Practice Questions with Answers - Multiple Choice Questions

Important Biology MCQs for Competitive Exams

MCQs on Botany for Competitive Exams

We have compiled MCQ questions with answers on Botany for you to practice for Civil Services Prelims. If you are preparing for CDS or CAPF these questions will also help you. These MCQ questions are asked in previous years and considered to be very important for UPSE IAS prelims.

1. The only snake that builds a nest is:
(a) Chain viper
(b) King Cobra
(c) Krait
(d) Saw-scaled viper

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Ans: (b) King Kobra is the only snake that not only lives in holes but also builds a nest.

2. Most of the desert plants bloom during night time because
(a) their blooming is controlled by low temperature
(b) they are sensitive to the phases of moon
(c) the desert insects eat away flowers during day time
(d) the desert insects are active during night time

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Ans: (a) The blooming of desert plants is controlled by low temperature.

3. Living organisms require at least 27 elements, of which 15 are metals. Among these, those required in major quantities, include
(a) potassium, manganese, molybdenum and calcium
(b) potassium, molybdenum, copper and calcium
(c) potassium, sodium, magnesium and calcium
(d) sodium, magnesium, copper and manganese

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Ans: (c) Living organism require about 27 elements of which 15 are metals. K, Mg, Na and Ca are required in major quantities. Minor quantity of Mn, Fe, Co, Cu,Zn and Mo and trace amount of V, Cr, Sn, Ni and Al are required by some organisms. Calcium, magnesium and phosphorus are essential parts of the bones and teeth. Calcium is necessary for blood clotting. Sodium helps in muscle activity and transmission of nerve.

4. It is possible to produce seedless tomato fruits by
(a) applying trace elements in tomato fruits
(b) spraying mineral solution on plants
(c) spraying hormones on flowers
(d) applying fertilizers containing radioactive

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Ans: (c) Hormone auxin is responsible to produce seedless tomato fruits.

5. Match List-I (Physiological processes) with List-II (Cell organelles) and select the correct answer by using the codes given below:
List- I List-II
A. Photosynthesis 1. Plasma membrane
B. Mineral uptake 2. Chloroplast
C. Respiration 3. Mitochondria
D. Protein synthesis 4. Ribosomes
(a) A – 1; B – 2; C – 3; D – 4
(b) A – 1; B – 2; C – 4; D – 3
(c) A – 2; B – 1; C – 3; D – 4
(d) A – 2; B – 1; C – 4; D – 2

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Ans: (c) Photosynthesis occurs in green plants by the help of chloroplast. Plasma membrane is a membrane of transport minerals. Cellular respiration related to mitochondria, by which energy releases. Ribosome is helps in protein synthesis.

6. Which one of the following is a modified stem?
(a) Carrot
(b) Sweet potato
(c) Coconut
(d) Potato

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Ans: (d) Potato tuber bears buds in small pits known as eyes. Buds develops to branches. Some of the branches become green, erect and leafy stems that grow horizontally under ground.

7. Which one of the following organisms is likely to show the highest concentration of DDT, once it has been introduced into the ecosystem?
(a) Grasshopper
(b) Toad
(c) Snake
(d) Cattle

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Ans: (c) DDT is non-biodegradable chemical. Biomagnification is the phenomenon of increasing concentration of compound in the tissue of organism, as the compound passes up a food chain, usually as a result of food intake. In this case, the concentration of compound will increase with increasing the tropic level. Biomagnifying pollutants which increases in concentration from producers – Primary consumers – Secondary consumers – Tertiary consumers -Top consumer. The snake is a tertiary consumer. So the DDT concentration will high in snake.

8. Match List-I with List-II and select the correct answer by using the codes given below the lists
List-I List-II
A. Fruit 1. Ovule
B. Seed 2. Leaf
C. Wood 3. Stem
D. Starch 4. Ovary
(a) A-2; B-1; C-3; D- 4
(b) A-4; B-1; C-3; D-2
(c) A-2; B-3; C-1; D-4
(d) A-4; B-3; C-1; D-2

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Ans: (b) After the pollination of ovary, fruit develops gradually from it. Stem of tree develops to wood. Seed develops from fertilized ovule. Leaf produces starch at the time of photosynthesis.

9. Which one of the following statements regarding starch and cellulose is not correct?
(a) Both of them are of plant origin
(b) Both of them are polymers
(c) Both of them give colour with iodine
(d) Both of them are made up of glucose molecules

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Ans: (c) Starch and cellulose both are plant origin. Starch deposits in plant cells, whereas cellulose is most important constituent of plant cell wall. Both starch and cellulose are polymers. Starch is branched polymer of a – D – glucose unit linked by a – 1, 4 glycosidic bond. Cellulose is a linear polymer of b – D – glucose unit. Glucose molecules are present in both starch and cellulose. Amylose in starch is responsible for the formation of deep blue colour in the presence of iodine but cellulose does not give any colour at the treatment with iodine, because amylose is absent in cellulose.

10. Ergotism is due to consumption of
(a) contaminated grains
(b) rotting vegetables
(c) contaminated water
(d) safe cooked food

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Ans: (a) Ergotism is the effect of long term ergot poisoning, due to ingestion of alkaloids produced by fungus Claviceps purpurea which is found in infected cereals and ryes.