Biology (Part-I) (UPSC)

Total Questions: 50

41. Which one the following group of a plant domesticated in the new world and introduced into the old world? [2014-1]

Correct Answer: (a) Tobacco, cocoas, and rubber
Solution:Encyclopedia Britannica: In the 15th and 16th centuries. during the Columbian Exchange: numerous plants, animals, and microbes from old world (Europe, Asia, and Africa) were introduced to the new world (Americas) and vice versa. From the image given in the link, it's evident that Cocoa and Tobacco were introduced from new world to old world so only A fits.

42. Recently, there was a growing awareness in our country about the importance of Himalayan nettle (Girardinia diversifolia) because it is found to be a sustainable source of : [2019-1]

Correct Answer: (d) textile fibre
Solution:There is a community in Khar, a hamlet in Darchula district in far-western Nepal, which produces fabrics from Himalayan nettle. The fabric and the things made from it are sold in local as well as national and international markets as high-end products so D: textile is most suitable.
• Furthermore, Himalayan nettle is widely used in traditional medicine to treat various ailments such as stomach disorders, chest pains, rheumatism, tuberculosis, headache, joint aches, diabetes, asthma, gastritis, headache, joint pain, tuberculosis, gonorrhoea and delivery problems.
• Other traditional uses relate to broken bones, internal injuries and blood purification. It is also famous for using its bark and fiber to make various clothes, ropes, carpets, bags and other household items. In that context, it is one of the main non-timber forest products used for the livelihood of rural communities in the Himalayan region. The young leaves and flowers are boiled into a green vegetable. Roasted seeds are consumed marinated.
• Himalayan nettle has a glossy exterior. It possesses the longest known thread and, after being sp
• Since there has been an increase in demand for sustainable fibres and cotton substitutes in Western nations, many farmers and producers in Germany have begun to grow nettle, which has shown to be quite adaptable and is distinguished by fineness and flexibility

43. Which of the following statements are correct regarding the general difference between plant and animal cells? [2020-1]

1. Plant cells have cellulose cell walls whilst animal cells do not.

2. Plant cells do not have plasma membrane unlike animal cells which do.

3. Mature plant cell has one large vacuole whilst an animal cell has many small vacuoles.

Select the correct answer using the code given below:

Correct Answer: (c) 1 and 3 only
Solution:NCERT Class 10 Science: page 61- Plant cells, in addition to the plasma membrane, have another rigid outer covering called the cell wall. So, statement#2 is incorrect, so by elimination answer is c.
FeatureAnimal CellPlant Cell
NucleusPresentPresent
CiliaPresentIt is very rare
ShapeRound (irregular shape)Rectangular (fixed shape)
ChloroplastAnimal cells don't have chloroplastsPlant cells have chloroplasts because they make their own food
CytoplasmPresentPresent
Endoplasmic Reticulum (Smooth and Rough)PresentPresent
RibosomesPresentPresent
MitochondriaPresentPresent
VacuoleOne or more small vacuoles (much smaller than plant cells).One. large central vacuole taking up 90% of cell volume.

44. According to India's National Policy on Biofuels, which of the following can be used as raw materials for the production of biofuels? [2020-1]

1. Cassava

2. Damaged wheat grains

3. Groundnut seeds

4. Horse gram

5. Rotten potatoes

6. Sugar beet

Select the correct answer using the code given below:

Correct Answer: (a) 1,2,5 and 6 only
Solution:National Policy on Biofuels 2018 identified following raw materials for biofuel generation: Molasses, Sugarcane juice, biomass in form of grasses, . agriculture residues (Rice straw, cotton stalk, corn cobs, saw dust, bagasse etc.), sugar containing materials like sugar beet, sweet sorghum, etc. starch containing materials such as corn, cassava, rotten potatoes etc., Damaged food grains like wheat, broken rice etc. In the entire policy document there is no mention of horse gram or groundnut so, #3 and #4 are wrong. By elimination we arrived at answer a.

45. Consider the following statements: [2023-1]

1. Some mushrooms have medicinal properties.

2. Some mushrooms have psychoactive properties.

3. Some mushrooms have insecticidal properties.

4. Some mushrooms have bioluminescent properties.

How many of the above statements are correct?

Correct Answer: (d) All four
Solution:The answer is (d). All four statements are correct. Some mushrooms have medicinal properties. For example, the shiitake mushroom is known to boost the immune system and fight cancer. Some mushrooms have psychoactive properties.

For example, the psilocybin mushroom is known to cause hallucinations and alter consciousness. Some mushrooms have insecticidal properties. For example, the oyster mushroom is known to kill mosquitoes. Some mushrooms have bioluminescent properties. For example, the jack-o'-lantern mushroom is known to glow in the dark.

