Is the endosymbiotic theory valid?
These theories were initially dismissed on the assumption that they did not contain DNA. This was proven false in the 1960s, leading Hans Ris to resurrect the idea. Endosymbiosis is a debate that has been widely accepted in the molecular biology world.
What is the basic argument of endosymbiotic theory?
The endosymbiotic theory states that some of the organelles in eukaryotic cells were once prokaryotic microbes. Mitochondria and chloroplasts are the same size as prokaryotic cells and divide by binary fission. Mitochondria and chloroplasts have their own DNA which is circular, not linear.
Which statement is true about the endosymbiotic theory?
Correct answer: The endosymbiotic theory states that ancient prokaryotes may have had a symbiotic relationship with early eukaryotes, leading them to become permanent organelles in the eukaryote. Chloroplasts, mitochondria, and flagella have all been tied to this theory.
Is the theory about the evolution of eukaryotic cells valid?
The timing of this dramatic evolutionary event (more likely a series of events) is not clear. The oldest fossil clearly related to modern eukaryotes is a red alga dating back to 1.2 billion years ago. However, many scientists place the appearance of eukaryotic cells at about 2 billion years.
How did different eukaryotic cells evolve?
According to the endosymbiotic theory, the first eukaryotic cells evolved from a symbiotic relationship between two or more prokaryotic cells. Smaller prokaryotic cells were engulfed by (or invaded) larger prokaryotic cells. They evolved into the mitochondria of eukaryotic cells.
What evidence has been found that supports the endosymbiotic theory?
Endosymbiotic Theory Evidence. The most convincing evidence supporting endosymbiotic theory has been obtained relatively recently, with the invention of DNA sequencing. DNA sequencing allows us to directly compare two molecules of DNA, and look at their exact sequences of amino acids.
Which of the following is not considered evidence that supports the endosymbiotic theory?
“The exterior structure similar to bacterial cell walls” IS NOT an evidence in favour of the endosymbiotic theory. Both mitochondria and chloroplasts are double membrane bound.
What are some differences between prokaryotic and eukaryotic cells?
There are several differences between the two, but the biggest distinction between them is that eukaryotic cells have a distinct nucleus containing the cell’s genetic material, while prokaryotic cells don’t have a nucleus and have free-floating genetic material instead.
What do prokaryotic and eukaryotic?
The primary distinction between these two types of organisms is that eukaryotic cells have a membrane-bound nucleus and prokaryotic cells do not. Prokaryotes, on the other hand, have no membrane-bound organelles. Another important difference is the DNA structure.
Which statements are true about lysosomes?
– Lysosomes are membrane spheres containing digestive enzymes. – Lysosomes neutralize toxic peroxide wastes. – Lysosomes occasionally break down healthy cells. – Lysosomes break down intruding bacteria and viruses.
What is the endosymbiotic theory of eukaryotic evolution?
The endosymbiotic theory explains how eukaryotic cells evolved. The large and small cells formed a symbiotic relationship in which both cells benefited. Some of the small cells were able to break down the large cell’s wastes for energy. They became the chloroplasts of eukaryotic cells.
What is the endosymbiotic theory of evolution?
The endosymbiotic theory is the accepted mechanism for how eukaryotic cells evolved from prokaryotic cells.
Why is endosymbiosis important to prokaryotes?
The term “endosymbiosis” means “to cooperate inside”. Whether the larger cell provided protection for the smaller cells, or the smaller cells provided energy to the larger cell, this arrangement seemed to be mutually beneficial to all of the prokaryotes.
What is endosymbiosis According to Margulis?
During Margulis’ research on the origin of eukaryotic cells, she studied data on prokaryotes, eukaryotes, and organelles, finally proposing that similarities between prokaryotes and organelles, combined with their appearance in the fossil record, was best explained by something called “endosymbiosis” (meaning “to cooperate inside.”)
What is the process of secondary endosymbiosis?
(c) Diagram shows the process of secondary endosymbiosis, whereby a primary plastid-containing alga is taken up by a heterotrophic eukaryote. Secondary endosymbiosis involves the large-scale movement of cyanobacterial and eukaryotic DNA from the primary host nucleus (N1) to the secondary host nucleus (N2), as well as DNA loss.