Botany
- Which one of the following is a characteristic feature of cropland ecosystem ? Answer: 2. Least genetic diversity Key idea: A cropland is a managed ecosystem where people grow one or a few crop species. This gives the l... 1
- Which of the following is required as inducer(s) for the expression of Lac operon ? Answer: 3. lactose Key idea: In the lac operon, lactose (as allolactose) is the inducer. It binds the repressor protein, which then leaves t... 1
- A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F_1 plants were selfed the resulting genotypes were in the ratio of : Answer: 1. 1 : 2 : 1 :: Tall homozygous : Tall heterozygous : Dwarf Key idea: A TT × tt cross gives all Tt in F₁. Selfing F₁ (Tt × Tt) gives... 1
- Match the terms in Column I with their description in Column II and choose the correct option :Column I: (a) Dominance; (b) Codominance; (c) Pleiotropy; (d) Polygenic inheritanceColumn II: (i) Many genes govern a single character; (ii) In a heterozyg… Answer: 2. (ii) (iii) (iv) (i) Key idea: Match each term with its meaning. Dominance: in a heterozygote only one allele expresses: (ii) Codo... 1
- Pick out the correct statements :(a) Haemophilia is a sex-linked recessive disease.(b) Down's syndrome is due to aneuploidy.(c) Phenylketonuria is an autosomal recessive gene disorder.(d) Sickle cell anaemia is an X - linked recessive gene disorder. Answer: 4. (a), (b) and (c) are correct. Key idea: Check each statement. (a) Haemophilia is X-linked recessive: correct. (b) Down syndrome i... 1
- A complex of ribosomes attached to a single strand of RNA is known as : Answer: 1. Polysome Key idea: Several ribosomes attached to one mRNA strand make a polysome (polyribosome), so many copies of a polypeptide... 1
- The *Avena* curvature is used for bioassay of : Answer: 3. IAA Key idea: The Avena (oat coleoptile) curvature test is a bioassay for the auxin IAA. Auxin placed on one side of a decapitate... 1
- The standard petal of a papilionaceous corolla is also called : Answer: 3. Vexillum Key idea: In a papilionaceous corolla (pea family), the large back petal is the standard or vexillum. There are two late... 1
- Tricarpellary, syncarpous gynoecium is found in flowers of : Answer: 1. Liliaceae Key idea: Liliaceae flowers have a tricarpellary, syncarpous gynoecium (superior ovary). Solanaceae has a bicarpellary... 1
- Proximal end of the filament of stamen is attached to the : Answer: 4. Thalamus or petal Key idea: A stamen has an anther (distal) and a filament (long, stalk-like). The proximal end of the filament a... 1
- A system of rotating crops with legume or grass pasture to improve soil structure and fertility is called : Answer: 1. Ley farming Key idea: Ley farming alternates cereal crops with legume or grass pasture for a few years to restore soil structure... 1
- The two polypeptides of human insulin are linked together by : Answer: 4. Disulphide bridges Key idea: Insulin has two chains, A (21 amino acids) and B (30 amino acids), held together by disulphide bridg... 1
- Mitochondria and chloroplast are :(a) semi-autonomous organelles.(b) formed by division of pre - existing organelles and they contain DNA but lack protein synthesizing machinery.Which one of the following options is correct ? Answer: 3. (a) is true but (b) is false. Key idea: Mitochondria and chloroplasts are semi-autonomous organelles. (a) True. They have their o... 1
- Which of the following statements is wrong for viroids ? Answer: 4. Their RNA is of high molecular weight Key idea: Viroids are infectious agents made only of a small, free RNA with no protein coat... 1
- Gause's principle of competitive exclusion states that : Answer: 3. No two species can occupy the same niche indefinitely for the same limiting resources. Key idea: Gause's principle says that two... 1
- Which of the following most appropriately describes haemophilia ? Answer: 2. X - linked recessive gene disorder Key idea: Haemophilia is caused by a recessive gene on the X chromosome, so it is the most pre... 1
- Emerson's enhancement effect and Red drop have been instrumental in the discovery of : Answer: 2. Two photosystems operating simultaneously Key idea: Red drop and Emerson's enhancement effect showed that two light reactions wor... 1
- In a chloroplast the highest number of protons are found in : Answer: 2. Lumen of thylakoids Key idea: During the light reactions, protons build up inside the thylakoid lumen. They come from water split... 1
- In which of the following, all three are macronutrients ? Answer: Dropped in the official answer key: full marks to every candidate Key idea: Macronutrients are C, H, O, N, P, S, K, Ca and Mg. Micro... 1
- The coconut water from tender coconut represents : Answer: 4. Free nuclear endosperm Key idea: Coconut water is a liquid free nuclear endosperm. In coconut, the triploid primary endosperm nuc... 1