As Cyanobacterial Populations Boomed, the Process of Photosynthesis Generated Significant

question 237

Multiple Choice

As cyanobacterial populations boomed, the process of photosynthesis generated significant levels of O₂ in the oceans and atmosphere.Which statement accurately describes conditions surrounding the evolution of eukaryotes and the early role of the proteobacterial endosymbiont that would eventually develop into a mitochondrion?

• A) The increase in O₂ resulted in an increase in the energy required to maintain the eukaryotic cell-the phagocytosis of a proteobacterium was originally intended as a form of food storage.
• B) The increase in O₂ resulted in a population boom for eukaryotes-those that enlisted the aid of a proteobacterial endosymbiont were more likely to find food sources than those that did not.
• C) The increase in O₂ had a reducing effect on most eukaryotes, and the acquisition of a proteobacterium that could reduce this O₂ into water allowed the eukaryotic host to survive.
• D) The increase in O₂ had did not have an effect on most eukaryotes, but the acquisition of a proteobacterium that coupled O₂ reduction with ATP production provided an additional source of energy to the eukaryotic host.
• E) The increase in O₂ had an oxidizing effect on most eukaryotes, and the acquisition of a proteobacterium that could reduce this O₂ into water allowed the eukaryotic host to survive.

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Definitions:

Venomous Snake

A snake that produces venom, a toxic substance used predominantly for immobilizing or killing prey and for defense against predators.

Cytokines

Small proteins released by cells that have a specific effect on the interactions and communications between cells or on the behavior of cells.

White Blood Cell

Leukocyte, of which there are several types, each having a specific function in protecting the body from invasion by foreign substances and organisms.

Universal Donor

A term often associated with blood type O negative, referring to individuals whose red blood cells can be transfused into persons of any other blood type without causing an adverse reaction.