Multicellularity and Large Body Size of Eukaryotic Organisms Requires High

question 16

Multiple Choice

Multicellularity and large body size of eukaryotic organisms requires high metabolic rates and efficient ATP production by aerobic respiration.How did bacteria change Earth's atmosphere to enable aerobic respiration?

• A)Oxygenic photosynthesis by cyanobacteria significantly increased the amount of oxygen in the atmosphere.
• B)Splitting of water during anaerobic respiration by cyanobacteria dramatically increased the amount of oxygen in the atmosphere.
• C)Nitrogen fixation by cyanobacteria decreased the amount of nitrogen in the atmosphere,leading to simultaneous increase of oxygen.
• D)Anaerobic respiration by cyanobacteria increased the amount of oxygen in the atmosphere by reducing the amount of iron oxides that are able to react instantly with oxygen.

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Definitions:

Protein Anions

Negatively charged proteins that play various roles in cellular functions, including maintaining cell structure and function.

Cell Membrane

The semipermeable membrane surrounding the cytoplasm of a cell, controlling the passage of substances in and out.

Concentration Gradient

The variation in the distribution of molecules or ions across a space or membrane, which often dictates the direction of particles’ movement (e.g., high to low concentration).

High Concentration

A state or condition of having a large amount of substance in a certain volume or area, or the ability to focus intensely on a task or activity.