Cell Biology Basics
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Questions and Answers

What contributed to Antonie van Leeuwenhoek's discovery of motile free living cells in 1674?

  • Discovery of protoplasm
  • Adoption of the electron microscope
  • Development of more complex lens grinding techniques (correct)
  • Use of chemical stains to differentiate cell structures

    • Which of the following statements about the contribution of Hugo von Mohl is correct?

  • He studied animal cells and proposed that cells are the basic building units of all animals
  • He identified the protoplasm as the physical basis of life (correct)
  • He observed a multitude of tiny pores in cork and coined the term 'cell'
  • He added the third tenet to cell theory: all cells arise from pre-existing cells

    • What was Rudolf Virchow's main contribution to cell theory?

  • Adding the tenet that all cells arise from pre-existing cells (correct)
  • Proposing that cells are the basic building units of all plants
  • Coining the term 'cell'
  • Introducing the concept of the protoplasm

    • Who first coined the term 'protoplasm' and in what year?

    <p>J.E Purkinje in 1839</p> Signup and view all the answers

    Which part of the cell contains hereditary information passed during cell division?

    <p>Nucleoplasm</p> Signup and view all the answers

    Who proposed that cells are the basic building units of all plants?

    <p>M.J. Schleiden</p> Signup and view all the answers

    Which microscope uses a beam of electrons to illuminate the sample?

    <p>Electron Microscope</p> Signup and view all the answers

    What best describes the function of protoplasm in the cell?

    <p>Provides the site where all cell functions take place and allows the cell to respond to stimuli</p> Signup and view all the answers

    What is the smallest unit of structure and function in a living organism?

    <p>Cells</p> Signup and view all the answers

    Who constructed the first simple microscope?

    <p>Antonie van Leeuwenhoek</p> Signup and view all the answers

    Which term describes an organism composed of only one cell?

    <p>Unicellular</p> Signup and view all the answers

    What was the maximum magnifying power of the microscopes built by Antonie van Leeuwenhoek?

    <p>200 times</p> Signup and view all the answers

    What is not a characteristic shared by all known living organisms?

    <p>Visible to the naked eye</p> Signup and view all the answers

    Which of the following is true of multicellular organisms?

    <p>They are composed of trillions of cells.</p> Signup and view all the answers

    How did the invention of the microscope contribute to the discovery of cells?

    <p>It allowed cells to be magnified and resolved.</p> Signup and view all the answers

    What did scientists need in order to start studying cells?

    <p>Technology to magnify cells</p> Signup and view all the answers

    Which of the following descriptions best represents the function of the cytoskeleton?

    <p>It provides shape to the cell and facilitates movement.</p> Signup and view all the answers

    Which cell organelle is responsible for separating the interior of the cell from the external environment?

    <p>Cell membrane</p> Signup and view all the answers

    Which statement about deutoplasmic bodies is correct?

    <p>They are non-living cytoplasmic inclusions.</p> Signup and view all the answers

    What are the components that make up protoplasm?

    <p>Cytoplasm and nucleoplasm</p> Signup and view all the answers

    Which of the following substances can be classified as cytoplasmic inclusions?

    <p>Calcium oxalate crystals</p> Signup and view all the answers

    What essential role does the cytoplasm play in cell metabolism?

    <p>It acts as the site for many vital biochemical reactions.</p> Signup and view all the answers

    Which cell organelle is primarily involved in the storage of materials like starch and glycogen?

    <p>Cytoplasmic inclusions</p> Signup and view all the answers

    Which organelles are described as 'little organs' performing specific functions within the cell?

    <p>Organelles</p> Signup and view all the answers

    Which of the following organisms is considered the largest unicellular organism?

    <p>Amoeba proteus</p> Signup and view all the answers

    How do unicellular organisms obtain nutrition?

    <p>Phagocytosis</p> Signup and view all the answers

    What serves as the protective outer boundary of a cell?

    <p>Plasma membrane</p> Signup and view all the answers

    In plant cells, where is the plasma membrane located?

    <p>After the cell wall</p> Signup and view all the answers

    Which type of unicellular organism is known to possess pseudopodia for movement?

    <p>Amoeba</p> Signup and view all the answers

    Which of the following structures within a cell is responsible for housing genetic material?

    <p>Nucleus</p> Signup and view all the answers

    What is the primary way in which multicellular organisms typically develop from a single cell?

    <p>Cell Division and Differentiation</p> Signup and view all the answers

    Which cell type is specifically adapted to conduct impulses?

