Plant Physiology: V. Plants: Economic Importance

Total Questions: 60

31. The most important stimulant present in tea leaves is: [U.P. P.C.S. (Mains) 2017]

(a) Caffeine
(b) Phenylalanine
(c) Brucine
(d) Theobromine

Correct Answer: (a) Caffeine

Solution:Caffeine is the world’s most widely consumed psychoactive drug or Central Nervous System (CNS) stimulant. It is mainly derived from tea leaves and coffee beans.

Caffeine is a methylxanthine alkaloid, a naturally occurring substance found in various plants. It's a stimulant, meaning it increases activity in the brain and nervous system. Its chemical formula is C8H10N4O2.

Caffeine acts as an adenosine receptor antagonist, blocking adenosine from binding to its receptors in the brain. Adenosine is a neurotransmitter that promotes relaxation and drowsiness. By blocking adenosine, caffeine reduces fatigue and increases alertness.

32. Seaweeds are an important source of which one of the following? [U.P. R.O/A.R.O. (Pre) 2017]

(a) Sulphur
(b) Chlorine
(c) Bromine
(d) Iodine

Correct Answer: (d) Iodine

Solution:Seaweed is a type of algae that grows in salt water and (like terrestrial plants) needs sunlight to thrive. There are over ten thousand varieties of seaweed, many of which are good to eat. Seaweeds are best known as the richest natural source of iodine.

Seaweed is a marine plant that grows in oceans and seas. It is nutrient-dense, containing 54 trace elements, vitamins, minerals, and amino acids.It helps combat cancer, diabetes, arthritis, heart disease, and high blood pressure while also boosting immunity. Unlike traditional crops, seaweed does not require land, freshwater, fertilizers, or pesticides, making it an eco-friendly and sustainable agricultural resource. Microscopic seaweeds, such as phytoplankton, form the foundation of marine food chains and play a key role in oceanic primary productivity. Large seaweeds, like giant kelp, create dense underwater forests that serve as biodiversity hotspots, offering shelter and food to a variety of species. Seaweeds contribute to oxygen generation and carbon sequestration, playing a significant role in climate regulation.

33. Consider the following: [I.A.S. (Pre) 2009]

Camphor
Chicory
Vanilla

Which of the above is/are plant product(s)?

(a) 1 and 2
(b) 3 only
(c) 1 and 3
(d) 1, 2 and 3

Correct Answer: (d) 1, 2 and 3

Solution:Camphor is a waxy, flammable, white or transparent solid with a strong aromatic odor. It is found in the wood of the camphor laurel (Cinnamomum camphora), a large evergreen tree found in Asia (particularly in Sumatra, Indonesia, and Borneo) and also from the unrelated Kapur tree, a tall timber tree from the same region. Chicory is a somewhat woody, perennial, herbaceous plant usually with bright blue flowers, rarely white or pink. Its many varieties are cultivated for salad leaves and its root powder is used to reduce the bitterness of coffee. Vanilla is a flavor derived from orchids of the genus Vanilla, primarily from the Mexican species, flat-leaved vanilla.

34. ‘Kuttu’ flour is obtained from - [U.P.P.C.S. (Mains) 2010]

(a) Tapioca
(b) Fagopyrum
(c) Plantago
(d) Eleusine

Correct Answer: (b) Fagopyrum

Solution:Kuttu flour is obtained from the plant of Buckwheat (Fagopyrum esculentum). This plant is cultivated for its grain-like seeds and is also used as a cover crop. Despite the name, buckwheat is not related to wheat, as it is not a grass. Instead, buckwheat is related to sorrel, knotweed, and rhubarb. Because its seeds are eaten, it is referred to as a pseudocereal.

35. In making the saffron spice, which one of the following parts of the plant is used? [I.A.S. (Pre) 2009]

(a) Leaf
(b) Petal
(c) Sepal
(d) Stigma

Correct Answer: (d) Stigma

Solution:Saffron is a spice derived from the flower of Crocus sativus, commonly known as the ‘saffron crocus’. Saffron crocus grows to about 20–30 cm (8–12 inch) and bears up to four flowers, each with three vivid crimson stigmas, which are the distal end of a carpel. The styles and stigmas, called threads, are collected and dried to be used mainly as a seasoning and coloring agent in food. Saffron is among the world’s most costly spices by weight.

36. Which of the following part in peppermint has maximum percentage of oil? [U.P.P.C.S. (Pre) 2009]

(a) Root
(b) Stem
(c) Leaf
(d) Flower

Correct Answer: (c) Leaf

Solution:Peppermint oil or menthol oil is made up of peppermint leaves by steam distillation process. Its scientific name is Mentha arvensis. The oil has a high concentration of natural pesticides. Its main constituents are menthol (40.7%) and menthone (23.4%).

37. Which of the following substances is obtained from a tree? [U.P.P.C.S. (Pre) 2020]

(a) Asafoetida
(b) Bitumen
(c) Tincal
(d) None of the above

Correct Answer: (a) Asafoetida

Solution:Asafoetida (Heeng) is the dried latex (oleo-gum resin), obtained from several species of Ferula which are herbaceous plants of the Umbelliferae family. It is extracted from the thirome and fleshy tap roots. This spice is used as digestive and, in food as a condiment, and in pickling.

38. Match List-I with List-II and select the correct answer using the code given below the lists: [U.P.P.C.S. (Pre) 2017]

List-I (Product)	List-II (Source)
A. Opium	1. Bark
B. Hing	2. Root
C. Rubber	3. Fruit
D. Quinine	4. Stem

Code:

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

Correct Answer: (b)

Solution:The correct matching is as follows:

Opium – Fruit
Hing – Root
Rubber – Stem
Quinine – Bark

Opium is obtained from the milky latex of Papaver somniferum. Hing is obtained mainly from the roots of a plant of Ferula species. Rubber is obtained from the liquid stuff turned out from the stem of a plant, and quinine is obtained from the bark of the cinchona tree.

39. Asafoetida is obtained from: [U.P. R.O./A.R.O. (Pre) (Re. Exam) 2016]

Correct Answer: (e) (a) & (b)

Solution:Asafoetida (Hing) is the dried latex (resin-like gum) obtained from several species of Ferula, which are herbaceous plants of the Umbelliferae family. The oleo-gum resin comes from the dried sap extracted from the rhizome (modified stem) and fleshy tap roots and is used as spice. Asafoetida is endemic to Afghanistan and Iran.

40. Quinine, which is a major drug for malaria, is obtained from - [R.A.S./R.T.S. (Pre) 1996]

(a) Angiosperm
(b) Bacteria
(c) Yeast
(d) Algae

Correct Answer: (a) Angiosperm

Solution:Quinine is a major drug used to treat malaria. Quinine is extracted from the bark of cinchona tree. It is an angiosperm plant. Quinine is a white crystalline alkaloid and bitter in taste. It is also used in the treatment of arthritis and prion- related disease.

The tree is named after a village about 70 km south of Guwahati, on the highway to Meghalaya capital Shillong.

The cinchona nursery was raised in the 19th century, probably around 1874, when Shillong became the British administrative headquarters for Assam Province.

Large swathes of Meghalaya used to be, and still are, malaria-prone.
The British had the foresight to start the plantation to combat malaria and other diseases caused by mosquitoes.

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