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Is evidence for the endosymbiont theory explaining the origin of mitochondria and chloroplasts?
Wiki User
∙ 6y ago
According to the endosymbiotic theory of the origin of both chloroplasts and mitochondria, the ancestors of these two organelles were free-living prokaryotic cells.
This theory states that an early eukaryotic cell engulfed a prokaryotic cell by endocytosis, much as one of our phagocytic white blood cells engulfs a bacterium.
On this occasion, however, for some reason (a mutation having changed a protein on the surface of the smaller cell, perhaps?) the prokaryote was not digested, but remained in a structure which evolved into the modern chloroplast, whose outer membrane was the infolded eukaryotic one, and with an inner membrane representing the original prokaryotic plasma membrane. This particular prokaryote was, unlike the larger cell, capable of photosynthesis.
In this relationship, both species benefited. The larger cell gained the ability to synthesize its own organic compounds from inorganic ones, and the smaller cell no longer had to search for protection or inorganic nutrients.
The same theory assigns the origin of mitochondriato a similar, much earlier, event involving the engulfing of an aerobic prokaryote by a larger cell.
"Endosymbiosis" refers to the relationship between two species (symbiosis) in which one is inside (endo-) the other.
Evidence for the theory includes:
the size and shape of the organelles;
their possession of a surrounding double membrane, the outer membrane more eukaryotic and the inner more prokaryotic in chemistry;
the presence of DNA in both organelles, in the form of a circular molecule lacking associated proteins, with genes, transcription, and translation;
the presence in both organelles of ribosomes that are similar in size to prokaryotic ones;
the division by both organelles in a manner like binary fission.
Wiki User
∙ 15y ago
Wiki User
∙ 11y agoThe theory of endosymbiosis relates to mitochondria and choloroplasts. It is theorised that these began as small, independent prokaryotes.
Some evidence in support of this theory includes that both mitochondria and chloroplasts have their own DNA, and that their processes more closely resemble those of prokaryotes than eukaryotes.
Wiki User
∙ 14y agoThe endosymbiont theory proposes that chloroplasts and mitochondria evolved from ________ and were engulfed by larger ________.
Wiki User
∙ 14y agoProkaryotes. Early bacteria.
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Why do scientists suspect that mitochondria and chloroplasts were originally prokaryotic cells?
Scientists saw that the membranes of mitochondria and chloroplasts resembled the cell membranes of free-living prokaryotes. This led to two hypotheses. One proposed that mitochondria evolved from endosymbiotic prokaryotes that were able to use oxygen to generate energy rich ATP. The other proposed that chloroplasts evolved from endosymbiotic prokaryotes that had he ability to photosynthesize. Mitochondria and chloroplasts share many features with free-living bacteria, such as there ribosomes have similar size and structure and they reproduce by binary fission. These similarities provide strong evidence of a common ancestry between bacteria and the organelles of living eukaryotic cells.
How many times is chloroplast larger than mitochondria?
This is a relatively complicated question as the exact origins of mitochondria and how they came to be included in eukaryotic cells is still under investigation and therefore open to debate.Everyone seems to agree though, that they originally come from bacterium and that they were assimilated into eukaryotic cells either because they were useful or through some form of symbiosis.As mitochondria are common to both plant and animal cells it could therefore be argued that they shared a common ancestor at some point in evolution.The inclusion of the chloroplast came later, and a separate line of mitochondrial and chloroplast carrying cells evolved - eventually becoming plants. The line without the chloroplast becoming animals.
Why are mitochondria and chloroplast considered cells or bacteria?
I'm not sure about chloroplasts, but with mitochondria evolutionary history has led biolgists to believe that the mitochondria now present in eukaryotic cells to have originated a couple billion years ago when a very basic eukaryotic cell injested (ate) a bacterial cell. Then, instead of digesting it for food, the bacterial cell just stayed inside and functioned with the eukaryotic cell. The evidence for this lies in the structure, genetic information (mitochondria have their own DNA and replicate separately) and proteins present. This is why it could be considered a cell (bacterial), because it, at one point in history, was an actual bacterial cell. i think the above answer is a little misleading to the question. so my answer is mitochondria and chloroplast are not considered cells or bacteria. bacteria is a cell and mitochondria and chloroplasts can be found in cells (plant and animal cells, not bacteria cells).
