The cyclic nitrogenous base used in transcription, uracil, is a ________.

A. protein
B. purine
C. porphyrin
D. pyrimidine


Answer: D

Biology & Microbiology

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Which of the following is the correct organizational hierarchy, from largest to smallest, in the hierarchical order of life? (Some levels have been omitted, so you are looking for the correct order.)

A. Biosphere ? Community ? Population ? Tissue ? Organ ? Cell ? Atom ? Molecule B. Ecosystem ? Population ? Community ? Organ system ? Organ ? Cell ? Molecule ? Atom C. Community ? Ecosystem ? Population ? Tissue ? Organ ? Cell ? Organelle ? Atom D. Ecosystem ? Community ? Population ? Organ ? Tissue ? Cell ? Molecule ? Atom

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While our personal genomes can identify genetic risk factors, disease risk is often greatly increased by (select all that apply)

A. diet. B. exercise. C. exposure to drugs and other chemicals in our environment. D. exposure to ultraviolet radiation. E. none of these

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The carcinogen aflatoxin is produced by the fungus

A. Claviceps purpurea. B. Staphylococcus aureus. C. Coccidioides immitis. D. Histoplasma capsulatum. E. Aspergillus flavus.

Biology & Microbiology

Each DNA strand serves as which of the following during DNA synthesis?

a. replicate b. substitute c. template d. source of nucleotides e. source of sugars

Biology & Microbiology