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Anatomy & Physiology: Cell Structure and Function

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Terms in this set (30)

  • What are the three basic components of most animal cells?

    Plasma membrane, cytoplasm (including cytosol, organelles, cytoskeleton), and nucleus.

  • What is the primary function of the plasma membrane?

    Physically isolates the cell, provides structural support, communicates with other cells, regulates transport, and identifies the cell.

  • What are the two fluid compartments defined by the plasma membrane?

    Intracellular fluid (cytosol) inside the cell and extracellular fluid (ECF) outside the cell.

  • What are the main components of the cytoplasm?

    Cytosol (watery gel), organelles (specialized molecular machines), and cytoskeleton (protein filament network).

  • What is the role of the nucleus in the cell?

    Contains most of the cell's DNA and is the site for RNA production, controlling cellular functions by coding and creating proteins.

  • Describe the structure of the phospholipid bilayer.

    Composed of hydrophilic polar phosphate heads facing water and hydrophobic nonpolar fatty acid tails facing inward, forming a barrier between ECF and cytosol.

  • What is the Fluid Mosaic Model of the plasma membrane?

    The plasma membrane is a dynamic mosaic of phospholipids, proteins, lipids, and carbohydrates that move laterally, providing fluidity and function.

  • Differentiate between integral and peripheral membrane proteins.

    Integral proteins span the membrane; peripheral proteins are found on one side and may be anchored or free.

  • List the main functional types of membrane proteins.

    Channels, carriers, receptors, enzymes, structural support proteins, and linker proteins.

  • What is the function of the ACE2 receptor in relation to COVID-19?

    ACE2 is an integral protein receptor that SARS-CoV-2 binds to for cell entry, allowing viral replication inside human cells.

  • What is the difference between agonist and antagonist drugs in membrane receptor interaction?

    Agonists mimic ligand actions; antagonists bind receptors but inhibit ligand effects.

  • What are the two main types of transport across the plasma membrane?

    Passive transport (no energy required) and active transport (requires ATP).

  • Define diffusion and its driving force.

    Movement of solute molecules from higher to lower concentration driven by a concentration gradient.

  • What is the difference between simple diffusion and facilitated diffusion?

    Simple diffusion passes nonpolar solutes directly through the bilayer; facilitated diffusion uses channel or carrier proteins for polar or charged solutes.

  • Explain osmosis and how water crosses the plasma membrane.

    Movement of water from lower to higher solute concentration through aquaporins or between phospholipids.

  • What stops net water movement during osmosis?

    Osmotic pressure (prevents water entry) and hydrostatic pressure (force exerted by water on container walls).

  • Define tonicity and its types with effects on cells.

    Comparison of solute concentrations affecting osmosis: isotonic (no change), hypertonic (cell shrinks), hypotonic (cell swells).

  • What is the role of the sodium-potassium pump in primary active transport?

    Moves 3 sodium ions out and 2 potassium ions into the cell against their concentration gradients using ATP.

  • Describe secondary active transport.

    Uses energy from a concentration gradient created by primary active transport to move another substance against its gradient, often coupled with passive transport.

  • What are the main types of vesicular transport?

    Endocytosis (phagocytosis, pinocytosis, receptor-mediated) and exocytosis, all requiring ATP.

  • What is the function of lysosomes?

    Membrane sacs containing acid hydrolases that digest macromolecules, degrade worn organelles, and destroy bacteria.

  • What are the three main types of cytoskeletal filaments?

    Actin filaments (support and movement), intermediate filaments (mechanical strength), and microtubules (organelle movement and cell shape).

  • What are microvilli, cilia, and flagella?

    Microvilli increase surface area; cilia move substances across cell surfaces; flagella propel whole cells.

  • What is the structure and function of the nucleus?

    Double membrane with nuclear pores, contains DNA and nucleolus, directs cellular activities and ribosome assembly.

  • What is chromatin and how does it differ from chromosomes?

    Chromatin is loosely coiled DNA during non-division; chromosomes are condensed DNA during cell division.

  • Outline the two main processes of protein synthesis.

    Transcription (DNA to mRNA) and translation (mRNA to polypeptide chain at ribosomes).

  • What is the role of tRNA in translation?

    Transfers specific amino acids to the ribosome, matching mRNA codons with anticodons to build proteins.

  • What are the phases of the cell cycle?

    Interphase (G1, S, G2 phases) for growth and DNA replication, and M phase for mitosis and cytokinesis.

  • What is apoptosis and its role in cell cycle control?

    Programmed cell death that removes damaged or unrepairable cells to maintain tissue health.

  • What distinguishes benign from malignant tumors?

    Benign tumors remain localized; malignant tumors invade tissues and can metastasize.