Bacteria do the same jobs without organelles
- The idea
- Predict
- See it
- Why
- Check
The idea
“A cell needs the organelle our cells use for a job, so no mitochondria means no electron transport.”
In your cells, many jobs have their own organelle. Yet a mitochondrion makes ATP with proteins in its inner membrane, and a bacterium's plasma membrane can hold the same kinds.
The short version
The mistake: A cell needs the organelle our cells use for a job, so no mitochondria means no electron transport.
What's actually true: Prokaryotes run electron transport in the plasma membrane, and glycolysis, the Krebs cycle and translation in the cytoplasm.
- Prokaryotes have no nucleus, mitochondria or chloroplasts. Their DNA sits in the cytoplasm, in a region called the nucleoid.
- Making most ATP takes a membrane that can hold an H+ gradient. A bacterium's plasma membrane is one.
- Glycolysis, the Krebs cycle and translation run in the cytoplasm. Cyanobacteria do the light reactions on thylakoids loose in the cytoplasm.
On the exam: No organelle doesn't mean no job. In a prokaryote, look to the plasma membrane and the cytoplasm.