by meepers anonymous
For those who do not understand the process, here is a simple analogy.
Think of DNA as a library. Along the DNA are sections which code for
proteins called genes. Genes are like books in the DNA library. Consider
all the books in the library to be recipe books because each one tells you
how to make a different protein. Every time the cell wants to make a
particular protein it transcribes a copy of the DNA called RNA. Basically
it’s like going to the library and taking a photocopy of the book you
want. Once we have the RNA, it can be translated into the specific
protein. In other words, cell reads the photocopy of the recipe and makes
Particular proteins transcribe RNA. However we need RNA to make proteins.
In other words, you need to make things from the recipe to build the
photocopying machine but you need the photocopying machine to get the
recipes. It a bit chicken and egg story. Which came first? This is where
ribozymes come in. They are RNA molecules BUT can perform the actions of
proteins, specifically proteins called enzymes which catalyze reactions.
Some say ribozymes may key to explaining the chicken and egg paradox and
hence the origin of life! Bree’s dad’s notebook featured the reaction a
type of ribozyme called hairpin ribozymes.
The aging process
All DNA in the cell is wrapped up tightly into structures called
chromosomes. Every time the cell divides, it makes a copy of the
chromosomes then the cell splits in half so that the 2 new cells each have
the right amount of DNA. The problem is when the cell is making a copy of
the chromosomes, it always ends up loosing a little bit at the end of the
chromosome called the telomeres. An enzyme called telomerase is
responsible for making these telomeres longer. However telomerase is
repressed in adult cells so the telomeres get shorter and shorter as we
get older and our cells have divided lots. It’s thought the telomeres act
as a biological clock, the shorter they get, the old we are. If we express
telomerase then could we potentially stop aging?
Can we stop aging?
Scientists can create & isolate ribozymes that cleave specific sequences.
This means we can target specific RNAs and hence those proteins with be
produced less because there is less RNA for the cell to read. If we knew
the proteins that repress telomerase we could target them. This would
allow telomerase to be expressed, extend the telomeres and maybe stop the
aging process? However, cancer cells can often have high telomerase
activity which allows them to grow out of control. So if we turn on
telomerase we might stop the aging process but we might get cancer
Is this the orders plan?
Wednesday, May 30, 2007
by meepers anonymous