Q151. The primary role of chlorophyll in photosynthesis is to:
Science and Technology: RAS Prelims MCQs
1113 RAS Prelims practice MCQs on science and technology are on this page, in 6 chapters. They cover the basics of everyday science, computers and information technology, defence and space technology in India, genetics, biotechnology and nanotechnology, science and technology policies and government programmes, and recent advances with Indian contributors and indigenisation. Each question has an answer and an explanation.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
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Q152. Match the processes in List I with their site of occurrence in the cell in List II.
| Process/Stage | Site of occurrence in the cell |
|---|---|
| A. Glycolysis | i. Mitochondrial matrix |
| B. Krebs Cycle (Citric Acid Cycle) | ii. Cytoplasm |
| C. Light reaction of photosynthesis | iii. Stroma of chloroplast |
| D. Dark reaction (Calvin cycle) | iv. Thylakoids of chloroplast |
Explanation
Glycolysis occurs in the cytoplasm, while the Krebs cycle takes place in the mitochondrial matrix. In photosynthesis, the light-dependent reactions occur within the thylakoid membranes of the chloroplast, where light is captured. The light-independent dark reactions, or the Calvin cycle, take place in the surrounding stroma. These specific locations ensure that the necessary enzymes and substrates are concentrated for metabolic activity.
Q153. During the light-dependent reactions of photosynthesis, oxygen gas is released as a byproduct of:
Explanation
During the initial light-dependent stage of photosynthesis, light energy is used to split water molecules into hydrogen ions, electrons, and oxygen gas. This process is known as photolysis. The electrons and hydrogen ions are utilized in the electron transport chain to generate ATP and NADPH, while the oxygen gas is released into the atmosphere as a vital byproduct of the reaction.
Q154. Tiny pores on the surface of plant leaves that facilitate gas exchange are called:
Explanation
Stomata are microscopic pores located primarily on the undersides of plant leaves. They are surrounded by specialized guard cells that regulate their opening and closing. These openings are essential for gas exchange, allowing carbon dioxide to enter for photosynthesis and oxygen to exit. However, they also facilitate transpiration, the loss of water vapor from the plant into the surrounding environment.
Q155. Aerobic respiration differs from anaerobic respiration in that it:
Explanation
Aerobic respiration is a high-efficiency metabolic process that completely breaks down glucose to produce energy, and it strictly requires the presence of oxygen. In contrast, anaerobic respiration occurs in the absence of oxygen and is much less efficient, producing far less ATP per glucose molecule. Aerobic respiration results in carbon dioxide and water, while anaerobic processes produce lactic acid or ethanol.
Q156. The universal energy currency molecule generated during cellular respiration is:
Explanation
Adenosine Triphosphate, commonly known as ATP, is the universal energy currency for all living cells. It stores chemical energy in high-energy phosphate bonds that can be easily broken to power various cellular processes, including muscle contraction, active transport, and chemical synthesis. ATP is continuously generated during cellular respiration and consumed during metabolic work, maintaining the life-sustaining activities of the organism.
Q157. Which of the following processes is common to both aerobic and anaerobic respiration?
Explanation
Glycolysis is the initial stage of glucose metabolism and is common to both aerobic and anaerobic respiration. This metabolic pathway occurs in the cytoplasm and does not require oxygen to function. It involves the breakdown of one glucose molecule into two molecules of pyruvate, producing a small net gain of ATP and providing the necessary precursors for subsequent metabolic stages.
Q158. Consider the following factors affecting the rate of photosynthesis:
I. Light intensity
II. Carbon dioxide concentration
III. Temperature
IV. Availability of water
V. Atmospheric nitrogen concentration
Which of the above statement(s) identify the primary limiting factors for photosynthesis?
I. Light intensity
II. Carbon dioxide concentration
III. Temperature
IV. Availability of water
V. Atmospheric nitrogen concentration
Which of the above statement(s) identify the primary limiting factors for photosynthesis?
Explanation
Several environmental factors directly influence the rate of photosynthesis. Light intensity provides the energy, carbon dioxide concentration supplies the raw material, and temperature affects the activity of the enzymes involved. Water availability is also crucial, as it is a reactant and maintains plant health. Atmospheric nitrogen, while abundant, is not a direct reactant or primary limiting factor for photosynthesis.
Q159. Muscle cramps in human bodies during heavy exercise are caused by the accumulation of:
Explanation
During intense physical exercise, the demand for energy may exceed the oxygen supply to the muscles. This leads to anaerobic respiration, where glucose is partially broken down into lactic acid instead of being completely oxidized. The accumulation of lactic acid in the muscle tissues causes a drop in pH, leading to fatigue and the painful involuntary contractions commonly known as muscle cramps.
Q160. The Respiratory Quotient (R.Q.) is defined as the ratio of:
Explanation
The Respiratory Quotient, or R.Q., is a dimensionless number used in biological calculations to determine the type of fuel being metabolized by an organism. It is calculated as the ratio of the volume of carbon dioxide evolved to the volume of oxygen consumed during respiration. The R.Q. value varies depending on whether carbohydrates, fats, or proteins are being used for energy.Answer key for these questions
| Q | Correct answer |
|---|---|
| 151 | (d) Absorb light energy |
| 152 | (a) A-ii, B-i, C-iv, D-iii |
| 153 | (c) The photolysis of water molecules |
| 154 | (a) Stomata |
| 155 | (d) Strictly requires the presence of oxygen |
| 156 | (b) ATP (Adenosine Triphosphate) |
| 157 | (c) Glycolysis |
| 158 | (a) I, II, III and IV |
| 159 | (a) Lactic acid |
| 160 | (b) Carbon dioxide evolved to oxygen consumed |
Key facts from Science and Technology
- The RPSC paper is General Knowledge and General Science, so science questions come with a strong dose of applied and recent topics.
- Everyday science questions test the laws and terms of physics, chemistry and biology through examples.
- Defence and space questions pair a missile, satellite or mission with its year and organisation.
- Policy questions ask for the year, the body and the aim of schemes like STIP, the National Quantum Mission and BioE3.
- Health, environment and agriculture are on a separate page, with their own chapters.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Science and Technology?
This page has 1113 practice MCQs on Science and Technology. Each has the correct answer, and most have an explanation.
Which chapters does the science and technology set cover?
Six chapters: basics of everyday science; computers, information and communication technology; defence and space technology in India; genetics, biotechnology and nanotechnology; science and technology policies and government programmes; and recent advances, Indian contributors and indigenisation.
Is science and technology part of the RAS Prelims syllabus?
Yes. The RPSC paper is called General Knowledge and General Science, and its syllabus lists science and technology topics along with environment, health, agriculture and government programmes, so questions can come from any of these areas.
How should I prepare science for RAS Prelims?
Revise the concepts by examples, then learn the missions, schemes and scientists with their year and organisation. Attempt each chapter, read the explanations and keep a list of the facts you missed.