Q2631. The genetically engineered bacterium Pseudomonas putida, known for degrading multiple components of petroleum oil, was developed by:
RAS Prelims MCQ Practice
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Q2632. Which of the following is a limitation of bioremediation?
Explanation
A major limitation of bioremediation is that it relies on living organisms, which are highly sensitive to their environment. Factors such as soil pH, temperature, moisture levels, and the availability of essential nutrients must be within a specific range for the microbes to survive and effectively degrade pollutants. If these conditions are not optimal, the cleanup process can be extremely slow.
Q2633. The use of fungi to degrade environmental contaminants is specifically known as:
Explanation
Mycoremediation is a specific form of bioremediation that utilizes fungi to decontaminate an environment. Fungi are particularly effective because they produce powerful extracellular enzymes that can break down complex and resistant pollutants, including plastics and heavy metals. Their extensive mycelial networks can penetrate deep into soil, allowing them to reach and neutralize contaminants that might be inaccessible to bacteria.
Q2634. Which of the following is an example of in-situ bioremediation?
Explanation
In-situ bioremediation refers to treating the contaminated material exactly where it is located, without excavating it. Bioventing is a classic in-situ technique where air and nutrients are delivered to the contaminated soil to stimulate the growth and activity of indigenous aerobic bacteria that break down organic pollutants. This contrasts with ex-situ methods like composting, which require material removal for treatment.
Q2635. Some plants hyperaccumulate heavy metals from contaminated soils. These plants can then be harvested and safely disposed of. This technique is called:
Explanation
Phytoextraction is a type of phytoremediation where specific plants absorb large amounts of heavy metals or other contaminants from the soil through their roots. These pollutants are then transported and stored in the plants above-ground tissues.
Q2636. Identify the incorrect statement about superbugs in bioremediation.
Explanation
Superbugs are multigene engineered microbes that degrade complex pollutants, the first patent for a living genetically modified organism was for a superbug, and their release is monitored. They do not degrade plastics instantly, so C is incorrect.
Q2637. Bioremediation of municipal wastewater typically involves secondary treatment, where aerobic bacteria consume organic waste to form masses called:
Explanation
In secondary treatment of wastewater, aerobic bacteria consume organic waste and grow into masses called flocs, which settle out.
Q2638. Consider the following steps of plant tissue culture (micropropagation):
A. Hardening and acclimatization of plantlets
B. Inoculation of explant on culture medium
C. Selection and sterilization of explant
D. Callus formation and regeneration of shoots/roots
Which of the following represents the correct sequence?
A. Hardening and acclimatization of plantlets
B. Inoculation of explant on culture medium
C. Selection and sterilization of explant
D. Callus formation and regeneration of shoots/roots
Which of the following represents the correct sequence?
Explanation
In micropropagation the explant is first selected and sterilised, then placed on the culture medium, then callus forms and shoots and roots regenerate, and finally the plantlets are hardened. The order is C, B, D, A.
Q2639. The capacity of a single plant cell to regenerate into an entire adult plant is known as:
Explanation
The capacity of a single plant cell to grow into a whole plant is called totipotency. It is the basis of plant tissue culture.
Q2640. In plant tissue culture, an unorganized mass of actively dividing cells is called a:
Explanation
An unorganised mass of actively dividing cells in plant tissue culture is called a callus.Answer key for these questions
| Q | Correct answer |
|---|---|
| 2631 | (a) Ananda Mohan Chakrabarty |
| 2632 | (c) Dependency on environmental parameters like pH and nutrients |
| 2633 | (d) Mycoremediation |
| 2634 | (b) Bioventing |
| 2635 | (a) Phytoextraction |
| 2636 | (c) They can degrade recalcitrant compounds like plastics instantly. |
| 2637 | (d) Flocs |
| 2638 | (a) C, B, D, A |
| 2639 | (b) Totipotency |
| 2640 | (a) Callus |
Frequently asked questions
How many RAS Prelims practice MCQs are there on RAS Prelims?
This page has 9654 practice MCQs on the RAS Prelims syllabus. Each has the correct answer, and most have an explanation.
How should I practise MCQs for RAS Prelims?
Attempt each question first, then open the answer and read the explanation. Practise one chapter at a time, note the facts you got wrong and revise them. Repeat the chapter after a few days.
Are these actual RAS Prelims past-paper questions?
No. These are practice questions written for the RAS Prelims syllabus. They follow the pattern the exam uses: factual questions, statement-based questions, match-the-list and assertion-reason.