Cell : The Unit of Life is a chapter in the CBSE Class 11 Biology syllabus from Biology. This chapter hub brings together revision notes, practice questions, worksheets, flashcards to help students learn, practice, and revise Cell : The Unit of Life effectively.

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Cell : The Unit of Life

NCERT Class 11 Biology Chapter 8: Cell : The Unit of Life (Pages 87–103)

Class 11 CBSE hub Biology chapters Biology

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Summary of Cell : The Unit of Life

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Cell : The Unit of Life at a Glance

Board

CBSE

Class

Class 11

Subject

Biology

Book

Biology

Chapter

Pages

87–103

Resources

6 study resources

Cell : The Unit of Life Summary

In this chapter, students will learn about cells, the fundamental units of life that make up all living organisms. The chapter starts by introducing the concept of cells and why they are important in biology. It explains how cells can be classified into two main types: prokaryotic and eukaryotic cells. Prokaryotic cells, which are simpler and smaller, lack a nucleus and other membrane-bound organelles, while eukaryotic cells are more complex, containing a nucleus and various organelles that perform specific functions. The chapter further explores the structure of a typical eukaryotic cell, detailing its components such as the cell membrane, cytoplasm, nucleus, and organelles like mitochondria, endoplasmic reticulum, and Golgi apparatus. Students will discover the role each component plays in cellular processes, including energy production, protein synthesis, and waste management. Another key section covers the differences between plant and animal cells, highlighting unique features in plant cells such as the cell wall and chloroplasts, which are essential for photosynthesis. The chapter emphasizes the significance of cell theory, which states that all living things are composed of cells, and that cells arise from pre-existing cells. This leads to discussions about cell division, including mitosis and meiosis, and their roles in growth, reproduction, and genetic diversity. Overall, this chapter provides a comprehensive overview of cell biology, equipping students with the critical knowledge needed to understand more complex biological concepts in later studies. By grasping the basics of cellular structure and function, students will appreciate how these tiny units contribute to the larger functions and systems of living organisms.

Cell : The Unit of Life Revision Guide

Download the Cell : The Unit of Life revision guide with key points, summaries, and quick revision notes for CBSE Class 11 Biology.

Key Points

Define a cell.

A cell is the basic structural and functional unit of life. Cells can be prokaryotic or eukaryotic.

Differentiate between prokaryotic and eukaryotic cells.

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have them.

Key organelles in eukaryotic cells.

Important organelles include the nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus.

Describe the structure of the cell membrane.

The cell membrane is a phospholipid bilayer that regulates what enters and exits the cell.

The role of ribosomes.

Ribosomes are responsible for protein synthesis by translating mRNA into proteins.

Functions of mitochondria.

Mitochondria are the powerhouses of the cell, generating ATP through cellular respiration.

Role of the endoplasmic reticulum.

The rough ER synthesizes proteins, while the smooth ER is involved in lipid synthesis and detoxification.

Explain the Golgi apparatus.

The Golgi apparatus modifies, sorts, and packages proteins for secretion or delivery to other organelles.

Identify functions of lysosomes.

Lysosomes digest and break down waste materials and cellular debris using enzymes.

Function of chloroplasts.

Chloroplasts collect sunlight and perform photosynthesis, converting light energy into chemical energy.

Explain homeostasis.

Homeostasis is the ability of a cell or organism to maintain stable internal conditions despite external changes.

Discuss cell division: mitosis vs. meiosis.

Mitosis produces two identical daughter cells for growth and repair, while meiosis produces four genetically diverse gametes.

Define osmosis.

Osmosis is the movement of water across a selectively permeable membrane from an area of low solute concentration to high.

Importance of surface area to volume ratio.

A higher surface area to volume ratio allows for more efficient transport of materials in and out of the cell.

Role of the cytoskeleton.

The cytoskeleton provides structural support and facilitates movement of organelles and the entire cell.

What are stem cells?

Stem cells are undifferentiated cells capable of giving rise to various cell types and are essential for growth and healing.

Define apoptosis.

Apoptosis is programmed cell death, an essential process for maintaining healthy tissue homeostasis.

