In their famous experiment, which of the following would Meselson and Stahl have observed after one cycle of replication in 14N medium if DNA replication was conservative?
A) DNA molecules containing one strand of 15N-DNA and one strand of 14N-DNA
B) DNA molecules containing two 15N-DNA strands only
C) DNA molecules containing two 14N-DNA strands only
D) An equal number of DNA molecules containing two 15N-DNA strands and DNA molecules containing two 14N-DNA strands.
E) A mix of DNA molecules corresponding to A and B.
D
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Specialized transduction
A. involves the random transmission of any gene. B. involves the transfer of a few specific genes. C. utilizes a defective virus. D. only involves genes near the viral DNA integration site. E. involves the transfer of a few specific genes, utilizes a defective virus AND only involves genes near the viral DNA integration site.
Ringworm is a skin infection with a fungus, not a worm! In this case, the fungus acts as a
a. decomposer. b. parasite. c. pathogen. d. predator
Which of the following actions occurs in many plants when CO2 concentrations are high?
A. CAM photosynthesis fixes CO2 at night. B. Water evaporates at a higher rate than usual. C. Guard cells lose turgor, and the stomata close. D. Calcium ions are transported faster through the phloem. E. Oxygen is used by plants for photosynthesis.
Which process can create new alleles?
A. natural selection B. mutation C. sexual reproduction D. genetic drift