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Makelsii Simmons and Jacy Schneider
DNA
What is DNA?
 DNA is short for: Deoxyribonucleic acid
 Deoxyribonucleic acid is what travels through
living organisms.
 Deoxyribonucleic acid travels through genetic
genes and genetic make-up making
generations of similar DNA (makes genes
pass through).
How is DNA formed?

Thirty-three independent mutant cell lines were selected in single steps for
resistance to low concentrations of N-(phosphonacetyl)-L-aspartate and the
structure of their amplified DNA was probed, using a set of recombinant
phage and cosmids containing a total of 380 kb of amplified DNA. In all 33
cell lines, the selected CAD gene and at least 65 kb of flanking DNA were
amplified, an average of 2.6-fold. Six other regions of DNA were coamplified in all 33 mutants, but sometimes to a different extent than CAD.
Novel joints, marking recombinations which link amplified regions to each
other, were found surprisingly rarely. There were only three within the 380
kb of DNA sequence examined in the total of 33 cell lines. Each novel joint
was present in only one copy per cell, was found in a different cell line and
was homologous to a different probe. The low frequency of novel joints is
consistent either with very large amplified regions in the single-step
mutants, possibly 10,000 kb of co-amplified DNA for each copy of the CAD
gene, or with a strong bias against recombination in the cloned sequences
used as probes. Our previous finding that CAD probes hybridize in situ to
unusually large chromosome arms in several single-step mutants is most
consistent with the first possibility.
What does DNA do for us?
 DNA is in the nucleus of each cell and it contains a long sequence of
chemicals that determines how all the cells are built. It is a genetic
blueprint.
 DNA stands for deoxyribonucleic acid but unlike other acids it does
not perform normal activities rather it has a very important and
complex job in the human body. As most of us are aware human
body is made up of cells. Or in other words cells are the building
blocks of our body. It performs all the vital functions extremely
important for our survival. Cells do not have a vacuum rather they
have many different cellular bodies in them. One of them is the
chromosome; it contains the genetic information of the body.
Chromosomes have DNA, which is a molecule that has two strands
containing genetic information. These strands are of nucleotide
sequence and are bonded together by the hydrogen bond. They are
also known as the spiral strands because they are twisted into a
spiral staircase.
History of DNA?
 RNA sequencing was one of the earliest forms of nucleotide
sequencing. The major landmark of RNA sequencing is the sequence
of the first complete gene and the complete genome of
Bacteriophage MS2, identified and published by Walter Fiers and his
coworkers at the University of Ghent (Ghent, Belgium), between
1972 and 1976.
 Prior to the development of rapid DNA sequencing methods in the
early 1970s by Frederick Sanger at the University of Cambridge, in
England and Walter Gilbert and Allan Maxam at Harvard,a number of
laborious methods were used. For instance, in 1973, Gilbert and
Maxam reported the sequence of 24 basepairs using a method
known as wandering-spot analysis.
 The chain-termination method developed by Sanger and coworkers
in 1975 soon became the method of choice, owing to its relative ease
and reliability.
DNA repair?
 DNA repair refers to a collection of processes by which a cell
identifies and corrects damage to the DNA molecules that encode
its genome. In human cells, both normal metabolic activities and
environmental factors such as UV light and radiation can cause DNA
damage, resulting in as many as 1 million individual molecular
lesions per cell per day. Many of these lesions cause structural
damage to the DNA molecule and can alter or eliminate the cell's
ability to transcribe the gene that the affected DNA encodes. Other
lesions induce potentially harmful mutations in the cell's genome,
which affect the survival of its daughter cells after it undergoes
mitosis. Consequently, the DNA repair process is constantly active as
it responds to damage in the DNA structure. When normal repair
processes fail, and when cellular apoptosis does not occur,
irreparable DNA damage may occur, including double-strand breaks
and DNA crosslink ages.
DNA stages?

Unwinding - DNA molecules consists of two individual strands of linked
nucleotides coiled around each other in a double helix. Before any form of
replication can occur, these two intertwined strands have to be separated.
This is more difficult than it looks. Imagine two lengths of string twisted
round and around each other in a double spiral. Hold each end of this
twisted pair firmly and then ask someone to pull the individual pieces of
string apart. It cannot be done.

Before the two strands of DNA can be separated, at least one of the strands
must be snapped, or broken to relieve the thermodynamic strain and allow a
point of rotation as the two halves of the DNA molecule are pulled apart.

Special unwinding proteins attach to the DNA. The weak but numerous
forces, called hydrogen bonds, that hold the base pairs together are further
weakened until the base pairs separate and the strands can be pulled further
and further apart. This creates a "Y"-shaped structure called a replication
fork, and it is at this fork that the next stage in the replication process takes
place.
What does DNA help with?
 Memory in gene transferring
 It helps us in curing diseases, solving crimes,
paternity tests, finding the relatedness of
species, and much more.
 DNA also helps determine paternity testing.
(Ex: “Baby Mama” shows where the people
are trying to determine who is the parents to
a child).
Pictures of DNA
Cont...
Cited
 http://en.wikipedia.org/wiki/DNA
 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1167090/
 http://answers.yahoo.com/question/index?qid=20080901
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014254AAZ01S5
http://www.whatdoesaparalegaldo.org/what-does-dnado.html
http://es.wikipedia.org/wiki/Secuenciaci%C3%B3n_de_A
DN
http://en.wikipedia.org/wiki/DNA_repair
http://www.brooklyn.cuny.edu/bc/ahp/LAD/C4/C4_Stage
sReplication.html
Cited cont...
 http://wiki.answers.com/Q/How_does_DNA_
help_us