Biology (Part-I) (UPSC)

Total Questions: 50

1. Most of the desert plants bloom during night time because : [1995]

(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

Correct Answer: (d) the desert insects are active during night time

Solution:Plant and animal activity happens at night in deserts due to high temperature. The desert insect pollinates flowers in night.

2. Living organisms require at least 27 elements, of which 15 are metals. Among these, those required in major quantities, include : [1996]

(a) potassium, manganese, molybdenum and calcium
(b) potassium, molybdenum, copper and calcium
(c) potassium, sodium, magnesium and calcium
(d) sodium, magnesium, copper and manganese

Correct Answer: (c) potassium, sodium, magnesium and calcium

Solution: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.

3. It is possible to produce seedless tomato fruits by : [1996]

(a) applying trace elements in tomato fruits
(b) spraying mineral solution on plants
(c) spraying hormones on flowers
(d) applying fertilizers containing radioactive elements

Correct Answer: (c) spraying hormones on flowers

Solution:Hormone auxin is responsible to produce seedless tomato fruits.

4. Match List-I (Physiological processes) with List-II (Cell organelles) and select the correct answer by using the codes given below: [1996]

List-I	List-II
A. Photosynthesis	1. Plasma membrane
B. Mineral uptake	2. Chloroplast
C. Respiration	3. Mitochondria
D. Protein synthesis	4. Ribosomes

Codes:

	A	B	C	D
(a)	1	2	3	4
(b)	1	2	4	3
(c)	2	1	3	4
(d)	2	1	4	2

Correct Answer: (c)

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

5. Which one of the following is a modified stem? [1996]

(a) Carrot
(b) Sweet potato
(c) Coconut
(d) Potato

Correct Answer: (d) Potato

Solution: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.

6. Which one of the following type of micro organisms is most widely used in industries? [1998]

(a) Bacteria
(b) Bacteria and fungi
(c) Bacteria and algae
(d) Bacteria, microalgae and fungi

Correct Answer: (d) Bacteria, microalgae and fungi

Solution:Bacteria, microalgae and fungi is most widely used in industries. Bacteria like Lactobacillus sp. is used in manufacturing of vinegar and alcohol by fementation process.

Most of algae are used as single cell protein (1.e. Spirulina). Different drugs like penicillin is manufactured from fungi Penicillium notatum.

7. Match List-I with List-II and select the correct answer by using the codes given below the lists [1998]

List-I	List-II
A. Fruit	1. Ovule
B. Seed	2. Leaf
C. Wood	3. Stem
D. Starch	4. Ovary

Codes:

	A	B	C	D
(a)	2	1	3	4
(b)	4	1	3	2
(c)	2	3	1	4
(d)	4	3	1	2

Correct Answer: (b)

Solution: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.

8. Which one of the following statements regarding starch and cellulose is not correct? [1998]

(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

Correct Answer: (c) Both of them give colour with iodine

Solution: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.

9. Ergotism is due to consumption of : [1998]

(a) contaminated grains
(b) rotting vegetables
(c) contaminated water
(d) safe cooked food

Correct Answer: (a) contaminated grains

Solution: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.

10. Which one of the following is a useful functional association between fungi and the roots of higher plants? [1999]

(a) Biofertilizer
(b) Coralloid root
(c) Lichen
(d) Mycorrhiza

Correct Answer: (d) Mycorrhiza

Solution:Mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant. Mycorrhiza takes carbohydrate from the plants. In return, the fungus helps the plant by supplying water and the important minerals.

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