Cell Biology Chapter: Organelles and Functions
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Questions and Answers

What is the primary function of the cell membrane?

  • To store genetic information
  • To allow selective passage of substances (correct)
  • To produce energy through respiration
  • To conduct nerve impulses
  • Which of the following correctly describes the structure of the cell membrane?

  • A rigid structure with no flexibility
  • A single layer of phospholipids with no proteins
  • A completely permeable structure allowing all substances to pass
  • A trilamellar membrane with two dark layers and a light layer (correct)
  • What type of proteins form pathways for water-soluble substances across the cell membrane?

  • Lipid proteins
  • Microtubule proteins
  • Peripheral proteins
  • Integral proteins (correct)
  • Which component of the cell membrane is responsible for its fluidity and flexibility?

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

    Which organelle is primarily involved in energy production within the cell?

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

    What is the role of ribosomes within the cell?

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

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

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

    Which structure is non-living and considered temporary within the cell?

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

    What is one of the main functions of the rough endoplasmic reticulum?

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

    Which of the following correctly describes the appearance of the smooth endoplasmic reticulum under electron microscopy?

    <p>Membrane-bound tubules with smooth membrane</p> Signup and view all the answers

    What is the role of the Golgi apparatus in relation to proteins?

    <p>Concentration and modification of proteins</p> Signup and view all the answers

    Which face of the Golgi apparatus is known as the convex face?

    <p>Forming face</p> Signup and view all the answers

    Which of the following is NOT a function of the smooth endoplasmic reticulum?

    <p>Modification of proteins</p> Signup and view all the answers

    What type of enzymes are lysosomes rich in?

    <p>Hydrolytic enzymes</p> Signup and view all the answers

    Where is the Golgi apparatus typically located in relation to the nucleus?

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

    Which of the following functions is primarily associated with lysosomes?

    <p>Digestion of cellular waste</p> Signup and view all the answers

    What structure is primarily responsible for the recognition functions of the cell surface?

    <p>Glycolipid and glycoprotein</p> Signup and view all the answers

    Which process requires energy and involves moving substances against their concentration gradient?

    <p>Active transport</p> Signup and view all the answers

    Which type of endocytosis involves the engulfing of large particles?

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

    What is the primary function of mitochondria in a cell?

    <p>Cellular respiration and energy production</p> Signup and view all the answers

    What distinguishes rough endoplasmic reticulum from smooth endoplasmic reticulum?

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

    What component of the mitochondria increases the surface area for enzyme deposition?

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

    How do substances leave the cell during exocytosis?

    <p>Through vesicular transport</p> Signup and view all the answers

    What role do matrix granules in mitochondria play?

    <p>Binding calcium and magnesium</p> Signup and view all the answers

    What are primary lysosomes formed from?

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

    Which type of lysosome is formed by the fusion of a primary lysosome with bacteria or viruses?

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

    Which statement about the nucleus is true?

    <p>It can have multiple nuclei in certain cell types</p> Signup and view all the answers

    What is the structure surrounding the nucleus called?

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

    What is the function of lysosomes regarding old organelles?

    <p>To remove them</p> Signup and view all the answers

    In which shape can the nucleus NOT appear?

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

    Which type of lysosome fuses with pinocytic vesicles?

    <p>Multivesicular lysosome</p> Signup and view all the answers

    How can the appearance of the nucleus be described in nerve cells?

    <p>Lightly stained and vesicular</p> Signup and view all the answers

    Study Notes

    The Cell

    • Fundamental unit of all living tissues.
    • Smallest living structure capable of independent growth, secretion, excretion, digestion, contraction, respiration and reproduction.
    • Variable in shape, size and function in different tissues.
    • Composed of cytoplasm and a nucleus.

    Cytoplasm

    • Contains various organelles essential for the cell's vital process.
    • Organized into membranous and non-membranous structures.

