ATAR Notes: Forum

Uni Stuff => Science => Faculties => Biology => Topic started by: monokekie on May 09, 2010, 02:41:39 pm

Title: What evidence support the theory of endosymbiosis of mitochondria n chloroplast?
Post by: monokekie on May 09, 2010, 02:41:39 pm
this question asks us to list three reasons, do you hav any idea? thank you!
Title: Re: What evidence support the theory of endosymbiosis of mitochondria n chloropl
Post by: lexitu on May 09, 2010, 06:08:02 pm
- Similar size to bacteria
- Similar structure (esp. chloroplasts are similar to modern day cyanobacteria)
- Both mitochondria and chloroplasts contain DNA which indicates that they could have once functioned independently
Title: Re: What evidence support the theory of endosymbiosis of mitochondria n chloroplast?
Post by: crayolé on May 09, 2010, 06:12:06 pm
They both contain DNA
The contain free ribosomes similar to those in bacteria
Both mitochondria and chloroplasts have small genomes compared to bacteria, this is because they developed an increased dependence on the eukaryotic host after the process of endosymbiosis which means they did not need much genetic information as the new host now did most of the work.

More information here
http://en.wikipedia.org/wiki/Endosymbiotic_theory

Should have everything you need to know ;]
Title: Re: What evidence support the theory of endosymbiosis of mitochondria n chloroplast?
Post by: happyhappyland on May 09, 2010, 09:14:57 pm
What about the double membranes? I dont understand why they significant
Title: Re: What evidence support the theory of endosymbiosis of mitochondria n chloroplast?
Post by: Edmund on May 11, 2010, 10:26:47 pm
Here are some I can think of:

Organelles similar to the one found in bacteria

Organelles have double membrane, shows that engulfment has occured (inner membrane therefore represents prok., outer represents euk. membrane)

Retain machinery such as 70S ribosomes for protein synthesis

Metabolism is similar to existing prokaryotic organisms (cynobacteria similar to chloroplast, and purple bacteria similar to mitochondria)

Some bacteria still have the bacterial peptidoglycan wall between inner and outer walls

These are also semi autonomous, they retain their own genome