Clues from bacteria
Mitochondria and plastids share features with bacteria.
A strange coincidence
Mitochondria and plastids sit inside bigger cells, yet some of their features match those of certain bacteria.
What might that suggest?
What this lesson covers
The idea
Mitochondria and plastids have their own DNA and ribosomes and make some of their own proteins, features of certain bacteria that suggest they share an evolutionary history with these single-celled organisms.
A strange coincidence
Mitochondria and plastids sit inside bigger cells, yet some of their features match those of certain bacteria.
What might that suggest?
- They may share an evolutionary history with these single-celled organisms
- It is only a coincidence with no meaning
- They are bacteria sitting in a dish
Hunt for clues
Look for each shared feature in all three.
Features like certain bacteria
Mitochondria and plastids have their own DNA and ribosomes, so they can make some of their own proteins. These features of certain bacteria suggest that mitochondria and plastids share an evolutionary history with these single-celled organisms.
Both mitochondria and chloroplasts are also double-membrane-bound organelles.
- Feature | Mitochondria and plastids | Certain bacteria
- Own DNA | yes | yes
- Own ribosomes | yes | yes
- Make some of their own proteins | yes | yes
Notes
Mitochondria and plastids have their own DNA and ribosomes and make some of their own proteins, like certain bacteria. This suggests a shared evolutionary history.
Check yourself
Mitochondria and plastids have their own…
So they can…
These features are similar to those of…
What do these shared features suggest?
- DNA and ribosomes — correct. Yes.
- cell wall and nucleus. They do not have these.
- chromosomes in a nucleus. They lie inside a cell and have their own DNA.
- make some of their own proteins — correct. Yes.
- make all the cell’s proteins. Only some.
- live outside the cell on their own. They are organelles inside the cell.
- certain bacteria — correct. Yes.
- viruses. NCERT names certain bacteria.
- plant cell walls. The features are DNA and ribosomes.
- A shared evolutionary history with these single-celled organisms — correct. Yes.
- That bacteria are made of mitochondria. It points to a shared history, not that.
- That the cell has no DNA. The organelles have their own DNA.