46. The only snake that builds a nest is: [1995]

Correct Answer: (b) King Cobra
Solution:King cobra is the only snake that not only lives in holes but also builds a nest.
About King Cobra:
• It is the world’s largest venomous snake and an active hunter.
• The main feature that distinguishes the king cobra from other cobras is the possession of 11 large scales on the crown of its head.
• It preys almost exclusively on other snakes, prowling in forests, fields, and villages in the daytime as well as at night.
• It was in 1836 that a broad spectrum of king cobra species was named as Ophiophagus hannah by Danish naturalist, Theodore Edward Cantor.
• The amount of venom that they can deliver in a single bite is enough to kill 10 people or even an elephant.
• The neurotoxin venom of king cobra affects the respiratory centres, causing respiratory arrest and cardiac failure.
• The king cobras are the only snakes in the world to build nests that are 4 ft x 3 ft and the female king cobras are found ferociously guarding them.
• The study identified four species of king cobra:
• Ophiophagus kaalinga: Found in the Western Ghats of southwestern India, this species has fewer than 40 bands on its body.
• Ophiophagus hannah: Inhabiting northern and eastern India, the Andaman Islands, eastern Pakistan, Indo-Burma, Indo-China, and Thailand, this species displays 50 to 70 bands.
• Ophiophagus bungarus: Found in the Malay Peninsula, Greater Sunda Islands, and parts of southern Philippines, it features more than 70 bands.
• Ophiophagus salvatana: Native to Luzon in the northern Philippines, this species lacks bands altogether.

47. Which one of the following sets is correctly matched? [1995]

(1) Diphtheria, Pneumonia and Leprosy: Hereditary

(2) AIDS, Syphilis and Gonorrhoea: Bacterial

(3) Colour blindness, Haemophilia and Sickle cell anaemia: Sex linked

(4) Polio, Japanese B encephalitis and Plague: Viral

Correct Answer: (b) only 3
Solution:Diphtheria, Leprosy, Plague are Bacterial diseases. AIDS, Polio, Pneumonia, Gonorrhoea, Syphilis- Viral disease. Japanese B encephalitis - Protozoan disease. Colour blindness and Haemophilia - Sex linked disease. Sickle cell anaemia is a genetic disease in which RBC became sickle shaped.

48. A person with 'AB' blood group is sometimes called a universal recipient because of the : [1995]

Correct Answer: (b) lack of antibodies in his blood
Solution:Person having blood group 'AB' is called universal recepient because the 'AB' blood group has no antibody in the blood plasma, So, the person can accept any type of blood group (i.e. A, B and O).
• Blood groups are classifications determined by the presence or absence of antigens on the surface of red blood cells and antibodies in the plasma.
• The most common system used is the ABO system, which categorizes blood into four groups: A, B, AB, and O. Blood type A has A antigens, B has B antigens, AB has both, and O has none.
• Another important factor is the Rh factor, which determines whether the blood type is positive (Rh+) or negative (Rh−). For instance, a person can be A+ or A−.
• The compatibility of blood groups is crucial in blood transfusions, organ transplants, and pregnancy.
• Incompatible blood can cause severe immune reactions. For example, O− is considered a universal donor, while AB+ is a universal recipient.
• Understanding blood groups helps ensure safe medical practices and prevents complications in life-saving procedures.

49. Which one of the following is a membrane that protects the developing embryo from desiccation? [1995]

Correct Answer: (a) Amnion
Solution:The amnion is a membrane that protects the developing embryo by a fluid-filled space called amniotic cavity. Amnion is formed above the embryo.
Amnion is the innermost layer that covers the foetus. It is filled with a clear liquid called amniotic fluid. The amniotic fluid expands, and the amnion eventually forms an amniotic sac.
The shape of the embryo is maintained because it is suspended in the amniotic fluid. The amniotic fluid provides equal pressure throughout the sac, and protects the embryo from outer hindrances by forming a cushion. It also allows the embryo to float freely in the sac, contributing to skeletomuscular development.
The amniotic fluid is released at the time of childbirth. The rupturing of the sac is a signal that the child is ready to come out of the womb.
Allantois is the layer present between amnion and chorion. It is a sac-like structure that literally translates to sausage (according to the Latin dictionary). It expands greatly between the two layers to serve as a temporary respiratory organ for the foetus, and its cavity stores all the foetal excretions. It is filled with a clear liquid.
The allantois is composed of blood vessels that allow exchange of gases from the developing embryo. The blood vessels eventually become the arteries and veins of the umbilical cord.
The allantois form a unique structure called urachus. It is a canal-like structure that is a remnant of allantois and is fibre-like. It serves as a site for the drainage of the urinary bladder of the foetus and also joins with the umbilical cord.

50. Which one of the following antimicrobial drugs, is suitable for treatment of both tuberculosis and leprosy? [1995]

Correct Answer: (d) Rifampicin
Solution:Leprosy is caused by Mycobacterium leprae and tuberculosis is caused by Mycobacterium tuberculosis. The effective drug for Mycobacterium species is Rifampicin.
Antimicrobial drugs are agents used to target and eliminate bacteria and are essential for treating infections of the nervous system such as bacterial meningitis.
The effectiveness of these drugs in bacterial meningitis is determined by their ability to penetrate the blood–brain barrier (BBB) and reach the central nervous system (CNS). The BBB is a highly selective interface between the blood and the brain parenchyma, composed of brain microvascular endothelial cells, basement membrane, pericytes, and the end feet of astrocytes, which together form the neurovascular unit and maintain BBB integrity.
This barrier strictly controls material exchange, protecting the CNS from toxic substances circulating in the blood. The selective permeability of the BBB significantly impacts the pharmacokinetics and pharmacodynamics of antimicrobial drugs, as penetration into the subarachnoid space is the first pharmacologic factor determining whether an antimicrobial agent can clear bacteria from the cerebrospinal fluid (CSF). Factors such as lipophilicity, molecular weight, protein-bound fraction, and molecular size influence BBB penetration, and the breakdown of the BBB during infection can enhance drug delivery to the CNS.