DNA: Difference between revisions
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==Major and Minor grooves== | ==Major and Minor grooves== | ||
The DNA double helix forms minor and major grooves. Minor grooves have two highly hydrophilic components, whereas major grooves | The DNA double helix forms minor and major grooves. Minor grooves have two highly hydrophilic components, whereas major grooves allow bases to be accessed by enzymes and proteins (an example being transcription factors). | ||
==Modifications== | ==Modifications== | ||
DNA modifications can be methylation, acetylation, ubiquilation, and phosphorylation. Acetylation activates chromatin, allowing protein synthesis to occur. Methylation deactivates DNA. | DNA modifications can be methylation, acetylation, ubiquilation, and phosphorylation. Acetylation activates chromatin, allowing protein synthesis to occur. Methylation deactivates DNA. | ||
Revision as of 01:49, 5 February 2014
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This article was marked by its author as Under construction, but the last edit is older than 30 days. If you want to edit this page, please try to contact its author first (you fill find him in the history). Watch the discussion as well. If the author will not continue in work, remove the template Last update: Wednesday, 05 Feb 2014 at 1.49 am. |
DNA (deoxyribonucleic acid) is the molecule containing the primary genetic information in the form of a linear sequence of nucleotides in groups of three (codon). A nucleotide is composed of a phosphorylated sugar and base. DNA bases are adenine, cytosine, guanine and thymine. The bases form complementary bases pairing, with two hydrogen bonds between cytosine and guanine, and three hydrogen bonds between thymine and adenine. DNA consists of a large number of repeats 100-6500 bp (base pairs).
Structure
Phosphorylation of nucleosides gives DNA a negative charge. DNA is negatively charged, it forms bonds with positively charged histones. Histones are responsible for compacting DNA. The structure formed is 8 histone proteins together in one unit with the DNA double helix wound twice around it.
Helix of DNA occur in three forms; α-helix, β-helix and z-helix. α-helix and β-helix are right handed. z-helix is left handed.
Major and Minor grooves
The DNA double helix forms minor and major grooves. Minor grooves have two highly hydrophilic components, whereas major grooves allow bases to be accessed by enzymes and proteins (an example being transcription factors).
Modifications
DNA modifications can be methylation, acetylation, ubiquilation, and phosphorylation. Acetylation activates chromatin, allowing protein synthesis to occur. Methylation deactivates DNA.
DNA forms
sDNA (satellite DNA) contains tandem repeats of nucleotide sequences of different lenghs. sDNA can be separated from the main DNA in gradient centrifugation, after which it appears as one or several bands separated from that of the main body of the DNA. Microsatellites are small (2-10) tandem repeats of DNA nucleotides. Minisatellites are tandem repeats of about 20-100 base pairs.
cDNA is a reverse transcriptase product. DNA can be natured and renatured continuously because it has a highly ordered structure.
