Study Notes
The ultrastructure of cells involves understanding the detailed structures within prokaryotic and eukaryotic cells. Prokaryotes have a simple cell structure without compartmentalization, while eukaryotes have a compartmentalized cell structure, allowing for specialized functions within organelles.
- Cytoplasm — internal fluid component of the cell Example: Found in both prokaryotic and eukaryotic cells
- Nucleoid — region of the cytoplasm where the DNA is located in prokaryotes Example: Contains circular DNA called a genophore
- Plasmids — autonomous circular DNA molecules in prokaryotes Example: Can be transferred between bacteria
- Ribosomes — complexes of RNA and protein for polypeptide synthesis Example: 70S in prokaryotes, 80S in eukaryotes
- Cell membrane — semi-permeable barrier surrounding the cell Example: Present in all cell types
- Cell wall — rigid outer covering made of peptidoglycan in prokaryotes Example: Provides shape and prevents lysis
- Lysosomes — membranous sacs with hydrolytic enzymes in eukaryotes Example: Break down macromolecules
- Mitochondria — site of aerobic respiration in eukaryotes Example: Produces ATP
- Chloroplast — site of photosynthesis in plant cells Example: Contains thylakoids for light absorption
- Golgi apparatus — processes and packages proteins in eukaryotes Example: Modifies proteins from the rER
- Vesicles — small membrane-bound sacs for transport Example: Move materials within cells
- Centrioles — microtubule organizing centers in animal cells Example: Involved in cell division
- Vacuole — fluid-filled cavity in plant cells Example: Maintains hydrostatic pressure
Exam Tips
Key Definitions to Remember
- Prokaryotic cell
- Eukaryotic cell
- Ribosome
- Mitochondria
- Chloroplast
Common Confusions
- Difference between prokaryotic and eukaryotic cells
- Function of lysosomes versus vacuoles
Typical Exam Questions
- What is the function of the mitochondria? Site of aerobic respiration and ATP production
- How do prokaryotic cells differ from eukaryotic cells? Prokaryotic cells lack compartmentalization and have no nucleus
- What role do chloroplasts play in plant cells? They are the site of photosynthesis
What Examiners Usually Test
- Identification of organelles in electron micrographs
- Differences between prokaryotic and eukaryotic cells
- Functions of specific organelles like lysosomes and Golgi apparatus