Study Notes
Cells are the fundamental units of life, with prokaryotic and eukaryotic cells differing in structure and complexity. Eukaryotic cells contain organelles that perform specific functions, while prokaryotic cells are simpler and lack a nucleus.
- Prokaryotic Cells — simple cells without a nucleus or membrane-bound organelles. Example: Bacteria and Archaea.
- Eukaryotic Cells — complex cells with a nucleus and membrane-bound organelles. Example: Human, plant, fungi, and protists.
- Cell Membrane — a partially permeable membrane controlling material movement in and out of the cell. Example: Phospholipid bilayer with proteins.
- Nucleus — contains the cell's genetic material and controls activities. Example: Chromatin and nucleolus.
- Mitochondria — powerhouse of the cell, producing ATP through aerobic respiration. Example: Double membrane with cristae.
- Chloroplast — site of photosynthesis in plant cells. Example: Contains chlorophyll and thylakoids.
- Ribosome — site of protein synthesis. Example: 80S in eukaryotes, 70S in prokaryotes.
- Virus — non-cellular particles that replicate inside host cells. Example: Protein coat and nucleic acid core.
Exam Tips
Key Definitions to Remember
- Prokaryotic Cells: Simple cells without a nucleus.
- Eukaryotic Cells: Complex cells with a nucleus.
- ATP: Energy currency of the cell.
Common Confusions
- Prokaryotic vs Eukaryotic cell structures.
- Functions of organelles like mitochondria and chloroplasts.
Typical Exam Questions
- What is the main function of mitochondria? Answer: To produce ATP through aerobic respiration.
- How do prokaryotic cells differ from eukaryotic cells? Answer: Prokaryotic cells lack a nucleus and membrane-bound organelles.
- What role does the cell membrane play? Answer: It controls the movement of substances in and out of the cell.
What Examiners Usually Test
- Differences between prokaryotic and eukaryotic cells.
- Functions and structures of cell organelles.
- The role of ATP in cellular processes.