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Chapter 3 Study Flashcards (Vocabulary)

Page 1

  • Fluid mosaic model of the plasma membrane
    • The plasma membrane is a dynamic, fluid structure composed of a phospholipid bilayer with embedded proteins. It is described as a mosaic of proteins in a phospholipid sea, allowing lateral movement of components and quick remodeling.
    • Key idea: membrane components are not static; lipids and proteins can move within the layer, contributing to membrane flexibility and function.
    • Significance: this fluidity enables membrane functions such as diffusion of small molecules, vesicle formation, and rapid responses to environmental changes.
  • Selective permeability of the plasma membrane
    • The membrane is selectively permeable, meaning it allows some substances to cross more easily than others.
    • Why selective? The lipid bilayer has a hydrophobic core that blocks many polar and charged molecules, while proteins embedded in the membrane provide specific pathways.
  • Role of the lipid bilayer in selectivity
    • The hydrophobic core of the lipid bilayer acts as a barrier to most polar substances, contributing to selective permeability.
    • Lipid composition and membrane fluidity influence what can passively diffuse or require transport proteins.
  • Role of proteins in selectivity
    • Transport proteins facilitate the movement of specific molecules across the membrane (channels, carriers, pumps).
    • Receptors, enzymes, and other membrane proteins also contribute to selective permeability and membrane signaling.
  • Active vs. passive transport
    • Active transport: requires energy (usually ATP) to move substances against their concentration gradient.
    • Passive transport: does not require energy; relies on the concentration gradient (diffusion, facilitated diffusion, osmosis).
    • Practical distinction: active transport can move substances uphill; passive transport moves substances downhill toward equilibrium.
  • Osmosis and red blood cells (RBCs)
    • Osmosis: movement of water across a selectively permeable membrane in response to solute concentration differences.
    • Hypotonic solution: water moves into the RBC, causing it to swell (hemolysis possible).
    • Hypertonic solution: water moves out of the RBC, causing it to shrink (crenation).
    • Isotonic solution: there is no net movement of water across the membrane.
    • Real-world relevance: cells regulate water balance to prevent lysis or shrinkage in varying extracellular environments.
  • Vesicular transport (introduction)
    • Vesicular transport moves large molecules or bulk quantities via vesicles.
    • Two main processes: endocytosis (into the cell) and exocytosis (out of the cell).
    • Significance: enables intake of large particles, secretion of substances, and membrane turnover.

Page 2

  • Vesicular transport mechanisms

    • Endocytosis: cells engulf extracellular material via vesicle formation. Subtypes include phagocytosis, pinocytosis, and receptor-mediated endocytosis (specific uptake).
    • Exocytosis: vesicles fuse with the plasma membrane to release their contents outside the cell.

  • Function of the cytoskeleton

    • Provides structural support to maintain cell shape.
    • Facilitates cell movement (migration, crawling) and changes in cell form.
    • Anchors organelles within the cytoplasm and participates in intracellular transport (tracks for motor proteins).
    • Role in cytokinesis and cell division through organization of the mitotic spindle and contractile rings.

  • The three types of cellular skeleton proteins

    • Microfilaments (actin): support cell shape, enable contractile movements (e.g., muscle contraction), and contribute to cell motility and microvilli structure.
    • Intermediate filaments: provide mechanical strength and resilience to cells, helping maintain cell integrity under stress.
    • Microtubules: act as tracks for vesicular transport and organize the cell during division (spindle formation); form the internal scaffold of cilia and flagella.

  • Membrane-bound organelles and their functions (as listed in the transcript)

    • Endoplasmic reticulum (ER): network of membranous tubules; rough ER hosts ribosomes for protein synthesis; smooth ER synthesizes lipids and detoxifies certain compounds.
    • Golgi apparatus: modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
    • Lysosomes: contain hydrolytic enzymes for digestion of macromolecules and old organelles; sites of cellular recycling.

  • Components and functions of these components (note on transcript)

    • The transcript says to list the components and the functions of these components but does not specify additional details beyond ER, Golgi, and lysosomes. See above for the functions of these organelles. For broader study, consult the presentation for a complete list of cellular components and roles.

  • Condensed chromatin and chromosomal terminology

    • Condensed chromatin is known as heterochromatin.

  • Human chromosome count in somatic cells

    • Each human somatic cell has 46 chromosomes.

  • Sex chromosomes: male vs female

    • Females have XX sex chromosomes; males have XY.

  • Gametes vs somatic cells

    • Gametes are haploid reproductive cells; somatic cells are diploid body cells. (Haploid = n; Diploid = 2n.)

  • Anabolism vs. catabolism

    • Anabolism builds complex molecules using energy; catabolism breaks down complex molecules, releasing energy.

  • Aerobic vs. anaerobic respiration

    • Aerobic respiration requires oxygen and yields more energy in the form of ATP.
    • Anaerobic respiration does not require oxygen and yields less ATP.
    • Conclusion: Aerobic respiration makes the most energy.

  • Transcription vs. translation

    • Transcription copies DNA into RNA.
    • Translation uses RNA to synthesize proteins.

  • Mitosis vs. meiosis

    • Mitosis produces identical diploid cells for growth and repair.
    • Meiosis produces genetically diverse haploid gametes for sexual reproduction.

  • Benign vs. malignant growth

    • Benign growth: non-cancerous.
    • Malignant growth: cancerous; invasive and capable of metastasis.

  • Aging

    • Aging is the gradual decline in physiological functions over time, increasing vulnerability to disease and death.

  • Apoptosis vs. necrosis

    • Apoptosis: programmed, controlled cell death without inflammation.
    • Necrosis: uncontrolled cell death due to injury, often accompanied by inflammation.

  • Connections to foundational principles and real-world relevance

    • The membrane structure concepts connect to fundamental chemistry (hydrophobic/hydrophilic interactions) and to cellular physiology (diffusion, osmosis, active transport).
    • Transport mechanisms (endocytosis/exocytosis) underpin nutrient uptake, neurotransmitter release, and immune responses.
    • The cytoskeleton and organelles coordinate intracellular trafficking, cell shape changes, and division—critical for development and tissue maintenance.
    • Genetic concepts (chromosome number, sex chromosomes, meiosis) relate to inheritance, fertility, and variation in populations.
    • Metabolic distinctions (anabolism/catabolism, aerobic/anaerobic respiration) underpin energy budgeting in cells and organisms, athletic performance, and disease states.

  • Ethical, philosophical, and practical implications

    • Understanding aging and cancer biology informs medical ethics, patient care, and public health strategies.
    • Insights into cell death (apoptosis vs. necrosis) influence approaches to treat neurodegenerative diseases, cancer, and tissue injury.
    • The balance between maintaining cellular function and preventing uncontrolled growth has direct implications for cancer prevention, early detection, and therapy development.