Question

Which of the following is not considered evidence that supports the endosymbiotic theory? Mitochondria and chloroplast chromosomes are structurally similar to bacterial chromosomes. Chloroplast DNA and mitochondria DNA is an exact copy of bacteria DNA. Mitochondria and chloroplast replicate/reproduce in a manner similar to prokaryotic cells. The ribosomes of mitochondria and chloroplast resemble those of bacteria.

Answer 1

The incorrect evidence is that Chloroplast DNA and mitochondria DNA are exact copies of bacteria DNA, as they are merely highly related but not identical due to gene transfer to the host nucleus.

Step-by-step explanation:

The piece of evidence that does not support the endosymbiotic theory is the claim that 'Chloroplast DNA and mitochondria DNA is an exact copy of bacteria DNA.' While it is true that mitochondrial DNA (mtDNA) and chloroplast DNA (cpDNA) are highly related to bacterial DNA, they are not exact copies. Over time, many genes originally present in the mtDNA and cpDNA have been transferred to the host cell's nuclear DNA, meaning these organelles' genomes are now reduced in size compared to those of their bacterial ancestors.

Mitochondria and chloroplasts share several key characteristics with bacteria that support endosymbiosis: binary fission similar to bacterial replication, the structural similarity of their DNA to bacterial chromosomes, and ribosomes that resemble those found in bacteria. These characteristics, along with the additional evidence such as similar biochemistry and plasma membranes, corroborate the endosymbiotic origin of these organelles.

Answer 2

The correct answer will be option-D

Step-by-step explanation:

The endosymbiont theory suggests that bacteria form a symbiotic relationship with the cells and transformed into mitochondria and chloroplast of the cells.

The evidence which suggests that theory are closely related to the bacteria are:

1. These organelles have theory own DNA in the form of a circular chromosome like that of bacteria.

2. The chromosome contains the same sequence of genes and non-coding DNA.

3. the organelle divides by same binary fission method as used by the bacteria to divide.

4. The organelle contains their own ribosomes which help them produce their own proteins but studies suggest that mammalian ribosomes are knwon as 55S mitoribosome composed of small 28S and large 39S subunits.

Thus, option-D is the correct answer.