The Fundamental Unit of Life — Important Questions
47 questions
With answersCBSE format
SUMMARY: This chapter focuses on the cell as the basic unit of life, exploring its structure, functions, and significance in living organisms. KEY TOPICS: cell theory, prokaryotic and eukaryotic cells, cell membrane, cell wall, cytoplasm, nucleus, organelles, endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria, plastids, vacuoles, cell division.
What is the basic structural and functional unit of life?
ATissue
BOrgan
CCell
DOrganism
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Correct answer: Option 3 — Cell
Q21 Mark
Which of the following is a characteristic of prokaryotic cells?
APresence of a nucleus
BLack of membrane-bound organelles
CMulticellular organization
DComplex structure
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Correct answer: Option 2 — Lack of membrane-bound organelles
Q31 Mark
What is the primary function of the cell membrane?
AEnergy production
BProtection and support
CRegulating entry and exit of substances
DStorage of genetic material
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Correct answer: Option 3 — Regulating entry and exit of substances
Q41 Mark
Which organelle is known as the powerhouse of the cell?
AGolgi apparatus
BLysosome
CMitochondria
DEndoplasmic reticulum
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Correct answer: Option 3 — Mitochondria
Q51 Mark
What is the function of lysosomes in a cell?
AProtein synthesis
BDigestion of waste materials
CEnergy production
DPhotosynthesis
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Correct answer: Option 2 — Digestion of waste materials
Q61 Mark
Which of the following is NOT a function of the endoplasmic reticulum?
ASynthesis of proteins
BTransport of materials
CStorage of genetic information
DLipid synthesis
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Correct answer: Option 3 — Storage of genetic information
Q71 Mark
What is the jelly-like substance inside the cell called?
ANucleus
BCytoplasm
CCell wall
DPlasma membrane
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Correct answer: Option 2 — Cytoplasm
Q81 Mark
Which structure in plant cells is responsible for photosynthesis?
AMitochondria
BChloroplasts
CVacuoles
DNucleus
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Correct answer: Option 2 — Chloroplasts
Q91 Mark
What is the role of the Golgi apparatus in a cell?
AEnergy production
BModification and packaging of proteins
CCell division
DPhotosynthesis
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Correct answer: Option 2 — Modification and packaging of proteins
Q101 Mark
Which of the following statements about the cell wall is true?
AIt is present in animal cells
BIt provides rigidity and protection
CIt is selectively permeable
DIt contains chlorophyll
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Correct answer: Option 2 — It provides rigidity and protection
Q111 Mark
During which phase of cell division does the nucleus divide?
AInterphase
BCytokinesis
CMitosis
DProphase
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Correct answer: Option 3 — Mitosis
Q121 Mark
What is the main component of the cell membrane?
AProteins
BCarbohydrates
CLipids
DNucleic acids
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Correct answer: Option 3 — Lipids
Q131 Mark
Which organelle is involved in the synthesis of ribosomes?
ANucleus
BMitochondria
CEndoplasmic reticulum
DGolgi apparatus
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Correct answer: Option 1 — Nucleus
Q141 Mark
What type of cells lack a defined nucleus?
AEukaryotic cells
BProkaryotic cells
CPlant cells
DAnimal cells
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Correct answer: Option 2 — Prokaryotic cells
Q151 Mark
Which of the following structures is responsible for storage in cells?
AVacuoles
BRibosomes
CMitochondria
DChloroplasts
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Correct answer: Option 1 — Vacuoles
Short Answer Questions10 questions
Q163 Marks
What is the cell theory and who proposed it?
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Cell theory states that all living organisms are composed of cells, and that the cell is the basic unit of life. It was proposed by scientists Matthias Schleiden, Theodor Schwann, and Rudolf Virchow in the 19th century.
Q173 Marks
Differentiate between prokaryotic and eukaryotic cells.
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Prokaryotic cells are unicellular organisms without a nucleus or membrane-bound organelles, while eukaryotic cells have a defined nucleus and organelles. Examples of prokaryotes include bacteria, whereas plants and animals are eukaryotes.
