Biology Chapter on Cells and Cell Theory
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Questions and Answers

What type of cells do prokaryotes lack?

  • True nucleus (correct)
  • Cytoplasm
  • Cell wall
  • Ribosomes

    • Which ribosome type is found in eukaryotic cells?

  • 70S
  • 80S (correct)
  • 90S
  • 50S

    • Which statement describes a feature of prokaryotic cells?

  • They have membrane-bound organelles.
  • They are typically multicellular.
  • They have haploid chromosomes. (correct)
  • They are generally larger in size.

    • Viruses can reproduce by:

    <p>Infecting and taking over living cells</p> Signup and view all the answers

    Which of the following statements about eukaryotic cells is correct?

    <p>They possess a true nucleus.</p> Signup and view all the answers

    What is the fundamental unit of all living things?

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

    Which of the following is NOT one of the components of the cell theory?

    <p>Cells contain the same DNA.</p> Signup and view all the answers

    What is the average number of cells in the human body?

    <p>30 trillion</p> Signup and view all the answers

    Who proposed the third part of the cell theory?

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

    What term refers to the study of the structure and components of cells?

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

    Which of the following features is characteristic of a bacterial cell?

    <p>Cell wall made of peptidoglycan</p> Signup and view all the answers

    What are considered organelles in a biological cell?

    <p>All structures within the cell</p> Signup and view all the answers

    Which scientist first examined cells and described them as ‘pore-like’ structures?

    <p>Robert Hooke</p> Signup and view all the answers

    What is a primary function of the cell wall in plant cells?

    <p>Providing mechanical support</p> Signup and view all the answers

    Which organelle is primarily responsible for energy production in plant cells?

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

    Which structure is unique to plant cells compared to animal cells?

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

    What is the primary function of chloroplasts in plant cells?

    <p>Absorption of light for photosynthesis</p> Signup and view all the answers

    What is the primary component of the plant cell wall?

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

    What are plasmodesmata primarily used for in plant cells?

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

    Which plastid is responsible for storing fats and oils in plant cells?

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

    What is contained within the stroma of chloroplasts?

    <p>Proteins and carbohydrates synthesis enzymes</p> Signup and view all the answers

    What role do vacuoles play in plant cells?

    <p>Regulating osmotic pressure</p> Signup and view all the answers

    Which type of cell does not possess a cell wall?

    <p>Animal cell</p> Signup and view all the answers

    What role do nuclear pores play in a cell?

    <p>Exchange materials between the nucleus and cytoplasm</p> Signup and view all the answers

    What is a characteristic feature of plastids in plant cells?

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

    What characterizes rough endoplasmic reticulum (ER)?

    <p>It is covered with ribosomes</p> Signup and view all the answers

    What is the genetic material contained in chromosomes?

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

    How do vesicles form from the endoplasmic reticulum?

    <p>By breaking off from the rough ER</p> Signup and view all the answers

    What is the nucleus primarily responsible for in a cell?

    <p>Control of cellular activities and inheritance</p> Signup and view all the answers

    What is the primary function of the cell membrane?

    <p>Protects contents and controls substance movement</p> Signup and view all the answers

    What are microtubules primarily made of?

    <p>Protein called tubulin</p> Signup and view all the answers

    Which organelle is involved in detoxifying poisons in the cell?

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

    What is the function of microvilli in animal cells?

    <p>Increase surface area for absorption</p> Signup and view all the answers

    What structure is formed by the assembly of microtubules?

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

    How do centrioles contribute to cell division?

    <p>Form spindle fibers</p> Signup and view all the answers

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

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

    Which organelle is structured with two centrioles?

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

    What role does the smooth endoplasmic reticulum (ER) play in a cell?

    <p>Storage and metabolism of lipids</p> Signup and view all the answers

    Which of the following best describes the Golgi apparatus?

    <p>A stack of flattened sacs that modifies and transports proteins</p> Signup and view all the answers

    What important function do lysosomes perform in the cell?

    <p>Break down unwanted materials using enzymes</p> Signup and view all the answers

    What is the primary function of mitochondria in a cell?

    <p>Production of ATP and energy metabolism</p> Signup and view all the answers

    How do lysosomes form phagolysosomes in white blood cells?

    <p>By fusing with vacuoles containing pathogens</p> Signup and view all the answers

    Which statement about the Golgi body is NOT correct?

    <p>It consists of a single structure with a uniform shape</p> Signup and view all the answers

    What determines the number of mitochondria present in a cell?

    <p>The energy demand of the cell</p> Signup and view all the answers

    Which enzyme type is found within lysosomes to aid in digestion?

    <p>Lipases, proteases, and glycosidases</p> Signup and view all the answers

    Study Notes

    Course Information

    • Course name: General Biology 1
    • Course code: BIO 101
    • Credit units: 2
    • Instructor: Olukemi Aromolaran (Ph.D.)
    • Office: COAES Building, Room 36
    • Office hours: 8 am – 5 pm
    • Taylor, D.J., Green, N.P.O, and Stout, G.W. (2010). Biological Sciences. Cambridge University Press, 10th Edition, South Africa.
    • Jones, M., Fosbery, R., Gregory, J., and Taylor, D. (2014). Cambridge International AS and A Level Biology. Cambridge University Press, 4th Edition, United Kingdom

    Course Outline

    • Cell structure and organization
      • What is a cell?
      • The cell theory
      • Plant cell, animal cell, and bacterial cell features
      • Similarities and differences between animal and plant cells
      • Cell structure
      • Organelles in the cell
      • Functions of the organelles
    • Characteristics of living things
    • Classification of living things

    Learning Objectives

    • Describe a biological cell
    • Explain the cell theory
    • Identify features of animal, plant, and bacterial cells
    • Describe structures within the cell and their functions

    Introduction

    • Robert Hooke (1665) observed cells in plant material.
    • Cells appear as empty boxes surrounded by walls.
    • The cell is the fundamental unit of life.

