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Anatomy & Physiology: Chapter 3 - The Cell

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Terms in this set (28)

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

    1. Plasma Membrane
    2. Cytoplasm (includes cytosol, organelles, cytoskeleton)
    3. Nucleus

  • What is the primary function of the plasma membrane?

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

  • Describe the structure of the phospholipid bilayer in the plasma membrane.

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

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

    The plasma membrane is a dynamic structure with phospholipids and proteins moving laterally, creating a fluid and mosaic-like arrangement.

  • Name the two main types of membrane proteins and their general locations.

    Integral proteins span the membrane; Peripheral proteins are found on one side of the membrane.

  • List four functional types of membrane proteins.

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

  • What is the role of the ACE2 receptor in COVID-19 infection?

    ACE2 is an integral membrane protein that SARS-CoV-2 spike protein binds to, allowing viral entry into human cells.

  • Define diffusion and its driving force.

    Diffusion is the 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 molecules directly through the bilayer; facilitated diffusion uses channel or carrier proteins for polar or charged molecules.

  • Explain osmosis and how water crosses the plasma membrane.

    Osmosis is the movement of water from low to high solute concentration across a selectively permeable membrane, via aquaporins or between phospholipids.

  • What are osmotic pressure and hydrostatic pressure?

    Osmotic pressure pulls water inward to a solution; hydrostatic pressure pushes water outward against a membrane.

  • Define tonicity and describe isotonic, hypertonic, and hypotonic solutions.

    Tonicity compares solute concentrations across membranes: isotonic (equal), hypertonic (higher outside, cell shrinks), hypotonic (lower outside, cell swells).

  • What is primary active transport and give an example?

    Movement of solutes against their gradient using ATP directly; example: Sodium-Potassium Pump moves 3 Na+ out and 2 K+ in.

  • Describe secondary active transport.

    Uses energy from an ion gradient created by primary active transport to move another solute against its gradient, often via symporters or antiporters.

  • What is the resting membrane potential?

    The electrical potential difference across the plasma membrane when the cell is at rest, typically negative inside relative to outside.

  • What are the main types of vesicular transport?

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

  • What is the function of mitochondria?

    Produce most of the cell's ATP through oxidative catabolism; contain their own DNA and ribosomes.

  • What are lysosomes and their function?

    Membrane-bound sacs with acid hydrolases that digest macromolecules, degrade worn organelles, and destroy bacteria.

  • Describe the cytoskeleton and its three main components.

    Network of protein filaments: actin filaments (support and movement), intermediate filaments (strength), microtubules (shape, organelle movement, cilia/flagella core).

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

    Directs cellular activities, houses DNA, and is the site of RNA production for protein synthesis.

  • Outline the three stages of transcription.

    Initiation (RNA polymerase binds promoter), elongation (RNA strand synthesis), termination (RNA polymerase detaches and mRNA is released).

  • What are the three types of RNA involved in protein synthesis?

    Messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).

  • Describe the three stages of translation.

    Initiation (assembly of ribosome and start codon recognition), elongation (amino acid chain formation), termination (release of completed polypeptide).

  • What is the cell cycle and its two major phases?

    Ordered series of events from cell formation to division; major phases are interphase (growth and DNA replication) and mitotic phase (cell division).

  • What happens during the S phase of interphase?

    DNA synthesis or replication, producing two identical DNA strands for daughter cells.

  • List the four stages of mitosis.

    Prophase, metaphase, anaphase, telophase (followed by cytokinesis).

  • What is apoptosis?

    Programmed cell death to remove damaged or unnecessary cells.

  • What distinguishes benign from malignant tumors?

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