The first terrestrial organisms are found in the fossil record at about _______ million years ago.
A. 4
B. 40
C. 400
D. 4000
C. 400
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Which of the following is not an accurate description of events leading to the lysogenic pathway following viral infection in a bacterium?
A. Upon infection, the linear bacteriophage DNA forms a circle and transcription is initiated at promoters PL and PR. The transcripts from PR encode the proteins cro and cII. B. Reduction in the concentration of cI protein is the most important contributor to lysogeny. C. Reduced protease activity due to poor conditions allows cII to accumulate, which then stimulates transcription from PE and thus expression of cI. D. cI protein binds to operator OR , preventing cro and cII expression. E. cI protein stimulates transcription from promoter PM, leading to even more cI production. The increased cI binds to operator OL and inhibits PL.
Which of the following is not a function of the midgut?
A. storage of ingested food B. chemical digestion of macromolecules by enzymes C. nutrient absorption D. nutrient absorption and chemical digestion of macromolecules E. All of these answer options are functions of the midgut.
Inherited mutations in the Xist promoter lead to defects in which epigenetic process?
A) RNAi B) X-inactivation C) genomic imprinting D) position effect variegation E) methylation of CpG islands
Competition shapes communities because there are usually limited
A. species. B. interactions. C. resources. D. nutrients.