NEET UG
- What is the site of perception of photoperiod necessary for induction of flowering in plants ? Answer: 4. Leaves Key idea: Photoperiod is sensed by the leaves. Leaves perceive the light/dark duration and produce a flowering stimulus (f... 1
- In some plants, the female gamete develops into embryo without fertilization. This phenomenon is known as : Answer: 4. Parthenogenesis Development of an egg or female gamete into an embryo without fertilisation is parthenogenesis. Autogamy is self-... 1
- What is the fate of the male gametes discharged in the synergid ? Answer: 4. One fuses with the egg and other fuses with central cell nuclei. Key idea: Double fertilisation: both male gametes released into... 1
- Persistent nucellus in the seed is known as : Answer: 2. Perisperm In most seeds the nucellus is used up. In some, such as black pepper and beet, a part of it persists and is called peri... 1
- Placentation, in which ovules develop on the inner wall of the ovary or in peripheral part, is : Answer: 3. Parietal Key idea: Placentation is the arrangement of ovules on the placenta inside the ovary. Marginal: along one margin of a si... 1
- Xylem translocates : Answer: 4. Water, mineral salts, some organic nitrogen and hormones Xylem sap carries mostly water and minerals, but also some organic nitro... 1
- Which of the statements given below is not true about formation of Annual Rings in trees ? Answer: 4. Annual rings are not prominent in trees of temperate region. Key idea: Annual rings are clearest where seasons differ sharply, so... 1
- Drug called 'Heroin' is synthesized by : Answer: 2. acetylation of morphine Key idea: Heroin (diacetylmorphine, smack) is made by acetylation of morphine. Morphine is extracted from... 1
- DNA precipitation out of a mixture of biomolecules can be achieved by treatment with : Answer: 2. Chilled ethanol DNA is precipitated by adding chilled ethanol, and it then appears as fine threads that can be spooled out. Optio... 1
- Following statements describe the characteristics of the enzyme Restriction Endonuclease. Identify the incorrect statement. Answer: 2. The enzyme binds DNA at specific sites and cuts only one of the two strands. Key idea: Restriction endonucleases cut both strands... 1
- Select the incorrect statement. Answer: 3. Inbreeding selects harmful recessive genes that reduce fertility and productivity. Inbreeding increases homozygosity, helps make... 1
- Tidal Volume and Expiratory Reserve Volume of an athlete is 500 mL and 1000 mL respectively. What will be his Expiratory Capacity if the Residual Volume is 1200 mL ? Answer: 1. 1500 mL Key idea: Expiratory capacity (EC) = tidal volume + expiratory reserve volume. EC = TV + ERV = 500 + 1000 = 1500\ mL . Th... 1
- What would be the heart rate of a person if the cardiac output is 5 L, blood volume in the ventricles at the end of diastole is 100 mL and at the end of ventricular systole is 50 mL ? Answer: 3. 100 beats per minute Cardiac output = stroke volume × heart rate. Stroke volume =100-50=50 mL. Heart rate=5000 mL/min/50 mL/beat=... 1
- Which of the following factors is responsible for the formation of concentrated urine ? Answer: 2. Maintaining hyperosmolarity towards inner medullary interstitium in the kidneys. Concentrated urine needs a steep osmotic gradien... 1
- Which of the following contraceptive methods do involve a role of hormone ? Answer: 1. Lactational amenorrhea, Pills, Emergency contraceptives Key idea: Only methods that change hormone levels involve a hormone. Oral... 1
- Which of the following is a commercial blood cholesterol lowering agent ? Answer: 2. Statin Statins (from the yeast Monascus purpureus) inhibit the enzyme that makes cholesterol, so they lower blood cholesterol. Cy... 1
- Concanavalin A is : Answer: 3. a lectin Concanavalin A is a lectin, a carbohydrate-binding protein extracted from jack bean. It is not an alkaloid, an essential... 1
- The correct sequence of phases of cell cycle is : Answer: 4. G ₁ → S → G ₂ → M The cell cycle runs G₁ → S → G₂ → M . G₁ is growth, S is DNA synthesis, G₂ is preparation for division, and M i... 1
- The shorter and longer arms of a submetacentric chromosome are referred to as : Answer: 2. p-arm and q-arm respectively By convention the shorter arm of a chromosome is the p-arm (petite) and the longer arm is the q-arm.... 1
- Which of the following statements is not correct ? Answer: 4. Lysosomes are formed by the process of packaging in the endoplasmic reticulum. Lysosomes are membrane-bound vesicles holding hydr... 1
- Consider the following statements :(A) Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group.(B) A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme.Select the correct option. Answer: 2. (A) is true but (B) is false. Statement A is true. A cofactor (organic or metal ion) that is tightly bound to the enzyme protein... 1
- Which of the following pair of organelles does not contain DNA ? Answer: 3. Lysosomes and Vacuoles Mitochondria and chloroplasts contain their own DNA, and the nucleus holds the cell's DNA. Lysosomes and v... 1
- Which of the following pairs of gases is mainly responsible for green house effect ? Answer: 4. Carbon dioxide and Methane The main greenhouse gases are CO₂ , CH₄ , N₂O and CFCs. Among the options, carbon dioxide and methane... 1
- Which of the following is the most important cause for animals and plants being driven to extinction ? Answer: 1. Habitat loss and fragmentation The "evil quartet" lists the causes of biodiversity loss. The most important is habitat loss and f... 1