Cell Biology - Cell Structure Overview

Study Notes

Cell Biology - Cell Structure

Two groups of cells: Prokaryotic and eukaryotic
Prokaryotic cells:
- Smaller in size
- Lack a nucleus
- Genetic material found in a single DNA loop
- May contain plasmids (small circular DNA)
- Examples: bacteria
Eukaryotic cells:
- More complex
- Have a nucleus
- Genetic material stored within the nucleus
- Examples: animal, plant, fungi, and protista
Organelles and their functions in animal and plant cells:
- Ribosomes: protein synthesis
- Mitochondria: aerobic respiration (energy release)
- Nucleus: controls cell activity, contains genetic material
- Cell membrane: controls movement of substances in and out of the cell
- Cytoplasm: liquid gel where most cell reactions happen (like anaerobic respiration)
Plant cells have additional organelles:
- Cell wall: provides strength, made of cellulose (also found in algae)
- Chloroplasts: contain chlorophyll for photosynthesis
- Vacuole: stores cell sap, helps maintain cell rigidity
Chloroplasts vs chlorophyll: Chloroplasts are organelles that contain chlorophyll, which is the green pigment that absorbs sunlight for photosynthesis.
Cell differentiation: As an organism develops, cells specialize for particular functions.
Specialized cells: cells with specific structures adapted for their functions.
Examples of specialized animal cells:
- Nerve cells: long axons for transmitting electrical impulses, specialized ends for releasing chemicals, abundant mitochondria for energy.
- Muscle cells: many mitochondria for rapid respiration, stores glycogen for energy.
- Sperm cells: tail for swimming, mitochondria for energy, acrosome (head) containing enzymes for fertilization.