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
41
What is the extra-chromosomal, small circular DNA found in many bacteria that often carries genes for antibiotic resistance?
Answer:
Plasmid
Plasmids are small, circular, double-stranded DNA molecules that are distinct from a cell's chromosomal DNA. They can replicate independently and often carry 'advantageous' genes, such as those providing resistance to antibiotics, which can be transferred between bacteria through a process called conjugation.
42
Which type of bacteria are shaped like spirals or coils?
Answer:
Spirilla
Spirilla are bacteria with a rigid spiral shape. Another type of spiral bacteria, known as spirochetes, are more flexible. Bacilli are rods, and Cocci are spheres. Understanding these shapes helps scientists identify and classify bacteria during clinical diagnosis.
43
Which protozoan is responsible for causing 'Malaria'?
Answer:
Plasmodium
Plasmodium is the genus of unicellular parasites that cause malaria. There are several species, with Plasmodium falciparum being the most deadly. They are transmitted by mosquitoes and spend part of their life cycle in the liver and red blood cells of humans.
44
Which group of microorganisms is considered 'non-living' outside of a host cell because they cannot reproduce or carry out metabolism independently?
Answer:
Viruses
Viruses are often described as obligate intracellular parasites because they lack the machinery for independent metabolism and reproduction. They consist of genetic material (DNA or RNA) wrapped in a protein coat called a capsid and must infect a living host cell to replicate themselves.
45
Which of the following protozoa causes 'Sleeping Sickness' and is transmitted by the tsetse fly?
Answer:
Trypanosoma
African Sleeping Sickness (Trypanosomiasis) is caused by the protozoan parasite Trypanosoma brucei. It is transmitted to humans through the bite of the tsetse fly. The parasite eventually enters the central nervous system, causing neurological symptoms and disrupted sleep patterns.
46
What is the genetic material found inside a virus?
Answer:
Either DNA or RNA, but never both
Viruses are unique because their genome can consist of either DNA or RNA, which can be single-stranded or double-stranded. However, a single virus particle (virion) will only contain one type of nucleic acid. This is one of the primary criteria used to classify different families of viruses.
47
What is the primary method of locomotion for the protozoan 'Euglena'?
Answer:
Flagellum
Euglena is a flagellated protozoan that possesses a long, whip-like tail called a flagellum. By whipping the flagellum back and forth, the Euglena can pull itself through its aquatic environment. Interestingly, Euglena also contains chloroplasts and can perform photosynthesis.
48
Which microorganism is considered a 'biological bridge' between living and non-living things?
Answer:
Virus
Viruses are considered to be at the edge of life because they exhibit living characteristics only when they are inside a host cell (like replication and evolution). Outside a host, they are inert crystalline structures with no metabolism, making them seem non-living.
49
What happens during the 'Lytic Cycle' of a virus?
Answer:
The virus replicates and causes the host cell to burst
In the lytic cycle, a virus infects a host cell, immediately hijacks its machinery to mass-produce new viral components, assembles them into new viruses, and then causes the host cell to rupture (lyse) to release the offspring. This is contrasted with the lysogenic cycle, where the virus remains dormant.
50
Tuberculosis (TB) is a contagious infection that usually attacks the lungs. It is caused by which type of pathogen?
Answer:
Bacterium
Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. It is primarily an airborne disease spread through respiratory droplets. Unlike viral infections, TB can be treated with a specific course of antibiotics over several months to eradicate the bacterial population.