what is dna?

Answer 1

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the biological development of a cellular form of life or a virus. All known cellular life and some viruses have DNAs. DNA is a long polymer of nucleotides (a polynucleotide) that encodes the sequence of amino acid residues in proteins, using the genetic code: each amino acid is represented by three consecutive nucleotides (a triplet code).

Kimberly, RRT

Answer 2

Known as the "king og Molecules" (biochemistry) a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix; associated with the transmission of genetic information

Answer 3

DNA is the chemical makeup of of the entire human body. It cannot be changed, altered, or falsified in any way.

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the biological development of a cellular form of life or a virus. All known cellular life and some viruses have DNAs. DNA is a long polymer of nucleotides (a polynucleotide) that encodes the sequence of amino acid residues in proteins, using the genetic code: each amino acid is represented by three consecutive nucleotides (a triplet code).

In eukaryotic cells, such as those of plants, animals, fungi and protists, most of the DNA is located in the cell nucleus, and each DNA molecule is usually packed into a chromosome and shaped as a double helix. By contrast, in simpler cells called prokaryotes, including the eubacteria and archaea, DNA is found directly in the cytoplasm (not separated by a nuclear envelope) and is circular. The cellular organelles known as chloroplasts and mitochondria also carry DNA. DNA is thought to have originated approximately 3.5 to 4.6 billion years ago. [1]

DNA is responsible for the genetic propagation of most inherited traits. In humans, these traits range from hair color to disease susceptibility. The genetic information encoded by an organism's DNA is called its genome. During cell division, DNA is replicated, and during reproduction is transmitted to offspring. The offspring's genome is a combination of the genomes of its parents. Lineage studies can be done because mitochondrial DNA only comes from the mother, and the Y chromosome only comes from the father.

In humans, the mother's mitochondrial DNA together with 23 chromosomes from each parent combine to form the genome of a zygote, the fertilized egg. As a result, with certain exceptions such as red blood cells, most human cells contain 23 pairs of chromosomes, together with mitochondrial DNA inherited from the mother.

Overview --- :

DNA consists of a pair of molecules, organized as strands running start-to-end and joined by hydrogen bonds along their lengths.[2] Each strand is a chain of chemical "building blocks", called nucleotides, of which there are four types: adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T).[2] (Thymine should not be confused with thiamine, which is vitamin B1.) The DNA of some organisms, most notably of the PBS1 phage, have Uracil (U) instead of T.[3] These allowable base components of nucleic acids can be arranged in the polymer in any order, giving the molecules a high degree of uniqueness.

DNA contains the genetic information, that is inherited by the offspring of an organism. This information is determined by the sequence of base pairs along its length. A strand of DNA contains genes, areas that regulate genes, and areas that either have no function, or a function yet unknown. Genes are the units of heredity and can be loosely viewed as the organism's "cookbook" or "blueprint". DNA is often referred to as the molecule of heredity.

Each base on one strand forms a bond with just one kind of base on another strand, called a "complementary" base: A bonds with T, and C bonds with G. Therefore, the whole double-strand sequence can be described by the sequence on one of the strands, chosen by convention.[2] Two nucleotides paired together are called a base pair. On rare occasions, wrong pairing can happen, when thymine goes into its enol form or cytosine goes into its imino form.

The double-stranded structure of DNA provides a simple mechanism for DNA replication: the two strands are separated, and then each strand's complement is recreated by exposing the strand to a mixture of the four bases. An enzyme makes the complement strand by finding the correct base in the mixture and bonding it with the original strand. In this way, the base on the old strand dictates which base appears on the new strand, and the cell ends up with an extra copy of its DNA.

Other interesting points:

DNA is an acid because of the phosphate groups between each deoxyribose. This is the primary reason why DNA has a negative charge.
The "polarity" of each pair is important: A+T is not the same as T+A, and C+G is not the same as G+C (note that the term "polarity" is never used in this context -- it's just a suggestive way to get the idea across).
Mutations are the results of the cells' attempts to repair chemical imperfections in this process, where a base is accidentally skipped, inserted, or incorrectly copied, or the chain is trimmed, or added to. Many mutations can be described as combinations of these accidental "operations". Mutations can also occur after chemical damage (through mutagens), light (UV damage), or through other more complicated gene swapping events.
DNA molecules that act as enzymes are known in laboratories, but none have been known to be found in life so far.
In addition to the traditionally viewed duplex form of DNA, DNA can also acquire triplex and quadruplex forms. They have Hoogsteen base pairing instead of the Watson-Crick base pairing found in duplex forms.
DNA differs chemically from ribonucleic acid (RNA) by having a sugar 2-deoxyribose instead of ribose in its backbone. In addition, in most[citation needed] RNA, the nucleotides thymine (T) are replaced by uracil (U).

Answer 4

http://en.wikipedia.org/wiki/DNA