what is the DNA?

Answer 1

It stands for Deoxyribonucleic acid. It is the double helix that contains the genetic instructions for the development and functioning of living organisms.

Answer 2

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and functioning of living organisms. All living things contain DNA genomes. A possible exception is a group of viruses that have RNA genomes, but viruses are not normally considered living organisms. The main role of DNA in the cell is the long-term storage of information. The genome is often compared to a set of blueprints, since it contains the instructions to construct other components of the cell, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the expression of genetic information.

In eukaryotes such as animals and plants, DNA is stored inside the cell nucleus, while in prokaryotes such as bacteria, the DNA is in the cell's cytoplasm. Unlike enzymes, DNA does not participate directly in most of the biochemical reactions it controls; rather, various enzymes act on DNA and copy its information into either more DNA, in DNA replication, or transcribe and translate it into protein. In chromosomes, chromatin proteins such as histones compact and organize DNA, which helps control its interactions with other proteins in the nucleus.

DNA is a long polymer of simple units called nucleotides, which are held together by a backbone made of sugars and phosphate groups. This backbone carries four types of molecules called bases, and it is the sequence of these four bases that encodes information. The major function of DNA is to encode the sequence of amino acid residues in proteins, using the genetic code. To read the genetic code, cells make a copy of a stretch of DNA in the nucleic acid RNA. Some RNA copies are used to direct protein biosynthesis, but others are used directly as parts of ribosomes or spliceosomes.

Answer 3

Molecular basis of heredity. It is a complex giant molecule that contains, in chemically coded form, the information needed for a cell to make proteins. In other words it determines the order in which amino acids are joined to make a specific protein in a cell. DNA is a ladder-like double-stranded nucleic acid, which forms the basis of genetic inheritance in all organisms, except for a few viruses that have only RNA. DNA is organized into chromosomes and, in organisms other than bacteria, it is found only in the cell nucleus.

DNA is a ladder-like molecule, which means that it is made up of two halves (the ladder sides), formed of chains of nucleotide subunits. Each nucleotide contains a deoxyribose sugar, a phosphate, and a base. A set of three bases – known as a codon – acts as a blueprint for the manufacture of a particular amino acid, the subunit of a protein molecule. The two halves are joined together by the bases – a purine (adenine or guanine) or pyrimidine (cytosine or thymine) – forming pairs (the rungs). The bases form into two specific base pairs: adenine with thymine and guanine with cytosine. The sequence of base pairs along the DNA acts as a code carrying information about the sequence of amino acids in proteins. Three base pairs in sequence (triplet) name an amino acid and the next three name the next amino acid that needs to be joined and so on, to make a specific protein. The specific way in which the pairs form means that the base sequence is preserved from generation to generation. Hereditary information is stored as a specific sequence of bases.

It is important that inherited information is passed on correctly. In the process of DNA replication, which takes place before any cell divides, the two halves of DNA separate and new halves are made. Because of specific base pairing, the inherited information is copied exactly. Despite this, a mistake sometimes occurs and the sequences of bases is altered. This changes the sequence of amino acids in a protein. This is mutation. Ionizing radiation increases the risk of mutation. In plants and animals DNA is organized into chromosomes and is found in the nucleus of cells. DNA in bacteria is organized differently. Bacteria have one large circular DNA molecule carrying most of their inherited information. Some bacteria also have small circular molecules of DNA, known as plasmids. These may be used in genetic engineering to transfer genes from one organism to another.

Answer 4

DNA is Deoxyribonucleic Acid. It is basically the unique "print" of every animal/individual. Everyone has their own specific DNA thread that makes them who they are. Often in news reports, you may hear rumors of deceased celebrities' DNA being copied. This means that they would extract their DNA and reproduce it to potentially "clone" the person. Of course, that'll never happen because it's immoral and unlawful.

Answer 5

A nucleic acid that carries the genetic information in the cell and is capable of self-replication and synthesis of RNA. DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. The sequence of nucleotides determines individual hereditary characteristics.

[D(EOXYRIBO)N(UCLEIC) A(CID).]