Cells and Their Functions
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Questions and Answers

Who is credited with coining the term 'cell'?

  • Anton van Leeuwenhoek
  • Louis Pasteur
  • Rudolf Virchow
  • Robert Hooke (correct)
  • What type of cell division do prokaryotic cells primarily undergo?

  • Binary fission (correct)
  • Meiosis
  • Mitosis
  • Budding
  • What distinguishes eukaryotic cells from prokaryotic cells?

  • Eukaryotic cells have DNA in a nucleoid.
  • Eukaryotic cells possess a true nucleus. (correct)
  • Eukaryotic cells undergo binary fission.
  • Eukaryotic cells are unicellular.
  • Which cellular process involves breaking down complex molecules to produce energy?

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

    What is the primary function of the cell membrane?

    <p>Substance entrance regulation</p> Signup and view all the answers

    Which organelle is primarily responsible for protein synthesis?

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

    What does the nucleus of a cell contain?

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

    What is the function of the rough endoplasmic reticulum?

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

    What is the primary function of ribosomes in a cell?

    <p>To produce proteins</p> Signup and view all the answers

    What structure is responsible for modifying and packaging proteins in the cell?

    <p>Golgi Apparatus</p> Signup and view all the answers

    What is the main role of the smooth endoplasmic reticulum?

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

    Which organelle is known as the powerhouse of the cell?

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

    What is the role of centrioles in animal cells?

    <p>Coordinate cell division</p> Signup and view all the answers

    Which component of the cell's internal environment holds all organelles in place?

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

    How does the nuclear envelope benefit the DNA inside the nucleus?

    <p>By allowing selective substance exchange</p> Signup and view all the answers

    What is the main function of lysosomes in a cell?

    <p>Break down waste materials</p> Signup and view all the answers

    What is the first step to prepare a microscope for observing a specimen?

    <p>Turn the revolving nosepiece to the lowest objective lens</p> Signup and view all the answers

    Which adjustment wheel is used to obtain a clearer image after focusing the specimen initially?

    <p>Fine adjustment wheel</p> Signup and view all the answers

    What action should one take when wishing to explore the specimen on the microscope?

    <p>Hold still or move the slide slowly</p> Signup and view all the answers

    In which order should the objective lenses be used while observing a specimen?

    <p>Low, medium, high</p> Signup and view all the answers

    Why is it necessary to use both the coarse and fine adjustment wheels?

    <p>To bring the specimen into focus properly</p> Signup and view all the answers

    What is the function of a microscope?

    <p>To magnify the structure of the specimen</p> Signup and view all the answers

    Which statement about cells is correct?

    <p>A cell is the smallest unit of a living thing</p> Signup and view all the answers

    What should be done after observing a specimen sufficiently?

    <p>Switch to the medium and high-power objective lens</p> Signup and view all the answers

    Study Notes

    What are Cells?

    • Cells are the smallest building blocks of living beings and the fundamental structure of organisms.
    • Organisms can be unicellular (made of one cell) or multicellular (made of many cells).
    • Humans have approximately 37.2 trillion cells.

    Discovery of the Cell

    • Robert Hooke coined the term "cell" in 1665 after observing cells under a microscope.
    • He is credited with the invention of the compound microscope and identified the cell as the basic unit of life.

    Types of Cells

    • Eukaryotic Cells: Have a true nucleus and contain DNA, with cell division occurring by mitosis or meiosis.
    • Prokaryotic Cells: Lack a true nucleus and have a nucleoid instead of DNA, with cell division occurring by binary fission.

    Cell Growth and Metabolism

    • Cell growth is achieved through metabolism, which is divided into:
      • Catabolism: Breaks down complex molecules to produce energy.
      • Anabolism: Utilizes energy to construct necessary molecules and perform biological functions.

    Functions of Cells

    • Key functions include cell division, transport, and metabolism.
    • Cells transport substances through the cell membrane.

    Cell Organelles

    • Organelles are mini-organ systems within a cell, including:
      • Cell membrane
      • Nucleus
      • Ribosomes
      • Rough and smooth endoplasmic reticulum
      • Golgi apparatus
      • Centrioles
      • Mitochondria
      • Vacuoles
      • Cytoplasm

    Cell Membrane

    • Comprised of a phospholipid bilayer, it is semi-permeable and controls substance entry.
    • The phospholipid head is hydrophilic, while the tail is hydrophobic.

    Nucleus

    • Encloses DNA within a double membrane called the nuclear envelope, featuring pores for substance exchange.
    • Chromatin condenses to form chromosomes during cell division, and ribosomes are produced in the nucleolus.

    Ribosomes

    • Responsible for protein synthesis as directed by DNA.
    • Can be found free in the cytoplasm or attached to the rough endoplasmic reticulum.

    Endoplasmic Reticulum

    • Rough Endoplasmic Reticulum: Studded with ribosomes that synthesize proteins for internal use or export.
    • Smooth Endoplasmic Reticulum: Lacks ribosomes and synthesizes lipids, detoxifies drugs, and carries proteins.

    Golgi Apparatus

    • Modifies, sorts, and packages proteins and materials from the endoplasmic reticulum for storage or secretion.

    Lysozymes

    • Membrane-bound sacs containing enzymes that break down food substances and waste materials.

    Centrioles and Vacuoles

    • Centrioles: Aid in coordinating cell division in animal cells.
    • Vacuoles: Store water, food, enzymes, and waste materials.

    Cytoplasm

    • A jelly-like substance that holds organelles in place.

    Mitochondria

    • Known as the powerhouse of the cell, they convert chemical energy from food into usable energy.
    • Composed of an outer membrane and an inner membrane with folds known as cristae.
    • Responsible for cellular respiration and contain their own DNA inherited from the mother.

    Using a Microscope

    • Steps include turning on the microscope, adjusting the light, placing the specimen, and focusing using coarse and fine adjustment wheels.
    • Observers can switch to medium and high-power lenses for detailed examination.

    Summary of Microscopes

    • Microscopes magnify specimen structures, enabling detailed visualization which requires specimens to be focused using adjustment wheels.

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    Description

    This quiz delves into the fundamental aspects of cells, exploring their discovery, structure, and various types. Understand the unique functions and biochemical organization that define plant, animal, and bacterial cells. Test your knowledge on the smallest building blocks of life!

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