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
11
Which of the following bacterial diseases is characterized by severe 'rice-water' stools and dehydration?
Answer:
Cholera
Cholera is caused by the bacterium Vibrio cholerae. The bacteria produce a toxin in the small intestine that causes the body to release massive amounts of water and salts, leading to extreme diarrhea (rice-water stools) and rapid, life-threatening dehydration.
12
Which of the following is an example of a unicellular fungus?
Answer:
Yeast
Most fungi, such as mushrooms and molds, are multicellular and grow in thread-like filaments. However, yeasts are a notable exception as they exist as single-celled organisms throughout their life cycle. They reproduce primarily through a process called budding.
13
Which of the following is a disease caused by protozoa that results in severe diarrhea and abdominal pain?
Answer:
Amoebic Dysentery
Amoebic dysentery is caused by the protozoan Entamoeba histolytica. It is usually contracted by consuming contaminated food or water. The parasite infects the large intestine, causing inflammation, ulcers, and painful diarrhea often containing blood or mucus.
14
Which of the following bacteria are found in the root nodules of leguminous plants and help in fixing atmospheric nitrogen?
Answer:
Rhizobium
Rhizobium is a genus of bacteria that lives in a symbiotic relationship with legumes (like peas and beans). They convert atmospheric nitrogen gas into ammonia, which the plant can use for growth. In return, the plant provides the bacteria with carbohydrates produced during photosynthesis.
15
What is the typical method of asexual reproduction in bacteria where a single cell divides into two identical daughter cells?
Answer:
Binary fission
Binary fission is the primary method of reproduction for bacteria. During this process, the bacterial DNA replicates, the cell elongates, and a septum forms in the middle, eventually splitting the cell into two genetically identical daughter cells. This allows bacterial populations to grow exponentially under favorable conditions.
16
A mass of fungal hyphae that forms the body of the fungus is called:
Answer:
Mycelium
The mycelium is the vegetative part of a fungus, consisting of a network of fine white filaments (hyphae). While we often only see the 'fruiting body' (like a mushroom) above ground, the extensive mycelium typically lives underground or inside a food source.
17
Which of the following fungal diseases is known for causing itchy, red, and cracked skin between the toes?
Answer:
Athletes Foot
Athlete's foot (tinea pedis) is a fungal infection that typically begins between the toes. It occurs most often in people whose feet have become very sweaty while confined within tight-fitting shoes. It is highly contagious and spreads via contact with infected skin or contaminated surfaces like floors.
18
Which of the following microorganisms is the smallest in size?
Answer:
Viruses
Viruses are significantly smaller than bacteria, fungi, and protozoa. While bacteria can be seen with a standard light microscope, viruses are so small (measured in nanometers) that they can only be visualized using an electron microscope.
19
What is the function of 'Pili' in some bacterial cells?
Answer:
Attachment to surfaces and genetic exchange
Pili (singular: pilus) are hair-like appendages found on the surface of many bacteria. They are used for attachment to host tissues or other surfaces. Special 'sex pili' are used during conjugation to transfer DNA (like plasmids) from one bacterium to another.
20
Which of these structures is NOT found in a bacterial cell?
Answer:
Mitochondria
Bacteria are prokaryotes, meaning they lack membrane-bound organelles. While they have ribosomes (for protein synthesis) and a plasma membrane, they do not have mitochondria, chloroplasts, or a nucleus. Instead, they produce energy using enzymes located on their plasma membrane.