Chapter 6: A Tour of the Cell
AP Biology
Link to Evolution• Miller-Urey – cellular
components synthesized from early Earth
• Formation of protocells• Fossil evidence suggests first
prokaryotic cells appeared 3.5 BYA
• First eukaryotes appeared 2.1 BYA• Endosymbiosis
• Multicellular organisms appeared 1.2 BYA
Organelles• A specialized structure that performs a certain function within
a cell• Number and complexity depends on cell type
All Cells Have…• Plasma membrane• Boundary of cell• Controls what enters, leaves• Role in communication
TEM cross-section of cell membrane
All Cells Have…
• Cytoplasm/Cytosol• Semi-fluid substance• Where organelles are found
All Cells Have…
• Chromosomes• Genetic material (DNA)
All Cells Have…• Ribosomes• Site where protein is made
Prokaryotes vs. EukaryotesProkaryotes
• Small in size (range: 2-20µm)• Genome is singular
chromosome not organized around proteins• Located in nucleoid region
(NO nucleus)
• No membrane-bound organelles
Eukaryotes• Large size (to 100µm) • Genome organized around
proteins; multiple chromosomes• Located in nucleus
• Contain membrane-bound organelles