Chapter 3 review

Chapter 3 Images

Overview of the Cell Structure

  • Plasma Membrane: Separates the cell's internal contents (cytoplasm) from the external environment.

  • Cytoplasm: Contains cytosol (fluid) and organelles (internal structures).

Cytoplasm Subdivisions

  • Cytosol: The fluid part of the cytoplasm.

  • Organelles: Structures suspended in cytosol that perform specific functions.

    • Classification of Organelles:

    • Membranous Organelles

    • Nonmembranous Organelles

Key Terms

  • Extracellular Fluid: The fluid environment outside of the cell, primarily known as interstitial fluid in tissues.

Nonmembranous Organelles

  • Microvilli: Extensions of the plasma membrane containing microfilaments.

    • Function: Increase surface area to facilitate the absorption of extracellular materials.

  • Cilia: Long extensions of the plasma membrane containing microtubules.

    • Types:

    • Primary Cilium: Acts as a sensor.

    • Motile Cilia: Move materials over cell surfaces.

  • Proteasomes: Hollow cylinders containing proteolytic enzymes.

    • Function: Breakdown and recycling of damaged or abnormal proteins.

Membranous Organelles

  • Golgi Apparatus: A stack of flattened membranes (cisternae) with functional chambers.

    • Functions:

    • Storage,

    • Alteration,

    • Packaging of secretory products,

    • Contains lysosomal enzymes.

  • Mitochondria: Double membrane organelles with an inner membrane folded into cristae.

    • Function: Responsible for producing 95% of ATP required by the cell.

  • Endoplasmic Reticulum (ER): A network of membranous channels that extends throughout the cytoplasm.

    • Types:

    • Rough ER: Has ribosomes; modifies and packages newly synthesized proteins.

    • Smooth ER: Lacks ribosomes; synthesizes lipids and carbohydrates, detoxifies drugs or toxins.

  • Lysosomes: Vesicles containing digestive enzymes.

    • Function: Intracellular removal of damaged organelles or pathogens.

  • Peroxisomes: Vesicles containing degradative enzymes.

    • Functions: Catabolism of fats and neutralization of toxic compounds.

  • Nucleus: Contains cell's genetic information.

    • Components:

    • Chromatin: DNA and proteins; visible as chromosomes during cell division.

    • Nuclear envelope: Double membrane surrounding the nucleus.

    • Nucleolus: Site of rRNA synthesis and assembly of ribosomal subunits.

    • Nucleoplasm: Fluid containing nucleotides, enzymes, and chromatin.

    • Function: Control of metabolism, genetic information storage and processing, and protein synthesis regulation.

Ribosomes

  • Composed of RNA and proteins.

  • Types:

    • Fixed Ribosomes: Bound to rough ER.

    • Free Ribosomes: Scattered in cytoplasm.

  • Function: Protein synthesis.

Cytoskeleton

  • Composed of proteins organized in fine filaments or slender tubes.

  • Functions:

    • Provides strength and support.

    • Aids in the movement of cellular structures and materials.