Lecture Notes: Cells and Their Structures

Introduction

• Topic: Cells and their subcellular structures.
• Objective: Understand similarities and differences between animal, plant, and bacterial cells.
• Outcome: Be able to label parts of a cell and describe their function.

What are Cells?

• Basic building blocks of life.
• Smallest unit of life that can replicate independently.
• Multicellular organisms (e.g., animals, plants) have many cells that divide for growth or replacing dead cells.
• Unicellular organisms (e.g., bacteria) where each cell is an entire organism.

Eukaryotic Cells: Animal and Plant Cells

Common Structures

• Cell Membrane: Controls substance movement in and out.
• Nucleus: Contains genetic material (DNA) and controls cell activities.
• Cytoplasm: Gel-like substance where organelles sit and chemical reactions occur.
• Mitochondria: Provide energy through aerobic respiration by breaking down glucose.
• Ribosomes: Site of protein synthesis.

Unique Plant Cell Structures

• Cell Wall: Made of cellulose; provides support and structure.
• Permanent Vacuole: Stores cell sap (sugars, salts, water).
• Chloroplasts: Site of photosynthesis; contain chlorophyll for absorbing sunlight.

Prokaryotic Cells: Bacterial Cells

• Unicellular organisms.
• Cell Membrane, Cell Wall, Ribosomes, Cytoplasm present.
• No Mitochondria or Chloroplasts.
• Genetic Material: Single circular strand of DNA in cytoplasm (nucleoid).
• Plasmids: Small rings of DNA carrying additional genes (e.g., antibiotic resistance).
• Flagella: Thread-like structures for movement.

Conclusion

• Overview of cell structures and functions.
• Practice: Suggested for further understanding through revision sites.

Additional Resources: For further practice, refer to the revision site mentioned in the presentation.

Note: Ensure to study and understand each subcellular structure's role for clarity in exams and practical applications.

End of Notes