FPSC (Federal Public Service Commission) · CSS (Central Superior Services)
8.3 Vaccines and Antibiotics
8. Microorganisms
· General Science/Everyday Science
200 MCQs
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1–20
of 200 MCQs
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1
Which of the following is a key preventive measure against waterborne diseases like Typhoid and Dysentery?
Answer:
Boiling or treating drinking water
Since waterborne pathogens are ingested, ensuring that drinking water is free from contamination is the most effective prevention. Boiling water kills most bacteria, viruses, and protozoa, making it safe for consumption.
2
An element has an atomic number of 20. In which group and period is it located?
Answer:
Group 2, Period 4
The electronic configuration of atomic number 20 (Calcium) is 2, 8, 8, 2. It has 4 shells (Period 4) and 2 valence electrons (Group 2).
3
Which of the following describes the 'Excited State' of an atom?
Answer:
When an electron has moved to a higher energy level
An atom enters an excited state when it absorbs energy, causing an electron to move from its ground state (lowest energy level) to a higher, less stable energy level.
4
What is the primary way 'Polio' is transmitted?
Answer:
Through the fecal-oral route (contaminated food or water)
The poliovirus is mainly spread through the fecal-oral route. This often happens in areas with poor sanitation where the virus from the feces of an infected person contaminates the water supply or food eaten by others.
5
Which of the following describes the transmission of 'Chickenpox'?
Answer:
Direct contact with the blisters or inhalation of airborne droplets
Chickenpox (Varicella) is highly contagious. It spreads through the air when an infected person coughs or sneezes, and also by direct contact with the fluid that leaks from the itchy, fluid-filled blisters (rash).
6
Which state of matter is the most compressible?
Answer:
Gas
Gases are highly compressible because their particles are separated by large distances. Applying pressure reduces the empty space between these particles, significantly decreasing the volume.
7
Which of the following is an example of an 'airborne' disease?
Answer:
Chickenpox
Chickenpox is highly contagious and spreads through the air when an infected person breathes, talks, coughs, or sneezes. The virus can also spread through contact with the fluid from the blisters, but the airborne route is a major pathway.
8
Which element has the electron configuration $[Ne] 3s^2 3p^1$?
Answer:
Aluminum
The total number of electrons is 10 (from Neon core) + 2 + 1 = 13. Aluminum is the element with atomic number 13.
9
Which of the following is a bacterial disease that often enters the body through deep cuts or wounds, leading to muscle stiffness?
Answer:
Tetanus
Tetanus is caused by the bacterium Clostridium tetani, which is commonly found in soil and manure. When it enters a wound, it produces a toxin that affects the nervous system, causing painful muscle contractions, particularly in the jaw and neck (lockjaw).
10
Which of these is a protozoan disease transmitted by the bite of a sandfly?
Answer:
Leishmaniasis
Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania. It is transmitted to humans through the bite of infected female phlebotomine sandflies and can cause skin ulcers or affect internal organs.
11
Which microorganism causes 'Oral Thrush', a condition where white patches appear on the tongue and mouth?
Answer:
A fungus (yeast) called Candida
Oral thrush is a yeast infection caused by the fungus Candida albicans. While Candida is normally present in the mouth in small amounts, it can overgrow if the immune system is weakened or if the balance of 'good' bacteria is disrupted by antibiotics.
12
Which of the following describes a 'cation'?
Answer:
A positively charged ion
A cation is formed when an atom loses electrons (negative charge), resulting in more protons than electrons and a net positive charge.
13
Ringworm is a common skin infection characterized by a red, itchy, circular rash. What type of pathogen causes this condition?
Answer:
Fungus
Despite its name, ringworm is not caused by a worm; it is a fungal infection of the skin. Fungi called dermatophytes thrive on keratin, a protein found in skin, hair, and nails, leading to the characteristic circular lesions.
14
Brownian motion provides evidence for:
Answer:
The existence of atoms and molecules in constant motion
Brownian motion is the random movement of particles suspended in a fluid resulting from their bombardment by fast-moving atoms or molecules in the gas or liquid.
15
Which shell has the highest energy in an atom of Aluminum (Atomic No. 13)?
Answer:
M shell
The electron configuration of Aluminum is $2, 8, 3$. The electrons occupy the K ($n=1$), L ($n=2$), and M ($n=3$) shells. Since energy increases with the distance from the nucleus, the M shell has the highest energy.
16
Which mode of transmission is responsible for spreading the Human Immunodeficiency Virus (HIV)?
Answer:
Exchange of infected body fluids
HIV is transmitted through specific body fluids, including blood, semen, vaginal fluids, and breast milk. Common routes include unprotected sexual contact, sharing contaminated needles, or from mother to child during childbirth or breastfeeding.
17
Which element in the third period has the highest first ionization energy?
Answer:
Argon
Argon, being a noble gas with a stable octet, requires the most energy to remove an electron. Generally, noble gases have the highest ionization energies in their respective periods.
18
Elements in Group 18 of the Periodic Table are known as:
Answer:
Noble Gases
Noble gases are characterized by having a completely filled valence shell ($ns^2 np^6$, except Helium). This stable electron configuration makes them chemically inert under standard conditions.
19
Which group of elements is known as 'Chalcogens'?
Answer:
Group 16
Group 16 elements (Oxygen, Sulfur, etc.) are called chalcogens, a name derived from the Greek word for 'ore-former', as many ores are oxides or sulfides.
20
What does the term 'asymptomatic carrier' mean in the context of infectious diseases?
Answer:
A person who is infected but shows no symptoms of the disease
An asymptomatic carrier is an individual who carries a pathogen and can transmit it to others but does not experience any symptoms themselves. This makes them 'silent' spreaders, as neither they nor those around them realize they are infected.