Explain cellular respiration.

Cellular respiration is the process of converting glucose and oxygen into ATP, releasing carbon dioxide and water as byproducts.

Role of cell signaling.

Cell signaling involves communication between cells through signaling molecules, crucial for coordination of biological functions.

The concept of the fluid mosaic model.

The fluid mosaic model describes the structure of cell membranes as flexible and composed of various components that can move.

Define diffusion.

Diffusion is the passive movement of particles from a region of higher concentration to one of lower concentration.

Cell : The Unit of Life Practice Questions & Answers

Practice important questions and exam-style problems from Cell : The Unit of Life. These questions cover key topics from the CBSE Class 11 Biology syllabus.

How to practice: Start with the questions below to test your understanding of Cell : The Unit of Life. Use the revision guide to review concepts you find difficult, then come back and retry the questions for better retention.

What is the basic structural and functional unit of all living organisms?

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What scientist is credited with the discovery of the cell?

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Which of the following statements is true about prokaryotic cells?

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What is the primary function of the cell membrane?

Single Answer MCQ

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Which of the following organelles is known as the powerhouse of the cell?

Single Answer MCQ

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What function do lysosomes perform in the cell?

Single Answer MCQ

Q-00055712

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What is the role of ribosomes in the cell?

Single Answer MCQ

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In what ways do plant cells differ from animal cells?

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Which organelle is responsible for modifying, sorting, and packaging proteins?

What is the primary role of the cytoskeleton in a cell?

Which of the following is NOT a major component of the cell theory?

What distinguishes eukaryotic cells from prokaryotic cells?

Which process involves the movement of substances across the cell membrane against their concentration gradient?

What is the main function of chloroplasts in plant cells?

What term describes the fluid mosaic model of cell membranes?

During which phase of the cell cycle does DNA replication occur?

What is the basic structural and functional unit of life?

Which organelle is known as the 'powerhouse of the cell'?

What component of the cell is primarily responsible for protein synthesis?

Which of the following is a function of the cell membrane?

Which structure is found in plant cells but not in animal cells?

The fluid part of the cell, where organelles are suspended, is called:

Which organelle is referred to as the 'control center' of the cell?

Which type of cell is primarily responsible for photosynthesis?

What is the primary role of the Golgi apparatus?

Which of the following structures is selectively permeable?

What is the main component of the cell membrane?

Which type of endoplasmic reticulum is involved in lipid synthesis?

What is the primary role of lysosomes in a cell?

Which of the following statements about prokaryotic cells is true?

In which part of the cell does the Calvin cycle occur?

The fluid mosaic model best describes which cellular structure?

Which of the following is NOT a characteristic of eukaryotic cells?

Which type of cell is characterized by the absence of a true nucleus?

What distinguishes eukaryotic cells from prokaryotic cells?

Which cell type primarily makes up multicellular organisms?

Which of the following is a feature of plant cells?

What is the primary function of the cell membrane?

Which of the following statements about animal cells is true?

What is the role of the ribosomes in eukaryotic cells?

What differentiates bacterial cells from archaean cells?

Which structure is absent in prokaryotic cells?

Which type of cell typically has more than one nucleus?

What is the main function of the vacuoles in plant cells?

How do eukaryotic cells reproduce?

What type of cell would you find chloroplasts in?

Which of the following organelles is involved in cellular respiration?

Which cellular structure is involved in the modification and packaging of proteins?

What type of cells are responsible for the immune response?

Which of the following best explains the endosymbiotic theory?

Which organelle is primarily responsible for detoxifying harmful substances in the liver?

What are the main differences between plant and animal cells?

What is the primary purpose of cell division?

Which phase of the cell cycle is primarily responsible for DNA replication?

During which stage of mitosis do sister chromatids separate?

What is the structure that forms during cytokinesis in plant cells?

Which of the following accurately describes meiosis?

What term describes the phase where chromosomes condense and become visible?

Which of the following correctly matches the type of cell division with its main purpose?

During which phase does crossing over occur?

What happens to the chromatin during prophase?

Which regulatory protein helps control the cell cycle?

