I. Main Components:

• Cell Membrane (Plasma Membrane): The outer boundary of the cell, composed of a phospholipid bilayer with embedded proteins.

  • Function: Controls the movement of substances in and out of the cell; cell signaling.

• Cytoplasm: The gel-like substance within the cell, excluding the nucleus, where organelles are suspended.

• Nucleus: A membrane-bound organelle containing the cell's genetic material (DNA).

  • Components:

    • Nuclear Envelope: Double membrane surrounding the nucleus with pores for transport.

    • Chromatin: DNA and associated proteins (histones).

    • Nucleolus: Site of ribosome synthesis.

  • Function: Controls cell activities; stores genetic information.

II. Organelles:

• Endoplasmic Reticulum (ER): A network of membranes involved in protein and lipid synthesis.

  • Types:

    • Rough ER: Studded with ribosomes; involved in protein synthesis and modification.

    • Smooth ER: Involved in lipid synthesis, detoxification, and calcium storage.

• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.

• Mitochondria: The "powerhouse" of the cell, responsible for ATP (energy) production through cellular respiration.

  • Structure: Double membrane; inner membrane folded into cristae.

• Lysosomes: Contain enzymes for breaking down cellular waste and debris.

• Peroxisomes: Involved in detoxification and lipid metabolism.

• Ribosomes: Site of protein synthesis; found free in the cytoplasm or bound to the ER.

• Cytoskeleton: A network of protein fibers providing structural support and facilitating cell movement.

  • Components: Microtubules, intermediate filaments, and actin filaments.

• Centrioles: Involved in cell division (especially in animal cells).

III. Other Structures (Plant Cells):

• Cell Wall: Rigid outer layer providing support and protection (made of cellulose in plants).

• Chloroplasts: Site of photosynthesis; contain chlorophyll.

• Vacuoles: Large storage vesicles; in plants, they help maintain cell turgor.