Overview
This lecture reviews key cell organelles and structures, describing their main functions and emphasizing their importance in cell and organismal health.
Common Cell Structures
- All cells have a cell membrane that regulates substance entry and exit, maintaining homeostasis.
- The cell wall provides structure and protection, present in most prokaryotes and some eukaryotes (e.g., plant cells).
- Cytoplasm is the cell's internal material (excluding the nucleus); the cytosol is its jelly-like part.
- All cells contain ribosomes, which synthesize proteins.
Eukaryotic Cell Organelles
- Centrioles are involved in cell division and found in animal cells.
- Chloroplasts are responsible for photosynthesis, found in plant cells.
- The endoplasmic reticulum (ER) transports and processes materials; rough ER makes proteins, and smooth ER makes lipids and detoxifies.
- The Golgi apparatus modifies, sorts, and packages materials for delivery.
- Lysosomes contain enzymes for breaking down substances, mainly in animal cells.
- Mitochondria perform cellular respiration to produce ATP, the cell's energy currency.
- The nucleus contains DNA and controls cell activities.
- Vacuoles store water, proteins, or waste; large central vacuole in plants, smaller vacuoles in animals.
The Importance of Organelle Function
- Dysfunction in organelles (ER, mitochondria, ribosomes) can cause cellular and organismal disease.
- Proper function of each organelle is vital for cell and overall health.
Key Terms & Definitions
- Homeostasis — maintenance of stable internal conditions in a cell or organism.
- Cell membrane — outer layer controlling material movement in and out of the cell.
- Cell wall — rigid structure providing protection and shape.
- Cytoplasm — internal material of the cell, excluding the nucleus.
- Cytosol — jelly-like substance within the cytoplasm.
- Centrioles — organelles aiding in cell division.
- Chloroplast — organelle for photosynthesis in plant cells.
- Endoplasmic reticulum (ER) — organelle for material transport and synthesis.
- Golgi apparatus — organelle for modifying and packaging substances.
- Lysosome — organelle containing digestive enzymes.
- Mitochondria — organelle producing ATP via cellular respiration.
- Nucleus — structure housing DNA and controlling cell functions.
- Ribosome — structure that synthesizes proteins.
- Vacuole — organelle for storage in cells.
Action Items / Next Steps
- Pause and practice identifying organelles and their functions on animal and plant cell diagrams.
- Review organelle functions for upcoming quizzes or tests.