What is a key difference between mitosis and meiosis?

Which of the following statements about the cell cycle is false?

What is the end result of meiosis?

What phase of the cell cycle is characterized by the absence of DNA synthesis?

What is the primary source of energy for cellular metabolism?

Which process converts glucose into ATP in the presence of oxygen?

What is the role of enzymes in cellular metabolism?

Which of the following statements about metabolic pathways is false?

What is the end product of glycolysis?

In which organelle does the Krebs cycle occur?

Which of the following is an example of an anabolic pathway?

What is produced during anaerobic respiration in humans?

What is the primary role of ATP in metabolism?

Which electron carriers are produced during the Krebs cycle?

Which of the following molecules directly enters the mitochondria for further oxidation?

What process converts light energy into chemical energy?

Which metabolic pathway is inhibited when there is a high concentration of ATP?

In animals, where does the majority of ATP production occur?

What is the main function of NAD+ in cellular metabolism?

Which byproduct is produced during alcoholic fermentation?

What is the primary role of ribosomes in the cell?

What is the primary role of signaling molecules in cell communication?

Which type of signaling occurs when cells communicate over long distances?

In paracrine signaling, what is the main characteristic of the signaling process?

What is a common function of gap junctions in cell communication?

Which of the following molecules serves as a common second messenger in signal transduction pathways?

Which type of signaling involves direct contact between cells?

Histamine is an example of which type of signaling molecule?

Which receptor type is primarily involved in responding to water-soluble signaling molecules?

What is the primary role of receptors in cell signaling?

A cellular response to a signal often involves which type of activity?

Which statement best describes autocrine signaling?

What type of molecules are typically involved in long-distance signaling?

What cellular structure is primarily responsible for receiving signals from extracellular molecules?

Which process involves the conversion of an extracellular signal into a functional response inside the cell?

Which of the following best describes 'cross-talk' in cell signaling?

What role does the cytoskeleton play in cell signaling?

Single Answer MCQ

Q-00055819

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Cell : The Unit of Life Practice Worksheets

Download and practice Cell : The Unit of Life worksheets to improve problem-solving accuracy and speed for CBSE Class 11 Biology exams.

Cell : The Unit of Life - Practice Worksheet

This worksheet covers essential long-answer questions to help you build confidence in Cell : The Unit of Life from Biology for Class 11 (Biology).

Practice

Questions

Define the cell theory and explain its significance in biology.

Cell theory states that all living organisms are composed of cells, and all cells arise from pre-existing cells. This theory is significant as it underlines the fundamental unit of life, emphasizing that cells are the basic structural, functional, and biological units of all living organisms. It revolutionized the understanding of biology by providing a unifying concept for all living things, establishing the groundwork for modern biology, and guiding research in areas such as cell biology, genetics, and physiology.

What are the major differences between prokaryotic and eukaryotic cells?

Prokaryotic cells are smaller, simpler, and lack a nucleus, while eukaryotic cells are larger, more complex, and have a membrane-bound nucleus. Prokaryotes can be unicellular and include bacteria, whereas eukaryotes can be unicellular or multicellular, including animals, plants, fungi, and protists. Eukaryotic cells contain various organelles (like mitochondria and endoplasmic reticulum) that perform specific functions, which are absent in prokaryotic cells. The structure of their DNA also differs, with prokaryotic DNA being circular and eukaryotic DNA being linear and associated with proteins.

Explain the function of the cell membrane and its importance to cellular processes.

The cell membrane is a semi-permeable barrier that regulates what enters and exits the cell, maintaining homeostasis. It consists of a lipid bilayer with embedded proteins that facilitate transport, signaling, and cell recognition. The membrane's fluid nature allows for movement and interaction of components, while its selective permeability is crucial for nutrient uptake, waste removal, and communication with the external environment. This functionality is vital for the survival of the cell and proper organism function.

Describe the major organelles found in a eukaryotic cell and their functions.

Major organelles include the nucleus, which houses genetic material; mitochondria, known as the powerhouse that produces ATP; endoplasmic reticulum (smooth and rough), which synthesizes proteins and lipids; Golgi apparatus, which modifies, sorts, and packages proteins; lysosomes, which digest waste materials; and ribosomes, which are sites of protein synthesis. Each organelle contributes to the complex life processes of the cell, working together in maintaining cellular health and function.

