Notes on Cell Biology Lecture

Introduction

• Captions available; follow the Amoeba Sisters on social media.
• Discussion of memorable science classroom experiences.
• Personal anecdote about observing an amoeba under a microscope, leading to a passion for science.

Modern Cell Theory

1. The cell is the smallest living unit in all organisms.
2. All living things are made of cells (unicellular or multicellular).
3. All cells come from pre-existing cells.

Types of Cells

• Unicellular: Example - Amoeba
• Multicellular: Example - Humans

Major Cell Groups

• Prokaryotes:

  • Examples: Bacteria and Archaea
  • Characteristics:
    • No nucleus
    • No membrane-bound organelles

• Eukaryotes:

  • Examples: Plants, Animals, Fungi, Protists
  • Characteristics:
    • Have a nucleus
    • Have membrane-bound organelles

Common Features of Prokaryotes and Eukaryotes

• Both contain:
  • Genetic material
  • Cytoplasm
  • Ribosomes (not membrane-bound)
  • Cell membranes

Functions of Organelles

Cell Membrane (Plasma Membrane)

• Selectively permeable, maintaining homeostasis.

Cytoplasm

• Jelly-like material surrounding internal structures.
• Contains the cytoskeleton for support and movement.

Ribosomes

• Function: Protein synthesis
• Location: Free in cytoplasm or attached to organelles.

Nucleus (Eukaryotes)

• Holds genetic material (DNA).
• Controls cell activities.
• Contains nucleolus for ribosome production.

Endoplasmic Reticulum (ER)

• Rough ER:
  • Has ribosomes; involved in protein processing and transport.
• Smooth ER:
  • No ribosomes; involved in detoxification and lipid production.

Golgi Apparatus

• Functions as the packaging center for molecules.
• Modifies and sorts materials received from the ER.

Mitochondria

• Powers the cell by producing ATP through cellular respiration.
• Requires glucose and oxygen for energy production.

Differences Between Plant and Animal Cells

• Chloroplasts: Present in plant cells for photosynthesis.
• Vacuoles:
  • Plant cells have a large central vacuole.
  • Animal cells have several smaller vacuoles.
• Cell Wall: Present in plant cells for protection and shape; absent in animal cells.

Summary of Protein Secretion Process

1. DNA in nucleus provides instructions.
2. Ribosome synthesizes protein.
3. Rough ER transports protein in vesicles to Golgi apparatus.
4. Golgi apparatus sorts and sends proteins to the membrane for secretion.

Conclusion

• Many more organelles and functions exist in eukaryotic cells to explore.
• Encouragement to stay curious and continue learning.