Cell Biology Cellular Organelles I: Endosymbiosis and membrane-bound organelles by Donna Hesterman, Nathan H Lents, Ph.D. Reading Quiz Teach with this 1. Eukaryotic cells are different from prokaryotic cells in that they have chloroplasts. have organelles bound by membranes. evolved from different ancestors than prokaryotic cells. are smaller and less complex than prokaryotic cells. 2. Lynn Margulis is credited with formulating the theory of endosymbiosis, which says mitochondria and chloroplasts in modern day eukaryotic cells descended from free-living bacteria that were engulfed by other prokaryotic cells 2 to 3 billion years ago. eukaryotic cells evolved from prokaryotic cells due to competition for resources in the harsh environment of a barren Earth before its atmosphere contained oxygen. eukaryotic cells are the evolutionary ancestors of modern day bacteria. prokaryotic cells were destroyed by the first eukaryotic cells on the planet. 3. Lynn Margulis was not able to offer conclusive evidence for her theory of endosymbiosis until she was able to show that mitochondria have circular DNA like bacteria. she was able to show that mitochondria reproduce through binary fission. she was able to show that mitochondria and chloroplasts look very much like bacteria. DNA evidence proved that mitochondria were more closely related to a lineage of ancient bacteria than to the DNA found in the nucleus of their host cells. 4. All organelles in eukaryotic cells are thought to have evolved from endosymbiosis. true false 5. Organelles, or separate compartments within the cell, are advantageous because they allow eukaryotic cells to be smaller on average and still contain the vital machinery they need. they seal each compartment completely and keep the organelles from interacting. they allow different chemical reactions within the cell to operate simultaneously without interference from the cytoplasm or other reactions happening in different organelles. they eliminate the need for communication with the exterior environment of the cell. 6. The Golgi apparatus is part of the __________ system that, among other things, connects the nucleus with the cell's outer environment. endosymbiosis endomembrane photosynthetic aerobic 7. Eukaryotic cells are larger on average than prokaryotic cells. true false 8. Where did Margulis get her inspiration for the theory of endosymbiosis? from DNA evidence after modern DNA sequencing was developed from her lichen research from studies on the Golgi apparatus from her observations of chloroplasts and mitochondria along with ideas presented by a 19th century Russian biologist 9. The fossil record is the only reliable evidence for piecing together the evolutionary history of eukaryotic cells. true false Score Quiz
