What was produced by photosynthesis before the cyanobacterial lineage developed on Earth?

A) oxygen
B) elemental sulfur
C) ferrous iron
D) hydrogen sulfide


Answer: B

Biology & Microbiology

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For a pure culture of Saccharomyces cerevisiae cells that were all derived from a single cell to mate,

A) a mating-type switch in one or more cells in the culture must occur. B) both the ? and the a gene must be fully expressed in the population. C) the ? gene must be fully repressed in the population. D) some cells must exist as diploids.

Biology & Microbiology

Which of the following diseases is not caused by a dimorphic fungus?

A) coccidioidomycosis B) cryptococcosis C) histoplasmosis D) sporotrichosis

Biology & Microbiology

Colonies that appear white and shinny are also considered:

a. translucent. b. transparent. c. mucoid. d. opaque.

Biology & Microbiology

Which of the following statements about poliovirus and SARS virus is TRUE?

a. Both have a VPg protein that facilitates replication. b. Both form polyproteins that undergo post-translational cleavage. c. Both have 30-kilobase genomes. d. Both have single-stranded plus-sense RNA genomes.

Biology & Microbiology