    Cell Theory

    • Matthias Schleiden and Theodor Schwann (1838)
      • All organisms are made up of cells.
      • The cell is the basic unit of structure and function of organisms.
    • Rudolf Virchow (1855)
      • All cells arise from pre-existing cells by cell division.

    What is a Cell?

    • A membrane-bound bag containing the chemistry of life.
    • The basic unit of living organisms.
    • Contains organelles for its functions.
    • The human body has approximately 30 trillion cells.

    Types of Cells: Prokaryotes and Eukaryotes

    • Edouard Chatton (1937) distinguished two cell types:
      • Prokaryotes:
        • Lack a true nucleus.
        • Lack membrane-bound organelles.
        • Smaller in size.
        • Haploid chromosomes.
        • 70S ribosomes.
        • Often surrounded by a cell wall (e.g., bacteria, archaea)
      • Eukaryotes:
        • Possess a true nucleus.
        • Membrane-bound organelles.
        • Larger in size.
        • Diploid chromosomes.
        • 80S ribosomes.
        • Some have cell walls (e.g., plants, fungi).

    Virus

    • No cell structure, no membrane-bound cytoplasm, no ribosomes.
    • Contains genetic material (DNA or RNA) and a protein coat (capsid).
    • Range in size from 20-300 nm.
    • Parasitic; reproduce only by infecting living cells.

    Plant Cell – Cellular Structure and Components

    • Diagrams of cellular structures and components of a plant cell are in the uploaded information.

    Common Features in Animal and Plant Cells

    • Many small structures (organelles):
    • Cell membrane
    • Cytoplasm
    • Nucleus
    • Mitochondria
    • Golgi bodies
    • Vacuole
    • Endoplasmic reticulum
    • Ribosomes
    • Cytoskeletons

    Differences Between Animal and Plant Cells

    • Animal cells do not have cell walls, large permanent vacuoles, or plastids.
    • Plant cells have cell walls; large, permanent vacuoles; plastids (chloroplasts, chromoplasts).

    Structures and Functions of Organelles

    • The functions of a cell's organelles are discussed in detail throughout the text.

    Cell Wall and Plasmodesmata

    • Provides shape and prevents bursting during osmosis.
    • Links plant cells via plasmodesmata.
    • Composition varies among organisms (e.g., bacterial cell walls - peptidoglycan).

    Functions of Cell Wall

    • Support
    • Defense
    • Cell gateway
    • Cell division
    • Communication
    • Storage

    Vacuoles

    • Plant cells have large central vacuoles surrounded by a tonoplast.
    • Contains fluids (pigments, enzymes, organic compounds, waste products).
    • Regulates osmotic pressure.

    Plastids

    • Found in plants and Euglenoids.
    • Double-membrane bound organelle with its own DNA and ribosomes.
    • Provide plants with pigments:
      • Chloroplasts
      • Chromoplasts
      • Leucoplasts

    Chloroplasts

    • Found in green parts of plants.
    • Contains chlorophyll.
    • The space within the chloroplast (stroma) contains enzymes for synthesising proteins and carbohydrates.

    Nucleus

    • The largest cell organelle surrounded by a nuclear envelope.
    • The nuclear envelope is continuous with the endoplasmic reticulum.
    • Contains chromosomes (DNA) organized into genes, controlling cell activities.
    • The nucleolus produces ribosomes.

    Endoplasmic Reticulum and Ribosomes

    • Extensive network of membranes in the cytoplasm.
    • Smooth ER or Rough ER.
    • Rough ER produces proteins; ribosomes are the sites of protein synthesis.

    Ribosomes

    • Made of RNA and protein.
    • Found freely in the cytoplasm and on the rough ER.

    Golgi Body (Apparatus/Complex)

    • Stack of flattened sacs near the nucleus; receives proteins from ER.
    • Modifies/packages proteins, forms vesicles.
    • Transports proteins.
    • Some enzymatic functions.

    Lysosomes

    • Spherical sacs surrounded by a membrane with hydrolytic enzymes to breakdown materials.

    Mitochondria

    • Oval-shaped organelles, surrounded by two membranes.
    • The powerhouses of the cell; produce ATP – the energy currency.

    ATP

    • ATP is generated in mitochondria via the Krebs cycle

    Cell Membrane

    • Thin semi-permeable layer surrounding the cytoplasm.
    • Mechanical barrier
    • Selectively permeable
    • Transports materials
    • Signals, receptors
    • Certain metabolic processes occur here (respiration, absorption, secretion)

    Fluid Mosaic Structure

    • Diagram of cell membrane showing proteins, lipids, and carbohydrates.

    Microtubules and Microtubule-Organizing Centers (MTOCs)

    • Hollow tubes made of tubulin.
    • Part of the cytoskeleton; shape and support.
    • Found in centrioles.

    Peroxisomes

    • Oxidise fatty acids and amino acids.
    • Detoxify poisons.

    Microvilli

    • Finger-like extensions of the cell membrane that increase surface area

    Centrosome

    • Organelle with two centrioles located perpendicularly.
    • Involved in cell division.

    Organization of Life (hierarchy)

    • Organelles
    • Cells
    • Tissues
    • Organs
    • Systems
    • Organisms
    • Populations
    • Communities
    • Ecosystems
    • Biosphere

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    Description

    This quiz covers fundamental concepts related to cells, including the differences between prokaryotic and eukaryotic cells, the components of the cell theory, and the history of cell discovery. Test your knowledge on the basic units of life and important cell characteristics. Perfect for biology students looking to reinforce their understanding of cellular biology.

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