    <p>Neuron</p> Signup and view all the answers

    What structural characteristic do all cells share, regardless of type?

    <p>Similar basic structural plan</p> Signup and view all the answers

    Which of the following is a characteristic feature of cell membranes?

    <p>They regulate the movement of substances in and out of cells</p> Signup and view all the answers

    Who first added the concept that all cells arise from pre-existing cells to the cell theory?

    <p>Rudolf Virchow</p> Signup and view all the answers

    Which of the following accurately describes the smallest known cell?

    <p>Mycoplasma</p> Signup and view all the answers

    What distinguishes the cytoplasm from the nucleoplasm?

    <p>Cytoplasm is the protoplasm outside the nucleus; nucleoplasm is the protoplasm within the nucleus</p> Signup and view all the answers

    Who described protoplasm as the 'Physical basis of life'?

    <p>Huxley</p> Signup and view all the answers

    Which cell structure is primarily involved in the streaming movements known as cyclosis?

    <p>Protoplasm</p> Signup and view all the answers

    Which of the following cells are typically the largest in humans?

    <p>Egg cells</p> Signup and view all the answers

    Based on the modern cell theory, which statement is correct?

    <p>Cells contain hereditary information that is passed during cell division.</p> Signup and view all the answers

    Which scientist proposed the idea that all living cells are composed of protoplasm?

    <p>Schultze</p> Signup and view all the answers

    What is the function of protoplasm in a cell?

    <p>Site where all life functions take place</p> Signup and view all the answers

    Which cells in the human body are known to be up to a meter long?

    <p>Nerve cells</p> Signup and view all the answers

    Which group of organisms includes organisms with freely permeable cell walls?

    <p>Plants, fungi, and prokaryotic cells</p> Signup and view all the answers

    What is the primary composition of the plasma membrane that helps in maintaining the flexibility of the cell?

    <p>Proteins and lipids</p> Signup and view all the answers

    Which of the following is NOT a function of the plasma membrane?

    <p>Rigid protective outer layer in plant cells</p> Signup and view all the answers

    What distinguishes multicellular organisms from unicellular organisms?

    <p>Formation of tissues from grouped cells</p> Signup and view all the answers

    Which structure in a cell is responsible for containing genetic material?

    <p>Nucleus</p> Signup and view all the answers

    What is the defining characteristic of an organelle?

    <p>Specialized structure within the cell performing specific functions</p> Signup and view all the answers

    The cell wall allows for which type of permeability?

    <p>Freely permeability</p> Signup and view all the answers

    Which of these is an example of a unicellular organism?

    <p>Yeast</p> Signup and view all the answers

    What is the main structural difference between plant and animal cells?

    <p>Presence of cell wall in plant cells</p> Signup and view all the answers

    Which of the following descriptions correctly defines the cell membrane?

    <p>A thin, elastic, selectively permeable membrane surrounding the cytoplasm</p> Signup and view all the answers

    Which organelle is responsible for autophagy?

    <p>Lysosomes</p> Signup and view all the answers

    In which cells are centrioles absent?

    <p>Plant cells</p> Signup and view all the answers

    What is the main function of leucoplasts?

    <p>Storage of food materials</p> Signup and view all the answers

    Where is the centrosome usually located in an animal cell?

    <p>Near the nucleus</p> Signup and view all the answers

    Which plastid is referred to as the kitchen of the cell?

    <p>Chloroplast</p> Signup and view all the answers

    Which statement correctly describes the nucleus?

    <p>It transfers hereditary information to the next generation.</p> Signup and view all the answers

    What pigment is found in chloroplasts that is essential for photosynthesis?

    <p>Chlorophyll</p> Signup and view all the answers

    What is referred to as the 'control center' of the cell?

    <p>Nucleus</p> Signup and view all the answers

    In which type of cells is the nucleus commonly located at the periphery?

    <p>Plant cells</p> Signup and view all the answers

    What specialized structure within the nucleus produces ribosomes?

    <p>Nucleolus</p> Signup and view all the answers

    Which function is NOT associated with the endoplasmic reticulum?

    <p>Production of ribosomes</p> Signup and view all the answers

    Which organelle is described as the powerhouse of the cell?

    <p>Mitochondria</p> Signup and view all the answers

    What is the main component of ribosomes?

    <p>Proteins and RNA</p> Signup and view all the answers

    Which function is associated with the Golgi apparatus?

    <p>Formation of egg yolk</p> Signup and view all the answers

    Which cell organelle is described as the protein factory?

    <p>Ribosomes</p> Signup and view all the answers

    Which of the following is NOT found in both prokaryotes and eukaryotes?

