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
21
Bacteria that require oxygen for their survival and growth are called:
Answer:
Aerobes
Aerobic bacteria (aerobes) use oxygen to break down food and produce energy through cellular respiration. In contrast, anaerobic bacteria (anaerobes) can live and grow without oxygen, and for some, oxygen is actually toxic.
22
Which microorganism is used in the large-scale production of citric acid for the food and beverage industry?
Answer:
Aspergillus niger (Fungus)
Aspergillus niger is a species of fungus that is widely used in biotechnology. It is primarily used for the industrial production of citric acid through the fermentation of sugar-rich substrates, as it naturally excretes the acid as a metabolic byproduct.
23
The process of using microorganisms like yeast to convert sugars into alcohol and carbon dioxide is called:
Answer:
Fermentation
Fermentation is an anaerobic metabolic process where organisms like yeast or bacteria break down carbohydrates into acids, gases, or alcohol. This process is fundamental to the production of bread, wine, beer, and yogurt.
24
Which of the following microorganisms is classified as prokaryotic because it lacks a true nucleus and membrane-bound organelles?
Answer:
Bacteria
Bacteria are single-celled organisms that do not have a nucleus or membrane-bound organelles, making them prokaryotes. Their genetic material is found in a region called the nucleoid, and they typically contain a cell wall made of peptidoglycan, unlike eukaryotic cells which have a defined nucleus.
25
Which of these is a viral disease that affects the human immune system, specifically targeting T-helper cells?
Answer:
AIDS
AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV). HIV attacks the immune system, specifically the CD4+ T-helper cells, which are vital for coordinating the body's immune response against infections. Tuberculosis and Cholera are bacterial, while Malaria is protozoan.
26
What is the protective protein shell that surrounds the genetic material of a virus called?
Answer:
Capsid
The capsid is a protein coat that protects the viral genome (either DNA or RNA) from environmental damage and assists in the attachment of the virus to host cells. Some viruses may also have an outer lipid layer called an envelope, but the protein shell is universally referred to as the capsid.
27
Bacteria that can manufacture their own food using sunlight or chemicals are called:
Answer:
Autotrophs
Autotrophic bacteria (like cyanobacteria) can produce their own organic nutrients from inorganic sources. Photoautotrophs use sunlight (photosynthesis), while chemoautotrophs use energy from chemical reactions (chemosynthesis). Heterotrophs must consume organic matter from others.
28
Which mode of nutrition is most common in fungi, where they obtain nutrients by absorbing organic matter from dead or decaying organisms?
Answer:
Saprotrophic
Fungi are saprotrophs, meaning they release digestive enzymes into their environment to break down complex organic matter from dead plants and animals into simpler substances. They then absorb these nutrients directly through their cell walls. This role is crucial for nutrient cycling in ecosystems.
29
Antibiotics like Penicillin are highly effective in treating infections caused by which of the following?
Answer:
Bacteria
Antibiotics are chemical substances specifically designed to kill or inhibit the growth of bacteria by targeting bacterial structures like the cell wall or metabolic processes like protein synthesis. They are ineffective against viruses, as viruses do not have the same biological structures or pathways that antibiotics target.
30
What are the long, thread-like structures that make up the body of a multicellular fungus called?
Answer:
Hyphae
Hyphae are the branching, tubular filaments that constitute the vegetative part of most fungi. A mass of interconnected hyphae is known as a mycelium. These structures provide a large surface area for the absorption of nutrients from the substrate the fungus is growing on.