Hi Matchette,
To answer your question we must first know what DNA is and some facts
about the cell. As much as possible, please read all the links below
so you can have a better understanding of the answer.
According to The New Dictionary of Cultural Literacy, DNA, or
deoxyribonucleic acid is:
"The molecule that carries genetic information in all living systems"
(Excerpted from Bartleby.com - DNA, The New Dictionary of Cultural
Literacy, Third Edition. Copyright © 2003 Bartleby.com
http://www.bartleby.com/59/21/dna.html )
If amino acid is the building block of life, DNA can be called as the
"blueprint" of life. You can compare it to a building's blueprint or
plan during construction. Whatever the plan is will determine the
outcome of the building. So if the plan is changed the building will
also change.
According to How Stuff Works:
"DNA guides the cell in its production of new enzymes."
(Excerpted from HowStuffWorks, Inc. - How Cells Work - Making Enzymes:
DNA., Copyright © 1998 - 2003
http://science.howstuffworks.com/cell4.htm )
This brings us to another question: what are enzymes?
"Enzymes have extremely interesting properties that make them little
chemical-reaction machines. The purpose of an enzyme in a cell is to
allow the cell to carry out chemical reactions very quickly. These
reactions allow the cell to build things or take things apart as
needed. This is how a cell grows and reproduces. At the most basic
level, a cell is really a little bag full of chemical reactions that
are made possible by enzymes!
Enzymes are made from amino acids, and they are proteins. When an
enzyme is formed, it is made by stringing together between 100 and
1,000 amino acids in a very specific and unique order. The chain of
amino acids then folds into a unique shape. That shape allows the
enzyme to carry out specific chemical reactions -- an enzyme acts as a
very efficient catalyst for a specific chemical reaction. The enzyme
speeds that reaction up tremendously."
(Excerpted from HowStuffWorks, Inc. - How Cells Work - Enzymes,
Copyright © 1998 - 2003 http://science.howstuffworks.com/cell4.htm )
You can find more info on enzyme through this link:
Bartleby.com
Enzyme
http://www.bartleby.com/65/en/enzyme.html
Confused? Enzyme is a protein produced by living cells and works as a
catalyst in a specific biochemical reaction. Remember our analogy
amino acid and DNA? Enzyme can be compared to as the construction
worker. You can also compare it to an engineer. If you have many
workers working on a specific part of the building, that part of the
building will be made faster. The more enzymes, the faster the
chemical reaction.
So you might be wondering what enzymes do.
"Cells use enzymes internally to grow, reproduce and create energy,
and they often excrete enzymes outside their cell walls as well."
Take note that we also compared enzyme to an engineer. The reason:
"A cell really is nothing but a set of chemical reactions, and enzymes
make those reactions happen properly."
"Inside a cell, hundreds of highly specialized enzymes carry out
extremely specific tasks that the cell needs to live its life. Some of
the more amazing enzymes found inside cells include:
Energy enzymes - A set of 10 enzymes allows a cell to perform
glycosis. Another eight enzymes control the citric-acid cycle (also
known as the Krebs cycle). These two processes together allow a cell
to turn glucose and oxygen into adenosine triphosphate, or ATP. In an
oxygen-consuming cell like E. coli or a human cell, one glucose
molecule forms 36 ATP molecules (in something like a yeast cell, which
lives its life without oxygen, only glycosis occurs and it produces
only two ATP molecules per glucose molecule). ATP is a fuel molecule
that is able to power enzymes by performing "uphill" chemical
reactions.
Restriction enzymes - Many bacteria are able to produce restriction
enzymes, which recognize very specific patterns in DNA chains and
break the DNA at those patterns. When a virus injects its DNA into a
bacterium, the restriction enzyme recognizes the viral DNA and cuts
it, effectively destroying the virus before it can reproduce.
DNA-manipulation enzymes - There are specialized enzymes that move
along DNA strands and repair them. There are other enzymes that can
untwist DNA strands to reproduce them (DNA polymerase). Still others
can find small patterns on DNA and attach to them, blocking access to
that section of DNA (DNA-binding proteins).
Enzyme-production enzymes - All of these enzymes have to come from
somewhere, so there are enzymes that produce the cell's enzymes!
Ribonucleic acid (RNA), in three different forms (messenger RNA,
transfer RNA and ribosomal RNA), is a big part of the process."
(Excerpts from HowStuffWorks, Inc. - How Cells Work - Enzymes at Work,
Copyright © 1998 - 2003 http://science.howstuffworks.com/cell3.htm )
Based on all the information above, we can finally answer the questions:
"What might happen to a cell whose DNA is destroyed?"
If DNA is destroyed, the cell will eventually die. Without the DNA to
guide the production of enzymes (i.e, what enzymes are needed at a
given time), the chemical reactions inside the cell will not happen
properly.
What might happen to a cell whose DNA is changed?
If you read all the information on the links mentioned above, you can
easily say that if DNA is changed, the cell will also change. You can
go back to our analogy of DNA being the blueprint of the building. The
amount of change is directly proportional to the condition of the
cell. So depending on the change, the cell may become weak or strong.
Damage to the DNA is also a change. Depending on the condition, if the
DNA is damaged, there is still a chance for the cell to repair it. It
is called "DNA repair".
Bartleby.com
DNA repair
http://www.bartleby.com/59/21/dnarepair.html
Also, depending on the condition and/or the cause of the change, the
cell may also be mutated. More information can be found through these
links:
Bartleby.com
Mutagen
http://www.bartleby.com/59/21/mutagen.html
Mutations
http://www.bartleby.com/59/21/mutations.html
Mutation
http://www.bartleby.com/65/mu/mutation.html
Additional Information:
HowStuffWorks, Inc.
How Cells Work
http://science.howstuffworks.com/cell.htm
How Gene Pools Work
http://science.howstuffworks.com/gene-pool.htm
Search Strategy
Keyword searches at HowStuffWorks.com and Bartleby.com
I hope this helps you. Should you have any comments/questions, please
feel free to post your clarification before rating this and I'll
attend to you as soon as possible. Thanks for asking.
Best regards,
Feilong |
