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klio [65]
3 years ago
13

Meselson and Stahl cultured E. coli for several generations in a medium with a heavy isotope of nitrogen, 15N. They transferred

the bacteria to a medium with a light isotope of nitrogen, 14 N. After two rounds of DNA replication, half the DNA molecules were light (both strands had 14N) and half were hybrids (15N-14N). What did the researchers conclude from these results?
Biology
1 answer:
Sidana [21]3 years ago
8 0

Answer:

DNA replication follows semi conservative mode of replication

Explanation:

The results of Meselson and Stahl's experiments can be explained by semi conservative mode of DNA replication. According to it, the two DNA strands separate and both are used for synthesis of new DNA strands such that the new DNA molecule has one parental and one new strand.

In the experiment, originally the medium was 15N so all the DNA molecules had 15N. Later the medium was changed to 14N. In first round of replication in new medium, the two 15N strands in a DNA molecule separated and formed new strands using 14N. So all the DNA molecules had one 15N and one 14N strand.

In the second round of replication, the 15N-14N hybrid DNA molecule separated again. Now, 15N gave rise to 14N strand and 14N strand also gave rise to 14N strand such that half of the DNA molecules were 15N-14N hybrids and half were 14N-14N. Hence, researchers concluded that DNA replicated according to semi conservative mode of replication.

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Answer:

The most appropriate answer would be option B.

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Black_prince [1.1K]

Answer:

BENEFITS:

The Descriptive investigation is used to describe a natural system when nothing or very little is known about the system. Like observing a new specimen in the microscope and describing it by observing the specimen.

A comparative analysis is used to compare two or more variable in nature by collecting data like observing the different colors of the rocks. It provides the data to show the similarity and dissimilarity of the population.

The Experimental investigation is used where experiments are performed to test and answer the scientific questions. The advantage is that data can be used as evidence for future research.

LIMITATIONS:

<u>descriptive  method  of  investigation </u>

It cannot be used to correct variable or be used to determine causes and  effect  of  the  problem

<u>experimental  method  of  investigation </u>

It might create an artificial situation that do not always represent the real  life situation

<u>comparative  method  of  investigation </u>

It  is not easy to control other variables that might influence the study

<em>Ngl, I just copy and pasted these answers from another brainly question</em>

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