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Anatomy & Physiology: Cell Structure and Membrane Transport

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Terms in this set (25)

  • What are the three basic structural components shared by all human cells?

    Plasma membrane, cytoplasm, and nucleus.

  • Describe the Fluid Mosaic Model of the plasma membrane.

    The plasma membrane is a dynamic, selectively permeable barrier made of a phospholipid bilayer with embedded proteins and carbohydrates.

  • What is the role of phospholipids in the plasma membrane?

    Phospholipids form the bilayer with hydrophilic heads facing outward and hydrophobic tails inward, creating a barrier to most molecules.

  • What function does cholesterol serve in the plasma membrane?

    Cholesterol adds membrane stiffness and stability.

  • What are integral and peripheral membrane proteins?

    Integral proteins span the membrane and act as channels, carriers, receptors, or enzymes. Peripheral proteins attach to integral proteins and support cell movement and enzymatic activity.

  • What is the glycocalyx and its function?

    A carbohydrate-rich layer on the cell surface that acts as a biological marker for cell recognition and immune response.

  • Name the three types of intercellular junctions and their functions.

    Tight junctions create impermeable barriers, desmosomes provide mechanical strength, and gap junctions allow ion and molecule passage for communication.

  • What is simple diffusion?

    Passive movement of lipid-soluble molecules directly through the plasma membrane down their concentration gradient.

  • How does facilitated diffusion differ from simple diffusion?

    Facilitated diffusion uses carrier or channel proteins to move substances down their concentration gradient without energy.

  • Define osmosis in terms of membrane transport.

    Osmosis is the passive diffusion of water molecules through a selectively permeable membrane.

  • What is primary active transport?

    Active transport that directly uses ATP to move substances against their concentration gradient, e.g., the Na+-K+ pump.

  • Explain secondary active transport.

    Uses energy stored in ion gradients created by primary active transport to move other substances against their gradient.

  • What are the main types of vesicular transport?

    Endocytosis (phagocytosis, pinocytosis, receptor-mediated) and exocytosis for moving large molecules across membranes.

  • What establishes and maintains the resting membrane potential?

    The Na+-K+ pump and selective permeability to K+ ions maintain the voltage difference across the membrane.

  • What is the function of mitochondria?

    Mitochondria generate ATP through aerobic respiration and contain their own DNA.

  • Differentiate between free and membrane-bound ribosomes.

    Free ribosomes synthesize proteins for internal use; membrane-bound ribosomes produce proteins for export or membrane insertion.

  • What are the roles of rough and smooth endoplasmic reticulum?

    Rough ER synthesizes proteins for secretion; smooth ER is involved in lipid metabolism and detoxification.

  • Describe the function of the Golgi apparatus.

    Modifies, sorts, and packages proteins and lipids for secretion or use within the cell.

  • What are lysosomes and peroxisomes responsible for?

    Lysosomes digest waste materials; peroxisomes detoxify harmful substances.

  • What components make up the cytoskeleton and their functions?

    Microfilaments provide cell shape and movement, intermediate filaments offer tensile strength, and microtubules assist in organelle transport and cell division.

  • What is the structure and function of the nucleus?

    The nucleus contains genetic material, is enclosed by a double membrane with pores, and includes nucleoli for ribosomal RNA synthesis.

  • Outline the phases of the cell cycle.

    Interphase (G1 growth, S DNA synthesis, G2 preparation) and mitosis (prophase, metaphase, anaphase, telophase) followed by cytokinesis.

  • What occurs during transcription and translation in protein synthesis?

    Transcription copies DNA into mRNA; translation decodes mRNA to assemble amino acids into proteins.

  • What is apoptosis and autophagy?

    Apoptosis is programmed cell death; autophagy is the disposal of damaged cell components.

  • How do telomeres relate to cell aging and cancer?

    Telomeres limit cell division; telomerase can extend telomeres, contributing to cancer cell immortality.