Many Cyanobacteria Carry Out Both Oxygenic Photosynthesis and Nitrogen Fixation

question 19

Multiple Choice

Many cyanobacteria carry out both oxygenic photosynthesis and nitrogen fixation, but oxygen inhibits nitrogen fixation. How do these cyanobacteria manage both processes?

• A) Nitrogen fixation is sequestered in special cells called heterocysts.
• B) The processes are seasonal; photosynthesis occurs in summer and nitrogen fixation takes place in winter.
• C) They trap the oxygen in special cells called heterocysts.
• D) They have special membranous structures like chloroplasts to separate the processes within the cell.
• E) They produce cells called akinetes for photosynthesis.

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