All Categories MCQs
Topic Notes: All Categories
General Description
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
651
In the symbol $^{23}_{11}Na$, what does the number 23 represent?
Answer:
The mass number
In standard nuclear notation, the superscript represents the mass number ($A$), which is the sum of protons and neutrons. The subscript represents the atomic number ($Z$).
652
Elements of Group 1 are collectively called:
Answer:
Alkali Metals
Group 1 elements (excluding Hydrogen) are called Alkali Metals because they react with water to form strong alkaline hydroxides. They have one valence electron ($ns^1$) and are highly reactive.
653
Which block of the Periodic Table contains the Transition Elements?
Answer:
d-block
The d-block consists of elements in Groups 3 to 12. They are called transition elements because they represent a transition in properties between the highly reactive metals of the s-block and the non-metals of the p-block.
654
Which of the following describes a 'Synthetic' antibiotic?
Answer:
An antibiotic produced entirely in a laboratory rather than by a living microorganism
While many early antibiotics (like penicillin) were natural products of molds or soil bacteria, many modern ones are synthetic or semi-synthetic. Scientists modify the chemical structure in the lab to make the drug more powerful, more stable, or better at evading resistance.
655
What is the primary role of 'Antiviral' drugs?
Answer:
To inhibit the development and replication of viruses within host cells
Antivirals do not 'kill' viruses directly because viruses are not alive in the traditional sense. Instead, these drugs block specific stages of the viral life cycle, such as entry into the host cell, replication of viral DNA/RNA, or the release of new viral particles.
656
How does 'Active Immunity' develop in a person?
Answer:
By the body producing its own antibodies in response to an infection or vaccine
Active immunity occurs when the body's own immune system produces antibodies and memory cells after being exposed to a pathogen or a vaccine. This type of immunity is long-lasting because the body 'remembers' how to fight the specific pathogen.
657
What is the charge of an alpha particle?
Answer:
+2
An alpha particle is identical to a helium nucleus, consisting of 2 protons and 2 neutrons. Since protons are positive and neutrons are neutral, the overall charge is +2.
658
Which of the following is a bacterial disease that causes a thick, gray coating in the throat, making it hard to breathe?
Answer:
Diphtheria
Diphtheria is a serious bacterial infection. The hallmark sign is a sheet of thick, gray material covering the back of the throat, which can block the airway. It is prevented by the DTaP vaccine, which also covers Tetanus and Pertussis (Whooping Cough).
659
Which of these describes a 'broad-spectrum' antibiotic?
Answer:
An antibiotic that is effective against a wide range of both Gram-positive and Gram-negative bacteria
Broad-spectrum antibiotics are used when the specific cause of an infection is unknown or when the infection is caused by multiple types of bacteria. While useful, their use can also kill 'good' bacteria in the gut, leading to side effects like diarrhea.
660
What is the purpose of 'Disinfectants' in controlling the spread of disease?
Answer:
To kill pathogens on inanimate objects and surfaces
Disinfectants are chemical agents used on non-living surfaces (like floors, countertops, and medical equipment) to destroy microorganisms. They are generally too toxic to be used directly on human skin or tissue.