Q183 Marks
What is the function of the cell membrane?
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The cell membrane acts as a protective barrier that regulates the entry and exit of substances, maintaining the internal environment of the cell. It is selectively permeable, allowing certain molecules to pass while blocking others.
Q193 Marks
Describe the structure and function of the nucleus.
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The nucleus is a membrane-bound organelle that contains the cell's genetic material (DNA). It controls cellular activities and is responsible for cell growth, metabolism, and reproduction by regulating gene expression.
Q203 Marks
What role do lysosomes play in a cell?
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Lysosomes are membrane-bound organelles that contain digestive enzymes. They break down waste materials and cellular debris, playing a crucial role in cellular digestion and recycling of components.
Q213 Marks
Explain the function of mitochondria in eukaryotic cells.
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Mitochondria are known as the powerhouse of the cell, as they generate adenosine triphosphate (ATP) through cellular respiration. They convert energy stored in food into a usable form for the cell.
Q223 Marks
What is the significance of the endoplasmic reticulum (ER) in a cell?
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The endoplasmic reticulum (ER) is involved in the synthesis of proteins and lipids. The rough ER has ribosomes for protein synthesis, while the smooth ER is involved in lipid synthesis and detoxification processes.
Q233 Marks
How do vacuoles function in plant cells?
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Vacuoles are large membrane-bound sacs that store nutrients, waste products, and help maintain turgor pressure in plant cells. They play a key role in maintaining cell rigidity and overall plant health.
Q243 Marks
What are plastids and their types?
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Plastids are organelles found in plant cells that are involved in the synthesis and storage of food. The main types include chloroplasts (for photosynthesis), chromoplasts (for pigment storage), and leucoplasts (for starch storage).
Q253 Marks
Describe the structure and function of the Golgi apparatus.
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The Golgi apparatus is a stack of membrane-bound vesicles that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles. It plays a crucial role in processing and transporting cellular products.
Long Answer Questions6 questions
Q266 Marks
Explain the cell theory and its significance in understanding the structure and function of living organisms.
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Cell theory is a fundamental concept in biology that states that all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells. This theory is significant because it provides a framework for understanding the organization of life, emphasizing that cells are the building blocks of all living things. It also highlights the continuity of life through cellular reproduction, which is essential for growth and healing in organisms.
Q276 Marks
Differentiate between prokaryotic and eukaryotic cells in terms of structure and function.
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Prokaryotic cells are simpler, smaller, and lack a defined nucleus and membrane-bound organelles, while eukaryotic cells are larger, more complex, and contain a nucleus and various organelles. Prokaryotic cells, such as bacteria, have their genetic material in a nucleoid region, whereas eukaryotic cells, such as plant and animal cells, have their DNA enclosed within a nuclear membrane. This structural difference leads to varied functions, with eukaryotic cells being capable of more complex processes due to their organelles.
Q286 Marks
Describe the structure and function of the cell membrane and its importance to cell survival.
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The cell membrane, also known as the plasma membrane, is a phospholipid bilayer that surrounds the cell, providing structural support and protecting the cell's interior. It is selectively permeable, allowing certain substances to enter or exit while keeping others out. This selective permeability is crucial for maintaining homeostasis, as it regulates the internal environment of the cell by controlling the movement of ions, nutrients, and waste products, thus ensuring the cell's survival and proper functioning.
Q296 Marks
What is the role of the nucleus in a eukaryotic cell? Discuss its structure and functions.
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The nucleus is a membrane-bound organelle that serves as the control center of a eukaryotic cell. It contains the cell's genetic material, DNA, organized into chromosomes. The nucleus is surrounded by a double membrane called the nuclear envelope, which has pores that regulate the exchange of materials between the nucleus and the cytoplasm. The nucleus is responsible for storing genetic information, coordinating cell activities such as growth, metabolism, and reproduction, and directing the synthesis of proteins by producing messenger RNA.
Q306 Marks
Explain the functions of the endoplasmic reticulum (ER) and its types.
