E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged
What density distribution of DNA would you expect in this experiment?
A) one high-density and one low-density band
B) one intermediate-density band
C) one high-density and one intermediate-density band
D) one low-density and one intermediate-density band
E) one low-density band
Answer: D
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Which reaction represents cellular respiration?
A. Sugar + Oxygen ? Carbon dioxide+ Water + ATP B. Water + ATP ? Carbon dioxide + Sugar C. Carbon dioxide + Water + ATP ? Sugar + Oxygen D. Oxygen + Carbon dioxide ? Sugar + Water + ATP
The difference between taste and smell
a. is how the receptor comes into contact with the binding site, be it direct touch or through diffusion in the air. b. depends on the cellular structure of the receptor, specifically, whether the cells are derived from microvilli or cilia and have microfilaments and microtubules, respectively. c. is present in al invertebrates that use one receptor for both functions. d. is the difference between thermoception and photoreception. e. is based on slight differences in chemoreception.
A ribosome has one binding site for mRNA and two binding sites for tRNAs
__________________ Indicate whether the statement is true or false.
Which element is most particularly associated with organic chemistry?
A. carbon B. sulfur C. nitrogen D. hydrogen E. oxygen