Answer:
<h2>D. Radioactive nitrogen in the DNA of the bacterial cells is present in one strand of the DNA of all of the cells.</h2>
Explanation:
As given here,
The nitrogenous base of DNA is radio active labeled, and is grown in normal unlabeled medium.
As we know that DNA replication occurs in semi-conservative way, so after one round of replication, one parental strand would be radio active and other newly synthesized strand would be unlabeled.
So here, after one round of replication, one strand of all the newly synthesized DNA would be radio active and other strand would be normal.
The answer is the base sequence of gene's promoter.
DNA is a two-stranded helix. One strand is called a template strand, the other one is called a coding strand. The template strand is copied into mRNA, and the coding strand is complementary to the template strand. RNA polymerase, an enzyme responsible for transcription, has to recognize the right strand before transcription begins. So, it recognizes one or more short sequences on the coding strand. This is the base sequence of gene's promoter. Thus, the complementary strand is the template strand.
Answer:
Explanation:
Natural selection is process of differential survival and reproduction of the organisms which have better phenotypic traits over the other members of the same species. These traits help the organism to survive in unfavorable conditions and they are passed from the parents to the offsprings and through successive generations of the species.
For example, the development of long neck of the giraffe helped them to grab leaves from tree tops.
The experiment is performed in order to either accept or reject the hypothesis based upon the results
