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Anatomy & Physiology: Cells, Tissues, and Cellular Processes

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  • What are the three main principles of the Cell Theory?

    1. All living things are made of one or more cells.
    2. Cells are the basic units of structure and function.
    3. All cells arise from existing cells.

  • What is the plasma membrane and its main function?

    The plasma membrane is a phospholipid bilayer that covers the cell surface and acts as a selectively permeable barrier between the cell and its environment.

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

    Polar heads face outward toward water; nonpolar tails face inward, repelling water but allowing lipid-soluble substances to pass.

  • Name two types of membrane proteins and their roles.

    Integral proteins are embedded in the membrane structure; peripheral proteins are on the surface and may act as enzymes or cell linkers.

  • List the main functions of membrane proteins.

    Anchoring, recognition, enzymatic activity, receptor binding, carrier transport, and channel formation.

  • What is the cytoplasm composed of and its function?

    Clear fluid called cytosol containing water, ions, nutrients, proteins, and waste; provides medium for intracellular reactions.

  • What are microfilaments and their role in the cytoskeleton?

    Composed of actin, they determine cell shape and anchor the cytoskeleton to membrane proteins.

  • What is the function of the rough and smooth endoplasmic reticulum?

    Rough ER assembles proteins with ribosomes; Smooth ER synthesizes lipids and detoxifies substances.

  • What is the role of the Golgi apparatus?

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

  • Describe the function of lysosomes.

    Digest and recycle cellular waste and damaged organelles.

  • What is the mitochondrion's primary function?

    Produce ATP, the cell's main energy source, through cellular respiration.

  • What is the nucleus and its main components?

    Contains DNA and controls cell functions; includes nuclear envelope, chromatin, nucleolus, and nuclear pores.

  • What is transcription in protein synthesis?

    Copying a DNA sequence into complementary mRNA.

  • How does DNA differ from RNA?

    DNA has deoxyribose sugar, is double-stranded, and contains thymine; RNA has ribose sugar, is single-stranded, and contains uracil.

  • What is translation in protein synthesis?

    Using mRNA to assemble amino acids into a protein at the ribosome.

  • Define diffusion and its types.

    Movement of molecules down a concentration gradient; includes simple diffusion (lipid-soluble molecules) and facilitated diffusion (large molecules via proteins).

  • What is osmosis?

    Diffusion of water through a selectively permeable membrane to balance solute concentrations.

  • Explain isotonic, hypertonic, and hypotonic solutions.

    Isotonic: equal solute concentration; hypertonic: higher solute outside, causing cell shrinkage; hypotonic: lower solute outside, causing cell swelling.

  • What is active transport and give an example?

    Movement of molecules against concentration gradient using energy; example: sodium-potassium pump.

  • Describe endocytosis and exocytosis.

    Endocytosis: cell engulfs substances into vesicles; exocytosis: vesicles release contents outside the cell.

  • What are the phases of the cell cycle?

    G1 (growth), S (DNA replication), G2 (preparation), and M phase (mitosis and cytokinesis).

  • What happens during mitosis?

    Division of the nucleus into two identical sets of chromosomes.

  • What is the function of epithelial tissue?

    Covers body surfaces, lines cavities, controls permeability, provides sensation, and produces secretions.

  • How are epithelial tissues classified?

    By cell layers: simple (one layer) or stratified (multiple layers); by cell shape: squamous, cuboidal, or columnar.

  • What are connective tissue's main components?

    Ground substance, fibers (collagen, elastic, reticular), and cells (fibroblasts, chondroblasts, osteoblasts).

  • Name three types of connective tissue proper.

    Loose connective tissue (areolar, adipose, reticular) and dense connective tissue (regular, irregular, elastic).

  • What are the main functions of muscle tissue?

    Movement, posture, and heat production; includes voluntary (skeletal) and involuntary (cardiac, smooth) muscles.

  • What is nervous tissue composed of and its function?

    Neurons and neuroglia; transmits electrical signals and supports neurons.

  • What are the key steps in tissue repair?

    Inflammation, organization (restoring blood supply), and regeneration or fibrosis (scar formation).