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The endoplasmic reticulum (ER) is a network of membranous tubules and sacs involved in the synthesis and transport of proteins and lipids. There are two types of ER: rough ER, which is studded with ribosomes and is primarily involved in protein synthesis and modification, and smooth ER, which lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium ion storage. The ER plays a critical role in the overall functioning of the cell by facilitating the production and transport of essential biomolecules.
Q316 Marks
Discuss the structure and function of the Golgi apparatus in the cell.
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The Golgi apparatus is a stack of flattened membrane-bound sacs known as cisternae. It functions as the cell's packaging and distribution center, modifying, sorting, and packaging proteins and lipids received from the endoplasmic reticulum. The Golgi apparatus is essential for the secretion of substances, such as hormones and enzymes, and for the formation of lysosomes. By processing and dispatching these molecules to their appropriate destinations, the Golgi apparatus plays a vital role in maintaining cellular organization and function.
Assertion–Reason Questions8 questions
Q321 Mark
Assertion (A): All living organisms are made up of cells.
Reason (R): The cell theory states that cells are the basic unit of life.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q331 Mark
Assertion (A): Prokaryotic cells lack a defined nucleus.
Reason (R): Prokaryotic cells are generally smaller and simpler than eukaryotic cells.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q341 Mark
Assertion (A): The cell membrane is selectively permeable.
Reason (R): It allows certain substances to pass while blocking others, maintaining homeostasis.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q351 Mark
Assertion (A): Mitochondria are known as the powerhouse of the cell.
Reason (R): They are responsible for energy production through cellular respiration.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q361 Mark
Assertion (A): Lysosomes are involved in protein synthesis.
Reason (R): Lysosomes contain enzymes that break down waste materials and cellular debris.
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Correct answer: Option 3 —
A is true, but R is false.
Q371 Mark
Assertion (A): Eukaryotic cells have membrane-bound organelles.
Reason (R): This structural complexity allows for compartmentalization of cellular functions.
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Correct answer: Option 1 —
Both A and R are true, and R is the correct explanation of A.
Q381 Mark
Assertion (A): Vacuoles are primarily found in animal cells.
Reason (R): Vacuoles store nutrients and waste products in cells.
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Correct answer: Option 3 —
A is true, but R is false.
Q391 Mark
Assertion (A): The Golgi apparatus modifies and packages proteins.
Reason (R): It is involved in the synthesis of lipids and carbohydrates.
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Correct answer: Option 3 —
A is true, but R is false.
Statement-Based Questions8 questions
Q401 Mark
Statement 1: All living organisms are made up of cells.
Statement 2: The cell is the smallest unit of life.
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Correct answer: Option 1 —
Both statements are true.
Q411 Mark
Statement 1: Prokaryotic cells lack a defined nucleus.
Statement 2: Eukaryotic cells are generally smaller than prokaryotic cells.
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Correct answer: Option 3 —
Only Statement 2 is true.
Q421 Mark
Statement 1: The cell membrane is selectively permeable.
Statement 2: The cell wall is present in animal cells.
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Correct answer: Option 4 —
Both statements are false.
Q431 Mark
Statement 1: Cytoplasm is the jelly-like substance within the cell.
Statement 2: The nucleus is responsible for energy production in the cell.
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Correct answer: Option 3 —
Only Statement 2 is true.
Q441 Mark
Statement 1: Lysosomes are known as the 'suicide bags' of the cell.
Statement 2: Mitochondria are involved in photosynthesis.
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Correct answer: Option 2 —
Only Statement 1 is true.
Q451 Mark
Statement 1: Plastids are found only in plant cells.
Statement 2: Vacuoles are responsible for storage and maintaining turgor pressure.
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Correct answer: Option 1 —
Both statements are true.
Q461 Mark
Statement 1: The endoplasmic reticulum is involved in protein synthesis.
Statement 2: The Golgi apparatus modifies and packages proteins.
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Correct answer: Option 1 —
Both statements are true.
Q471 Mark
Statement 1: Cell division occurs only in eukaryotic cells.
Statement 2: Binary fission is a method of cell division in prokaryotes.
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Correct answer: Option 3 —
Only Statement 2 is true.
