Anatomy of the Cell
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Questions and Answers

What is the primary function of kinesin in cellular transport?

  • Moves toward the cell periphery (correct)
  • Facilitates movement along the rough ER
  • Transports substances to the nucleus
  • Moves toward the cell center

    • What type of chromatin is associated with actively transcribing DNA?

  • Euchromatin (correct)
  • Inactive chromatin
  • Condensed chromatin
  • Heterochromatin

    • Which structure is responsible for the formation of ribosomes?

  • Endoplasmic reticulum
  • Nuclear envelope
  • Cytoplasm
  • Nucleolus (correct)

    • What characterizes the rough endoplasmic reticulum (RER)?

    <p>Studded with ribosomes</p> Signup and view all the answers

    What is the main role of the nuclear pores?

    <p>Allowing transport of molecules across the nuclear envelope</p> Signup and view all the answers

    What is the primary function of the smooth endoplasmic reticulum (SER)?

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

    Which of the following describes the outer nuclear membrane?

    <p>Studded with ribosomes</p> Signup and view all the answers

    How do the amounts of rough and smooth ER influence cell activity?

    <p>More rough ER indicates a more active cell</p> Signup and view all the answers

    What is the primary function of mitochondria within the cytoplasm?

    <p>Energy production</p> Signup and view all the answers

    Which structure is primarily involved in the synthesis of cholesterol and lipids?

    <p>Smooth Endoplasmic Reticulum (SER)</p> Signup and view all the answers

    Which component of the cytoskeleton is composed of 2 actin strands and is involved in cellular movement?

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

    Which of the following is true regarding inclusions in the cytoplasm?

    <p>They are dispensable and can be transient.</p> Signup and view all the answers

    What role does the Golgi Apparatus serve in the cytoplasm?

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

    Which cytoskeletal element originates from the centrosome and is involved in cilia and flagella formation?

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

    Which feature distinguishes intermediate filaments within the cytoskeleton?

    <p>They are more than 50 types and provide strength.</p> Signup and view all the answers

    What is the main purpose of lysosomes in the cytoplasm?

    <p>Intracellular digestion using hydrolytic enzymes</p> Signup and view all the answers

    What is the primary function of the plasmalemma in eukaryotic cells?

    <p>To form a barrier between the cytoplasm and the external environment</p> Signup and view all the answers

    Which structure in the cell is primarily responsible for maintaining cell shape and integrity?

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

    What is one key characteristic that distinguishes eukaryotic cells from prokaryotic cells?

    <p>Eukaryotic cells have membrane-bound organelles</p> Signup and view all the answers

    What kind of molecules can pass through the cell membrane most easily?

    <p>Small hydrophobic molecules</p> Signup and view all the answers

    Which of the following components is NOT a part of a eukaryotic cell?

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

    What role do integral proteins play in the plasmalemma?

    <p>Transporting substances across the membrane</p> Signup and view all the answers

    How do intercellular junctions contribute to tissue integrity?

    <p>By forming tight seals that prevent leakage</p> Signup and view all the answers

    The main composition of the cytosol includes all of the following EXCEPT:

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

    What feature of membrane proteins allows for selective engagement with various substances?

    <p>Their lateral mobility within the membrane</p> Signup and view all the answers

    Which of the following statements is true about inclusions in eukaryotic cells?

    <p>They are always membrane-bound</p> Signup and view all the answers

    What is the primary function of the Golgi apparatus?

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

    Which of the following best describes the structure of mitochondria?

    <p>Oblong organelles with extensively folded inner membranes</p> Signup and view all the answers

    What type of intracellular junction is responsible for preventing diffusion between cells?

    <p>Occluding junctions</p> Signup and view all the answers

    Which junction type provides mechanical strength and prevents separation between cells?

    <p>Anchoring junctions</p> Signup and view all the answers

    Which type of junction allows for the rapid movement of molecules between adjacent cells?

    <p>Gap junctions</p> Signup and view all the answers

    What is the main role of vesicles in cellular transport?

    <p>To encapsulate and transport materials in and out of the cell</p> Signup and view all the answers

    Which structure in mitochondria is primarily involved in ATP production?

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

    What is the function of connexons in gap junctions?

    <p>To facilitate selective diffusion through pores</p> Signup and view all the answers

    Which process uses energy to transport materials into a cell?

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

    What is the significance of desmosomes in epithelial tissue?

