A2.2.5 - prokaryotic cell structures

prokaryotic cells

cells that lack a true nucleus and membrane-bound organelles

What is the form and func. of pilli in prokaryotic cells?

• form: small, hair-like appendages

• function: adhesion + transfer of genetic material between bacteria

What is the form and func. of the cell wall in prokaryotic cells?

• form: rigid outer layer made of peptidoglycan

• func: 

  • structural support, protection, and shape. 

  • prevent over-expansion from water

What is peptidoglycan?

A polymer made of sugars (glycans) and amino acids, forming a rigid mesh-like structure.

What is the func. of the plasma membrane in prokaryotic cells?

• transport nutrients and waste

• maintains homeostasis

• site of ATP synthesis (as they lack mitochondria)

What can be found in the cytoplasm of prokaryotic cells?

• enzymes → catalyze biochemical reactions

• 70s ribosomes → synthesize proteins

• nucleoid region: strands of DNA

How is DNA organized in the nucleoid region?

“naked DNA” - a single, circular molecule that is not wrapped around histone protein or enclosed by a nucleus, as in eukaryotic cells

What are plasmids in prokaryotic cells, and what do they do?

• smaller DNA molecules

• carry genes that confer advantages (ex. antibiotic resistance)

What are 70s ribosomes, and where can they be found?

• small ribosomes responsible for protein synthesis

• location: prokaryotic cells + mitochondria and chloroplast

significance of prokaryotic simplicity

• insight into origins of life + evolution of cellular complexity

• allows for rapid adaptation + efficient resource use

• found virtually everywhere on earth

What is the func. of flagellum in prokaryotic cells?

• locomotion

• often a sensory organelle