What is the role of ribosomes in protein synthesis?

Ribosomes play a crucial role in protein synthesis by translating messenger RNA (mRNA) into a polypeptide chain (protein). They can be found freely floating in the cytoplasm or attached to the rough endoplasmic reticulum. During translation, ribosomes read the sequence of mRNA codons, matching them with corresponding transfer RNA (tRNA) molecules that carry amino acids. This process results in the synthesis of proteins, following the genetic instructions encoded in the DNA.

Discuss the differences between plant and animal cells.

Plant cells have a rigid cell wall made of cellulose, which provides structure and support, whereas animal cells have only a flexible cell membrane. Additionally, plant cells contain chloroplasts for photosynthesis, which are absent in animal cells. Vacuoles in plant cells are large and serve as storage for nutrients and even waste products, whereas animal cells may have smaller vacuoles. Furthermore, plant cells are generally more rectangular in shape, while animal cells can vary in shape and size.

What is osmosis, and how does it affect the volume of cells?

Osmosis is the passive movement of water molecules through a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. This process can greatly affect cell volume; for instance, in a hypotonic solution, cells may swell and potentially burst due to excess water intake, while in a hypertonic solution, cells can shrink as water exits the cell. This movement is essential for maintaining cellular functions and homeostasis.

Explain the process of cellular respiration and its significance.

Cellular respiration is the biochemical process where cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water. This process involves glycolysis, the Krebs cycle, and oxidative phosphorylation. Cellular respiration is crucial as it provides energy for various cellular functions, including growth, reproduction, and maintenance. It ensures that metabolism runs effectively, thus supporting life processes across all organisms.

Illustrate and explain the steps of the cell cycle.

The cell cycle consists of several key phases: interphase (which includes G1, S, and G2 phases) and mitotic phase (M phase). In the G1 phase, the cell grows and synthesizes proteins; in S phase, DNA is replicated; in G2 phase, cells prepare for mitosis. The mitotic phase includes prophase, metaphase, anaphase, and telophase, culminating in cytokinesis, where the cytoplasm divides, producing two daughter cells. Understanding the cell cycle is essential for studying growth, development, and cancer.

Cell : The Unit of Life - Mastery Worksheet

This worksheet challenges you with deeper, multi-concept long-answer questions from Cell : The Unit of Life to prepare for higher-weightage questions in Class 11.

Mastery

Questions

Explain the structure and function of the cell membrane. How does it control the movement of substances in and out of the cell? Use a diagram to support your explanation.

The cell membrane, also known as the plasma membrane, is composed of a phospholipid bilayer with embedded proteins. It is selectively permeable, allowing some substances to pass while restricting others. Passive transport (e.g., diffusion, osmosis) and active transport (e.g., pump mechanisms) are key processes. A diagram illustrating the phospholipid arrangement, protein channels, and examples of substances crossing should accompany the explanation.

Compare prokaryotic and eukaryotic cells in terms of structure and function. Discuss specific examples that illustrate the differences.

Prokaryotic cells, lacking a nucleus and membrane-bound organelles, are generally smaller and less complex than eukaryotic cells, which contain a nucleus and various organelles. For example, a bacterial cell (prokaryote) vs. a plant cell (eukaryote). Diagrams of each cell type can be used to highlight differences such as the presence of a cell wall in prokaryotes and chloroplasts in plant eukaryotes.

Describe the process of protein synthesis, including transcription and translation. What roles do ribosomes and mRNA play in this process?

Protein synthesis involves two main stages: transcription and translation. During transcription, DNA is transcribed to produce mRNA in the nucleus. This mRNA exits to the cytoplasm, where ribosomes translate the mRNA sequence into an amino acid chain, forming a protein. Diagrams illustrating transcription and translation phases, along with ribosome functions, should be included.

How do the structures of plant and animal cells differ? Discuss how these differences relate to their functions.

