Overview
This lecture introduces the structure and function of a typical human cell by comparing its organelles to parts of a city, explaining their roles in cellular processes.
Introduction to Cells
- Cells are the smallest functional units in the human body and require a microscope to be seen.
- Cells provide structure, take in nutrients, convert nutrients into energy, and store DNA.
Cell Organelles and Their Functions
- Organelles are specialized structures within the cell, each serving a specific function.
The Nucleus
- The nucleus stores genetic material (DNA) and directs cell activities, similar to a city mayor.
- It contains the information the cell needs to perform its functions.
Endoplasmic Reticulum (ER)
- The ER is the cell's highway system, transporting materials around the cell.
- Rough ER, with ribosomes attached, produces proteins.
- Smooth ER, without ribosomes, produces lipids for cell membranes.
- Proteins and lipids are packaged in vesicles for transport.
Golgi Apparatus
- The Golgi apparatus functions as the cell’s post office, modifying, sorting, and shipping proteins and other materials received from the ER.
Ribosomes
- Ribosomes are the cell’s construction workers, found on the rough ER and floating freely.
- They produce proteins necessary for repairing damage and maintaining organelles.
Cytoplasm
- The cytoplasm is a fluid solution of water and nutrients filling the cell, allowing movement and providing an environment for organelles to operate.
Lysosomes
- Lysosomes are the cell’s recycling centers, breaking down waste and converting it into reusable materials.
Mitochondria
- Mitochondria, known as the powerhouse, generate energy through cellular respiration, supplying power to all organelles.
Cell Membrane
- The cell membrane is a protective, flexible barrier that controls what enters and exits the cell, safeguarding its contents.
Key Terms & Definitions
- Organelle — specialized structure in a cell with a specific function
- Nucleus — stores DNA and directs cell activities
- Endoplasmic Reticulum (ER) — network that produces and transports proteins and lipids
- Ribosome — structure that synthesizes proteins
- Golgi Apparatus — modifies and distributes proteins and other molecules
- Cytoplasm — jelly-like fluid that fills the cell and supports organelles
- Lysosome — organelle that digests and recycles cellular waste
- Mitochondria — organelle that produces energy for the cell
- Cell Membrane — flexible barrier controlling passage of substances in and out of the cell
Action Items / Next Steps
- Review diagrams showing each organelle's real appearance
- Study the functions of each organelle for possible quiz or exam questions