Cellular Organelles I: Membrane-bound Organelles

Eukaryotic cells are different from prokaryotic cells in that they

• a.have chloroplasts.
• b.have organelles bound by membranes.
• c.evolved from different ancestors than prokaryotic cells.
• d.are smaller and less complex than prokaryotic cells.

Lynn Margulis is credited with formulating the theory of endosymbiosis, which says

• a.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.
• b.eukaryotic cells evolved from prokaryotic cells due to competition for resources in the harsh environment of a barren Earth before its atmosphere contained oxygen.
• c.eukaryotic cells are the evolutionary ancestors of modern day bacteria.
• d.prokaryotic cells were destroyed by the first eukaryotic cells on the planet.

Lynn Margulis was not able to offer conclusive evidence for her theory of endosymbiosis until

• a.she was able to show that mitochondria have circular DNA like bacteria.
• b.she was able to show that mitochondria reproduce through binary fission.
• c.she was able to show that mitochondria and chloroplasts look very much like bacteria.
• d.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.

All organelles in eukaryotic cells are thought to have evolved from endosymbiosis.

• a.true
• b.false

Organelles, or separate compartments within the cell, are advantageous because

• a.they allow eukaryotic cells to be smaller on average and still contain the vital machinery they need.
• b.they seal each compartment completely and keep the organelles from interacting.
• c.they allow different chemical reactions within the cell to operate simultaneously without interference from the cytoplasm or other reactions happening in different organelles.
• d.they eliminate the need for communication with the exterior environment of the cell.

The Golgi apparatus is part of the __________ system that, among other things, connects the nucleus with the cell's outer environment.

• a.endosymbiosis
• b.endomembrane
• c.photosynthetic
• d.aerobic

Eukaryotic cells are larger on average than prokaryotic cells.

• a.true
• b.false

Where did Margulis get her inspiration for the theory of endosymbiosis?

• a.from DNA evidence after modern DNA sequencing was developed
• b.from her lichen research
• c.from studies on the Golgi apparatus
• d.from her observations of chloroplasts and mitochondria along with ideas presented by a 19th century Russian biologist

The fossil record is the only reliable evidence for piecing together the evolutionary history of eukaryotic cells.

• a.true
• b.false