Plant cells have a rigid cell wall, chloroplasts, and large vacuoles, which provide structural support and enable photosynthesis. Animal cells contain centrioles and often have smaller vacuoles and no cell wall. Illustrate these differences with labeled diagrams to show each cell type and discuss related functions, including energy production and storage.

Explain the importance of the cell cycle, especially the phases of mitosis. How does this process contribute to growth and repair in an organism?

The cell cycle consists of interphase and the mitotic phase. Mitosis includes prophase, metaphase, anaphase, and telophase, which ensure accurate segregation of chromosomes into daughter cells. Discuss the significance of each phase for cellular replication and how this process underpins growth, repair, and maintenance of tissues. Include a diagram of the mitosis stages.

Discuss the concept of cellular differentiation. How do stem cells differ from differentiated cells?

Cellular differentiation is the process by which unspecialized cells, like stem cells, develop into specialized cell types with distinct functions. Stem cells can self-renew and differentiate into multiple cell types, while differentiated cells perform specific roles. Examples include hematopoietic stem cells differentiating into various blood cells. Illustrative diagrams may be beneficial.

What is the role of enzymes in cellular processes? Describe how enzyme activity can be affected by temperature and pH.

Enzymes are biological catalysts that speed up biochemical reactions by lowering activation energy. Their activity is influenced by temperature (increased rates until denaturation) and pH (optimal ranges for different enzymes). Examples of enzyme-substrate interaction and resulting product formation should be included, along with a graph showing enzyme activity against temperature and pH.

Describe how cellular respiration occurs in both aerobic and anaerobic conditions, including key differences in energy yield.

Cellular respiration involves glycolysis, followed by either aerobic respiration (with oxygen) producing ~36 ATP per glucose molecule via the Krebs cycle and electron transport chain, or anaerobic respiration (without oxygen) resulting in ~2 ATP via fermentation processes. Use diagrams to illustrate pathways and the comparative ATP yields.

Analyze the role of the cytoskeleton in maintaining cell shape and facilitating movement. Discuss types of cytoskeletal elements.

The cytoskeleton is made up of microfilaments, intermediate filaments, and microtubules, providing structural support, shape maintenance, and enabling intracellular transport and cell movement. Discuss specific roles, such as the movement of vesicles along microtubules and muscle contraction via actin filaments. Diagrams showcasing these components should be included.

Cell : The Unit of Life - Challenge Worksheet

The final worksheet presents challenging long-answer questions that test your depth of understanding and exam-readiness for Cell : The Unit of Life in Class 11.

Challenge

Questions

Evaluate the implications of cell theory in understanding disease progression.

Discuss how disruptions in cellular processes contribute to disease. Analyze examples such as cancer and viral infections, and address potential counterarguments regarding non-cellular based diseases.

Analyze the role of mitochondria in energy production and its implications for cellular ageing.

Evaluate the relationship between mitochondrial activity and ATP production, linking it to theories of ageing and longevity. Reflect on possible counterpoints regarding other ageing factors.

Critically assess the impact of environmental factors on cell membrane integrity and function.

Discuss how various environmental stresses, such as toxins and temperature changes, affect membrane fluidity. Provide counterpoints emphasizing cellular adaptations.

Discuss the ethical implications of stem cell research in regenerative medicine.

Debate the potential benefits of stem cell therapy in curing diseases against ethical concerns surrounding stem cell sources. Provide examples of successful applications and controversies.

Evaluate the relationship between cell division and cancer development.

Examine the molecular mechanisms of cell cycle regulation and how mutations can lead to uncontrolled cell proliferation. Counterpose with the body’s natural defense mechanisms.

How does cellular differentiation contribute to the complexity of multicellular organisms?

Analyze the processes of differentiation and development from stem cells to specialized cells, assessing the balance between differentiation and stemness. Include examples and counterarguments on potential failure of differentiation.

Assess how advances in microscopy have enhanced our understanding of cellular structures.

Discuss the evolution of microscopy technology and its impact on cell biology research. Analyze limitations of traditional methods versus newer techniques.

Examine the cell's response to stress and its implications for aging.

