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Hi, how are you? Today we will talk of hereditary information. You wonder what is in common between the T2 bacteriophage
and this two researchers Hershey
and Chase.
Well, this phage is well known because it injects some material that Hershey and Chase did not know.
They did not know the nature of the hereditary material that promotes the ability to self-replicate
Basically what this virus does is making copies of itself.
So these researchers had the great idea of using a technological advance of the time in order to solve the problem
of figuring out what this unknown element.
They used a blender. Yes, a kitchen blender.
Like I said, the virus injects its material
we don't know which type of material yet.
We have here our unknown material
and we know that it has a capsule that is mostly proteic and that once
injected this material it has the ability to self-replicate.
Now:
How can we identify the material that gives him that ability?
The scientists reasoned that if it was a protein
then the protein have a significant amount of sulfur
and that sulfur can be marked using sulfur-35.
This is a radioactive isotope. It means that emits radioactivity and can be detected by a device.
However, if it was DNA
DNA has a big amount of phosphorus
and phosphorus can also be used as there is a phosphorus-32, a radioactive isotope.
But how does that relate with a blender?
Well, this is the blender experiment
and I will show you why.
They used a blender to detach the virion from the cell membrane of the infected cell.
Once they passed through the blender, they detached and the capsule stayed above
This capsule, as I said, it's mostly protein. On the other hand, what they got was a set of
infected cells with our unknown material.
We don't know yet whether protein or DNA.
Now, what they did was to mark the experiment 1) with sulfur-35.
And the experiment 2) with phosphorus-32
So,
once the cell was infected, they took the culture medium and licuified it. By doing that,
they were able to get to layers
all bacteria stacked at the bottom
and the proteic stuff disolved above.
When they counted the radioactivity they saw that most of the radioactivity due to the
sulfur-35 which marked most overwhelmingly proteins
was in the supernatant at the top and very little amount stayed with the cellular components.
Instead, in the experiment number two, what they observed was different.
They saw that most of the radioactivity emitted by the phosphor 32 was located with bacteria
in the bottom of the test tube. Bare capsules emitted virtually no radioactivity.
This indicates that in fact the agent injected was DNA,
which contains the greatest amount of phosphorus and therefore they concluded that this molecule
was responsible for hereditary transmission.
Well, I hope you have enjoyed this experiment and do not miss our new content. Subscribe to our channel.
See you around.