Q1: Who first introduced the concept of the cell in 1665? (a) Charles Darwin (b) Robert Hooke (c) Louis Pasteur (d) Gregor Mendel
Solution:
Ans: (b) Explanation: Robert Hooke introduced the concept of the cell in 1665 when he observed cells in cork tree bark through a microscope, marking the beginning of cell biology.
Q2: Which is the largest cell in the human body? (a) Nerve cell (b) Red blood cell (c) Female ovum (d) White blood cell
Solution:
Ans: (c) Explanation: The female ovum (egg cell) is the largest cell in the human body, measuring approximately 100 micrometers in diameter, making it visible to the naked eye.
Q3: What is the primary function of mitochondria in a cell? (a) Protein synthesis (b) Waste disposal (c) ATP generation (d) Genetic material storage
Solution:
Ans: (c) Explanation: Mitochondria are known as the powerhouses of the cell because they generate ATP through cellular respiration, providing energy for various cellular activities and metabolic processes.
Q4: Which organelle is responsible for modifying and packaging proteins for transport? (a) Ribosomes (b) Golgi apparatus (c) Lysosomes (d) Endoplasmic reticulum
Solution:
Ans: (b) Explanation: The Golgi apparatus modifies, sorts, and packages proteins and lipids for transport to their final destinations, playing a crucial role in protein secretion and lysosome formation.
Q5: Why are red blood cells circular and biconcave in shape? (a) To store more oxygen (b) To divide rapidly (c) To pass through capillaries easily (d) To engulf pathogens
Solution:
Ans: (c) Explanation: Red blood cells are circular and biconcave to allow easy passage through narrow blood capillaries and maximize surface area for efficient oxygen transport throughout the body.
Fill in the Blanks
Q1: The _____ is the control centre of the cell that contains genetic material.
Solution:
Ans: Nucleus
Q2: Amoeba is an example of a _____ organism.
Solution:
Ans: Unicellular
Q3: The smallest known cell is _____ which is a type of bacteria.
Solution:
Ans: Mycoplasma gallisepticum
Q4: _____ are known as the protein factories of the cell.
Solution:
Ans: Ribosomes
Q5: The _____ are bean-shaped cells found in plant leaves that control stomatal opening.
Solution:
Ans: Guard cells
True or False
Q1: All living organisms start their life as a single cell according to Cell Theory.
Solution:
Ans: True Explanation: Cell Theory states that all living organisms begin life as a single cell which has the ability to perform metabolic processes necessary for life.
Q2: The egg of an ostrich is the smallest cell in the world.
Solution:
Ans: False Explanation: The egg of an ostrich is actually the largest cell in the world, measuring several centimeters in diameter, not the smallest cell.
Ans: False Explanation: Prokaryotic cells lack membrane-bound organelles, and their nuclear material lies freely in the cytoplasm, unlike eukaryotic cells which have organised organelles.
Q4: White blood cells have an amoeboid shape that allows them to engulf pathogens.
Solution:
Ans: True Explanation: White blood cells possess an amoeboid shape with pseudopodia extensions, enabling them to change shape, squeeze through capillaries, and engulf harmful pathogens effectively.
Q5: Lysosomes are responsible for generating ATP in the cell.
Solution:
Ans: False Explanation: Lysosomes are the waste disposal system that degrades cellular waste and damaged organelles. Mitochondria, not lysosomes, are responsible for ATP generation in cells.
Match the Following
Solution:
Ans:
1 - D: The nerve cell or neuron is the longest cell in the human body, extending several feet especially from spinal cord to limbs.
2 - A: Ribosomes are the protein factories that synthesize proteins by translating mRNA information and assembling amino acids into polypeptide chains.
3 - E: The cell membrane acts as a barrier controlling the entry and exit of substances, maintaining homeostasis and facilitating cellular communication.
4 - C: The endoplasmic reticulum is involved in lipid and protein synthesis, transport of molecules, and detoxification of drugs and harmful substances.
5 - B: Lysosomes are the waste disposal system that degrades and recycles cellular waste, damaged organelles, and removes harmful substances from cells.
Short Answer Questions
Q1: Explain the difference between unicellular and multi-cellular organisms with examples.
Solution:
Ans: Unicellular organisms consist of a single cell that performs all necessary life functions, such as Amoeba which lives in water and changes shape to move and capture food. Multi-cellular organisms contain many specialized cells performing different functions. Plants have cells adapted for photosynthesis whilst humans have cells for digestion, circulation, and movement. Examples of multi-cellular organisms include plants, animals, and humans.
Q2: What are the main functions of the nucleus in a cell?
Solution:
Ans: The nucleus is the control centre of the cell containing genetic material (DNA) that carries information for protein synthesis. It regulates cellular activities by controlling gene expression and plays a crucial role in cell division by ensuring proper distribution of genetic material to daughter cells. The nucleus is also involved in producing ribosomes which are essential for protein synthesis, making it vital for cell survival and function.
Q3: Describe the structure and function of red blood cells and white blood cells.