    <p>Provide tensile strength to resist mechanical stress</p> Signup and view all the answers

    Study Notes

    Anatomy of the Cell

    • The cell is the basic structural unit of all living organisms.
    • Eukaryotes have a defined nucleus and contain an outer cell membrane, inner cytosol, cytoskeleton, membrane-bound organelles and inclusions.

    The Cell Membrane (Plasmalemma)

    • Separates the intracellular environment from the extracellular environment.
    • Selectively permeable barrier, allowing some molecules to pass through while preventing others.
    • Composed of a phospholipid bilayer with hydrophilic heads on the outer and inner surfaces and hydrophobic tails at the center.
    • Integral membrane proteins are embedded in the bilayer and function as receptors, channels, transporters, enzymes, and cell attachment proteins.
    • The membrane can exocytose (transport out of the cell) and endocytose (transport into the cell) material.
    • Fluid and can change shape easily. Membrane proteins can diffuse laterally in the membrane, but many are anchored and not evenly distributed.
    • Highly permeable to small hydrophobic molecules, water, and oxygen.
    • Virtually impermeable to charged ions.

    The Cytoplasm

    • Contains organelles and inclusions.
    • Organelles are specialized structures with specific functions.
    • Inclusions are components synthesized by the cell or taken up from the extracellular environment.

    Organelles

    • Mitochondria are responsible for energy production (ATP).
    • Rough endoplasmic reticulum (RER) is involved in protein synthesis and the initiation of glycoprotein formation.
    • Smooth endoplasmic reticulum (SER) synthesizes lipids and cholesterol and plays a role in detoxification.
    • Golgi apparatus modifies and packages macromolecules synthesized in the ER.
    • Lysosomes contain hydrolytic enzymes for intracellular digestion.
    • Nucleus contains the genetic code.

    Cytoskeleton

    • A network of proteins that determines cell shape and fluidity.
    • Helps move organelles and the cell itself.
    • Microfilaments are composed of two actin strands and are involved in cellular movement, cell division, and muscle contraction.
    • Intermediate filaments are composed of various proteins and bind intracellular elements together.
    • Microtubules are composed of alpha and beta tubulin and originate from the centrosome. They are important for cilia, flagella, and the mitotic spindle.

    Nucleus

    • Enclosed by a double nuclear membrane.
    • Contains chromosomes (DNA), which can be in a dispersed form called euchromatin (actively transcribed) or a condensed form called heterochromatin (not actively transcribed).
    • Nuclear pores allow transport of molecules between the nucleus and cytoplasm.
    • Site of RNA synthesis, including mRNA, tRNA, and rRNA (produced in the nucleolus).

    Ribosomes

    • Formed in the nucleolus.
    • Important for protein synthesis.
    • The small subunit binds RNA, and the large subunit catalyzes peptide bond formation.
    • Ribosomes are exported from the nucleus through the nuclear pore complex.

    Endoplasmic Reticulum

    • A network of interconnected membrane-bound compartments within the cell.
    • RER is studded with ribosomes and is involved in protein synthesis and the initiation of glycoprotein formation.
    • SER is involved in lipid synthesis and the processing of proteins from the RER.

    Golgi Apparatus

    • Composed of flattened, membrane-bound cisternae.
    • Modifies and packages macromolecules synthesized in the ER, including adding sugars, cleaving proteins, and sorting macromolecules into vesicles.

    Mitochondria

    • Oblong, cylindrical organelles with an outer and inner membrane.
    • The inner membrane is folded into cristae, which increase surface area.
    • The power generators of the cell, producing ATP through oxidative phosphorylation.
    • Also involved in lipid and protein synthesis.
    • Contain their own DNA and protein production system.

    Intercellular Junctions

    • Link cells together to form functional units, particularly in epithelial cells.
    • Occluding (tight) junctions form a diffusion barrier and prevent water flow between cells (e.g., in bladder and kidney).
    • Anchoring junctions provide mechanical strength, such as adherens junctions (anchor cells) and desmosomes (link intermediate filaments).
    • Communicating (gap) junctions allow movement of molecules between cells through pores formed by connexon proteins.

    Cellular Transport

    • Diffusion, transport proteins (pumps or channels), and vesicular transport (requires ATP) are the primary methods of material movement across the cell membrane.
    • Endocytosis transports material from the extracellular space into the cell.

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    Anatomy of the Cell PDF

    Description

    Explore the fundamental structure and function of eukaryotic cells in this quiz. Learn about the cell membrane, including its selective permeability and membrane proteins. Test your knowledge on the various components of the cell and their roles in maintaining cellular integrity.

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