    <p>Mitochondria</p> Signup and view all the answers

    Which of these is a function of lysosomes?

    <p>Removal of cell debris</p> Signup and view all the answers

    Which structure in the mitochondria contains ATP producing particles?

    <p>Cristae</p> Signup and view all the answers

    What is the main function of chromoplasts?

    <p>Photosynthesis</p> Signup and view all the answers

    Which structure contains enzymes that can digest all organic materials?

    <p>Lysosomes</p> Signup and view all the answers

    Which process is primarily associated with the rough endoplasmic reticulum (RER)?

    <p>Protein synthesis</p> Signup and view all the answers

    Which of the following is NOT a function of the cytoplasm?

    <p>Forming the outer boundary of the cell</p> Signup and view all the answers

    What differentiates the smooth endoplasmic reticulum (SER) from the rough endoplasmic reticulum (RER)?

    <p>SER synthesizes lipids and steroids</p> Signup and view all the answers

    Which of the following substances are considered cytoplasmic inclusions?

    <p>Crystals</p> Signup and view all the answers

    What is the main purpose of the cell wall?

    <p>To give the cell a definite shape and rigidity</p> Signup and view all the answers

    Cytoplasm contains several living and non-living structures. Which of the following are living structures?

    <p>Endoplasmic reticulum</p> Signup and view all the answers

    Which cell organelle is directly involved in the synthesis of lipids?

    <p>Smooth endoplasmic reticulum</p> Signup and view all the answers

    Which statement best describes the role of the cytoskeleton?

    <p>It provides shape to the cell and facilitates movement</p> Signup and view all the answers

    Which of the following structures is continuous with the outer nuclear membrane?

    <p>Endoplasmic reticulum</p> Signup and view all the answers

    Which cell organelle is primarily involved in cellular transport by forming transport vesicles?

    <p>Smooth endoplasmic reticulum</p> Signup and view all the answers

    What distinguishes eukaryotic cells from prokaryotic cells?

    <p>The presence of a membrane-bound nucleus in eukaryotic cells</p> Signup and view all the answers

    Which of the following is NOT a function of the nucleus in a cell?

    <p>Storing waste products</p> Signup and view all the answers

    During which phase are chromosomes organized into chromatin?

    <p>Interphase</p> Signup and view all the answers

    Which structure is prominent in plant cells but not typically found in prokaryotic cells?

    <p>Plastids</p> Signup and view all the answers

    Which type of cells contains large and prominent vacuoles?

    <p>Plant cells</p> Signup and view all the answers

    What organelles are absent in prokaryotic cells?

    <p>Nuclear membrane</p> Signup and view all the answers

    What type of storage is NOT typically considered a cytoplasmic inclusion?

    <p>Ribosomes</p> Signup and view all the answers

    What component surrounds the vacuole in plant cells?

    <p>Tonoplast</p> Signup and view all the answers

    What term describes the basic structural, functional, and biological unit of all known living organisms?

    <p>Cell</p> Signup and view all the answers

    Who manufactured the first simple microscope using a single biconcave lens?

    <p>Antonie van Leeuwenhoek</p> Signup and view all the answers

    Study Notes

    The Cell - The Basic Unit of Life

    • The cell is the smallest unit of structure and function of a living organism.
    • Cells are made up of building blocks called cells, which are the basic units of life.

    Discovery of Cells

    • The discovery of cells became possible only after the invention of the microscope.
    • Antonie van Leeuwenhoek constructed the first simple microscope in 1674.
    • Robert Hooke discovered the cell in 1665 and coined the term "cell".

    Cell Theory

    • The cell theory states that:
      • All living organisms are made up of one or more cells.
      • The cell is the smallest unit of structure and function of all living beings.
      • All cells arise from pre-existing cells.
      • Cells contain hereditary information which is passed from cell to cell during cell division.
      • The chemical composition and metabolic activities of all cells are fundamentally similar.

    Protoplasm

    • Protoplasm is the living substance of the cell.
    • It is a translucent, granular, slimy, semi-fluid or viscous fluid.
    • Protoplasm is divided into two parts: cytoplasm and nucleoplasm.
    • Functions of protoplasm:
      • Provides the site where all cell functions take place.
      • Allows cells to respond to various stimuli.

    Diversity in Cells

    • Cells show great variations in shape and size.
    • Size of cells can vary from 5 to 20 µm (1µm = 1/1000 mm = 10-6 m).
    • The smallest cells are bacteria or prokaryotic cells (0.2-0.5 µm).

