DNA, RNA, and Protein: Life at its simplest

DNA: Deoxyribonucleic acid. The double-stranded chemical instruction manual for everything a plant or animal does: grow, divide, even when and how to die. Very stable, has error detection and repair mechanisms. Stays in the cell nucleus. Can make good copies of itself.

RNA: Ribonucleic acid. Single-stranded where DNA is double-stranded, messenger RNA carries single pages of instructions out of the nucleus to places they're needed throughout the cell. No error detection or repair; makes flawed copies of itself. Evolves ten times faster than DNA. Transfer RNA helps translate the mRNA message into chains of amino acids in the ribosomes.

[Diagram of RNA vs. DNA: chemical structure and composition]


Base: a building block of DNA and RNA. There are five different bases: Adenine, Thymine, Guanine, Cytosine, and Uracil (which is found only in RNA and replaces Thymine in DNA).


Ribosomes: Message centers throughout the cell where the information from DNA arrives in the form of messenger RNA. The RNA message gets translated into a form the ribosome can understand and tells it which protein building blocks it needs and in what order to assemble them. Ribosomal RNA helps the translation go smoothly.

Amino acids: Polypeptide (protein) building blocks.

Polypeptides: chains of amino acids. Proteins are made up of several or many polypeptides.

Proteins: Chemicals that make up cell and organ structure and carry out reactions throughout the body, from breaking down food to fighting off disease.


--------------------------------------------------------------------------------

DNA is transcribed into mRNA which is translated into amino acids.
This is


(diagram source)


Everything you ever wanted to know about DNA, RNA, and proteins

Single-stranded DNA

Single-stranded DNA (single-stranded DNA) to most of the DNA double helix structure, but once or heat processing base will become a single-stranded state. Single-stranded DNA refers to the existence of such a state of the DNA. Single-stranded DNA molecule in the fluid nature of the absorption spectrum, the base nature of the response, and so on are different and the double-stranded DNA. Some of the phage particle contains a single circular chain of DNA, this kind of phage DNA in the cell proliferation when the formation of double-stranded DNA.

DNA loop

Closed-loop DNA (closed circular DNA) no fracture of the ring double-stranded DNA, also known as the super-helix DNA. Due to their double-stranded helical structure of the closure, resulting in a further rotation of the entire DNA molecule formed by the three-tier structure of the song. In addition, if a chain of 2 or on different parts of a fracture, it will become a spin-free song of the open-loop DNA molecules. Cells extracted from the DNA plasmid or virus, there are elements of open-loop and closed loop these two elements. Both can be combined with the ability of the different pigments, and the two separated.

Complementary DNA

Complementary DNA (cDNA, complementary DNA) genes constitute the double-stranded DNA molecule with a single strand as a template, the transcription produce its complementary sequence of messenger RNA molecules, and then in the role of the enzyme reverse transcriptase, to mRNA molecules as a template, with a synthetic mRNA sequence complementary single-stranded DNA, and then to single-stranded DNA template for the synthesis of another with complementary single-stranded DNA, the two complementary single-stranded DNA molecule to form a double-stranded cDNA molecules. As a result, double-stranded molecule of the cDNA sequences With the transcription of the mRNA molecules have the gene are the same. Therefore, a cDNA molecules on behalf of a gene. CDNA, but still different from the genes because genes produce mRNA transcription, the number of non-coding sequences of introns that have been removed, reservations Only the coding sequence, that is, the exons. CDNA sequences so than the much shorter sequences, as in cDNA gene does not include the non-coding sequences --- intron.

DNA restriction fragment length polymorphism analysis

In the human genome, an average of about 200 base pair mutation can occur (known as the neutral mutation), neutral mutations lead to inter-individual differences in the nucleotide sequence, referred to as DNA polymorphism. DNA polymorphism occurred in a number of restriction enzyme recognition site, the enzyme will have a length of DNA fragments of different fragments, known as restriction fragment length polymorphism (RFLP). RFLR by way of Mendelian genetics, in a particular family, if a particular gene and disease-specific fragment polymorphism closely linked, polymorphic fragments that can be used as a form of "genetic markers" to judge family members or Whether the fetus for disease gene carriers. Type A hemophilia, cystic fibrosis and phenylketonuria, and so on can be diagnosed using this method.

DNA treatment

Gene therapy is the use of normal genes into cells to correct gene replacement and a treatment. At present, in a broad sense, some will be transferred to patients with genetic material inside cells to play a role in the body in order to achieve the purpose of methods to treat disease, also referred to as gene therapy.
At present, gene therapy method used can be basically divided into the following categories:
1  DNA correction
DNA refers to the correction of the abnormal pathogenic DNA chain base to carry out correct, and be a normal part of the reservation.
2. DNA replacement
DNA is the replacement with normal DNA in the body through DNA homologous recombination, the replacement of in-situ cell disease pathogen DNA, the DNA inside cells so that the full restoration of normalcy