What is the Margulis Endosymbiotic hypothesis?
The endosymbiotic theory concerns the origins of mitochondria and chloroplasts, which are organelles of eukaryotic cells. In 1981, Margulis published Symbiosis in Cell Evolution in which she proposed that the eukaryotic cells originated as communities of interacting entities that joined together in a specific order.
What is evidence for the Endosymbiotic hypothesis?
Numerous lines of evidence exist, including that mitochondria and chloroplasts have their own circular DNA (prokaryotes also have circular DNA), mitochondria and chloroplasts have a double membrane (the inner membrane would have initially been the ingested prokaryote’s single membrane, and the outer membrane initially …
What is the Endosymbiotic hypothesis of eukaryotic development?
The endosymbiotic theory states that some of the organelles in today’s eukaryotic cells were once prokaryotic microbes. They eventually lost their cell wall and much of their DNA because they were not of benefit within the host cell. Mitochondria and chloroplasts cannot grow outside their host cell.
What is the main structural difference between eukaryotes and prokaryotes?
Eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not. Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal DNA.
How did Lynn Margulis use evidence which opposed a hypothesis to support her own hypothesis?
How did she use evidence which opposed a hypothesis to support her own hypothesis? She found no evidence to support the step-by-step evolution of mitochondria within cells. No cells have been seen with simple forms of mitochondria showing these steps.
Can a mitochondria survive on its own?
This loss of genes by the endosymbiont is probably one explanation why mitochondria cannot live without a host. Despite the transfer of genes between mitochondria and the nucleus, mitochondria retain much of their own independent genetic material.
How does the endosymbiotic theory explain the origin of eukaryotes?
Mitochondria and the origin of eukaryotes The leading hypothesis, called the endosymbiotic theory, is that eukaryotes arose as a result of a fusion of Archaean cells with bacteria, where an ancient Archaean engulfed (but did not eat) an ancient, aerobic bacterial cell.
How do mitochondria support the endosymbiotic theory?
There is broad evidence to show that mitochondria and plastids arose from bacteria and one of the strongest arguments to support the endosymbiotic theory is that both mitochondria and plastids contain DNA that is different from that of the cell nucleus and that they have their own protein biosynthesis machinery.
What effect do you expect the structural differences between prokaryotes and eukaryotes to have?
What effect do you expect the structural differences between prokaryotes and eukaryotes to have on their functions? Eukaryotes are more complex so they are capable of doing more things. If a cell is missing a nucleus, what will so be missing?
How are the Alphaproteobacteria related to other organisms?
The Alphaproteobacteria form one of the most abundant groups of bacteria on Earth, and one that is closely linked to all complex forms of life. Many bacteria within this class live inside the cells of other organisms. For example, mitochondria – the powerhouses of animal, plant and other eukaryotic cells – evolved from bacteria within this group.
How are Proteobacteria used in the field of Microbiology?
Because of their symbiotic properties, scientists often use Alphaproteobacteria of the genus Agrobacterium to transfer foreign DNA into plant genomes, and they also have many other biotechnological properties.
Which is the Gram negative class of Proteobacteria?
These classes include: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Epsilonproteobacteria and Zetaproteobacteria. Alphaproteobacteria is a class of Proteobacteria; like all Proteobacteria, they are Gram-negative.
Why are Proteobacteria named after the Greek god Proteus?
Because of the great diversity of forms found in this group, the Proteobacteria are named after Proteus, a Greek god of the sea, capable of assuming many different shapes, and it is therefore not named after the genus Proteus. All proteobacteria are Gram-negative, with an outer membrane mainly composed of lipopolysaccharides.