Discuss mechanisms like the heat shock response or oxidative stress responses, linking these to aging theories. Counterpoint with potential for cellular repair mechanisms.

Critically evaluate the concept of the endosymbiotic theory and its importance in cell evolution.

Analyze evidence supporting the endosymbiotic theory while addressing challenges to this viewpoint. Discuss implications for the understanding of eukaryotic cell evolution.

Debate the role of cells in the immune response to pathogens.

Evaluate how various cell types (T-cells, B-cells) contribute to immunity and how their dysfunction can lead to autoimmune diseases. Include counterarguments regarding the role of innate immunity.

Cell : The Unit of Life Frequently Asked Questions

Explore the chapter 'Cell: The Unit of Life' for Class 11 biology, detailing the structure, functions, and types of cells essential for life.

QWhat is the basic unit of life?

The basic unit of life is the cell. Cells are the smallest structural and functional units in living organisms, responsible for carrying out various biological processes necessary for life.

QWhat are the two main types of cells?

The two main types of cells are prokaryotic and eukaryotic cells. Prokaryotic cells are simpler and do not have a nucleus, while eukaryotic cells are more complex and contain a nucleus and organelles.

QWhat is the function of the nucleus?

The nucleus is often referred to as the control center of the cell, containing genetic material (DNA) that regulates cellular activities, including growth, metabolism, and reproduction.

QWhat are organelles?

Organelles are specialized structures within a cell that perform specific functions. Examples include mitochondria, responsible for energy production, and ribosomes, which synthesize proteins.

QHow do cells divide?

Cells divide through a process called mitosis or meiosis. Mitosis results in two identical daughter cells and is essential for growth and tissue repair, while meiosis produces gametes for sexual reproduction.

QWhat role do cell membranes play?

Cell membranes act as a barrier between the cell's interior and its environment, regulating what enters and exits the cell, thus maintaining homeostasis.

QWhat is cellular metabolism?

Cellular metabolism encompasses all biochemical reactions occurring within a cell, including energy production, nutrient synthesis, and waste removal, vital for maintaining life.

QWhat is the importance of DNA in cells?

DNA holds the genetic instructions necessary for the development, functioning, growth, and reproduction of all living organisms, making it essential for heredity.

QHow do cells communicate with each other?

Cells communicate using chemical signals such as hormones or neurotransmitters. Receptors on cell surfaces detect these signals, triggering responses within the cell.

QWhat is the significance of cell differentiation?

Cell differentiation is the process by which a cell develops into a specialized cell type, allowing for the formation of various tissues and organs with specific functions in multicellular organisms.

QWhat can you say about the cell theory?

The cell theory states that all living organisms are made up of cells, and cells are the basic unit of life. This theory is fundamental to understanding biology and living systems.

QWhat are stem cells?

Stem cells are unique cells capable of self-renewal and differentiation into various cell types. They play a crucial role in development, growth, and tissue regeneration.

QHow do plants and animal cells differ?

Plant cells have a rigid cell wall, chloroplasts for photosynthesis, and large central vacuoles, while animal cells do not have cell walls and contain smaller vacuoles.

QWhat is apoptosis?

Apoptosis is a programmed cell death process that enables the body to remove damaged or unnecessary cells, playing a crucial role in maintaining healthy tissues.

QWhat are the functions of the mitochondria?

Mitochondria, known as the powerhouse of the cell, are responsible for producing ATP through cellular respiration, supplying energy for various cellular activities.

QWhat is the structure of a cell membrane?

Cell membranes are primarily composed of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates, providing fluidity and functionality.

QWhat is cellular respiration?

Cellular respiration is a metabolic process in which cells convert nutrients and oxygen into energy (ATP) while releasing carbon dioxide and water as byproducts.

QWhat is the role of ribosomes?

Ribosomes are cellular structures responsible for protein synthesis, translating messenger RNA (mRNA) into proteins, which are essential for various cellular functions.

QWhat is homeostasis in cells?

Homeostasis refers to the ability of a cell to maintain a stable internal environment despite external changes, crucial for optimal functioning and survival.

QHow do viruses differ from living cells?

