Free Biodiversity and Variety of Life MCQs with Answers

3111. When an anopheles of mosquito bites a healthy person if injects:

• A. Merozoites
• B. Sporozoites
• C. Gametocytes
• D. Oocytes

Explanation: The well-matured sporozoites are injected into the human host through the saliva of an Anopheles mosquito when it bites to feed on the blood. When mosquitoes bite, they inject a tiny amount of their saliva (less than a microliter), which contains a specialized, potent cocktail of molecules that numb the pain of the bite and stop the blood from clotting.

3112. Who stated this hypothesis? Mosquitoes are involved in the spread of malaria

• A. Ronald
• B. AFA king
• C. Laveran
• D. Aristotle

Explanation: Charles Louis Alphonse Laveran, a French physician, was the one who stated the hypothesis that mosquitoes are involved in the spread of malaria. Laveran made this observation in 1880 when he discovered the presence of parasites in the blood of malaria patients and later found the same parasites in the stomachs of mosquitoes.

3113. Carotenoid pigments are present in:

• A. Euglenophyta
• B. Pyrrophyta
• C. Chrysophyta
• D. Both A and B

Explanation: Euglenophyta, commonly known as euglenoids, are a group of unicellular organisms that possess chloroplasts and are capable of photosynthesis. They contain various pigments, including carotenoids, which contribute to the coloration of these organisms. Pyrrophyta, also known as dinoflagellates, are another group of unicellular organisms. Pyrrophyta also contains carotenoid pigments, which give them their characteristic colors. Therefore, carotenoid pigments are found in both Euglenophyta and Pyrrophyta.

3114. The malarial patient feels chill and fever when:

• A. merozoites increase their population in RBC and burst open the RBC
• B. sporozoites enter the bloodstream
• C. sporozoites enter the liver cells.
• D. merozoites come out of the liver cells.

Explanation: During the erythrocytic stage of the plasmodium life cycle, merozoites invade red blood cells and reproduce inside them. As the number of merozoites increases within the RBCs, the RBCs eventually burst open (lysis), releasing more merozoites into the bloodstream. This bursting of infected RBCs leads to the release of toxic substances and triggers an immune response, resulting in symptoms such as chills and fever.

3115. The hypothesis of Ronald Ross relating to malaria was:

• A. Plasmodia are the cause of malaria.
• B. Bad air is involved in the spread of malaria.
• C. Mosquitoes are possible carriers of Plasmodium.
• D. Malaria is caused by bad air coming from marshy places.

Explanation: Ronald Ross's hypothesis and subsequent research demonstrated that mosquitoes, particularly the Anopheles species, are vectors for the Plasmodium parasite, which leads to malaria. This was a groundbreaking discovery because it identified the mosquito as the carrier rather than attributing the disease to environmental factors like bad air, as suggested by the miasma theory. The other options incorrectly focus on outdated or already known aspects of malaria transmission, rather than Ross's specific contribution.

3116. Entamoeba belongs to the phylum:

• A. sporozoa
• B. sarcodina
• C. mastigophora
• D. microspora

Explanation: Entamoeba belongs to the subphylum Sarcodina, which includes protozoans that move and feed using temporary projections of their cell bodies called pseudopodia. This is unlike Sporozoa, which are non-motile and known for their spore-forming stages; Mastigophora, which use flagella for movement; and Microspora, which are spore-forming unicellular parasites.

3117. Select the correct statement:

• A. Cholera, typhoid, and tetanus are well-known diseases caused by viruses.
• B. Dinoflagellates, euglenoids and slime moulds are placed under kingdom Monera
• C. Members of kingdom Protista are primarily aquatic
• D. Dinoflagellates are the chief 'producers' in the oceans

Explanation: The kingdom Protista consists of a diverse group of eukaryotic microorganisms, many of which are found in aquatic environments. Protists can be found in freshwater, marine habitats, and even moist terrestrial environments. They include various organisms such as algae, protozoa, and slime moulds.

3118. The cell wall of fungus like protista is composed of:

• A. Chitin
• B. Cellulose
• C. Murein
• D. Lignin

Explanation: The cell wall of fungus like protista is composed of chitin.

3119. All of the following belong to phylum Protista except:

• A. Protomycota
• B. Gymnomycota
• C. Oomycota
• D. Deuteromycota

Explanation: Phylum Deuteromycota is a polyphyletic group of asexually-reproducing fungi that do not display a sexual phase; they are known as imperfect.

3120. Balantidium coli lives in the intestinal tract of:

• A. Pigs and rats
• B. Pigs and monkeys
• C. Rats and dogs
• D. Cats and sheep

Explanation: Swine are the primary reservoir hosts of Balantidium coli. Humans can also be reservoirs, and other potential animal hosts include non-human primates. Balantidium coli is a normal inhabitant of the cecum and colon of non-human primates and pigs.Mode of Transmission:Balantidium coli is transmitted through the fecal-oral route. Humans can become infected by eating and drinking contaminated food and water that has come into contact with infective animal or human fecal matter.Signs and Symptoms:Balantidium coli infects the large intestine in humans and produces infective microscopic cysts that are passed in the feces, potentially leading to re-infection or infection of others. Immune-compromised people are the most likely to experience more severe signs and symptoms. These include persistent diarrhea, dysentery, abdominal pain, weight loss, nausea, and vomiting. If left untreated, perforation of the colon can occur.