Lecture on Eukaryotic Animal Cells

Overview

• All animals are made of eukaryotic cells.
• Eukaryotic: Cells with a true nucleus.

Comparison: Animal vs. Plant Cells

• Plant cells have a rigid cell wall made of cellulose, contain organelles for photosynthesis.
• Animal cells have a flexible membrane allowing for different cell types and tissues.
• This flexibility enables movement and complex structures in animals (muscle, nerve cells).

Historical Context

• 1665: Robert Hooke discovered cells, named for their resemblance to monk cells.

Eukaryotic Cell Structure

Cell Membrane

• Encloses the cell, selectively permeable, acts as barrier and border monitor.

Cytoplasm and Cytoskeleton

• Cytoplasm: Solution of water and nutrients.
• Cytoskeleton: Protein strands providing structural support.

Organelles

1. Endoplasmic Reticulum (ER)

• Rough ER: With ribosomes, synthesizes and packages proteins.
• Smooth ER: No ribosomes, produces lipids, detoxifies, stores ions.

2. Ribosomes

• Assemble amino acids into polypeptides.
• Located freely in cytoplasm or on the nuclear envelope.

3. Golgi Apparatus

• Processes and packages proteins.
• Creates vesicles to transport molecules.

4. Lysosomes

• Breakdown waste and debris, recycling center of the cell.

5. Nucleus

• Stores DNA, the control center of the cell.
• Nuclear membrane with nucleoplasm for protection.
• Contains nucleolus, which produces ribosomal RNA.

6. Mitochondria

• Powerhouse, site of respiration, produces ATP.
• Contains its own DNA, passed maternally.

Additional Structures

• Cilia and Flagella: For movement, composed of microtubules in a 9+2 structure.

Mitochondrial Importance

• Evolutionary history suggests mitochondria were once independent.
• Mitochondrial DNA is inherited maternally, tracing human ancestry.

Final Notes

• Eukaryotic cells are complex and essential for animal life.
• Understanding cell structures and functions is crucial in biology.

Questions and Further Learning

• Explore more through linked episodes or ask questions online to clarify concepts.