Notes on Prokaryotic and Eukaryotic Cells

Two Types of Cells

• Cells are generally categorized into two types based on the presence of a nucleus:
  • Prokaryotic Cells
  • Eukaryotic Cells

Nucleus

• The nucleus is a membrane-bound structure in the cytoplasm containing most of the cell's DNA.

Prokaryotic Cells

• Characteristics:
  • Lack a nucleus; DNA is located in the cytoplasm
  • Found in single-celled organisms, such as bacteria
  • Represent the oldest type of organisms and remain the most common today
• Cell Structure:
  • Plasma membrane
  • Cytoplasm
  • Ribosomes
  • DNA

Video Resource

• Prokaryotic cells are described in detail in a video at: YouTube Video on Prokaryotic Cells

Eukaryotic Cells

• Characteristics:
  • Contain a nucleus
  • Generally larger than prokaryotic cells
  • Found in multicellular organisms such as fungi, plants, and animals
• Organelles:
  • Mitochondria: Provide energy
  • Vacuoles: Store substances
  • Greater variety of organelles allows for more functions and cell specificity

Cell Structure

• Eukaryotic cells have a more complex structure compared to prokaryotic cells

Comparisons

• Eukaryotic cells are compared to a plastic bag filled with Jell-O, where the cytoplasm contains various organelles.

Summary

• Prokaryotic Cells: No nucleus, contain only ribosomes
• Eukaryotic Cells: Have a nucleus and various other organelles

Practice Questions

• What types of organisms are prokaryotic?
• What organisms have eukaryotic cells?
• Compare prokaryotic to eukaryotic cells.
• Describe where the DNA is located in a prokaryotic cell.

Additional Resources

• Explore More I: Cell Structure and Function Hartnell College Tutorial
• Explore More II: Eukaryotic vs. Prokaryotic Cells
• Explore More III: Typical Animal Cell

Review Questions

• Define cell nucleus.
• What is the main difference between prokaryotic and eukaryotic cells?
• Give an example of a prokaryotic cell.
• Define organelle.
• What is the advantage of having organelles?