Multiple Choice
Single-celled prokaryotes had Earth to themselves for approximately __________.
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24. History of Life on Earth
History of Life on Earth
Multiple Choice
What evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic endosymbionts?
A
They have a single circular chromosome similar to bacterial chromosomes.
B
They have flagella similar to bacterial flagella.
C
Their ribosomes are more like prokaryotic ribosomes than eukaryotic ribosomes.
D
They divide by a process similar to meiosis.
E
The first and third responses are correct.
Verified step by step guidance1
Understand the endosymbiotic theory, which suggests that mitochondria and plastids (such as chloroplasts) originated as free-living prokaryotes that were engulfed by an ancestral eukaryotic cell.
Examine the evidence that supports this theory: mitochondria and plastids have their own DNA, which is organized in a single circular chromosome, similar to the DNA found in prokaryotes.
Consider the structure of ribosomes: mitochondria and plastids have ribosomes that are more similar in size and structure to prokaryotic ribosomes than to eukaryotic ribosomes, supporting the idea of a prokaryotic origin.
Evaluate the process of division: mitochondria and plastids divide by binary fission, a process similar to how prokaryotes reproduce, rather than by meiosis, which is used by eukaryotic cells for sexual reproduction.
Conclude that the presence of a single circular chromosome and prokaryotic-like ribosomes in mitochondria and plastids are key pieces of evidence supporting their evolution from prokaryotic endosymbionts.
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