Question

Which statement below correctly explains and gives the importance of the endosymbiotic theory?

Answer 1

Answer:

The statement that best explains the endosymbiotic theory is that the inner and outer membrane of the mitochondria indicates these were once free living organisms which were taken into an early cell via endocytosis. The theory was further supported by the fact that mitochondria have their own DNA and replicate via binary fission (option B).

Explanation:

The endosymbiotic theory is due to the evolutionary biologist Lynn Margulies, who through his postulates tried to establish evidence of the origin of eukaryotic cells, by incorporating a prokaryotic cell into the interior of others.

Mitochondria -besides chloroplasts- are one of the examples that support the endosymbiotic theory.  Both mitochondria and chloroplasts have characteristics and behavior similar to that of a bacterium (prokaryote):

• They have their own circular double-stranded DNA.
• They have 70S ribosomes.
• Protein synthesis capacity.
• They have membranes that allow them to carry out their functions.
• Their division is carried out by binary fission.

These characteristics support that some organelles were at some time independent prokaryotic cells that were incorporated into other cells, by endocytosis.

Learn more:

Importance of endosymbiotic theory brainly.com/question/583859

Answer 2

Answer:

The correct answer is B) The endosymbiotic theory states that the inner and outer membrane of the mitochondria indicates these were once free living organisms which were taken into an early cell via endocytosis. The theory was further supported by the fact that mitochondria have their own DNA and replicate via binary fission.

Explanation:

The endosymbiotic theory essentially states that some organules of the eukaryotic cells, such as mitochondria and chloroplasts, were once free-living bacteria. Probably, these organisms must have been phagocytized, but not digested by another cell. On the contrary, these bacteria were able to adapt to its host in such a way that the two cells established a dependent relationship with each other.

Due to its similarities to other free-living bacteria, it has been speculated that chloroplasts must derivate from cyanobacteria and that mitochondria must derivate from rickettsias.

The new bond between these cells would be of mutual benefit and became so dependant that they would not be able to survive without the other one.

This theory is supported by a few characteristics of the chloroplasts and mitochondria that suggest that they once were a free cell. For example,

• Both organelles present their own genetic material. This DNI is independent of the DNA of the cells, is bi-catenary and circular, identical to DNA of the bacteria, and very different from the one of the eukaryotic cells.

• These organelles divide by binary fission and not by mitosis, and are capable of synthesizing their own ribosomes and organelles.

• Both organelles present a double membrane, characteristic that reinforce the idea of being phagocyted. The internal membrane looks identical to the membrane of bacterias, while the external membrane looks like the eukaryotic one.  

• In fact, in this internal membrane are placed the energy centers, exactly as it occurs in bacterias membrane.  

• Finally, the sizes of the organelles are similar to the size of some procaryotes.