1.5 The origin of cells Flashcards
What does cell theory postulate about the nature of living organisms and cell reproduction?
Cell theory postulates that living organisms consist of one or more cells and that cells arise from pre-existing cells.
Who provided crucial evidence against spontaneous generation, supporting that cells come from pre-existing cells?
Louis Pasteur.
Describe Pasteur’s experiment that disproved spontaneous generation.
Pasteur boiled nutrient broth in swan-neck flasks, leaving one sealed, another open, and the third exposed to air. Only the exposed broth became cloudy with microbial growth, disproving spontaneous generation.
What hypothesis does the Miller–Urey experiment support regarding the origin of the first cell?
The hypothesis that the first cell came from non-living material, as simple organic molecules can be synthesized from inorganic compounds under conditions similar to early Earth.
What does the endosymbiotic theory explain about eukaryotic cells?
It explains the origin of eukaryotic cells from prokaryotic organisms through a process where mitochondria and chloroplasts, once free-living prokaryotes, were taken in by a larger host cell.
Name two organelles that are evidence for the endosymbiotic theory.
Mitochondria and chloroplasts.
List three pieces of evidence supporting the endosymbiotic theory.
Both mitochondria and chloroplasts have double membranes, circular naked DNA like prokaryotes, and divide by binary fission.
How did mitochondria and chloroplasts benefit their host cells according to the endosymbiotic theory?
Mitochondria provided energy through aerobic respiration, and chloroplasts converted light energy to chemical energy, producing sugars through photosynthesis.
