NEET UG
- A cell organelle containing hydrolytic enzymes is Answer: 4. lysosome Lysosomes are membrane-bound sacs filled with hydrolytic enzymes (acid hydrolases) that digest proteins, lipids, carbohy... 1
- How many hot spots of biodiversity in the world have been identified till date by Norman Myers? Answer: 2. 34 Biodiversity hotspots are regions with very high species richness and many endemic species that are under threat. Norman Myers... 1
- Which of the following is correctly matched? Answer: 2. *Parthenium hysterophorus*—Threat to biodiversity Parthenium hysterophorus (carrot grass) is an invasive weed that threatens nati... 1
- The primary producers of the deep-sea hydrothermal vent ecosystem are Answer: 1. chemosynthetic bacteria No sunlight reaches deep-sea hydrothermal vents. The primary producers are chemosynthetic bacteria, which... 1
- Which of the following is correct for r-selected species? Answer: 4. Large number of progeny with small size r-selected species have a high intrinsic rate of increase: they produce a large number of... 1
- If '+' sign is assigned to beneficial interaction, '–' sign to detrimental and '0' sign to neutral interaction, then the population interaction represented by '+' '–' refers to Answer: 3. parasitism In parasitism the parasite benefits (+) and the host is harmed (−). Amensalism: 0, − Commensalism: +, 0 Mutualism: +,... 1
- The mechanism that causes a gene to move from one linkage group to another is called Answer: 2. translocation A gene moves from one linkage group (chromosome) to another by translocation, the transfer of a chromosome segment... 1
- Taylor conducted the experiments to prove semiconservative mode of chromosome replication on Answer: 1. *Vicia faba* Taylor and co-workers (1957) used radioactive thymidine with root tip cells of Vicia faba (broad bean) to show that... 1
- A true breeding plant is Answer: 2. near homozygous and produces offspring of its own kind A true-breeding line, after repeated self-pollination, is nearly homozygou... 1
- The equivalent of a structural gene is Answer: 1. cistron A cistron is the functional unit of DNA that codes for one polypeptide, so it is equivalent to a structural gene. An oper... 1
- Which of the following rRNAs acts as structural RNA as well as ribozyme in bacteria? Answer: 2. 23 S rRNA In bacteria, the 23S rRNA of the large subunit acts as the peptidyl transferase ribozyme that forms peptide bonds, besi... 1
- Which of the following biomolecules is common to respiration-mediated breakdown of fats, carbohydrates and proteins? Answer: 3. Acetyl CoA Carbohydrates, fats and proteins are all finally oxidised through the Krebs cycle, which they enter as acetyl CoA. Pyr... 1
- The process which makes major difference between C_3 and C_4 plants is Answer: 2. photorespiration The big difference is photorespiration. In C₃ plants RuBisCO also acts as an oxygenase, causing a loss of fixed... 1
- A few drops of sap were collected by cutting across a plant stem by a suitable method. The sap was tested chemically. Which one of the following test results indicates that it is phloem sap? Answer: 1. Alkaline Phloem sap is rich in sugar (mainly sucrose), has a high refractive index because of dissolved solutes, and is alkaline... 1
- Which is essential for the growth of root tip? Answer: 2. Ca Calcium is needed for the formation of the middle lamella (calcium pectate) of the cell wall and for the spindle during cell d... 1
- You are given a tissue with its potential for differentiation in an artificial culture. Which of the following pairs of hormones would you add to the medium to secure shoots as well as roots? Answer: 1. Auxin and cytokinin In tissue culture, the ratio of auxin to cytokinin controls differentiation. A balanced supply gives both roo... 1
- Phytochrome is a Answer: 3. chromoprotein Phytochrome is a pigment protein with a light-absorbing non-protein part (a linear tetrapyrrole, phytochromobilin)... 1
- Which one of the following statements is not correct? Answer: 2. In potato, banana and ginger, the plantlets arise from the internodes present in the modified stem. In potato, banana and ginger... 1
- Which one of the following generates new genetic combinations leading to variation? Answer: 2. Sexual reproduction Sexual reproduction involves meiosis (crossing over, independent assortment) and fusion of gametes from two p... 1
- In majority of angiosperms Answer: 2. reduction division occurs in the megaspore mother cells In most angiosperms the megaspore mother cell (2n) divides by meiosis (re... 1
- The ovule of an angiosperm is technically equivalent to Answer: 4. megasporangium The ovule is the structure in which the megaspore mother cell and then the embryo sac form. It is therefore equiva... 1
- Pollination in water hyacinth and water lily is brought about by the agency of Answer: 1. insects or wind Water hyacinth and water lily are aquatic plants, but their flowers rise above the water and are pollinated by in... 1
- Match Column—I with Column—II and select the correct option using the codes given below :Column—I: a. Pistils fused together; b. Formation of gametes; c. Hyphae of higher Ascomycetes; d. Unisexual female flowerColumn—II: (i) Gametogenesis; (ii) Pisti… Answer: 3. (iii) (i) (iv) (ii) Match each term by its meaning: a. Pistils fused together = syncarpous (iii) b. Formation of gametes = gameto... 1
- Which kind of therapy was given in 1990 to a four-year-old girl with adenosine deaminase (ADA) deficiency? Answer: 4. Gene therapy In 1990 a four-year-old girl with ADA deficiency received the first clinical gene therapy: lymphocytes were taken, a... 1