Comparing Prokaryotic & Eukaryotic Cells (College Board AP® Biology): Study Guide

Compartmentalization in prokaryotes and eukaryotes

• Membranes compartmentalize cells from their external environment

• Membrane-bound organelles offer compartmentalization within cells

  • They ensure that specific metabolic processes are kept separate from the rest of the cell

• There are distinct differences in the utilization of compartmentalization in eukaryotic and prokaryotic cells

• Both cell types have a plasma membrane that acts as a selective barrier, maintaining internal environments distinct from the external environment

Eukaryotes

• Animal and plant cells are types of eukaryotic cells

• Eukaryote cells are compartmentalized to create partitions within the cell for specialized reactions to take place

• Organelles within eukaryotes are typically membrane bound such as the nucleus, endoplasmic reticulum, Golgi apparatus and mitochondria

• These internal membranes facilitate cellular processes by

  • Ensuring that competing interactions are minimized

  • Increasing the surface areas where reactions can occur

Examples of compartmentalization

• Eukaryotic cells have a membrane-bound nucleus that encloses their genetic material

  • This provides a distinct compartment for transcription of DNA during protein synthesis

• Protein synthesis and transport occurs within a intermembrane system through the presence of ER, Golgi apparatus and vesicles

• Energy is released in specialized organelles, such as mitochondria (for cellular respiration) or chloroplasts (for photosynthesis)

• Vacuoles or vesicles are used for storage, waste management, and maintaining osmotic balance

Prokaryotes

• Prokaryotes are single-celled organisms that lack a nucleus and other membrane-bound organelles

  • Bacteria are a type of prokaryote

• They are smaller than eukaryotic cells

Examples of compartmentalization

• The genetic material of prokaryotic cells is not packaged within a membrane-bound nucleus and is found within a region called a nucleoid

• Metabolic processes like photosynthesis or nitrogen fixation occur in specialized areas instead of organelles

• Due to a lack of mitochondria, energy release occurs across the plasma membrane or within infoldings of structures called mesosomes

• Molecules such as glycogen are stored within storage granules

Comparing eukaryotic and prokaryotic compartmentalization