Cell The Building Block of Life Class 9 Worksheet with Answers Science Chapter 2 - #NCSOLVE 📚

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Class 9 Cell The Building Block of Life Worksheet

Worksheet On Cell The Building Block of Life Class 9

Cell The Building Block of Life Worksheet Class 9

→ Cell: The basic structural and functional unit of life.

→ Thermophile: Heat-loving microorganisms that live in extreme hot environments like hot springs.

→ Palaeoscience: The branch of science that studies ancient life and early Earth conditions using evidence like fossils and mineral deposits.

→ Limit of Resolution: The ability to distinguish two close points as separate; for the human eye, it is about 0.1 mm.

→ Cell Biologists: Scientists who study cells, their structure, functions, and activities.

→ Lens: A curved transparent material that bends light to magnify or make objects appear larger.

→ Magnification: The enlargement of an object’s image using lenses to see fine details.

→ Microscope: An instrument that uses lenses to magnify small objects not visible to the naked eye.

→ Light Microscope: A microscope that uses light to magnify objects.

→ Electron Microscope: A powerful microscope that uses a beam of electrons instead of light to provide very high magnification.

→ Cell Membrane (Plasma Membrane): A thin, selectively permeable boundary that controls the movement of substances in and out of the cell.

→ Selectively Permeable: Allowing some substances to pass through while preventing others.

→ Osmosis: Movement of water from higher water concentration to lower water concentration through a selectively permeable membrane.

→ Concentration Gradient: Difference in concentration between two regions.

→ Diffusion: The net movement of particles from higher to lower concentration.

→ Isotonic Solution: A solution with the same solute concentration inside and outside the cell, causing no net movement of water, so the cell size remains the same.

→ Hypotonic Solution: A solution with lower solute concentration outside the cell, causing water to enter the cell and the cell to swell.

→ Hypertonic Solution: A solution with higher solute concentration outside the cell, causing water to move out of the cell and the cell to shrink.

→ Fluid-Mosaic Model: A model that describes the cell membrane as a flexible layer of lipids with proteins embedded in it.

→ Cell Wall: A rigid outer layer surrounding the cell membrane that provides shape, support, and protection to the plant cell.

→ Prokaryotic Cells: Simple cells without a true nucleus and membrane-bound organelles; their genetic material is present in the nucleoid (e.g., bacteria).

→ Eukaryotic Cells: Complex cells with a well-defined nucleus and membrane-bound organelles (e.g., plant and animal cells).

→ Viruses, Viroids, and Prions: Very small infectious agents that do not have cells.

→ Cytoskeleton: A network of protein fibres that provides shape, support, and movement to the cell.

→ Chromatin: A thread-like structure of DNA and proteins present in the nucleus that condenses to form chromosomes during cell division.

→ Nucleoid: The region in prokaryotic cells where genetic material is present without a nuclear membrane.

→ Cristae: Finger-like projections of the inner membrane of mitochondria that increase the surface area for chemical reactions and help in energy production.

→ Plastids: Double-membrane organelles found in plant cells that are involved in food synthesis, storage, and imparting colour to plants.

→ Stroma: The semi-fluid substance inside the chloroplast where sugars synthesised during photosynthesis are stored along with starch granules.

→ Cell Sap: The liquid inside the vacuole that stores water, nutrients, and wastes.

→ Cell Division: The process by which new cells are formed from existing cells.

→ Cell Cycle: A controlled and orderly series of events in eukaryotic cells leading to cell division.

→ Mitosis: Cell division producing two identical daughter cells for growth and repair.

→ Meiosis: Cell division producing four daughter cells with half the number of chromosomes of the parent cell; it helps in sexual reproduction and creates variation.

→ Cell Culture: The process of growing cells outside a living organism in a controlled laboratory environment.

→ Vaccine: A substance that helps the body develop immunity against a disease.

→ Totipotency: The ability of a single cell to develop into a complete organism under suitable conditions.

→ Contact Inhibition: Property of normal cells to stop dividing when they touch neighbouring cells.

→ Tumour: Abnormal mass of cells formed due to uncontrolled cell division.

→ Cancer: Disease caused by uncontrolled cell division.

→ Programmed Cell Death (PCD): Natural and controlled process in which a cell intentionally dies as part of growth, development, or maintaining balance within an organism.

Class 9 Science Exploration Chapter 2 Worksheet

Class 9 Science Cell The Building Block of Life Worksheet

A. Multiple-Choice Questions

Question 1.
Which of the following can be seen only with the help of an electron microscope?
(a) Nucleus
(b) Ribosomes
(c) Fish egg
(d) Mitochondria

Question 2.
The limit of resolution of the human eye is
(a) 2.5 mm
(b) 0.25 mm
(c) 0.01 mm
(d) 0.1 mm

Question 3.
Which of the following characteristics classify bacterial cells as prokaryotic?
(a) They lack a well-defined nucleus.
(b) They have large vacuoles,
(c) They contain chloroplasts.
(d) They are multicellular.

