thalamus or petal Key idea: A stamen has an anther (distal) and a filament (long, stalk-like). The proximal end of the filament a... 1
- Which of the following approaches does not give the defined action of contraceptive ? Answer: 4. Vasectomy - prevents spermatogenesis Key idea: Vasectomy blocks the transport of sperms; it does not stop spermatogenesis. In vas... 1
- Which of the following biphenyls is optically active ? Answer: 2. [structure shown in figure] Key idea: a biphenyl is optically active (shows atropisomerism) only if rotation about the central bo... 1
- For the following reactions :(a) CH_3CH_2CH_2Br + KOH → CH_3CH=CH_2 + KBr + H_2O(b) (CH3)2CHBr + KOH -> (CH3)2CHOH + KBr (structures shown in figure)(c) cyclohexene + Br_2 -> 1,2-dibromocyclohexane (structures shown in figure)Which of the following s… Answer: 2. (a) is elimination, (b) is substitution and (c) is addition reaction. Key idea: identify what happens to the substrate. (a) CH₃CH... 1
- At 100°C the vapour pressure of a solution of 6.5 g of a solute in 100 g water is 732 mm. If K_b = 0.52, the boiling point of this solution will be : Answer: 1. 101°C Key idea: use the lowering of vapour pressure to get the mole fraction, and then the boiling point elevation. At 100°C pure... 1
- The correct statement regarding RNA and DNA, respectively is : Answer: 2. The sugar component in RNA is ribose and the sugar component in DNA is 2'-deoxyribose. Key idea: RNA has the sugar D-ribose and D... 1
- The correct statement regarding the basicity of arylamines is : Answer: 1. Arylamines are generally less basic than alkylamines because the nitrogen lone-pair electrons are delocalized by interaction with... 1
- Which one given below is a non-reducing sugar ? Answer: 4. Sucrose Key idea: a sugar is non-reducing when both anomeric carbons are tied up in the glycosidic bond, leaving no free hemiacet... 1
- The pair of electron in the given carbanion, CH_3C C^, is present in which of the following orbitals ? Answer: 4. sp Key idea: the carbanion carbon in CH₃Cequiv C^- is triply bonded to another carbon, so it has 2 regions of electron density an... 1
- Gause's principle of competitive exclusion states that : Answer: 3. No two species can occupy the same niche indefinitely for the same limiting resources. Key idea: Gause's principle says that two... 1
- The two polypeptides of human insulin are linked together by : Answer: 4. Disulphide bridges Key idea: Insulin has two chains, A (21 amino acids) and B (30 amino acids), held together by disulphide bridg... 1
- The coconut water from tender coconut represents : Answer: 4. Free nuclear endosperm Key idea: Coconut water is a liquid free nuclear endosperm. In coconut, the triploid primary endosperm nuc... 1
- Which of the following statements is wrong for viroids ? Answer: 4. Their RNA is of high molecular weight Key idea: Viroids are infectious agents made only of a small, free RNA with no protein coat... 1
- Which of the following features is not present in the Phylum - Arthropoda ? Answer: 3. Parapodia Key idea: Arthropods have a chitinous exoskeleton, a metamerically segmented body and jointed appendages. Parapodia are... 1
- Which of the following most appropriately describes haemophilia ? Answer: 2. X - linked recessive gene disorder Key idea: Haemophilia is caused by a recessive gene on the X chromosome, so it is the most pre... 1
- Emerson's enhancement effect and Red drop have been instrumental in the discovery of : Answer: 2. Two photosystems operating simultaneously Key idea: Red drop and Emerson's enhancement effect showed that two light reactions wor... 1
- In which of the following, all three are macronutrients ? Answer: Dropped in the official answer key: full marks to every candidate Key idea: Macronutrients are C, H, O, N, P, S, K, Ca and Mg. Micro... 1