(180) Biology: Cell Structure I Nucleus Medical Media

Chapter 1: Introduction to Cells

  • Cells are the smallest living units of an organism.

  • All cells have three common features:

    • Cell membrane: separates the inside of the cell from its environment.

    • Cytoplasm: a jelly-like fluid inside the cell.

    • DNA: the cell's genetic material.

Chapter 2: Eukaryotic and Prokaryotic Cells

  • Eukaryotic cells:

    • More advanced and complex cells found in plants and animals.

    • Have organelles, including the nucleus and other specialized parts.

  • Prokaryotic cells:

    • Unicellular organisms, such as bacteria.

    • Lack a nucleus and membrane-enclosed organelles.

    • Have genetic material, but it's not contained within a nucleus.

Chapter 3: Organelles

  • Organelles are specialized parts of a cell with unique functions.

  • Nucleus:

    • Control center of the cell.

    • Contains DNA or genetic material.

    • Nucleolus: structure where ribosomes are made.

  • Ribosomes:

    • Synthesize proteins.

    • Can float freely in the cytoplasm or attach to the endoplasmic reticulum (ER).

  • Endoplasmic Reticulum (ER):

    • Membrane-enclosed passageway for transporting materials.

    • Rough ER has ribosomes attached, while smooth ER doesn't.

  • Golgi Apparatus:

    • Receives proteins and other materials from the ER.

    • Customizes proteins into usable forms for the cell.

  • Vacuoles:

    • Sac-like structures that store different materials.

    • Central vacuole in plant cells stores water.

  • Lysosomes:

    • Organelles in animal cells that break down cellular debris.

  • Mitochondria:

    • Powerhouse of the cell.

    • Produces ATP molecules for energy through cellular respiration.

  • Cytoskeleton:

    • Maintains cell shape.

    • Includes microfilaments and microtubules.

  • Chloroplasts:

    • Found in plant cells.

    • Site of photosynthesis.

    • Contains chlorophyll, a green pigment.

  • Cell Wall:

    • Found in plant cells.

    • Provides shape, support, and protection.

  • Unique structures in some cells:

    • Cilia: hair-like projections that help trap particles in the respiratory tract.

    • Flagella: tail-like structure that aids in cell movement.

    • Sperm cells have flagella.

Chapter 4: Summary

  • Eukaryotic cells have a nucleus and membrane-enclosed organelles, while prokaryotic cells lack these features.

  • All cells have a cell membrane, cytoplasm, and genetic material.

  • Both plant and animal cells have mitochondria, while only plant cells have chloroplasts.

  • Various unique structures exist in specific cells, such as cilia and flagella.