Botany
- Identify the correct statements :A. Detrivores perform fragmentation.B. The humus is further degraded by some microbes during mineralization.C. Water soluble inorganic nutrients go down into the soil and get precipitated by a process called leaching.… Answer: 2. A, B, C only Key idea: Check each statement on decomposition. A is true: detritivores break detritus into smaller pieces (fragmen... 1
- The phenomenon of pleiotropism refers to Answer: 4. a single gene affecting multiple phenotypic expression. Key idea: Pleiotropy is the effect of a single gene on multiple phenotypi... 1
- Unequivocal proof that DNA is the genetic material was first proposed by Answer: 3. Alfred Hershey and Martha Chase Key idea: Hershey and Chase (1952) gave the unequivocal proof that DNA is the genetic material. T... 1
- In tissue culture experiments, leaf mesophyll cells are put in a culture medium to form callus. This phenomenon may be called as : Answer: 3. Dedifferentiation Key idea: When mature, differentiated cells (such as leaf mesophyll) go back to a meristematic state and divide... 1
- The reaction centre in PS II has an absorption maxima at Answer: 2. 680 nm Key idea: The reaction centre of PS II is P680, with absorption maximum at 680 nm. The reaction centre of PS I is P700 (70... 1
- Which of the following combinations is required for chemiosmosis? Answer: 2. membrane, proton pump, proton gradient, ATP synthase Key idea: Chemiosmosis needs a membrane, a proton pump, a proton gradient an... 1
- Match List I with List II :List I | List IIA. Iron | I. Synthesis of auxinB. Zinc | II. Component of nitrate reductaseC. Boron | III. Activator of catalaseD. Molybdenum | IV. Cell elongation and differentiationChoose the correct answer from the optio… Answer: 4. A-III, B-I, C-IV, D-II Key idea: Match each element with its role. Iron: activator of catalase (III). Zinc: needed for synthesis... 1
- Spraying of which of the following phytohormone on juvenile conifers helps in hastening the maturity period, that leads to early seed production? Answer: 3. Gibberellic Acid Key idea: Spraying gibberellic acid (GA) on juvenile conifers hastens maturity, so they produce seeds early. ABA... 1
- Given below are two statements :Statement I : The forces generated by transpiration can lift a xylem-sized column of water over 130 meters height.Statement II : Transpiration cools leaf surfaces sometimes 10 to 15 degrees, by evaporative cooling.In t… Answer: 2. Both Statement I and Statement II are correct. Key idea: Both statements are standard facts about transpiration. Statement I is c... 1
- In angiosperm, the haploid, diploid and triploid structures of a fertilized embryo sac sequentially are : Answer: 4. Synergids, Zygote and Primary endosperm nucleus Key idea: In a fertilised embryo sac, count ploidy for each structure. Synergids:... 1
- What is the function of tassels in the corn cob? Answer: 3. To trap pollen grains Key idea: In maize (corn) the tassels are the long, silky styles and stigmas of the female inflorescence (c... 1
- Large, colourful, fragrant flowers with nectar are seen in : Answer: 2. insect pollinated plants Key idea: Insect-pollinated flowers are large, colourful and fragrant, and offer nectar as a reward. Win... 1
- Axile placentation is observed in Answer: 1. China rose, Petunia and Lemon Key idea: Axile placentation (ovary with two or more chambers, ovules on central axis) is found in... 1
- Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R :Assertion A : Late wood has fewer xylary elements with narrow vessels.Reason R : Cambium is less active in winters.In the light of the above statem… Answer: 2. Both A and R are true and R is the correct explanation of A. Key idea: In winter the cambium is less active and forms fewer xylar... 1
- Given below are two statements :Statement I : Endarch and exarch are the terms often used for describing the position of secondary xylem in the plant body.Statement II : Exarch condition is the most common feature of the root system.In the light of t… Answer: 1. Statement I is incorrect but Statement II is true. Key idea: Endarch and exarch describe the position of primary xylem. Statement... 1
- Identify the correct statements :A. Lenticels are the lens-shaped openings permitting the exchange of gases.B. Bark formed early in the season is called hard bark.C. Bark is a technical term that refers to all tissues exterior to vascular cambium.D.… Answer: 3. A and D only Key idea: Check each statement. A is true: lenticels allow gas exchange. B is false: bark formed early in the season... 1
- Cellulose does not form blue colour with Iodine because Answer: 4. It does not contain complex helices and hence cannot hold iodine molecules. Key idea: The blue colour of the starch-iodine test c... 1
- Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R :Assertion A : The first stage of gametophyte in the life cycle of moss is protonema stage.Reason R : Protonema develops directly from spores produc… Answer: 2. Both A and R are correct and R is the correct explanation of A. Key idea: In mosses the haploid spore germinates into a creeping,... 1
- The thickness of ozone in a column of air in the atmosphere is measured in terms of : Answer: 2. Dobson units Key idea: Ozone thickness in a column of air is measured in Dobson units (DU). Kilobase measures DNA length, decibel... 1
- Among 'The Evil Quartet', which one is considered the most important cause driving extinction of species? Answer: 2. Habitat loss and fragmentation Key idea: Of the four causes in the "Evil Quartet", habitat loss and fragmentation is the most imp... 1
- Frequency of recombination between gene pairs on same chromosome as a measure of the distance between genes to map their position on chromosome, was used for the first time by Answer: 4. Alfred Sturtevant Key idea: Alfred Sturtevant, a student of T. H. Morgan, used the frequency of recombination between gene pairs... 1
- How many ATP and NADPH_2 are required for the synthesis of one molecule of Glucose during Calvin cycle? Answer: 3. 18 ATP and 12 NADPH ₂ Key idea: One CO₂ fixed in the Calvin cycle needs 3 ATP and 2 NADPH. Glucose has 6 carbons, so 6 turns are... 1
- Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R :Assertion A : ATP is used at two steps in glycolysis.Reason R : First ATP is used in converting glucose into glucose-6-phosphate and second ATP is… Answer: 2. Both A and R are true and R is the correct explanation of A. Key idea: Two ATP molecules are invested in the preparatory phase of... 1
- Which micronutrient is required for splitting of water molecule during photosynthesis? Answer: 2. manganese Key idea: Manganese (Mn) is needed for the water-splitting (photolysis) step of the light reaction, which releases O₂ ,... 1