Free Biodiversity and Variety of Life MCQs with Answers

191. Which one of the following organisms are indicator of SO2 pollution of air?

• A. Mosses
• B. Lichens
• C. Mushrooms
• D. Puffballs

Explanation: Let's explain each option individually: a) Mosses: Mosses are sensitive to air pollution, including sulfur dioxide (SO2) pollution, but they are not the primary indicator species for SO2 pollution. While mosses can be affected by air pollutants and can show signs of stress or damage in polluted environments, their response to SO2 pollution is not as specific or pronounced as some other organisms, like lichens. b) Lichens: This option is correct. Lichens are excellent indicators of SO2 pollution in the air. Lichens are unique organisms composed of a symbiotic association between a fungus and an alga or a cyanobacterium. They are highly sensitive to air pollution, particularly sulfur dioxide (SO2) and other sulfur-containing compounds. Lichens are efficient at absorbing and accumulating airborne pollutants, including SO2, from the atmosphere. As a result, they are particularly useful as bioindicators in air quality monitoring programs. The presence, absence, or health of certain lichen species in a given area can provide valuable information about the level of air pollution, especially SO2 pollution. c) Mushrooms: Mushrooms, as fruiting bodies of fungi, do not directly serve as indicators of SO2 pollution. However, fungi, including mushrooms, can be impacted by air pollution in general, depending on the type and severity of pollutants in the environment. d) Puffballs: Puffballs are a type of fungi that produce spores inside an enclosed fruiting body. Similar to mushrooms, puffballs do not directly function as indicators of SO2 pollution. While fungi, including puffballs, can be influenced by air quality, they are not specific indicators of SO2 pollution. In summary, the correct answer is b) Lichens. Lichens are excellent indicators of SO2 pollution in the air due to their high sensitivity to sulfur dioxide and their ability to accumulate airborne pollutants, making them valuable bioindicators in air quality monitoring programs. The other options (mosses, mushrooms, and puffballs) may also be influenced by air pollution but are not as specific or reliable indicators of SO2 pollution as lichens.

192. In Amoeba and Paramecium osmoregulation occurs through

• A. Pseudopodia
• B. Nucleus
• C. Contractile vacuole
• D. General surface

Explanation: In both Amoeba and Paramecium, osmoregulation occurs through a specialized organelle called the contractile vacuole. The contractile vacuole is responsible for regulating the water content and maintaining the osmotic balance within these single-celled organisms. As they live in aquatic environments, water constantly moves into their cells by osmosis, and the contractile vacuole helps them remove excess water to prevent bursting or lysing.

193. African sleeping sickness is due to

• A. Plasmodium vivax transmitted by tsetse fly
• B. Trypanosoma lewsii transmitted by bed bug
• C. Trypanosoma gambiense transmitted by Glossina palpalis
• D. Entamoeba gingivalis spread by housefly

Explanation: Trypanosoma gambiense is one of the subspecies of Trypanosoma brucei that causes African sleeping sickness in West and Central Africa. Glossina palpalis is one of the tsetse fly species responsible for transmitting this subspecies. So, this option accurately identifies one of the causative agents (T. gambiense) and one of the vectors (G. palpalis) responsible for transmitting the disease.

194. Malignant tertian malarial parasite, belongs to class

• A. Plasmodium falciparum
• B. P. vivax
• C. P. ovale
• D. P. malariae

Explanation: Malignant tertian malarial parasite is caused by Plasmodium falciparum. Plasmodium falciparum is one of the species of protozoan parasites responsible for causing malaria in humans. It is known for causing severe and potentially fatal cases of malaria, especially in young children and non-immune individuals. The disease caused by Plasmodium falciparum is often referred to as "malignant tertian malaria."

195. Plasmodium, the malarial parasite, belongs to class

• A. Sarcodina
• B. Ciliata
• C. Sporozoa
• D. Dinophyceae

Explanation: Plasmodium, the malarial parasite, belongs to class Sporozoa. This class is a group of parasitic protozoans that are characterized by forming spores during some part of their life cycle. Plasmodium species, which are responsible for causing malaria in humans and other animals, are obligate intracellular parasites belonging to the class Sporozoa.

196. Amoebiasis is prevented by

• A. Eating balanced food
• B. Eating plenty of fruits
• C. Drinking boiled water
• D. Using mosquito nets

Explanation: Amoebiasis, also known as amebiasis, is a gastrointestinal infection caused by the protozoan parasite Entamoeba histolytica. One of the primary modes of transmission of this parasite is through contaminated water sources, especially those containing cysts of the parasite. Drinking boiled water is an effective preventive measure because boiling water can kill the cysts and other harmful microorganisms, reducing the risk of infection.

197. Which is true about Trypanosoma?

• A. Polymorphic
• B. Monogenetic
• C. Facultative parasite
• D. Nonpathogenic

Explanation: Trypanosoma is polymorphic. Polymorphism refers to the existence of different forms or morphological variations within a species. Trypanosoma species exhibit polymorphism, meaning they can have varying morphological forms during different stages of their life cycle. For example, Trypanosoma brucei, the species responsible for causing African trypanosomiasis, displays different morphological forms in its mammalian host and the tsetse fly vector.

198. Genetic information in Paramecium is contained in

• A. Micronucleus
• B. Macronucleus
• C. Both micronucleus and macronucleus
• D. Mitochondria

Explanation: Paramecium contains a single large macronucleus and one small micronucleus. The macronucleus controls metabolism such as feeding and maintaenance, whereas the micronucleus takes an important role in reproduction and stores genetic information, hence it is also termed as reproductive nucleus whereas macronucleus is termed as vegetative nucleus.

199. The infective stage of malarial parasite, Plasmodium that enters human body is

• A. Merozoite
• B. Sporozoite
• C. Trophozoite
• D. Minuta form

Explanation: Sporozoites are the form of Plasmodium that is transmitted to humans through the bite of an infected female Anopheles mosquito. When the mosquito feeds on an infected human, it ingests the sexual forms of the parasite, which then develop into sporozoites within the mosquito's salivary glands. Sporozoites are injected into the human bloodstream during a mosquito bite and travel to the liver, where they infect liver cells to initiate the liver stage of the malaria life cycle.

200. The main difference in Gram (+)ve and Gram (-)ve bacteria resides in their

• A. Cell wall
• B. Cell membrane
• C. Cytoplasm
• D. Flagella

Explanation: Gram-positive bacteria have a thick layer of peptidoglycan in their cell wall, which retains the crystal violet stain used in the Gram staining technique. This thick peptidoglycan layer is responsible for giving them their characteristic purple color when viewed under a microscope. On the other hand, Gram-negative bacteria have a thinner layer of peptidoglycan and an additional outer membrane composed of lipopolysaccharides. The thinner peptidoglycan layer in Gram-negative bacteria does not retain the crystal violet stain, and they appear pink when counterstained with safranin in the Gram staining process.