Cell Physiology - Part 2
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Questions and Answers

What is the primary effect of osmosis in a hypotonic solution on a cell?

  • The cell will swell and may burst. (correct)
  • The cell will become more rigid.
  • The cell will remain unchanged.
  • The cell will shrink and lose function.

    • Which transport method uses energy to move substances against their concentration gradient?

  • Simple diffusion
  • Active transport (correct)
  • Facilitated diffusion
  • Osmosis

    • What occurs to a cell placed in a hypertonic solution?

  • The cell shrinks and crenates. (correct)
  • Water enters the cell rapidly.
  • The cell maintains its normal shape.
  • The cell swells and becomes larger.

    • Which statement is true regarding simple diffusion?

    <p>It occurs passively and moves substances downhill.</p> Signup and view all the answers

    What term describes the process when the cell membrane engulfs material from outside the cell?

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

    What is the primary function of the plasma membrane?

    <p>Serve as the cell's outer boundary</p> Signup and view all the answers

    Which part of the cell contains the DNA?

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

    What is cytosol primarily composed of?

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

    Which model describes the arrangement of molecules in the plasma membrane?

    <p>Fluid mosaic model</p> Signup and view all the answers

    What role do integral proteins play in the plasma membrane?

    <p>Act as gatekeepers for substances</p> Signup and view all the answers

    What are chromosomes made up of?

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

    What substance acts as a barrier to certain substances within the plasma membrane?

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

    Which type of protein is most likely to span the entire lipid bilayer?

    <p>Transmembrane proteins</p> Signup and view all the answers

    What is the outcome of meiosis 1?

    <p>Two haploid cells are produced.</p> Signup and view all the answers

    During which phase are two identical nuclei formed?

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

    What is the primary purpose of cytokinesis?

    <p>Division of the cell's cytoplasm</p> Signup and view all the answers

    How many chromosomes do gametes contain?

    <p>23 single chromosomes</p> Signup and view all the answers

    What restores the diploid number of chromosomes after fertilization?

    <p>Fusion of two gametes</p> Signup and view all the answers

    What distinguishes active diffusion from passive diffusion?

    <p>Active diffusion uses ATP.</p> Signup and view all the answers

    What is the end result of meiosis 2?

    <p>Four genetically different haploid gametes</p> Signup and view all the answers

    Which of the following statements about haploid cells is correct?

    <p>They are reproductive cells.</p> Signup and view all the answers

    Which of the following correctly describes isotonic solutions?

    <p>They are preferred for cell survival.</p> Signup and view all the answers

    Which process occurs in the gonads to produce gametes?

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

    What is the main process through which water moves across a selectively permeable membrane?

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

    What type of endocytosis involves the engulfing of large particles or cells?

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

    What is the role of aquaporins in cellular transport?

    <p>To facilitate water movement</p> Signup and view all the answers

    Which of the following correctly describes the sodium-potassium pump?

    <p>It is an active transport mechanism.</p> Signup and view all the answers

    What is the primary function of ribosomes in the cell?

    <p>To facilitate protein synthesis</p> Signup and view all the answers

    Which cytoskeletal component is involved in providing structural support and intracellular transport?

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

    Which process involves the fusing of vesicles with the plasma membrane to release their contents?

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

    What type of facilitated diffusion specifically involves the movement of potassium ions?

    <p>Gated K+ channel</p> Signup and view all the answers

    What is transcytosis?

    <p>Movement into and out of the cell via vesicles</p> Signup and view all the answers

    Which cellular component is primarily responsible for moving fluids along the cell surface?

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

    What is the main function of ribosomes in the cytosol?

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

    Which organelle is primarily involved in the modification and packaging of proteins?

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

    What is the primary role of lysosomes?

    <p>Digesting harmful substances</p> Signup and view all the answers

    Which structure is mainly responsible for detoxifying harmful substances, including alcohol?

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

    In which phase of the cell cycle does DNA replication occur?

    <p>S phase</p> Signup and view all the answers

    What cellular structure is known as the 'powerhouse' of the cell?

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

    What distinguishes somatic cells in humans?

