Cell: The Building Block of Life - Chapter 2 Class 9 Exploration

Q 1
Question
Differentiate between the following pairs of terms based on the clues given in parentheses: (i) Cell membrane and cell wall (permeability) (ii) RER and SER (structure) (iii) Chloroplasts and chromoplasts (pigments)
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Q 2
Question
Two similar animal cells are placed in two different solutions: Cell X is placed in pure water. Cell Y is placed in a concentrated salt solution. Cells are observed after some time. Cell X swells, and Cell Y shrinks. Which statement provides the correct explanation for the above observations? (i) Salt molecules moved into Cell Y, causing it to shrink. (ii) Water moved into Cell X and more water moved out of Cell Y than the salt solution entered in it. (iii) Water moved into Cell X and moved out of Cell Y through the cell membrane. (iv) Solute movement caused osmosis in both cells.
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Q 3
Question
Look at the diagram of a cell in Fig. 2.20. Identify the parts labelled from (a) to (g) and correctly match them with their functions given below: (i) Controlling all the activities of a cell. (ii) Site of cellular respiration. (iii) Storage organelle that also provides rigidity to the cell. (iv) Separates the cell contents from surroundings. (v) Provides structural rigidity to the cell. (vi) Packs and stores materials received from ER. (vii) Helps in manufacturing food.
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Q 4
Question
Which of the following option(s) of the pairs of cell organelles are correctly placed under the given categories? (i) Present in plant cells: Leucoplast | Absent in animal cells: Cell wall. (ii) Mitochondria | Ribosome. (iii) Cell wall | Golgi apparatus. (iv) Lysosome | Endoplasmic reticulum.
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Q 5
Question
Two students, Renu and Rohit, were having a discussion on the plastids. Renu emphasised that all parts of the plants, even roots, contain plastids. However, Rohit did not agree with the statement and told her that plastids are absent in plant roots since the roots are underground and do not need to perform photosynthesis. Who is correct? Justify your answer.
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Q 6
Question
Mitochondria and chloroplasts are two important organelles in a plant cell. Discuss how these two organelles are structurally and functionally similar to each other, and different from each other.
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Q 7
Question
Which of the following pairs of cell organelles contains DNA? (i) Chloroplasts, Ribosomes (ii) Mitochondria, Nucleus (iii) Golgi bodies, Ribosomes (iv) Nucleus, Lysosomes
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Q 8
Question
A researcher carried out an experiment in which she took two carrots of similar size. She placed one carrot in plain water and the other carrot in concentrated salt solution (Fig. 2.21). After 24 hours she recorded her observations. (i) What hypothesis does she want to test through this experiment? (ii) What would you suggest for the improvement of this experiment? (iii) Why does the carrot in plain water stay stiff and crunchy, but the carrot in concentrated salt solution become rubbery and limp?
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Q 9
Question
Indicate the presence or absence of following structures in bacterial and animal cells: Chromosome, Nucleus, Mitochondria, Golgi complex, Chromoplasts.
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Q 10
Question
Carry out the following experiment: Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Place each of the potato cups in a beaker containing water (Fig. 2.22). Now, set up the experiment as follows: (a) Keep Cup A empty. (b) Add one teaspoon sugar in Cup B. (c) Add one teaspoon salt in Cup C. (d) Add one teaspoon sugar in the boiled potato in Cup D. Observe the four potato cups at least two hours and answer: (i) Explain why water gathers in the hollowed portion of Cup B and Cup C. (ii) Why is Cup A necessary for this experiment? (iii) Explain why water does not gather in the hollowed portions of Cups A and D.
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Q 11
Question
Identify the pair that incorrectly matches the cell organelle with its function. (i) Ribosome — Protein synthesis (ii) SER — Lipid and cellulose synthesis (iii) Lysosome — Digestion of foreign agents
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Q 12
Question
What outcome do you expect, if all the mitochondria are removed from a eukaryotic cell?
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Q 13
Question
Which phenomenon inhibits the formation of tumors in the human body? Can plants also develop tumors? Explain.
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Q 14
Question
The cell membrane of a cell is made up of proteins and lipids. Which cell organelles help in the synthesis of cell membrane? Write the path of these compounds from their site of synthesis to the cell membrane and show this through a labelled diagram.
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Q 15
Question
What would happen if gametes are formed by mitotic divisions?
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Q 16
Question
A farmer, Deepa, was very happy with the harvest of amla (Indian Gooseberry) and lemons on her farm. However, she could sell only one-fourth of the produce in the local market. Recognising that a significant amount of produce may be lost post-harvest, she employed a traditional yet scientifically sound method to extend the shelf life of amla and lemons. She turned perishable produce into profitable products, such as pickles and sharbat. She used the excess produce to prepare pickles, murabbas, and sharbat by adding appropriate amounts of salt, sugar, or jaggery to small pieces of fruit and their juices. These were then stored in small glass bottles for sale, helping her prevent the wastage of post-harvest produce. Based on the above passage answer the following questions: (i) Which scientific concept has the farmer applied in the preservation of the farm produce? (ii) How does the addition of high concentrations of salt and sugar create an environment that prevents the growth of spoilage-causing bacteria and fungi? (iii) Suggest a healthy recipe of this kind for food preservation. (iv) What are the scientific values addressed in this case?
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Project 1
Project
Use selected software or digital tools to create animations or simulations of cell division and share them in the class.
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Key Points
A clear animation makes cell division easy to follow.
Key Points / Good Practices
Pick simple free tools like PowerPoint, Canva or Scratch.
Show the parent cell, then chromosomes, then two daughter cells.
Make mitosis and meiosis as separate short clips.
Label each stage in clear, simple words.
Keep the animation slow so the class can follow.
Add a short voice-over or captions to explain each step.
A simple, labelled animation helps everyone see how cells divide.

Project 2
Project
Create a model of any type of a 'synthetic cell' using low-cost eco-friendly material.
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Key Points
A model shows cell parts using cheap, green materials.
Key Points / Good Practices
Use clay, dough, paper, beads or recycled items.
Make a clear boundary for the cell membrane.
Add organelles like nucleus, mitochondria and vacuole.
Use different colours so each part stands out.
Label every part with a small flag or sticker.
Avoid plastic; pick eco-friendly materials.
A neat, labelled, eco-friendly model makes cell parts easy to learn.

Project 3
Project
Build a mitosis or meiosis model with your classmates for your science project or exhibition. How did teamwork contribute to the success of the activity? Did this activity change your perspective or understanding of the cell division topic in any way? If so, explain how?
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Key Points
Teamwork makes a clear, stage-by-stage division model.
Key Points / Good Practices
Use wool or pipe cleaners for chromosomes.
Show each stage of mitosis or meiosis in order.
Split tasks: some build, some label, some present.
Teamwork shares the work and brings new ideas.
Building it by hand makes the stages easier to remember.
Practise explaining the model before the exhibition.
Working as a team builds a clearer model and deeper understanding.

Project 4
Project
Develop a nukkad natak for community awareness in simple dialogues about the different functions of cell organelles.
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Key Points
A street play teaches organelle jobs in a fun way.
Key Points / Good Practices
Give each actor one organelle to play.
The nucleus is the "boss" giving instructions.
Mitochondria says it makes energy for the cell.
The Golgi apparatus acts as the "post office".
Use simple dialogues and a little humour.
Perform in a public spot to spread awareness.
A simple, funny play helps the community learn what organelles do.