What is the evidence that mitochondria and chloroplasts are semiautnomous oranelles?
Two pertinent pieces. One is the genetic material kept on round form in these organelles that still codes for a few proteins, The other pertinent evidence is the means of reproduction of these organelles; they preform cellular fission, just as bacteria would.
American biologist who provided evidence for the endosymbiotic theory which explains the origin of chloroplasts and mitochondra?
Lynn Margulis was the American biologist who provided evidence for this theory.
Which is used as evidence for the idea that the domain Eukarya evolved from unicellular organisms?
Mitochondria and chloroplasts have their own DNA.
Is used as evidence for the idea that multicellular organisms evolved from prokaryotes?
Mitochondria and chloroplasts have their own DNA.
What is used as evidence for the idea that the domain Eukarya evolved from unicellular organisms?
mitochondria and chloroplasts have their own DNA
What is used as evidence for the idea of a domain Eukarya evolved from unicellular organisms?
Mitochondria and chloroplasts have their own dna
Which is used as evidence for the idea that multicellular organisms evolved from prokaryotes?
Mitochondria and chloroplasts have their own DNA
What is the evidence for endosymbiotic hypothesis?
The endosymbiotic hypothesis postulates that an early eukaryotic cells lacking mitochondria and chloroplasts phagocytosed early aerobic prokaryotes and photosynthetic prokaryotes and rather than
What part of the cell contains DNA apart from the nucleus?
The mitochondria contain their own DNA in plants and animals; and chloroplasts contain their own DNA in plants and other photosynthetic organisms. Both of these structures divide (almost like cells) inside the cells.*This is also evidence for the theory of endosymbiosis, in which early cells ate early prokarotic cells (bacteria) and gained new organelles.
What evidence is there for endosymbiotic theory?
One evidence is that both mitochondria and chloroplasts have their own circular piece of DNA that actually codes for a few proteins. This DNA is of the prokaryote type and strongly suggests that the mitochondria and chloroplast were once free living organisms that, one way or another, joined in a symbiotic relationship with a proto eukaryote cell.
A certain protein is found in mitochondria chloroplasts and bacteria This provides evidence that plants and bacteria?
have some similar DNA base sequences. if you're using castle learning, its number 1 (:
Why do scientists suspect that mitochondria and chloroplasts were originally prokaryotic cells?
Scientists saw that the membranes of mitochondria and chloroplasts resembled the cell membranes of free-living prokaryotes. This led to two hypotheses. One proposed that mitochondria evolved from endosymbiotic prokaryotes that were able to use oxygen to generate energy rich ATP. The other proposed that chloroplasts evolved from endosymbiotic prokaryotes that had he ability to photosynthesize. Mitochondria and chloroplasts share many features with free-living bacteria, such as there ribosomes have similar size and structure and they reproduce by binary fission. These similarities provide strong evidence of a common ancestry between bacteria and the organelles of living eukaryotic cells.
Discuss evidence that supports the endosymbiotic theory of eukaryotic evolution?
1.) Mitochondria and plastids are relatively the same size as bacteria 2.) Mitochondria and plastids have nucleiod DNA molecules - just like bacteria. 3.) Mitochondria and plastids reproduce the same way as bacteria - binary fission.
How many times is chloroplast larger than mitochondria?
This is a relatively complicated question as the exact origins of mitochondria and how they came to be included in eukaryotic cells is still under investigation and therefore open to debate.Everyone seems to agree though, that they originally come from bacterium and that they were assimilated into eukaryotic cells either because they were useful or through some form of symbiosis.As mitochondria are common to both plant and animal cells it could therefore be argued that they shared a common ancestor at some point in evolution.The inclusion of the chloroplast came later, and a separate line of mitochondrial and chloroplast carrying cells evolved - eventually becoming plants. The line without the chloroplast becoming animals.
