Anatomy and Physiology / Unit 2: Cells and Tissues
2.2 Cell Organelles and Their Functions
Notes
A typical human cell has a plasma membrane, cytoplasm (cytosol plus organelles) and a nucleus.
- Nucleus: holds DNA, controls the cell; contains the nucleolus, which makes ribosomal parts.
- Ribosomes: make proteins. Rough ER (with ribosomes) makes proteins for export; smooth ER makes lipids and detoxifies drugs.
- Golgi apparatus: modifies, packages and ships proteins.
- Mitochondria: make most ATP through cellular respiration.
- Lysosomes: digestive enzymes break down worn-out parts and bacteria. Peroxisomes break down toxins such as hydrogen peroxide.
- Cytoskeleton: gives shape and movement. Centrioles help divide chromosomes. Cilia and flagella move fluid or the cell.
- Example: a muscle cell has very many mitochondria because it needs a lot of ATP.
Practice
Which organelle is the main site of ATP production?
Mitochondria carry out aerobic cellular respiration to make most of the cell's ATP.
A cell that secretes a large amount of protein hormone would be expected to have a well-developed:
Proteins for export are made on the rough ER, then modified and packaged by the Golgi apparatus.
A white blood cell engulfs a bacterium. Which organelle will digest it?
Lysosomes contain digestive enzymes that break down engulfed material.
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