Question 4.
forms a network of fine fibres, providing structural support, maintains cell shape, and cell movement in eukaryotes.
(a) Cytoskeleton
(b) Leucoplasts
(c) Nucleus
(d) Vacuole

Question 5.
Which option correctly identifies the structures labelled X and Y in the given diagram of the nucleus?

(a) X – Nucleolus; Y – Chromatin
(b) X – Chromatin; Y-Nucleolus
(c) X – Nuclear pore; Y- Nucleolus
(d) X – Chromatin; Y- Nuclear pore

Question 6.
Which statement correctly differentiates mitosis and meiosis?
(a) Mitosis produces four daughter cells, while meiosis produces two daughter cells.
(b) Mitosis occurs only in reproductive organs, while meiosis occurs in all body cells.
(c) Mitosis produces genetically identical daughter cells, while meiosis produces genetically different daughter cells.
(d) Mitosis reduces chromosome number by half, while meiosis maintains the same number of chromosomes.

Question 7.
This question consists of an Assertion (A) and a Reason (R). Read the Assertion and Reason and choose the appropriate answer.
Assertion (A): All plastids contain chlorophyll.
Reason (R): Chromoplasts give colour to flowers.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.

Question 8.
This question consists of an Assertion (A) and a Reason (R). Read the Assertion and Reason and choose the appropriate answer.
Assertion (A): Cancer cells form tumours.
Reason (R): Cancer cells show contact inhibition.?
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.

B. State True (T) or False (F).

Question 1.
Prokaryotes do not have a membrane-bound nucleus.

Question 2.
Chromoplasts are present in potatoes that make it colourless.

Question 3.
Viroids have a protein coat.

Question 4.
Mitosis produces two identical daughter cells.

Question 5.
The cell wall prevents plasmolysis.

Question 6.
Chromatin condenses into chromosomes during division.

Question 7.
Vacuoles are larger in animal cells.

C. Fill in the blanks.

Question 1.
Arun Kumar Sharma was an Indian scientist famous for his work on ______.

Question 2.
______ is the energy currency of the cell.

Question 3.
Starch and crystals of calcium oxalate or silica in plant cells are known as _______.

Question 4.
________ is involved in synthesis and storage of fats and hormones.

Question 5.
Errors in _______ lead to uncontrolled cell divisions, while errors in ______ may result in genetic disorders.

Question 6.
Movement of water from higher to lower concentration through a semi-permeable membrane is called ______

D. Assign one word to the following.

Question 1.
The process that creates genetic diversity in gametes.

Question 2.
Genetically regulated and organised process of selective cell destruction.

Question 3.
The process by which new cells form from pre-existing cells.

Question 4.
Genetic region without a nuclear membrane in bacteria.

Question 5.
Organelles that act as waste digesters.

Question 6.
The process that prevents uncontrolled division in normal cells.

Question 7.
Heat-loving bacteria in hot springs.

Question 8.
Net movement of particles from a higher to a lower concentration.

Question 9.
Fluid-mosaic structure that is selectively permeable and allows movement of water through osmosis.

Question 10.
Solution that causes a potato piece to shrink.?

E. Match the Columns.

Question 1
Match the diagrams given in Column I with the terms given in Column II.
Column I

Question 2.
Match the Column I with Column II

Column I	Column II
(i) Mitosis	(a) Genetic diversity
(ii) Meiosis	(b) Identical daughter cells
(iii) Gene	(c) Visible during division
(iv) Chromosome	(d) Functional segment of DNA

F. Differentiate between the following.

Question 1.
Differentiate between the Nucleus and Nucleolus

Question 2.
Differentiate between the Cell Membrane and Nuclear Membrane

Question 3.
Differentiate between the Hypertonic Solution and Hypotonic Solution

G. Write the correct biological term for each description.

Question 1.
Powerhouse of the cell

Question 2.
Packaging and shipping centre of the cell

Question 3.
Manufacturing factory of the cell

Question 4.
House of coded instructions of the cell

Question 5.
Protein factory of the cell

Question 6.
The clean-up system of the cell

H. Very Short Answer Type Questions

Question 1.
Name the scientists who proposed the cell theory.

Question 2.
Write the full form of DNA.

Question 3.
What is the near point of human eye?

I. Short Answer Type Questions

Question 1.
Write a short note on the discovery of cells by Robert Hooke.

Question 2.
Why do errors in meiosis affect offspring more severely than errors in mitosis?

Question 3.
Write a short note on the Endoplasmic Reticulum.

J. Long Answer Type Questions

Question 1.
Describe meiosis in detail with the help of a diagram.

Question 2.
Explain the differences between plant and animal cells with examples.

Question 3.
Briefly describe the three basic parts of a eukaryotic cell.

Wonder Why

A. Read the paragraph and answer the following questions.
Amit wondered why pancreatic cells appeared different under an electron microscope. His teacher explained that these cells contain abundant rough endoplasmic reticulum (RER) with attached ribosomes for protein synthesis, while liver cells have more smooth endoplasmic reticulum (SER) for lipid synthesis. Both cell types contain mitochondria with cristae folds to generate ATP. These cells also contain Golgi apparatus, which plays an important role in processing materials inside the cell. The teacher emphasised that this precise “cellular factory” coordination is absent in prokaryotes, which lack membrane-bound organelles.

