Lecture on Animal Cells and Eukaryotic Cells

Basics of Animal Cells

• Animals, including carcasses, are made of eukaryotic cells.
• Eukaryotic cells: Have a true nucleus containing DNA and various organelles.
• Organelles: Different types, each with specific functions, surrounded by the cell membrane.

Comparison with Plant Cells

• Plant cells are also eukaryotic but have a rigid cell wall made of cellulose.
• Plant cells can produce their own food through organelles not present in animal cells.
• Animal cells have flexible membranes allowing more variety in cell, organ, and tissue types.

Unique Features of Animal Cells

• Flexible membranes allow for movement, nerve structures, and muscle cells.
• Specialized muscle tissue is unique to animals, aiding in movement and survival.

Historical Context

• Cells first discovered by Robert Hooke in 1665.

The Cell as a City

• Cell Membrane: Acts like a border, selective permeability.
• Cytoplasm: Contains nutrients, filled with cytoskeleton for structure.
• Cytoskeleton: Protein strands that reinforce the cell.
• Centrosomes: Assemble microtubules, act like steel girders.

Organelles and Their Functions

Endoplasmic Reticulum (ER)

• Rough ER: Has ribosomes, synthesizes and packages proteins.
• Smooth ER: Produces lipids, detoxifies substances, stores ions.

Ribosomes

• Assemble amino acids into polypeptides.
• Found in cytoplasm or attached to the nuclear envelope.

Golgi Apparatus

• Processes and packages proteins.
• Can create small hormones from proteins and combine them with carbohydrates.

Lysosomes

• Breakdown cellular waste and debris for recycling.

Nucleus & Nucleolus

• Nucleus: Stores DNA, governs the cell's functions.
• Chromatin: Web-like substance housing DNA.
• Nucleolus: Produces ribosomal RNA.

Powerhouse of the Cell: Mitochondria

• Site of cellular respiration, converts food into ATP.
• Once free-living bacteria, have own DNA, replicate independently within cells.
• Mitochondrial DNA is maternally inherited.

Evolutionary Insight

• Mitochondria were integrated into animal cells millions of years ago.
• Mitochondrial Eve suggests all humans share maternal mitochondrial lineage dating back 200,000 years.

Learning Tools

• Links to previous episodes and videos for further learning.
• Encouragement to ask questions for clarification.