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
81
Pasteurization is a process used to make milk safe to drink. What does this process involve?
Answer:
Heating the milk to a specific temperature for a short time
Pasteurization involves heating liquids (like milk or juice) to a temperature high enough to kill most harmful pathogens (like Salmonella or E. coli) without significantly changing the taste or nutritional value of the food.
82
Why is 'Selective Toxicity' the most important principle in antibiotic development?
Answer:
It ensures the drug is only toxic to the pathogen and not the human host
Selective toxicity means the drug must be highly effective against the microbe but have minimal or no side effects for the human. This is achieved by targeting biological differences between human cells and microbial cells.
83
Elements with atomic numbers 58 to 71 are known as:
Answer:
Lanthanides
Lanthanides are a series of 14 elements following Lanthanum in the f-block. They are characterized by the filling of the $4f$ subshell and are often referred to as 'rare earth elements'.
84
Which type of vaccine uses a toxin produced by a bacterium (that has been made harmless) to trigger immunity?
Answer:
Toxoid vaccine
Some bacteria cause disease by secreting toxins (like Tetanus or Diphtheria). Toxoid vaccines use a weakened version of these toxins (toxoids) so the immune system learns to neutralize the toxin rather than the bacterium itself.
85
Which of the following is true for the Halogens?
Answer:
They are all diatomic molecules
Halogens ($F_2$, $Cl_2$, $Br_2$, $I_2$) exist as diatomic molecules in their elemental state. They are highly electronegative and need one electron to reach a noble gas configuration.
86
Which of the following is a common symptom of a 'Tetanus' infection?
Answer:
Lockjaw and muscle spasms
Tetanus toxin interferes with the nerves that control muscles. One of the first and most common symptoms is 'lockjaw' (trismus), where the jaw muscles become so stiff that the person cannot open their mouth or swallow.
87
What is the term for the energy required to remove an electron from a gaseous atom?
Answer:
Ionization energy
Ionization energy is the minimum amount of energy needed to remove the most loosely bound electron from an isolated neutral gaseous atom. It generally increases across a period and decreases down a group.
88
Which microorganism is responsible for 'Pneumonia', an infection that inflames the air sacs in one or both lungs?
Answer:
Bacteria, viruses, or even fungi
Pneumonia is a general term for lung inflammation with fluid. It can be caused by various pathogens, including bacteria (like Streptococcus pneumoniae), viruses (like Influenza or RSV), and sometimes fungi in people with weak immune systems.
89
Who is credited with the accidental discovery of the first antibiotic, Penicillin, in 1928?
Answer:
Alexander Fleming
Alexander Fleming discovered penicillin when he noticed that a mold called Penicillium notatum had contaminated a Petri dish of Staphylococcus bacteria and created a zone where the bacteria could not grow. This led to the development of the world's first life-saving antibiotic.
90
Which of the following elements has the highest electronegativity?
Answer:
Fluorine
Fluorine is the most electronegative element on the Pauling scale (assigned a value of 4.0). It has a very small atomic radius and high nuclear charge, giving it a strong tendency to attract shared electron pairs.