NEET UG
- 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
- The water potential of pure water is : Answer: 4. Zero Key idea: Water potential ( Psi_w ) of pure water at standard conditions is taken as the maximum reference value. It is zero... 1
- Double fertilization is exhibited by : Answer: 3. Angiosperms Key idea: In double fertilisation, one male gamete fuses with the egg (syngamy) and the other with the two polar nucl... 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
- 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 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
- Which of the following are not polymeric ? Answer: 3. Lipids Key idea: A polymer is a long chain of repeating monomer units. Proteins: chains of amino acids. Polysaccharides: chains o... 1
- DNA fragments are : Answer: 1. Negatively charged Key idea: DNA has a phosphate group on each nucleotide. The phosphate groups carry a negative charge, so every... 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- Which of the following statements is not correct ? Answer: 3. Denaturation makes the proteins more active. Key idea: denaturation destroys the 3-D structure. On denaturation (heat, acid), sec... 1
- Which is the incorrect statement ? Answer: 3. Frenkel defect is favoured in those ionic compounds in which sizes of cation and anions are almost equal. Key idea: Frenkel defec... 1
- Which one of the following pairs of species have the same bond order ? Answer: 2. CN^-, CO Key idea: compare bond orders from molecular orbital theory (isoelectronic species have equal bond orders). CN^- and CO... 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
- Which of the following pairs of compounds is isoelectronic and isostructural ? Answer: 2. IBr₂^-, XeF₂ Key idea: isoelectronic means equal number of valence electrons, isostructural means same shape. XeF₂ : 8 + 14 = 22... 1
- A first order reaction has a specific reaction rate of 10^-2\ sec^-1. How much time will it take for 20 g of the reactant to reduce to 5 g ? Answer: 1. 138.6 sec Key idea: first-order integrated rate law t=2.303/kloga/a-x . t=dfrac2.30310⁻²log20/5=230.3×0.602=138.6\ s . Check: 20... 1