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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.
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What parts of a cell do scientists think were once free-living organisms?
Mitochondria and chloroplasts are thought to have once been a free prokaryotic cell.
Is mitochondria green?
No. As far as many scientists are concerned, mitochondria have no colour. Chloroplast, the organelle which creates glucose in plants, is green.
Where do scientists believe mitochondria and chloroplasts originated?
Some scientists believe that mitochondria and chloroplasts were at one time independent-living bacteria that were engulfed by eukaryotic cells, forming an endosymbiotic relationship. This is because both mitochondria and chloroplasts have their own DNA and replicate themselves within the cells in which they occur.
How do the finding of margulis and other scientists-that mitochondria and cholarplasts have third own DNA like a cell nucleus-support the hypothesis of endosymbiosis?
concept that mitochondria and chloroplasts are the result of years of evolution initiated by the endocytosis of bacteria and blue-green algae which, instead of becoming digested, became symbiotic.
What is found in mitochondria and chloroplasts that is not found in any other organelle except the nucleus leading scientists to believe that these two organelles are actually ancient prokayotes?
Mitochondria and chloroplasts contain their own DNA, separate from the cell's nuclear DNA. This unique DNA is circular, similar to bacterial DNA, leading scientists to hypothesize that these organelles were once independent bacteria that were engulfed by a precursor to eukaryotic cells in a symbiotic relationship.
What parts of a cell do scientists think were once free-living organisms?
Mitochondria and chloroplasts are thought to have once been a free prokaryotic cell.
Why did scientists place bacteria in their kingdom the monera?
Scientists placed bacteria in their own kingdom, the Monera, because bacteria lack the nuclei, mitochondria, and chloroplasts found in other forms of life
Is mitochondria green?
No. As far as many scientists are concerned, mitochondria have no colour. Chloroplast, the organelle which creates glucose in plants, is green.
Why did the scientists place bacteria in their own kingdom the Monera?
Scientists placed bacteria in their own kingdom, the Monera, because bacteria lack the nuclei, mitochondria, and chloroplasts found in other forms of life
How do some scientists think that the first eukaryotes evolved?
By various bacteria ingesting but not digesting other bacteria, most likely the precursors of mitochondria (and/or chloroplasts).
Where do scientists believe mitochondria and chloroplasts originated?
Some scientists believe that mitochondria and chloroplasts were at one time independent-living bacteria that were engulfed by eukaryotic cells, forming an endosymbiotic relationship. This is because both mitochondria and chloroplasts have their own DNA and replicate themselves within the cells in which they occur.
Do bacteria have plastids?
No, bacteria do not have plastids. Plastids are organelles found in plant cells and some protists, responsible for functions like photosynthesis and storage of nutrients. Bacteria do not contain plastids in their cellular structure.
What were the characteristic of mitocondria and chloroplast that caused scientists to hypothosize that they were originaly prokaryotic cells that were engulfed by early eukaryotic cells?
Following characteristics of mitochondria and chloroplast led Margulis (1983) and other scientists to hypothesized that mitochondria and chloroplast were Bacteria and Cyanobacteria that were engulfed by Amoeboid Eucaryotic cells and became symbiotic organelles. 1; Both mitochondria and chloroplast (M&C) are self replicating. 2; Both possess small circular DNA molecule similar to Plasmids. 3; Both possess an outer membrane similar to eukaryotic cell membrane. 4; Both possess an inner membrane simillar to prokaryotic cell membrane as it lacks sterols. 5; Both possess ribosome similar to prokaryotes and smaller than eukaryotic ribosomes. 6; Both produce their own m RNA and some proteins . 7; Both can produce their own ATP. 8; Both are semidependent on animal or plant cell. this hypothesis is called Endosymbiont hypothesis,
What role did microscopes play in the origin of the endosymbiotic theory more than 100 years ago?
Microscopes allowed scientists to observe cellular structures in detail, leading to the discovery of organelles like mitochondria and chloroplasts. These observations contributed to the development of the endosymbiotic theory, which proposes that these organelles originated from engulfed prokaryotic cells that formed a symbiotic relationship within eukaryotic cells.
Why did scientist place bacteria in Their own kingdom monera?
Scientists placed bacteria in their own kingdom, the Monera, because bacteria lack the nuclei, mitochondria, and chloroplasts found in other forms of life
Why do scientists believe that mitochondria may have evolved from bacteria?
Scientists believe that mitochondria may have evolved from bacteria because they have their own DNA, replicate independently within cells, and have similar characteristics to certain types of bacteria. Additionally, the endosymbiotic theory suggests that mitochondria were once free-living bacteria that were engulfed by early eukaryotic cells and formed a symbiotic relationship.
Which technique helped scientists in the 1800 to identify cell organelles?
The development of the light microscope in the 1800s helped scientists identify cell organelles. This allowed for better visualization of the internal structure of cells and facilitated the discovery and characterization of organelles such as the nucleus, mitochondria, and chloroplasts.
