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
171
Which of the following is an example of an antibiotic that inhibits protein synthesis by binding to bacterial ribosomes?
Answer:
Tetracycline
While Penicillin targets the cell wall, Tetracycline works by binding to the 30S subunit of the bacterial ribosome. This physically blocks the attachment of tRNA, stopping the bacteria from making the proteins they need to grow and survive.
172
How do bacteria often share antibiotic resistance genes with other bacteria?
Answer:
By exchanging small circular pieces of DNA called plasmids
Bacteria can perform horizontal gene transfer. A common method is conjugation, where one bacterium transfers a plasmid (which often contains resistance genes) to another bacterium. This allows resistance to spread rapidly through a population, even between different species.
173
Why is it important to complete a full course of antibiotics prescribed by a doctor?
Answer:
To prevent the bacteria from developing antibiotic resistance
If a patient stops taking antibiotics early, the weaker bacteria might be killed, but the more resilient ones may survive and multiply. These surviving bacteria can develop resistance to the drug, making future infections much harder to treat.
174
What is 'Absolute Zero' on the Celsius scale?
Answer:
-273.15°C
Absolute zero ($0 K$) is the theoretical temperature at which all molecular motion stops. On the Celsius scale, this corresponds to approximately -273.15°C.
175
What does an 'Antibiogram' help a doctor determine in a hospital setting?
Answer:
Which specific antibiotics the infecting bacteria are sensitive or resistant to
An antibiogram is a laboratory report that tests a sample of bacteria against various antibiotics. It tells the doctor exactly which drug will be most effective at killing that specific strain, preventing the use of ineffective medicines.
176
The tendency of an atom to attract a shared pair of electrons towards itself is called:
Answer:
Electronegativity
Electronegativity is a chemical property that describes the power of an atom in a molecule to attract shared electrons to itself. Fluorine is the most electronegative element.
177
Which of these diseases is prevented by the BCG (Bacille Calmette-Guérin) vaccine?
Answer:
Tuberculosis
The BCG vaccine is primarily used against Tuberculosis (TB). It is often administered to infants and small children in countries where TB is common to protect them from severe forms of the disease, such as TB meningitis.
178
Which of the following is an example of an amorphous solid?
Answer:
Glass
Amorphous solids, like glass or plastic, lack a long-range periodic order in their atomic arrangement. Unlike crystalline solids (e.g., diamond or salt), they do not have a sharp melting point.
179
What is 'Antigenic Drift' and how does it affect vaccination, particularly for the flu?
Answer:
The virus slowly mutates its surface proteins, meaning old antibodies may no longer recognize it
Antigenic drift is the process of small, gradual mutations in viral genes. For the influenza virus, these changes eventually lead to new strains that the 'memory' from last year's vaccine doesn't recognize, which is why a new flu shot is needed every year.
180
In Rutherford's gold foil experiment, why did most alpha particles pass straight through the foil?
Answer:
The atom is mostly empty space
Rutherford concluded that since the vast majority of alpha particles passed through the foil without deflection, the atom must consist mainly of empty space, with the mass concentrated in a tiny central nucleus.