Solution:
Ans: Red blood cells are circular and biconcave in shape, allowing easy passage through blood capillaries and maximizing surface area for oxygen transport throughout the body. White blood cells have an amoeboid shape with pseudopodia extensions, enabling them to change shape and squeeze through capillaries. This unique structure allows white blood cells to engulf pathogens and protect the body from infections, whilst red blood cells focus on oxygen delivery.
Q4: Why is the nucleus essential for normal life? Support your answer with experimental evidence.
Solution:
Ans: The nucleus contains DNA that regulates all cellular activities and is responsible for inheritance of traits. When the nucleus is removed from an Amoeba, it cannot survive because essential genetic instructions are missing. However, if a nucleus from a healthy Amoeba is transplanted into an enucleated Amoeba, the recipient survives and divides because it receives necessary genetic instructions. This demonstrates that the nucleus is vital for cell survival and reproduction.
Q5: What are the key differences between eukaryotic and prokaryotic cells?
Solution:
Ans: Eukaryotic cells contain membrane-bound cell organelles and the nucleus contents are separated from the cytoplasm by a nuclear membrane. Examples include animal cells and plant cells. Prokaryotic cells lack membrane-bound organelles and their nuclear material lies freely in the cytoplasm without a nuclear membrane. Bacteria are examples of prokaryotic cells. This fundamental difference affects cellular organization, with eukaryotic cells being more complex and compartmentalized than prokaryotic cells.
Long Answer Questions
Q1: Analyse the role of mitochondria and lysosomes in maintaining cellular health. Compare their functions and explain how they work together to keep cells functioning properly.
Solution:
Ans: Mitochondria are powerhouses generating ATP through cellular respiration, converting glucose and oxygen into energy, carbon dioxide, and water. They regulate cellular metabolism and play a role in apoptosis. Lysosomes function as waste disposal systems, degrading cellular waste, damaged organelles, and foreign substances. They remove harmful materials and process nutrients. Together, they maintain cellular health by providing energy whilst removing damaged components. When mitochondria become damaged, lysosomes degrade them through autophagy. Both organelles ensure cellular homeostasis, with mitochondria providing energy for lysosomal activities and lysosomes clearing dysfunctional mitochondria, creating a balanced cellular environment essential for survival.
Q2: Evaluate the importance of cell shape in relation to cell function. Justify your answer using examples of different cell types from the human body.
Solution:
Ans: Cell shape is directly related to function, optimizing cells for specific tasks. Red blood cells are circular and biconcave, maximizing surface area for oxygen transport whilst allowing easy passage through narrow capillaries. Nerve cells are long and slender with extended axons, enabling transmission of electrical impulses over long distances from spinal cord to limbs. White blood cells have amoeboid shapes with pseudopodia, allowing shape changes to squeeze through capillaries and engulf pathogens effectively. These specialized shapes demonstrate evolutionary adaptation where structure supports function. If cells had uniform shapes, they could not perform diverse functions efficiently, proving that structural specialization is essential for physiological processes.
Q3: Analyse the process of protein synthesis and transport in a cell. Describe how different organelles work together from protein creation to secretion outside the cell.
Solution:
Ans: Protein synthesis begins when the nucleus provides genetic instructions through mRNA. Ribosomes translate this mRNA, assembling amino acids into polypeptide chains. The endoplasmic reticulum synthesizes and transports these proteins, ensuring quality control. Proteins then move to the Golgi apparatus where they are modified, sorted, and packaged for transport to final destinations. The Golgi apparatus plays a crucial role in protein secretion outside the cell. This coordinated process demonstrates cellular cooperation, with each organelle performing specific functions. The nucleus controls, ribosomes build, endoplasmic reticulum processes, and Golgi apparatus packages, creating an efficient assembly line for protein production and distribution essential for cellular function.
The document Worksheet with Solutions: Cell - The Structural and Functional Unit of Life is a part of the Class 10 Course Biology Class 10 ICSE.
FAQs on Worksheet with Solutions: Cell - The Structural and Functional Unit of Life
1. What is a cell?
Ans. A cell is the basic structural and functional unit of life, which can exist independently or as part of a multicellular organism. It is responsible for carrying out various biological processes essential for survival.
2. What is the difference between prokaryotic and eukaryotic cells?
Ans. Prokaryotic cells are simple, unicellular organisms that lack a defined nucleus and membrane-bound organelles, while eukaryotic cells are more complex, can be unicellular or multicellular, and possess a defined nucleus and various organelles.
3. What are the main components of a cell?
Ans. The main components of a cell include the cell membrane, cytoplasm, nucleus, and various organelles such as mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes, each performing specific functions.
4. How do cells obtain energy?
Ans. Cells obtain energy primarily through cellular respiration, a process that converts glucose and oxygen into adenosine triphosphate (ATP), which is then used to power various cellular activities.
5. What role do organelles play in a cell?
Ans. Organelles are specialised structures within a cell that perform distinct functions, such as energy production (mitochondria), protein synthesis (ribosomes), and waste processing (lysosomes), contributing to the overall functioning and maintenance of the cell.
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