#neet
- A baby boy aged two years is admitted to play school and passes through a dental check - up. The dentist observed that the boy had twenty teeth. Which teeth were absent ? Answer: 2. Pre-molars Key idea: A two-year-old has milk (temporary) teeth only, with dental formula 2102/2102 . Per half-jaw: 2 incisors, 1... 1
- Which of the following statements is correct ? Answer: 4. The ascending limb of loop of Henle is impermeable to water. Key idea: The two limbs of the loop of Henle differ in permeability,... 1
- Adult human RBCs are enucleate. Which of the following statement(s) is/are most appropriate explanation for this feature ?(a) They do not need to reproduce(b) They are somatic cells(c) They do not metabolize(d) All their internal space is available f… Answer: 2. (a), (c) and (d) Key idea: Losing the nucleus suits the RBC for its single job, carrying oxygen. (a) Mature RBCs do not divide, s... 1
- An important characteristic that Hemichordates share with Chordates is : Answer: 2. pharynx with gill slits Key idea: Hemichordates (e.g. Balanoglossus) share pharyngeal gill slits with chordates. (1) Hemichordate... 1
- Alexander Von Humbolt described for the first time : Answer: 2. Species area relationships Key idea: Alexander von Humboldt studied plant diversity in South American forests. He found that spec... 1
- Identify the wrong statement in context of heartwood : Answer: 2. It conducts water and minerals efficiently Key idea: Heartwood is the old, central secondary xylem that has stopped conducting. I... 1
- Which one of the following statements is correct, with reference to enzymes ? Answer: 1. Holoenzyme = Apoenzyme + Coenzyme Key idea: An active conjugated enzyme has a protein part and a non-protein part. The protein pa... 1
- Root hairs develop from the region of : Answer: 4. Maturation Key idea: Root zones from tip upward: root cap, meristematic, elongation, maturation. Cells in the maturation zone dif... 1
- Among the following characters, which one was not considered by Mendel in his experiments on pea ? Answer: 1. Trichomes - Glandular or non-glandular Key idea: Mendel studied 7 contrasting pairs in pea. Seed colour (green/yellow), pod shape... 1
- Which of the following facilitates opening of stomatal aperture ? Answer: 2. Radial orientation of cellulose microfibrils in the cell wall of guard cells Key idea: A stoma opens when guard cells become turg... 1
- The association of histone H1 with a nucleosome indicates : Answer: 2. The DNA is condensed into a Chromatin Fibre. Key idea: Histone H1 is the linker histone that seals the nucleosome. H1 binds the l... 1
- The process of separation and purification of expressed protein before marketing is called : Answer: 1. Downstream processing Key idea: Making a product has two stages. Upstream processing covers growing the cells in a bioreactor. Do... 1
- Capacitation occurs in : Answer: 3. Female Reproductive tract Key idea: Freshly ejaculated sperm cannot fertilise an ovum yet. They must spend some time in the secre... 1
- Select the mismatch :(1) Rhodospirillum - Mycorrhiza(2) Anabaena - Nitrogen fixer(3) Rhizobium - Alfalfa(4) Frankia - Alnus Answer: 1. Rhodospirillum - Mycorrhiza Key idea: Match each microbe with its true role. Rhodospirillum is a photosynthetic purple bacterium... 1
- Homozygous purelines in cattle can be obtained by : Answer: 4. mating of related individuals of same breed. Key idea: Inbreeding increases homozygosity. Mating of closely related individuals o... 1
- The DNA fragments separated on an agarose gel can be visualised after staining with : Answer: 3. Ethidium bromide Key idea: DNA bands on agarose are seen with a dye that binds DNA and fluoresces. Ethidium bromide intercalates... 1
- Out of 'X' pairs of ribs in humans only 'Y' pairs are true ribs. Select the option that correctly represents values of X and Y and provides their explanation : Answer: 4. X=12, Y=7 True ribs are attached dorsally to vertebral column and ventrally to the sternum. Key idea: Humans have 12 pairs of rib... 1
- Which cells of 'Crypts of Lieberkuhn' secrete antibacterial lysozyme ? Answer: 1. Paneth cells Key idea: The crypts of Lieberkuhn in the intestine hold several cell types. Paneth cells secrete lysozyme and defen... 1
- Match the interhalogen compounds of column I with the geometry in column II and assign the correct code.Column I | Column II(a) XX' | (i) T-shape(b) XX_3' | (ii) Pentagonal bipyramidal(c) XX_5' | (iii) Linear(d) XX_7' | (iv) Square-pyramidal| (v) Tet… Answer: 1. (iii) (i) (iv) (ii) Key idea: use VSEPR for interhalogens. (a) XX': linear (iii) (b) XX₃' : T-shape (i) (3 bond pairs, 2 lone pai... 1
- The species, having bond angles of 120° is : Answer: 3. BCl₃ Key idea: 120^° belongs to a trigonal planar molecule with no lone pair on the central atom. BCl₃ : B has 3 bond pairs, sp²... 1
- Predict the correct intermediate and product in the following reaction :H_3C-C CH [HgSO_4]H_2O,\ H_2SO_4 intermediate (A) → product (B) Answer: 3. A : H₃C-C(OH)=CH₂ B : H₃C-C(=O)-CH₃ Key idea: hydration of an alkyne (Kucherov reaction) first gives an enol, which tautomerises... 1
- If molality of the dilute solution is doubled, the value of molal depression constant (K_f) will be : Answer: 3. unchanged Key idea: K_f is a property of the solvent only. Δ T_f = K_f m . K_f is the depression for a 1 molal solution and depen... 1
- The heating of phenyl-methyl ethers with HI produces. Answer: 2. phenol Key idea: HI cleaves an aryl alkyl ether at the alkyl-oxygen bond. C₆H₅OCH₃ + HI → C₆H₅OH + CH₃I . The oxygen is protonate... 1
- In the electrochemical cell :Zn|ZnSO_4(0.01\ M)||CuSO_4(1.0\ M)|Cu, the emf of this Daniel cell is E_1. When the concentration of ZnSO_4 is changed to 1.0 M and that of CuSO_4 changed to 0.01 M, the emf changes to E_2. From the followings, which one… Answer: 2. E₁ > E₂ Key idea: apply the Nernst equation, E = E^° - 0.059/2logdfrac[Zn²⁺][Cu²⁺] . E₁ : log0.01/1=-2 , so E₁ = E^° + 0.059 . E₂... 1