    Membranous Organelles

    • Cell membrane: Thin boundary of the cell.
    • Mitochondria: Responsible for cellular respiration and ATP production.
    • Endoplasmic reticulum: Extensive network responsible for protein synthesis (rough ER) and lipid synthesis (smooth ER).
    • Golgi apparatus: Involved in protein/lipid modification, packaging and secretion.
    • Lysosomes: Digest cellular waste and foreign materials like bacteria and viruses.
    • Peroxisomes: Breakdown fatty acids and detoxify harmful substances.

    Non-Membranous Organelles

    • Ribosomes: Protein synthesis machines found free in the cytoplasm or attached to the rough endoplasmic reticulum.
    • Cytoskeleton: Network of protein filaments that provide structural support and facilitate cell movement.
    • Microtubules
    • Filaments (thin, intermediate, thick)

    Cell Membrane

    • Outermost layer of the cell, composed of a phospholipid bilayer, proteins and carbohydrates.
    • Lipid component allows passage of fat-soluble substances.
    • Proteins act as channels for water-soluble substances and receptors for signals.
    • Carbohydrates (glycolipids and glycoproteins) form the cell coat (glycocalyx) which plays important roles in recognition and cell immunity.
    • Permeable to some substances, but acts as a barrier for others.

    Mitochondrial Structure

    • Round or oval-shaped organelles with a double membrane:
      • Outer membrane: smooth layer
      • Inner membrane: Folded into cristae that increase surface area for oxidative phosphorylation.
      • Matrix: Contains enzymes, DNA, RNA, lipids, proteins, and carbohydrates.

    Mitochondrial Function

    • Production of cellular energy (ATP).
    • Responsible for cell respiration.
    • Replicate themselves independently.

    Endoplasmic Reticulum

    • Extensive, interconnected network of membranes responsible for protein and lipid synthesis.

    Rough Endoplasmic Reticulum

    • Ribosomes attach to its surface and are responsible for protein synthesis.
    • Packages proteins and transports them to the golgi apparatus.

    Smooth Endoplasmic Reticulum

    • Lacks ribosomes and is involved in lipid and steroid hormone synthesis, glycogen storage, detoxification and calcium ion regulation.

    Golgi Apparatus

    • Stack of flattened, sac-like structures ("cisternae").
    • Receives proteins and lipids from the ER.
    • Modifies these substances by adding carbohydrates.
    • Packages and packages proteins into secretory vesicles.
    • Forms lysosomes.
    • Maintains cell membrane stability.

    Lysosomes

    • Small, spherical organelles containing hydrolytic enzymes.
    • Responsible for intracellular digestion.
    • Originate from the Golgi apparatus.

    Lysosome Types

    • Primary lysosomes: Newly formed and homogenous.
    • Secondary lysosomes Contain ingested material and enzymes: - Heterolysosomes (phagosomes) - Contain bacteria or viruses. - Multivesicular lysosomes - Contain pinocytic vesicles. - Autolysosomes - Contain old organelles.
      - Residual bodies - Contain undigested remnants.

    Lysosomal Function

    • Digestion of nutrients and cellular waste.
    • Defense against bacteria and viruses.
    • Removal of damaged organelles.
    • Removal of dead cells (autolysis).
    • Activation of inactive hormones (thyroid hormone).
    • Penetration of sperm into the ovum.

    The Nucleus

    • Largest and most prominent organelle in most cells.
    • Control center of the cell, containing DNA and RNA.
    • Absent in red blood cells and platelets.

    Nuclear Structure

    • Nuclear envelope: Double membrane with nuclear pores that allow passage of molecules between the nucleus and cytoplasm.
    • Chromatin: DNA and associated proteins condensed into chromosomes during cell division.
    • Nucleolus: Region of the nucleus involved in ribosome synthesis.
    • Nuclear sap: Gel-like substance filling the nucleus.

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    Description

    Explore the fundamental concepts of cell biology, focusing on the structure and function of various organelles. This quiz will test your understanding of both membranous and non-membranous organelles and their roles in cellular processes. Perfect for students learning about the building blocks of life.

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