Question 1.
Why are pancreatic cells rich in RER?

Question 2.
What makes RER appear rough under the microscope?

Question 3.
How does the Golgi apparatus help these cells in protein transport and secretion??

Question 4.
Why can prokaryotes not specialise like pancreatic cells?

B. Give reasons for the following. Interpret/Analyse

Question 1.
The presence of cristae on the inner membrane of mitochondria.

Question 2.
The Golgi apparatus is known as the packaging and shipping centre.

Question 3.
Eukaryotes need the Golgi after RER, unlike prokaryotes.

Question 4.
Chromoplasts in petals evolved despite no photosynthetic role.

Question 5.
Human cheek cells shrink more than Rhoeo peels in hypertonic sugar.

Question 6.
Prokaryotic thermophiles survive in Ladakh hot springs while complex eukaryotes cannot.

C. Observe the images. Identify and write the names of cells.

Now, answer the following questions.
Question 1.
What will happen if B cells are kept in a hypotonic solution? Why?

Question 2.
What will happen if A cells are kept in a hypertonic solution? Why?

D. A scientist observed that a fully mature plant cell can give rise to an entire plant in laboratory conditions. Explain the concept behind this property of plant cells.

E. How does Programmed Cell Death help in shaping the human body during development?

Learn By Doing

A. Take three glasses— (I) one with plain water, (II) one with concentrated sugar/salt solution, and (III) one with a dilute solution sugar/salt solution. Place equal-sized pieces of carrot in each glass for about 1 hour. Observe the changes and label the setups correctly as hypotonic, hypertonic and isotonic solution.

Now, answer the following questions based on your observation.

Question 1.
What changes do you observe in the carrot pieces in each solution?

Question 2.
Which solution makes the carrot piece firm and why?

Question 3.
Which solution makes the carrot piece soft or shrunken and why?

B. Give two examples of the following situations.

Question 1.
Cells that undergo meiosis

Question 2.
Cells lacking cell wall

Question 3.
Single membrane organelles

Question 4.
Hypertonic solutions

Question 5.
Unicellular organisms

Question 6.
Plants having leucoplast

C. Observe the given image carefully, and answer the following questions.

Question 1.
What does the given image represent?

Question 2.
State the importance of this type of division.

Question 3.
What happens to the chromosome number after this division?

Question 4.
Briefly describe the steps involved in preparing and observing this stage under a microscope.

Explore With Curiosity

A. Using the microscope in your school laboratory, identify and label the parts shown in the given image. Then, carefully observe and handle the microscope to understand the function of each part while focusing on a slide, and record the use of each part in your notebook.

B. What would happen if

Question 1.
The lysosomes disappeared completely from the cell.

Question 2.
The plasma membrane became impermeable.

Question 3.
You put a freshwater fish in seawater.

Question 4.
Mitochondria stopped producing ATP for the cell.

C. A scientist was studying cells using a simple microscope and could observe only basic structures like the nucleus and cell boundary. However, many tiny internal structures remained invisible. Later, the scientist started using an advanced
instrument, as shown in the image below, and was able to observe very fine details inside the cell.

While preparing onion peel and human cheek cell slides, the scientist observed that without adding a stain, the cells appeared nearly transparent. After staining, certain structures became much more distinct than others.

Observe and analyse the situation, then answer the following questions.
Question 1.
Name the advanced instrument that the scientist use(d)

Question 2.
Why is staining necessary for observing onion peel and cheek cells?

Question 3.
Why was the scientist unable to see certain structures with a simple microscope?

Question 4.
How did the advanced instrument help in observing more details inside the cell?

Suggested Activities

A. To compare prokaryotic and eukaryotic cells, collect yoghurt (prokaryotic bacteria) and onion peels (eukaryotic plant cells). Prepare wet mounts of both samples and observe under a microscope, noting size differences, the presence of a nucleus, and organelle visibility. Sketch your observations, measure relative sizes using microscope. Create a comparison table showing how prokaryotic cells are smaller and simpler, while eukaryotic cells are larger and more complex. Discuss why prokaryotic cells can divide faster due to their simple structure.

B. Design and prepare a three-dimensional model of a cell using low-cost, eco-friendly materials. Clearly show and label important cell parts such as the cell membrane, cytoplasm, nucleus, and other organelles. Explain the function of each part and present the model neatly and creatively.

C. Visit a plant nursery or botanical garden and ask growers about wilting prevention. Collect leaf samples from turgid/wilted plants, prepare temporary slides of leaf peel, and observe vacuole shrinkage under a microscope. Research how cell wall rigidity supports osmosis in plants compared to flexibility in animal cells.

The post Cell The Building Block of Life Class 9 Worksheet with Answers Science Chapter 2 appeared first on Learn CBSE.

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