Function of Cell Structures

Cellular Boundaries and Surface Structures

• Plasma Membrane

  • Function: Controls movement of substances into and out of the cell.

  • Anatomical Diagram Label: Label 5.

• Microvilli (Singular: Microvillus)

  • Function: Folds of the plasma membrane that increase the surface area of the cell to increase absorption or secretion.

  • Anatomical Diagram Label: Label 7 (microvillus).

• Cilia (Singular: Cilium)

  • Function: Abundant, hair-like cell projections that move fluids and particles along the cell surface.

  • Anatomical Diagram Label: Label 9 (cilium).

• Flagella (Singular: Flagellum)

  • Function: Long cell projection that uses whip-like motion to move sperm.

  • Anatomical Diagram Label: Label 8 (flagellum).

Nuclear Structures and Genetic Material

• Nucleus

  • Function: Contains DNA molecules and the nucleolus.

  • Anatomical Diagram Label: Label 14.

• Nuclear Membrane

  • Function: Serves as the enclosing membrane boundary for the cell nucleus.

  • Anatomical Diagram Label: Label 12.

• Nucleolus

  • Function: Assembly site for ribosomes.

  • Anatomical Diagram Label: Label 13.

• Chromatin

  • Structure & Function: Long thin strands within the nucleus. Each strand is composed of one DNA molecule and associated proteins.

  • Anatomical Diagram Label: Label 11.

Cytoplasm and Cytosol

• Cytoplasm

  • Description & Function: The area of the cell between the plasma membrane and the nucleus. It consists of a gel-like fluid and includes cytosol and organelles.

  • Anatomical Diagram Label: Label 15 (gel-like fluid).

• Cytosol

  • Function: Fluid portion of cytoplasm in which many of the cell's chemical reactions occur.

Endomembrane System and Synthesis Organelles

• Ribosomes (Singular: Ribosome)

  • Function: Site of protein synthesis located in the cytosol and on the rough endoplasmic reticulum (RER).

  • Appearance: Visualized as a small dot.

  • Anatomical Diagram Label: Label 17 (small dot).

• Rough Endoplasmic Reticulum (RER)

  • Function: Synthesizes proteins and phospholipids used in the plasma membrane and organelles, or secreted via exocytosis.

  • Anatomical Diagram Label: Label 16.

• Smooth Endoplasmic Reticulum (SER)

  • Function: Synthesizes fatty acids and steroids, detoxifies toxic substances, and stores calcium.

  • Anatomical Diagram Label: Label 3.

• Golgi Complex

  • Function: Receives and modifies proteins from the RER; sorts and modifies them for transport.

  • Anatomical Diagram Label: Label 18.

• Secretory Vesicles

  • Function: Secrete substances outside the cell by exocytosis.

  • Anatomical Diagram Label: Label 10.

Metabolic, Catabolic, and Energy Organelles

• Mitochondria (Singular: Mitochondrion)

  • Function: Makes ATP via aerobic cellular respiration.

  • Anatomical Diagram Label: Label 1 (mitochondrion).

• Lysosomes (Singular: Lysosome)

  • Function: Enzymes digest and recycle worn-out organelles and substances entering the cell; can digest the cell.

  • Anatomical Diagram Label: Label 4 (lysosome).

• Peroxisomes (Singular: Peroxisome)

  • Function: Produce hydrogen peroxide; detoxify harmful substances.

  • Anatomical Diagram Label: Label 2 (peroxisome).

Cytoskeleton and Centrosomes

• Cytoskeleton

  • Structure & Function: Consists of three kinds of protein filaments; maintains cell shape and is involved in cell movement and the movement of organelles.

• Centrosomes (Centrioles)

  • Function: Form the mitotic spindle; needed to form cilia and flagella.

  • Anatomical Diagram Label: Label 6 (centrioles).

Anatomical Sectional Drawing Index

• 1: Mitochondrion

• 2: Peroxisome

• 3: Smooth endoplasmic reticulum

• 4: Lysosome

• 5: Plasma membrane

• 6: Centrioles

• 7: Microvillus

• 8: Flagellum

• 9: Cilium

• 10: Secretory vesicle

• 11: Chromatin

• 12: Nuclear membrane

• 13: Nucleolus

• 14: Nucleus

• 15: Cytoplasm (gel-like fluid)

• 16: Rough endoplasmic reticulum

• 17: Ribosome (small dot)

• 18: Golgi complex