    Unicellular and Multicellular Organisms

    • Unicellular organisms:
      • Are known as single-celled organisms.
      • Examples include Amoeba, Paramecium, Euglena, Yeast, and Bacteria.
      • The process of life is carried out in the cell.
    • Multicellular organisms:
      • Consist of more than one cell.
      • Examples include plants, animals, and some algae.
      • Arise from a single cell and grow into a multicellular organism.

    Structure of a Cell

    • A cell is made up of various components, which can be divided into three main functional regions:
      1. Cell membrane or Plasma membrane, and Cell wall
      2. Cytoplasm
      3. Nucleus, which contains the genetic material DNA (deoxyribonucleic acid)

    Cell Membrane

    • The cell membrane is the outer boundary of a cell.
    • It acts as a barrier between the inner and outer surface of a cell.
    • The cell membrane is selectively permeable, which helps in maintaining a constant internal environment inside the cell (Homeostasis).

    Cell Wall

    • The cell wall is a rigid, protective layer outside the cell membrane.
    • It is non-living and is mainly made up of cellulose.
    • Found in plants, fungi, and prokaryotic cells.

    Cytoplasm

    • The cytoplasm is a semi-fluid, gel-like substance enclosed within the cell membrane.
    • It lies between the nucleus and plasma membrane of the cell.
    • Functions of cytoplasm:
      • Provides a medium for the organelles to remain suspended.
      • Is a source of vital chemicals such as enzymes, vitamins, amino acids, glucose, ions, etc.

    Cell Organelles

    • An organelle is a unique part of a cell that has a specific function.
    • Examples of cell organelles:
      • Mitochondria
      • Endoplasmic reticulum (ER)
      • Golgi apparatus
      • Vacuoles
      • Lysosomes
      • Chloroplasts (in plant cells)

    Endoplasmic Reticulum (ER)

    • The endoplasmic reticulum (ER) is a type of organelle in the cells.
    • There are two types of ER:
      • Rough Endoplasmic Reticulum (RER)
      • Smooth Endoplasmic Reticulum (SER)
    • Functions of ER:
      • Cellular transport
      • Formation of the skeletal framework
      • Formation of nuclear membrane during cell division### Cell Organelles
    • Ribosomes: Dense granular organelles composed of RNA and proteins, responsible for protein synthesis, found in both prokaryotes and eukaryotes except mammalian RBCs.
    • Mitochondria: Membrane-bound organelles, found in most eukaryotic cells, responsible for generating energy in the form of ATP, characterized by a double membrane with inner membrane folds (cristae).
    • Golgi Apparatus: Membrane-bound organelle, responsible for protein modification, sorting, packaging, and dispatch, found in most eukaryotes, exists as a network near the nucleus in animal cells and as dictyosomes in plant cells.
    • Lysosomes: Membrane-bound vesicles containing digestive enzymes, responsible for breaking down cellular waste and foreign substances, found in most eukaryotic cells.
    • Centrioles and Centrosomes: Found only in animal cells, responsible for cell division, composed of two centrioles that play a major role in spindle fiber formation.
    • Plastids: Double-membranous organelles found in plants and algae, responsible for manufacturing and storing food and photosynthetic pigments, classified into leucoplasts and chromoplasts.

    Plastids

    • Leucoplasts: Colorless plastids, responsible for storing food materials.
    • Chromoplasts: Colored plastids, responsible for storing photosynthetic pigments, include chloroplasts which contain chlorophyll and are responsible for photosynthesis.

    Cell Structure and Function

    • Nucleus: Double membrane-bound organelle, responsible for storing genetic information, controlling cell growth and reproduction, found in eukaryotic cells.
    • Cytoplasmic Inclusions: Diverse intracellular structures, including vacuoles, lipid droplets, and crystals, responsible for storing food, water, and waste products.

    Cell Types

    • Prokaryotic Cells: Cells without a nucleus, found in single-celled organisms such as bacteria, characterized by a nucleoid and lack of membrane-bound organelles.
    • Eukaryotic Cells: Cells with a membrane-bound nucleus, found in unicellular and multicellular organisms, characterized by a larger size and presence of membrane-bound organelles.

    Key Points

    • Cell: The basic structural, functional, and biological unit of all known living organisms.
    • Cell wall: Present in plant cells, pushes cytoplasm towards the periphery, and forms a thin lining against the cell wall.

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    Description

    Learn about the cell, the basic unit of life, its discovery, and the cell theory. Understand the structure and function of cells and their significance in living organisms.

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