Anatomy & Physiology Week 2: Cellular Organization
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Questions and Answers

What are glycoproteins primarily composed of?

  • Proteins with lipid groups attached
  • Carbohydrates alone
  • Lipid molecules
  • Proteins with carbohydrate groups attached (correct)

    • Which type of membrane proteins act as channels and transporters?

  • Integral proteins
  • Transmembrane proteins (correct)
  • Surface proteins
  • Peripheral proteins

    • What is the primary energy source used in active processes for transporting substances across the membrane?

  • Glucose
  • ATP (correct)
  • Fatty acids
  • NADH

    • In passive processes, how do substances typically move across the cell membrane?

    <p>With the concentration gradient without energy input</p> Signup and view all the answers

    Which component forms the 'sugary coating' around the cell membrane?

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

    What factor does NOT influence the rate of diffusion across a membrane?

    <p>Electric charge of the substance</p> Signup and view all the answers

    Which of the following substances can easily pass through the lipid bilayer?

    <p>Oxygen and carbon dioxide</p> Signup and view all the answers

    What role do enzymes play in the cell membrane?

    <p>Catalyzing chemical reactions</p> Signup and view all the answers

    What is the primary function of the plasma membrane?

    <p>To form the cell's outer boundary and act as a barrier</p> Signup and view all the answers

    What does the cytoplasm consist of?

    <p>The fluid portion called cytosol and organelles</p> Signup and view all the answers

    What structure within the nucleus contains DNA?

    <p>Chromosomes</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

    Which type of protein extends through the lipid bilayer of the plasma membrane?

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

    What is cytosol primarily composed of?

    <p>Mostly water</p> Signup and view all the answers

    What role do integral proteins play in the plasma membrane?

    <p>They act as gatekeepers to certain molecules and ions</p> Signup and view all the answers

    What is the composition of the lipid bilayer in the plasma membrane?

    <p>Phospholipids, cholesterol, and glycolipids</p> Signup and view all the answers

    What is the main purpose of meiosis?

    <p>To create gametes with half the number of chromosomes</p> Signup and view all the answers

    During which phase are two identical nuclei formed around the chromosomes?

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

    What is the result of cytokinesis?

    <p>The division of a cell’s cytoplasm</p> Signup and view all the answers

    What ultimately restores the diploid number of chromosomes during reproduction?

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

    How many genetically different haploid gametes are produced from one diploid cell after meiosis?

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

    What is the primary function of the cytosol?

    <p>Surrounds organelles and site of chemical reactions</p> Signup and view all the answers

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

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

    What is the primary role of lysosomes?

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

    Which cellular structure is abundant in the liver and detoxifies harmful substances?

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

    What do mitochondria generate that is crucial for cellular functions?

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

    What primarily facilitates the movement of potassium ions across a cell membrane?

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

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

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

    What is the main purpose of the sodium-potassium pump?

    <p>To transport sodium and potassium ions across the plasma membrane</p> Signup and view all the answers

    How many pairs of chromosomes are found in human somatic cells?

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

    Which type of endocytosis involves the uptake of large particles or cells?

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

    What is the term used for the division of somatic cells?

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

    What role do aquaporins serve in the cell membrane?

    <p>Facilitating the movement of water</p> Signup and view all the answers

    What are homologous chromosomes?

    <p>Chromosomes that carry the same genes but may have different alleles</p> Signup and view all the answers

    Which event occurs during anaphase in mitosis?

    <p>Chromatid pairs split and move to opposite poles</p> Signup and view all the answers

    What is a characteristic of osmotic movement?

    <p>It moves water from an area of low solute concentration to high solute concentration</p> Signup and view all the answers

    What is the function of the nuclear envelope?

    <p>Protect genetic material</p> Signup and view all the answers

    What defines transcytosis?

    <p>The combination of exocytosis and endocytosis</p> Signup and view all the answers

    Which type of vesicle-mediated transport helps move materials out of the cell?

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

    What feature is associated with the inner mitochondrial membrane?

