Cells: Structure and Function

Overview of Cells

• Smallest unit of life; key building blocks for tissues and organs.

• Exhibit diversity in shape and function based on roles.

Cell Structure

• Main parts of a cell: Nucleus, Cell membrane, Cytoplasm.

• Cell membrane functions:

  • Boundary, regulates movement, signal transduction, cell adhesion.

Membrane Composition

• Composed of lipids (phospholipid bilayer), proteins, and carbohydrates.

• Cholesterol stabilizes membrane; allows lipid-soluble molecules to pass.

Cytoplasm Components

• Cytosol, organelles, cytoskeleton (microtubules, microfilaments).

• Organelles perform specific functions:

  • Mitochondria (ATP production), Golgi Apparatus (protein packaging), Ribosomes (protein synthesis).

Cell Movement Mechanisms

• Passive transport: no energy required (Diffusion, Osmosis, Filtration).

• Active transport: energy required (Na+-K+ ATPase, Endocytosis, Exocytosis).

Cell Cycle

• Phases: Interphase, Mitosis, Cytokinesis.

• Mitosis: Division process includes Prophase, Metaphase, Anaphase, Telophase.

• Meiosis: Produces gametes with half the chromosome number.

Cell Differentiation and Death

• Stem cells can differentiate into specialized cells.

• Apoptosis: programmed cell death for tissue remodeling and cellular regulation.