Viruses are not considered living cells as they cannot reproduce or carry out metabolic processes independently; they require a host cell to replicate.

QWhat is the function of lysosomes?

Lysosomes are organelles that contain digestive enzymes, responsible for breaking down waste materials and cellular debris, aiding in recycling cellular components.

QWhat is endocytosis?

Endocytosis is the process by which cells engulf external substances, bringing them into the cell in vesicles, crucial for nutrient uptake and cell signaling.

QWhat is exocytosis?

Exocytosis is the process of vesicles fusing with the cell membrane to release their contents outside the cell, important for secretion and membrane trafficking.

QWhat are chloroplasts?

Chloroplasts are plant cell organelles responsible for photosynthesis, converting sunlight, carbon dioxide, and water into glucose and oxygen.

QHow do cells maintain their structure?

Cells maintain their structure through a combination of cytoskeletal elements, cell walls in plants, and cell membrane integrity, which together provide support and shape.

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Cell : The Unit of Life Flashcards

Revise key terms and definitions from Cell : The Unit of Life with interactive flashcards. Quick recall practice for CBSE Class 11 Biology.

These flash cards cover important concepts from Cell : The Unit of Life in Biology for Class 11 (Biology).

1/20

What is the basic unit of life?

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The cell is considered the basic unit of life because it is the smallest structural and functional unit that can carry out all life's processes.

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2/20

Define prokaryotic cells.

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Prokaryotic cells are unicellular organisms that lack a nucleus and membrane-bound organelles. They are smaller and simpler than eukaryotic cells.

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What distinguishes eukaryotic cells from prokaryotic cells?

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Eukaryotic cells have a defined nucleus and membrane-bound organelles while prokaryotic cells do not.

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4/20

What is the function of the cell membrane?

4/20

The cell membrane controls the movement of substances in and out of the cell and maintains the internal environment.

5/20

List the main components of the cell theory.

5/20

The cell theory states that: 1) All living organisms are composed of cells. 2) The cell is the basic unit of life. 3) All cells arise from pre-existing cells.

6/20

What is cytoplasm?

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Cytoplasm is the jelly-like substance within the cell membrane, containing organelles, cytosol, and various molecules.

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Name two types of endoplasmic reticulum.

7/20

The two types of endoplasmic reticulum are rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).

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What is the role of ribosomes?

8/20

Ribosomes are responsible for protein synthesis in the cell, translating mRNA into polypeptides.

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What is the function of mitochondria?

9/20

Mitochondria are known as the powerhouse of the cell, producing ATP through cellular respiration.

10/20

Define diffusion.

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Diffusion is the spontaneous movement of particles from an area of higher concentration to an area of lower concentration.

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What is osmosis?

11/20

Osmosis is the diffusion of water molecules across a selectively permeable membrane from a region of low solute concentration to high solute concentration.

12/20

Explain the role of lysosomes.

12/20

Lysosomes are organelles that contain digestive enzymes to break down waste materials and cellular debris.

13/20

What are chloroplasts?

13/20

Chloroplasts are organelles found in plant cells that conduct photosynthesis, converting light energy into chemical energy.

14/20

What is the structure of the cell wall?

14/20

The cell wall is a rigid outer layer that provides structural support and protection, primarily made of cellulose in plants.

15/20

Differentiate between active and passive transport.

15/20

Active transport requires energy to move substances against their concentration gradient, while passive transport does not require energy and occurs along the concentration gradient.

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What is a vacuole?

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A vacuole is a membrane-bound sac within the cell that stores substances, such as nutrients, waste products, and water.

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What are stem cells?

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Stem cells are undifferentiated cells that have the potential to develop into various cell types and have important roles in growth and repair.

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How do cellular organelles contribute to cell function?

18/20

Cellular organelles perform specialized functions that facilitate the overall operation of the cell, such as energy production, synthesis, and waste management.

19/20

Explain the term 'selectively permeable'.

19/20

Selectively permeable refers to a membrane's ability to allow certain molecules to pass while restricting others, thus maintaining homeostasis.

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What is the main function of the Golgi apparatus?

20/20

The Golgi apparatus modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

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