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

    What are cilia primarily used for?

    <p>Movement of fluids along a cell surface</p> Signup and view all the answers

    What is the role of proteasomes in the cell?

    <p>Destroy unneeded or damaged proteins</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

    Study Notes

    Generalized Cell Structure

    • Plasma Membrane:

      • Outer boundary separating internal and external environments.
      • Acts as a selective barrier and facilitates cell communication.
      • Comprised of a lipid bilayer and proteins, following the fluid mosaic model.

    • Cytoplasm:

      • Contains all cell contents between plasma membrane and nucleus.
      • Composed of cytosol (mainly water) and organelles which perform specific functions.

    • Nucleus:

      • Large organelle housing DNA organized into chromosomes.
      • Each chromosome consists of DNA and proteins, containing thousands of genes.

    Membrane Structure

    • Lipid Bilayer:

      • Composed of phospholipids, cholesterol, and glycolipids.
      • Integral proteins exist within the bilayer; transmembrane proteins span its width.

    • Membrane Proteins:

      • Ion Channels: Allow ions to pass through.
      • Transporters: Move substances across the membrane.
      • Receptors: Bind ligands for cellular recognition.
      • Enzymes: Catalyze chemical reactions.
      • Cell-identity Markers: Help distinguish between self and non-self.

    Transport Mechanisms

    • Passive Processes:

      • No energy required for substance movement; relies on kinetic energy.

    • Active Processes:

      • Energy from ATP used to move substances against a concentration gradient.

    • Diffusion Factors:

      • Concentration gradient steepness, temperature, mass of substances, surface area, and diffusion distance.

    • Types of Diffusion:

      • Simple Diffusion: Movement through lipid bilayer.
      • Channel-mediated Facilitation: Utilizes protein channels.
      • Carrier-mediated Facilitation: Involves transport proteins for selective movement.

    Osmosis and Tonicity

    • Osmosis:

      • Water movement across a selectively permeable membrane from high to low water concentration.

    • Tonicity Effects on RBCs:

      • Isotonic: Equal solute concentration; cells retain normal shape.

    Vesicular Transport

    • Vesicle Functions:
      • Enable transport within cells.
      • Types include endocytosis (materials entering), exocytosis (vesicles fusing to release contents), and transcytosis (combination of both).

    Organelles Overview

    • Cytoskeleton:

      • Network of protein filaments providing structure and support.

    • Centrosome:

      • Contains centrioles, assisting in cell division.

    • Cilia and Flagella:

      • Cilia: Move fluids across cell surfaces.
      • Flagella: Propel entire cells (e.g., sperm).

    • Ribosomes:

      • Sites for protein synthesis.

    • Endoplasmic Reticulum:

      • Rough ER: Studded with ribosomes for protein production.
      • Smooth ER: Lacks ribosomes; synthesizes fatty acids and detoxifies substances.

    • Golgi Complex:

      • Modifies, sorts, and packages proteins for transport.

    • Lysosomes:

      • Contain enzymes for digestion of substances.

    • Mitochondria:

      • Known as the cell's powerhouses, generating ATP.

    Cell Division

    • Somatic Cell Division (Mitosis):

      • Cell cycle includes replication of DNA and division into two identical daughter cells.

    • Interphase:

      • Non-dividing phase where DNA replicates.

    • Mitotic Phase:

      • Divided into prophase, metaphase, anaphase, and telophase.

    • Reproductive Cell Division (Meiosis):

      • Occurs in gonads yielding gametes with half the chromosome number (haploid).

    • Meiosis Process:

      • Consists of two stages, resulting in four genetically different haploid cells.

    Membrane Composition

    • Hydrophilic heads face outward, hydrophobic tails face inward, contributing to membrane structure and function.

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    Description

    This quiz covers the cellular level of organization, focusing on the structure and function of the plasma membrane in generalized cells. Dive into how the plasma membrane acts as a selective barrier and its significance in maintaining the cell's internal environment.

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