AP Biology : Understand endosymbiotic theory

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #581 : Cellular Biology

Mitochondria and chloroplasts have their own DNA, which is similar to the DNA of

Possible Answers:

humans

fungi

protozoa

bacteria

Correct answer:

bacteria

Explanation:

Bacteria, a prokaryote, has circular DNA, as do mitochondria and chloroplasts. This provides support for the Endosymbiotic Theory, which states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote).

Example Question #582 : Cellular Biology

Reproduction of chloroplasts and mitochondria occurs via

Possible Answers:

Meiosis

Mitosis

Fission-like process, similar to the reproduction process of eukaryotes

Fission-like process, similar to the reproduction process of bacteria

Correct answer:

Fission-like process, similar to the reproduction process of bacteria

Explanation:

Chloroplasts and mitochondria reproduce through fission, the same process through which bacteria reproduce. Eukaryotes reproduce through mitosis or meiosis, depending upon the type of cell.

Example Question #583 : Cellular Biology

Supporting the Endosymbiotic Theory, mitochondria and chloroplasts have a _________ membrane.

Possible Answers:

single

double

thick

thin

Correct answer:

double

Explanation:

The Endosymbiotic Theory states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote). Mitochondria and chloroplasts have a double membrane (the inner membrane would have initially been the ingested prokaryote’s single membrane).

Example Question #584 : Cellular Biology

Mitochondria and chloroplasts have ribosomes that are ___, similar to __ cells.

Possible Answers:

70S, eukaryotic

70 S, prokaryotic

80S, eukaryotic

80S, prokaryotic

Correct answer:

70 S, prokaryotic

Explanation:

Prokaryotic cells, mitochondria, and chloroplasts have 70S ribosomes, whereas eukaryotic cells have 80S ribosomes. This provides support for the Endosymbiotic Theory, which states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote).

Example Question #585 : Cellular Biology

The Endosymbiotic Theory posits that, before being engulfed by a eukaryotic cell, they were

Possible Answers:

Viruses

Free-living prokaryotes

Organelles

Free-living eukaryotes

Correct answer:

Free-living prokaryotes

Explanation:

The Endosymbiotic Theory states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote). The aerobic bacteria were initially free-living prokaryotes, before being ingested by anaerobic bacteria.

Example Question #586 : Cellular Biology

Which of the following is NOT evidence for the Endosymbiotic Theory?

Possible Answers:

Mitochondria and chloroplasts have circular DNA

Mitochondria and chloroplasts have 70S ribosomes

Mitochondria and chloroplasts have a single membrane

Mitochondria and chloroplasts have a double membrane

Correct answer:

Mitochondria and chloroplasts have a single membrane

Explanation:

The Endosymbiotic Theory states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote). This theory explains the origin of eukaryotic cells. Numerous lines of evidence exist, including that mitochondria and chloroplasts have their own circular DNA (prokaryotes also have circular DNA), mitochondria and chloroplasts have a double membrane (the inner membrane would have initially been the ingested prokaryote’s single membrane, and the outer membrane initially would have come from the cell that engulfed it), mitochondria and chloroplasts have 70S ribosomes (prokaryotes 70S have ribosomes, whereas eukaryotes have 80S ribosomes).

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