Botany
- Match the trophic levels with their correct species examples in grassland ecosystem.(a) Fourth trophic level (i) Crow(b) Second trophic level (ii) Vulture(c) First trophic level (iii) Rabbit(d) Third trophic level (iv) GrassSelect the correct option… Answer: 1. (a) (ii), (b) (iii), (c) (iv), (d) (i) In a grassland food chain: grass (producer, 1st level) - rabbit (primary consumer, 2nd) -... 1
- In relation to Gross primary productivity and Net primary productivity of an ecosystem, which one of the following statements is correct ? Answer: 2. Gross primary productivity is always more than net primary productivity. Net primary productivity = Gross primary productivity mi... 1
- If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is 6.6×10^9 bp, then the length of the DNA is approximately : Answer: 3. 2.2 meters Length = number of bp x distance per bp. L = 6.6×10⁹×0.34×10⁻⁹\ m = 2.244\ m≈ 2.2\ m So the answer is about 2.2 metres... 1
- How many true breeding pea plant varieties did Mendel select as pairs, which were similar except in one character with contrasting traits ? Answer: 3. 14 Mendel selected 14 true-breeding pea varieties, which formed seven pairs. Each pair differed in only one character with contra... 1
- Name the enzyme that facilitates opening of DNA helix during transcription. Answer: 4. RNA polymerase During transcription, RNA polymerase itself unwinds the DNA helix locally and synthesises RNA. DNA helicase opens... 1
- In light reaction, plastoquinone facilitates the transfer of electrons from : Answer: 1. PS-II to Cytb ₆ f complex In the Z-scheme, electrons from PS II go to plastoquinone (PQ), then to the Cyt b6f complex, then plast... 1
- Name the plant growth regulator which upon spraying on sugarcane crop, increases the length of stem, thus increasing the yield of sugarcane crop. Answer: 2. Gibberellin Gibberellin promotes stem elongation (internode length). Spraying it on sugarcane raises stem length and hence yield... 1
- Which of the following is not an inhibitory substance governing seed dormancy ? Answer: 1. Gibberellic acid Seed dormancy is maintained by inhibitors such as abscisic acid, phenolic acids and para-ascorbic acid. Gibberel... 1
- In water hyacinth and water lily, pollination takes place by : Answer: 1. insects or wind Water hyacinth and water lily are aquatic plants but their flowers rise above water, so they are pollinated by in... 1
- The ovary is half inferior in : Answer: 4. Plum The position of the ovary relative to other floral parts decides this. In plum (and rose, peach) the flower is perigynous an... 1
- Which of the following is put into Anaerobic sludge digester for further sewage treatment ? Answer: 4. Activated sludge Key idea: In secondary treatment, a part of the activated sludge is passed to anaerobic sludge digesters. Bacter... 1
- Secondary metabolites such as nicotine, strychnine and caffeine are produced by plants for their : Answer: 3. Defence action Key idea: Secondary metabolites are not needed for basic growth but have ecological roles. Nicotine, strychnine an... 1
- Match the following :(a) Inhibitor of catalytic activity (i) Ricin(b) Possess peptide bonds (ii) Malonate(c) Cell wall material in fungi (iii) Chitin(d) Secondary metabolite (iv) CollagenChoose the correct option from the following : Answer: 1. (a) (ii), (b) (iv), (c) (iii), (d) (i) Key idea: Match each item with its category. Inhibitor of catalytic activity: malonate (co... 1
- According to Robert May, the global species diversity is about : Answer: 4. 7 million Key idea: Robert May estimated global species diversity at about 7 million. The IUCN figure of described species is abo... 1
- Which of the following regions of the globe exhibits highest species diversity ? Answer: 4. Amazon forests Key idea: The Amazon rainforest has the highest species diversity on Earth. It holds more than 40,000 plant specie... 1
- The first phase of translation is : Answer: 3. Aminoacylation of tRNA Key idea: Translation begins with charging of tRNA. The first phase is aminoacylation: an amino acid is ac... 1
- The oxygenation activity of RuBisCo enzyme in photorespiration leads to the formation of : Answer: 2. 1 molecule of 3-C compound Key idea: In photorespiration RuBisCO acts as an oxygenase on RuBP. RuBP (5C) plus O₂ gives one molecu... 1
- Match the following concerning essential elements and their functions in plants :(a) Iron (i) Photolysis of water(b) Zinc (ii) Pollen germination(c) Boron (iii) Required for chlorophyll biosynthesis(d) Manganese (iv) IAA biosynthesisSelect the correc… Answer: 3. (a) (iii), (b) (iv), (c) (ii), (d) (i) Key idea: Recall the role of each element. Iron: needed for chlorophyll biosynthesis (iii)... 1
- The process responsible for facilitating loss of water in liquid form from the tip of grass blades at night and in early morning is : Answer: 2. Root pressure Key idea: Loss of liquid water from leaf tips at night is guttation, caused by root pressure. At night, with high s... 1
- Ray florets have : Answer: 1. Inferior ovary Key idea: In sunflower (family Asteraceae), ray florets are female or sterile and have an inferior ovary. Asterace... 1
- Identify the incorrect statement. Answer: 3. Sapwood is the innermost secondary xylem and is lighter in colour. Key idea: Heartwood is the innermost secondary xylem and is da... 1
- The transverse section of a plant shows following anatomical features :(a) Large number of scattered vascular bundles surrounded by bundle sheath.(b) Large conspicuous parenchymatous ground tissue.(c) Vascular bundles conjoint and closed.(d) Phloem p… Answer: 1. Monocotyledonous stem Key idea: Scattered, conjoint, closed vascular bundles with bundle sheaths and no phloem parenchyma indicat... 1
- The product(s) of reaction catalyzed by nitrogenase in root nodules of leguminous plants is/are : Answer: 4. Ammonia and hydrogen Key idea: Nitrogenase reduces nitrogen to ammonia and releases hydrogen. The reaction is N₂ + 8e^- + 8H^+ +... 1
- Identify the substances having glycosidic bond and peptide bond, respectively in their structure : Answer: 4. Inulin, insulin Key idea: Glycosidic bonds link sugars in polysaccharides; peptide bonds link amino acids in proteins. Inulin is... 1