Key Points from the Lecture on Cellular Components

Lysosomes and Peroxisomes

• Known as the waste disposal of the cell.
• Small, rounded, spherical structures.
• Contain hydrolytic enzymes for breaking down molecules and organelles.

Golgi Bodies

• Part of the endoplasmic reticulum.
• Appear as flattened collections of sacs and tubes.
• Function as the cell's mailroom: receive, package, and distribute proteins throughout the cell.

Mitochondria

• Referred to as the powerhouse of the cell for both plants and animals.
• Sausage-shaped structure composed of a phospholipid bilayer.
• Produce ATP during cellular respiration, providing energy for cell activities.
• Higher energy demand in cells leads to more mitochondria.

Cytoskeleton

• Maintains cell shape, acting as the cell framework.
• Provides structural support with microfilaments and microtubules.

Chloroplasts

• Present only in plant cells and some protists.
• Site of photosynthesis; capture sunlight energy.
• Contain chlorophyll, giving plants their green color.

Flagella and Cilia

• Appendages attached to the plasma membrane for movement.
• Cilia line the respiratory tract, removing dust and particles.
• Flagella, a tail-like structure, helps bacteria move; in humans, observed in sperm cells.

Centrioles

• Rod-like structures aiding in cell division during mitosis.
• Help distribute chromosomes by migrating to opposite poles and producing the spindle apparatus.

Plasma Membrane

• Separates the cell from its environment or other cells.
• Controls the substances entering and exiting the cell, e.g., food and oxygen, while rejecting harmful wastes.

Cell Wall

• Found only in plant cells, providing support, shape, and protection.
• Located outside the cell membrane, giving plant cells a rectangular shape.

Comparison: Plant Cells vs. Animal Cells

• Plant cells:
  • Have plastids, chloroplasts, cell walls, central vacuoles, and plasmodesmata.
  • Store glucose as starch.
  • Fixed, regular shape.
• Animal cells:
  • Have centrioles and cholesterol in the cell membrane.
  • Store glucose as glycogen.
  • Amorphous shape.

Conclusion

• The presentation covered various cellular components and their functions.
• A comprehension check was suggested to test understanding of the material.