1. During the carboxylation phase of the Calvin cycle, CO₂ combines with

A. ribulose 1,5 – bisphosphate
B. phosphoglyceraldehyde
C. pyruvic acid
D. oxaloacetic acid

2. Which of the following groups contain(s) many unique coenzymes, such as coenzyme M and coenzyme F420?

A. Sulfate-reducing bacteria
B. Methanotrophs (methane-oxidizing microbes)
C. Methanogens (methane-producing microbes)
D. Acetogens (acetigens; acetate-producing microbes)

3. In passive diffusion, solute molecules cross the membrane as a result of

A. concentration difference
B. pressure difference
C. ionic difference
D. all of these

4. In an oxygenic photosynthesis, the green and the purple bacteria do not use which of the following one as an electron source?

A. H₂O
B. H₂
C. H₂S
D. S (elemental sulfur)

5. Radioisotopes are frequently used in the study of cells. Assume a culture of E. coli is grown in a culture medium containing radioactive phosphorous. At the end of 48 hours, it is expected to find the radioactive label located in

A. enzymes
B. RNA
C. phospholipids
D. all of these