    <p>They contain two sets of chromosomes.</p> Signup and view all the answers

    Which part of the nucleus allows for the movement of substances between the nucleus and cytoplasm?

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

    During which mitotic phase do the chromatin fibers condense into visible chromosomes?

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

    What is the purpose of the cytoskeleton within the cell?

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

    Study Notes

    The Cellular Level of Organization

    • Plasma membrane acts as the outer boundary of the cell, separating internal and external environments while being selectively permeable.
    • Cytoplasm contains all cell contents between plasma membrane and nucleus, including cytosol (fluid portion) and organelles (subcellular structures).
    • Fluid mosaic model describes the membrane's structure, with lipids forming a barrier and proteins acting as gatekeepers for substances.

    Nucleus

    • The nucleus is a large organelle housing DNA and chromosomes, which contain genes, the hereditary units of the cell.
    • The nuclear envelope consists of a double membrane with nuclear pores regulating transport in and out.

    Membrane Structure

    • Composed of a lipid bilayer featuring phospholipids, cholesterol, and glycolipids.
    • Integral proteins (transmembrane and peripheral) are embedded within or attached to the membrane surface.

    Transport Mechanisms

    • Transport through membranes can occur via:
      • Facilitated Diffusion: Channel-mediated or carrier-mediated for diffusing molecules.
      • Active Transport: Uses energy to move substances against concentration gradients (e.g., Na+/K+ pump).
      • Osmosis: Movement of water across a selectively permeable membrane from high water concentration to low water concentration.
    • Vesicular Transport: Involves endocytosis (intake of materials), exocytosis (release of materials), and transcytosis (combined transport).

    Types of Endocytosis

    • Receptor-mediated Endocytosis: Selective uptake following ligand binding.
    • Phagocytosis: Cell “eating” to incorporate larger particles.
    • Bulk-phase Endocytosis (Pinocytosis): Non-specific uptake of fluid.

    Organelles

    • Centrosome: Contains centrioles and pericentriolar material, plays a role in cell division.
    • Cilia and Flagella: Hair-like structures aiding in movement; cilia move fluids, while flagella facilitate the movement of entire cells.
    • Ribosomes: Sites for protein synthesis, either free or attached to endoplasmic reticulum (ER).
    • Endoplasmic Reticulum (ER):
      • Rough ER is involved in protein production due to ribosomes.
      • Smooth ER synthesizes lipids and detoxifies drugs.
    • Golgi Complex: Modifies, sorts, and packages proteins using cisternae.
    • Lysosomes: Contain digestive enzymes, involved in breaking down waste.
    • Peroxisomes: Detoxify harmful substances such as alcohol.
    • Proteasomes: Degrade damaged or unneeded proteins.

    Mitochondria

    • Known as the cell’s powerhouses, generating ATP through cellular respiration.
    • Feature double membranes with inner folds called cristae and a central matrix.

    Cell Division

    • Somatic Cell Division (Mitosis): Divides a body cell into two identical daughter cells containing the same chromosome number (diploid, 46 chromosomes).
      • Interphase consists of G1, S (DNA replication), and G2 phases.
      • The mitotic phase involves prophase, metaphase, anaphase, and telophase.
    • Reproductive Cell Division (Meiosis): Reduces chromosome number by half to create haploid gametes (23 chromosomes), occurring in gonads.
      • Includes two rounds: meiosis I and II.

    Solutions and Tonicity

    • Isotonic Solution: Equal solute concentrations, maintaining cell shape and size.
    • Hypotonic Solution: Lower external solute concentration, leading to cell swelling and potential lysis.
    • Hypertonic Solution: Higher external solute concentration, causing cell shrinkage (crenation).

    Diffusion Types

    • Passive Diffusion: No energy required, movement driven by concentration gradients.
    • Active Transport: Energy-dependent movement against gradients, utilizing ATP for ion transport (e.g., sodium/potassium exchange).

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    Description

    Explore the intricate details of cellular organization including the functions and structures of the plasma membrane, nucleus, and transport mechanisms. This quiz will test your knowledge on the fluid mosaic model and the components that facilitate cellular functions and transport. Gain a deeper understanding of how cells maintain their structure and function.

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