Cell Structure and Function

Cells

Definition and Structure

• A cell is the basic structural and functional unit of living organisms
• Consists of:
  • Plasma membrane (cell membrane): a thin layer of lipid and protein molecules that separates the cell from its environment
  • Cytoplasm: a jelly-like substance inside the cell membrane where metabolic processes take place
  • Nucleus: contains most of the cell's genetic material (DNA)
  • Organelles: specialized structures within the cell that perform specific functions (e.g. mitochondria, ribosomes)

Cell Membrane

• Semi-permeable: allows certain substances to pass through while keeping others out
• Functions:
  • Regulates what enters and leaves the cell
  • Maintains cell shape
  • Provides mechanical support

Cellular Organelles

• Mitochondria: generates energy for the cell through cellular respiration
• Ribosomes: site of protein synthesis
• Endoplasmic Reticulum (ER): involved in protein synthesis, lipid synthesis, and detoxification
• Golgi Apparatus: processes and packages proteins and lipids for transport out of the cell
• Lysosomes: contains digestive enzymes that break down and recycle cellular waste and foreign substances
• Cytoskeleton: provides structural support, shape, and movement to the cell

Cell Types

• Prokaryotic cells: lack a true nucleus and membrane-bound organelles (e.g. bacteria)
• Eukaryotic cells: have a true nucleus and membrane-bound organelles (e.g. plants, animals, fungi)

Cellular Processes

• Metabolism: the process of converting energy and nutrients into cellular components
• Cell division: the process of cell growth and reproduction (mitosis, meiosis)
• Cell signaling: the process of communication between cells through signaling molecules

Cells

Definition and Structure

• Cells are the basic structural and functional units of living organisms
• Composed of a plasma membrane, cytoplasm, nucleus, and organelles
• Plasma membrane is a thin layer of lipid and protein molecules separating the cell from its environment
• Cytoplasm is a jelly-like substance inside the cell membrane where metabolic processes occur
• Nucleus contains most of the cell's genetic material (DNA)
• Organelles are specialized structures that perform specific functions

Cell Membrane

• Semi-permeable, allowing certain substances to pass through while keeping others out
• Regulates what enters and leaves the cell
• Maintains cell shape
• Provides mechanical support

Cellular Organelles

Mitochondria

• Generates energy for the cell through cellular respiration

Ribosomes

• Site of protein synthesis

Endoplasmic Reticulum (ER)

• Involved in protein synthesis, lipid synthesis, and detoxification

Golgi Apparatus

• Processes and packages proteins and lipids for transport out of the cell

Lysosomes

• Contains digestive enzymes that break down and recycle cellular waste and foreign substances

Cytoskeleton

• Provides structural support, shape, and movement to the cell

Cell Types

Prokaryotic Cells

• Lack a true nucleus and membrane-bound organelles
• Examples: bacteria

Eukaryotic Cells

• Have a true nucleus and membrane-bound organelles
• Examples: plants, animals, fungi

Cellular Processes

Metabolism

• Converts energy and nutrients into cellular components

Cell Division

• Process of cell growth and reproduction (mitosis, meiosis)

Cell Signaling

• Communication between cells through signaling molecules

Learn about the components of a cell, including the plasma membrane, cytoplasm, nucleus, and organelles, and their roles in cellular processes.