Class 10 Biology Chapter 5
Important Questions

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Here, you'll find important questions related to Chapter 5 : Photosynthesis for ICSE Class 10 Biology. These questions have been crafted to assist students in their preparation for the ICSE Class 10 Biology Examination in 2023–24. By practising various question types, students can clarify their doubts, enhance their exam readiness, boost their confidence, and refine their problem-solving skills.


In the Fifth chapter,  Photosynthesis of ICSE Class 10 Biology, which focuses on the fascinating process of photosynthesis, students encounter a fundamental biological phenomenon that plays a crucial role in sustaining life on Earth. This chapter, titled "Photosynthesis," not only delves into the intricate mechanisms behind this vital process but also provides a comprehensive understanding of its significance in the realm of biology. As students prepare for their ICSE Class 10 Biology examination, they often seek clarity on essential concepts, which is why we have compiled a list of biology important questions for Class 10 ICSE, specifically pertaining to the chapter on photosynthesis. These questions aim to reinforce your knowledge and help you excel in your studies. So, let's embark on this educational journey to explore the world of photosynthesis and answer some critical biology questions for Class 10 ICSE.

What is Photosynthesis ?

Photosynthesis is a fundamental biological process that occurs in green plants, algae, and certain bacteria. It is the process by which these organisms convert light energy from the sun into chemical energy in the form of glucose (a type of sugar) while releasing oxygen as a byproduct. This remarkable process is crucial for sustaining life on Earth.
During photosynthesis, plants and other photosynthetic organisms use specialised pigments called chlorophyll, which are located in chloroplasts, to capture sunlight. They absorb light energy and use it to convert carbon dioxide (CO2) and water (H2O) into glucose (C6H12O6) and oxygen (O2) through a series of complex chemical reactions. The glucose produced serves as a source of energy and building blocks for the plant, while the oxygen is released into the atmosphere, making it available for other living organisms, including humans, to breathe.
In the ICSE Class 10 Biology curriculum, the process of photosynthesis is extensively studied, particularly in the chapter titled "Photosynthesis." This chapter delves into the mechanisms, factors, and significance of photosynthesis, offering students a comprehensive understanding of this vital biological process. As students navigate through the ICSE Class 10 Biology syllabus, they encounter important questions related to photosynthesis, which play a key role in assessing their knowledge and comprehension of this essential biological phenomenon. Mastering these biology questions for Class 10 ICSE can significantly enhance a student's grasp of photosynthesis and its broader implications in the natural world.

icse class 10 biology chapter photosynthesis

Class 10 Biology Photosynthesis Important Questions and Answers

Q1. The raw materials for photosynthesis are:


(a) Water, carbon dioxide and solar energy
(b) Carbon dioxide, oxygen and solar energy
(c) Carbon dioxide, starch and solar energy
(d) Carbon dioxide, oxygen and water

Ans. (a) Water, carbon dioxide and solar energy

Raw materials for photosynthesis are carbon dioxide, water, and solar energy . Carbon dioxide is produced through the exchange of gases. This function is performed by stomata. Water is absorbed by roots from the soil, whether from irrigation or rain. Chlorophyll absorbs solar energy.

Q2. Stomata open during the day and closes at night because:


(a) Photosynthesis occurs during the day time only
(b) Enzymes convert starch into sugar at elevated pH at night
(c) Loss of sugar increases osmotic concentration of the cell sap
(d) None of the above

Ans. (a)
Photosynthesis requires sunlight and it requires opening and closing of stomata. That’s why stomata open or close at day time.

Q3. How is the rate of Photosynthesis affected when a green plant gets green light ?

The rate of photosynthesis decreases and finally stops when the green plant gets green light because green light is not absorbed but reflected back by the plants.

Q4. Write an experiment to demonstrate that CO2 is necessary for photosynthesis.

Take a destarched plant. Insert one of its leaves in a conical flask which contains potassium hydroxide. Leave it in the sunlight. After a few hours, test this leaf and any other leaf of this plant for starch. The leaf which was exposed to the atmospheric air turns blue black and the one in the flask containing KOH does not turn blue black after iodine test. This experiment shows that CO2 is necessary for photosynthesis as KOH absorbs CO2.

Q5. Why is photosynthesis important in nature ?

Photosynthesis is necessary in nature because of the following reasons :
(i) The body of all living organisms, both plants and animals, is dependent on the food that has been synthesised in a green cell by photosynthesis.
(ii) The purification of the atmosphere whereby the volume of CO2 remains fairly constant due to the photosynthetic activity of green plants.
(iii) Oxygen is given out during photosynthesis which is necessary to sustain life on earth.

icse class 10 biology chapter photosynthesisicse class 10 biology chapter photosynthesis

 ICSE Class 10 Biology Chapter wise Important Questions:

Chapter No. Chapter Name
Chapter 1 Structure of Chromosome, Cell Cycle and Cell division
Chapter 2 Genetics: Mendel's law of Inheritance
Chapter 3 Absorption by Roots- The Processes Involved
Chapter 4 Transpiration
Chapter 5 Photosynthesis
Chapter 6 Chemical Coordination in Plants
Chapter 7 The Circulatory System
Chapter 8 The Excretory System
Chapter 9 The Nervous System and Sense Organs
Chapter 10 The Endocrine System
Chapter 11 The Reproductive System
Chapter 12 Human Population
Chapter 13 Human Evolution
Chapter 14 Pollution


Photosynthesis is a remarkable and indispensable biological process that underpins life on our planet. offers a valuable resource in the form of a comprehensive collection of questions. These questions are designed to reinforce your knowledge and help you grasp the intricacies of this essential biological process.

Frequently Asked Questions

Q1 : Are photosynthesis and cellular respiration the same process?

Ans: Both photosynthesis and cellular respiration have similar reactions. In photosynthesis carbon dioxide and water is converted into oxygen and glucose. While in cellular respiration oxygen and glucose is converted into water and carbon dioxide. Plants have the ability to not carry out photosynthesis and cellular respiration. However, humans can also do cellular respiration.

Q2 : Can photosynthesis occur in artificial light?

Ans:  Yes, photosynthesis can be conducted in artificial light only if the plant receives the correct wavelengths of light.

Q3 : How does photosynthesis occur in desert plants?

Ans: During the night, desert plants open their stomata and absorb carbon dioxide. When the stomata is closed during the day, the planet uses the stored carbon dioxide to conduct the process of photosynthesis.

Q4 : What things are required for photosynthesis?

Ans:  Plants need these three things to perform photosynthesis: sunlight, carbon dioxide and water.

Q5 : Where does photosynthesis take place in plants?

Ans: Chloroplasts, which contain the chlorophyll, is the place where the photosynthesis is conducted in plants.

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