General Science/Everyday Science MCQs
Topic Notes: General Science/Everyday Science
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
31
Which of the following microorganisms is used to produce the antibiotic Penicillin?
Answer:
Penicillium (Fungus)
Penicillin, the first true antibiotic, was discovered by Alexander Fleming from a mold (fungus) named Penicillium notatum. This fungus produces the chemical as a defense mechanism to kill competing bacteria by preventing them from forming stable cell walls.
32
Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. What type of microorganism causes Malaria?
Answer:
Protozoa
Malaria is caused by Plasmodium, which is a genus of unicellular eukaryotes belonging to the group Protozoa. These protozoans have complex life cycles involving both humans and mosquito hosts. They primarily attack red blood cells, leading to symptoms like fever, chills, and anemia.
33
Which of the following is a symptom or disease caused by a fungal infection in humans?
Answer:
Ringworm
Ringworm is a common fungal skin infection characterized by a red, itchy, circular rash. Despite its name, it is not caused by a worm but by various types of fungi known as dermatophytes. Common cold and Polio are viral, while Typhoid is a bacterial infection.
34
The organism 'Paramecium' moves through water using tiny hair-like projections called:
Answer:
Cilia
Paramecium is a ciliated protozoan. Its cell surface is covered with thousands of short, hair-like structures called cilia. The coordinated beating of these cilia allows the Paramecium to swim rapidly through aquatic environments and also helps sweep food particles into its oral groove.
35
What is the defining characteristic of 'Eukaryotic' microorganisms like fungi and protozoa compared to 'Prokaryotic' bacteria?
Answer:
They have a membrane-bound nucleus
The fundamental difference between eukaryotes and prokaryotes is the presence of a membrane-bound nucleus. Eukaryotic cells (found in fungi, protozoa, plants, and animals) protect their DNA inside a nucleus and contain other specialized compartments like mitochondria, whereas prokaryotic cells (bacteria) do not.
36
Which of the following structures is used by Amoeba for locomotion and capturing food?
Answer:
Pseudopodia
Amoeba move and feed using pseudopodia, or 'false feet,' which are temporary projections of the cytoplasm. By extending these projections, the organism can crawl along surfaces and surround food particles to engulf them through a process known as phagocytosis.
37
Which microorganism is responsible for the 'spoiling' of milk into curd through the production of lactic acid?
Answer:
Lactobacillus
Lactobacillus is a genus of Gram-positive, rod-shaped bacteria. They convert lactose (milk sugar) into lactic acid during fermentation. The increase in acidity causes milk proteins to coagulate, turning the liquid milk into solid curd or yogurt.
38
Which microorganism is unicellular, eukaryotic, and widely used in the food industry for the fermentation of bread and alcoholic beverages?
Answer:
Yeast
Yeast is a unicellular fungus that carries out fermentation, a process that converts sugars into ethanol and carbon dioxide. In bread making, the carbon dioxide gas produced causes the dough to rise, while in brewing, the ethanol produced is the desired product for alcoholic drinks.
39
In protozoa like Paramecium, what is the function of the contractile vacuole?
Answer:
Osmoregulation (expelling excess water)
Because many protozoa live in freshwater environments that are hypotonic to their cytoplasm, water constantly enters the cell via osmosis. The contractile vacuole acts as a pump, collecting this excess water and periodically contracting to expel it from the cell, preventing the organism from bursting.
40
Which of the following is NOT a viral disease?
Answer:
Tetanus
Tetanus is a bacterial disease caused by Clostridium tetani, which enters the body through wounds. It produces a toxin that causes painful muscle contractions (lockjaw). Mumps, Chickenpox, and Measles are all caused by different types of viruses.