Eukaryotic vs Prokaryotic Cells: Essential Review

Cell Classification

• Two broad groups: eukaryotic cells vs prokaryotic cells
• All living organisms fall into one of these cellular categories

Key Structural Differences

• Nucleus:
  • Eukaryotes: true double-membrane nucleus containing DNA
  • Prokaryotes: no nucleus; DNA in nucleoid (open region)
• Organelles (membrane-bound):
  • Present in eukaryotes (mitochondria, rough/smooth ER, Golgi, chloroplasts in plants)
  • Absent in prokaryotes
• Ribosomes:
  • Both have them; eukaryotic ribosomes are larger, membrane-bound
• DNA organization:
  • Eukaryotes: multiple, tightly packed chromosomes
  • Prokaryotes: single circular loop of stable chromosomal DNA

Size & Complexity

• Eukaryotic cells generally larger
• Prokaryotic cells smaller with higher surface-area : volume ratio \Rightarrow higher metabolic & growth rates, shorter generation times

Organismal Level

• Eukaryotes: animals, plants, fungi, protozoa; mostly multicellular (exceptions: amoeba, paramecium, yeast)
• Prokaryotes: bacteria, archaea; always unicellular

Reproduction

• Eukaryotes: primarily sexual reproduction \Rightarrow genetic recombination
• Prokaryotes: asexual binary fission \Rightarrow clonal offspring

Shared Features

• Cell (plasma) membrane of phospholipids & proteins; selective barrier
• Cytoplasm / cytosol: site of metabolic reactions (e.g., protein synthesis)
• Ribosomes (protein synthesis)
• DNA as hereditary material regulating cell functions