Chloroplasts as organisms

  • Thread starter FireBones
  • Start date
In summary, there has been discussion around whether chloroplasts and mitochondria should be considered independent organisms living in symbiosis with the cell, as they fulfill the criteria of a "living thing." However, current cells do not classify them as living organisms due to their loss of necessary genes and dependence on host proteins. It has also been noted that there are bacteria that require similar help for metabolism, blurring the lines of classification.
  • #1
103
0
I know that most people believe that chloroplasts and mitochondria evolved in eukaryotic cells by endosymbiosis, but has there been any push (or even any discussion) on whether they should actually be considered independent organisms living in symbiosis with the cell?

They fulfill most (if not all) the criteria for a "living thing."

My efforts at research through google ran up against a brick wall since the keywords I thought of all led me to the endosymbiosis theory itself rather than the question of classification.
 
Biology news on Phys.org
  • #2
They are not considered living organisms in present cells because they lost a lot of genes necessary to survive independently and need host proteins to perform functions for them
 
  • #3
mazinse said:
They are not considered living organisms in present cells because they lost a lot of genes necessary to survive independently and need host proteins to perform functions for them

Thanks, but I was under the impression that the ability to survive independently was not required so long as the entity could undergo metabolism (at all)...aren't there several bacteria that require this type of help as well?
 
  • #4
FireBones said:
Thanks, but I was under the impression that the ability to survive independently was not required so long as the entity could undergo metabolism (at all)...aren't there several bacteria that require this type of help as well?

well that's an interesting way of putting it. if you really want to hit that gray area then yeah, think of them that way.
 
  • #5


I can understand the curiosity and interest in considering chloroplasts and mitochondria as independent organisms living in symbiosis with the cell. However, the current scientific consensus is that these organelles are not considered separate organisms, but rather integral parts of eukaryotic cells.

The endosymbiosis theory, first proposed by Lynn Margulis in the 1960s, provides a well-supported explanation for the origin of chloroplasts and mitochondria in eukaryotic cells. It states that these organelles were originally free-living prokaryotic organisms that were engulfed by larger cells and over time developed a symbiotic relationship, eventually becoming permanent components of the cell.

While chloroplasts and mitochondria do possess some characteristics of living organisms, such as their own DNA and ability to reproduce, they are still dependent on the host cell for survival. They cannot exist independently and are unable to carry out all the functions necessary for life on their own.

Furthermore, the classification of an organism is based on a combination of factors, including genetic relatedness, physical structure, and ecological interactions. In the case of chloroplasts and mitochondria, their genetic makeup and structure are closely related to bacteria, but their ecological interactions are solely within the eukaryotic cell. Therefore, it is more accurate to classify them as organelles rather than independent organisms.

While there may be some debate or discussion on this topic in the scientific community, the current evidence and understanding supports the endosymbiosis theory and the classification of chloroplasts and mitochondria as organelles. As with any scientific theory, it is always open to further investigation and potential revisions as new evidence arises.
 

1. What are chloroplasts and what is their role in organisms?

Chloroplasts are organelles found in plant cells that are responsible for photosynthesis. They contain chlorophyll, a pigment that absorbs light energy and converts it into chemical energy in the form of glucose.

2. How do chloroplasts reproduce and maintain their numbers?

Chloroplasts reproduce through a process called binary fission, where they divide into two daughter chloroplasts. They also have their own DNA and can replicate themselves within the cell. They can also be inherited from parent plants during reproduction.

3. Can non-plant organisms have chloroplasts?

Yes, some non-plant organisms such as certain species of algae and protists also have chloroplasts. These organisms are photosynthetic and have evolved to have chloroplasts through endosymbiosis, where one organism engulfs another and forms a symbiotic relationship.

4. How do chloroplasts adapt to different environmental conditions?

Chloroplasts have evolved to have various adaptations to different environmental conditions. For example, in hot and dry environments, they may have a thicker outer membrane to prevent water loss, and in low light conditions, they may increase the amount of chlorophyll to absorb more light energy.

5. Can chloroplasts be genetically modified?

Yes, chloroplasts can be genetically modified to improve their efficiency and ability to produce specific compounds. This is done through genetic engineering techniques, where foreign genes are inserted into the chloroplast DNA. This has the potential to enhance plant growth and produce valuable products such as pharmaceuticals and biofuels.

Suggested for: Chloroplasts as organisms

Replies
2
Views
1K
Replies
2
Views
2K
Replies
61
Views
3K
Replies
6
Views
1K
Replies
5
Views
2K
Replies
1
Views
1K
Back
Top