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