Biotech Articles
Publish Your Research Online
Get Recognition - International Audience

Request for an Author Account   |   Login   |   Submit Article
 
 
HOME FAQ TOP AUTHORS FORUMS PUBLISH ARTICLE
 
 

Deoxyribonucleic Acid Synthesis - DNA Synthesis

BY: Zandro Cabaral | Category: Bioinformatics | Submitted: 2011-01-29 20:07:03
       Author Photo
Article Summary: "This is a summary on the synthesis of DNA in the body. An overview of my own research in Biochemistry..."


Share with Facebook Share with Linkedin Share with Twitter Share with Pinterest Email this article
     


Prokaryote means "before the nucleus;" it includes bacteria and blue-green algae. A Prokaryotic Deoxyribonucleic acid is one large circular deoxyribonucleic acid chromosome located in the cytoplasm-since there is no nuclear membrane to hold on to. Prokaryotes have 1 large chromosome which replicates and divides at the time of cell division The Plasmids are small circular Deoxyribonucleic acid molecules also found in the cytoplasm of some bacteria code for extra chromosomal genes. Replication and inheritance of these genes is independent from that of the chromosome. More than on than type of plasmid may be present in a bacterium and a single bacterium can have hundreds of plasmids. Plasmid genes have often been found to carry genes encoding for antibiotic resistance. Under certain circumstances, the plasmid of a Deoxyribonucleic acid is incorporated into the large circular chromosome and its deoxyribonucleic acid is then replicated and inherited with it. A mitochondrial Deoxyribonucleic acid is a circular deoxyribonucleic acid chromosome similar to the large bacterial chromosome.

Eukaryote means "true nucleus." Eukaryotes are highly organized organisms; plants, animals and single-celled organisms, except bacteria and blue-green algae. Their genetic material is contained within an intracellular nuclear membrane. Eukaryotes have much more Deoxyribonucleic acid, which is divided into a number of chromosomes. Every organism has a specific number of chromosomes. There are 46 chromosomes in humans. Each chromosome is replicated and then evenly divided during cell division assuring that each cell gets the right number of chromosomes. Humans are diploid. This means that there are 2 of each of the 23 types of chromosomes. One inherited from the father and one from the mother. This leads us to another genetic event which is the Packing of the Deoxyribonucleic acid.

The Deoxyribonucleic acid is organized into clumps called nucleosomes by complexing with histones, giving it the appearance of "thread beads." It then wraps around the histone 2 times. A nucleosome is a DNA-wrapped histone core. Histone core is formed from 8 histone molecules around 140 base pairs. Further packing of the Deoxyribonucleic acid due to hydrophobic interactions and in association with other non-histone proteins will pack it into a chromatin. A Hetechromatin is very densely packed and inactive chromatin. A Euchromatin is an active chromatin.

After the packing of Deoxyribonucleic acids, Replication of DNA follows. The Replication is by semiconservative replication. After replication, each of the new double helixes is made of one original strand and one newly synthesized strand. Double stranded DNA unwinds and 2 single strands are exposed forming a "replication fork" which moves along the chain as DNA is replicated. This occurs in both directions with 2 replication forks in an anti-parallel, 5' to 3' direction. These processes are facilitated by the following enzymes:

• DNA Helicase binds to single stranded DNA at the replication fork and opens the double stranded DNA similar to pushing a zipper apart. This unwinds the DNA, and it requires Adenosine Triphosphate to open the DNA.

• Helix-destabilizing proteins then bind to and stabilize single strands of DNA. The helix-destabilizing proteins are also called single stranded DNA-binding proteins. As the replication fork proceeds, it causes twisting which is relieved by topoisomerases.

• Type I Topoisomerase or swivelase binds to and cleaves one of the single strands of DNA. This is called nuclease activity. This allows the DNA to untwist around the axis of the phosphodiester bond of the intact DNA strand and then reconnects the single strand. This is called a ligase activity.

• Type IITopoisomerase or gyrase binds to and cleaves both single strands at the same time and results in a negative twisting which relaxes both strands and then reseals the strands. Quinolones inhibit DNA gyrase.

• Ligases connect two strands of DNA end to end. This enzyme seals the DNA strands. The process requires Adenoaine Triphosphate or Nitric Acid Dehydrogenase.


The next step involves a Primase. The Primase is an RNA polymerase which uses triphosphate ribonucleotides to form a short strand of Ribonucleic Acid complementary to DNA near the replication fork which serves as the double stranded primer necessary for DNA polymerase III. Later, DNA polymerase I, an exonuclease, removes the RNA primer and replaces it with DNA. A Deoxyribonucleic Acid polymerase III reads each of the old strands in the 3' to 5' direction and uses the appropriate triphosphate deoxyribonucleotides to synthesize new complementary strands in the 5' to 3' direction. The energy to drive these reactions is provided by the high energy triphosphate.

About Author / Additional Info:
PART 1:
http://www.biotecharticles.com/Bioinformatics-Article/Deoxyribonucleic-Acid-Synthesis-Mechanisms-of-DNA-Repair-616.html

Search this site & forums
Share this article with friends:



Share with Facebook Share with Linkedin Share with Twitter Share with Pinterest Email this article

More Social Bookmarks (Digg etc..)


Comments on this article: (0 comments so far)

Comment By Comment

Leave a Comment   |   Article Views: 3397



Additional Articles:

•   Different Techniques of Blotting

•   AFLP Markers in Crop Improvement

•   Black Caraway - A highly valuable but endangered plant genetic resource of Jammu and Kashmir

•   Genetic Use Restriction Technology (GURT) in Crop Plants.




Latest Articles in "Bioinformatics" category:
•   Career as Bioinformatician and Biostatistician

•   Expander: A Tool of Bioinformatics

•   Role of Bioinformatics in Drug Discovery

•   Importance and Applications of Bioinformatics in Molecular Medicine

•   Bioinformaticist vs. Bioinformatician - Definition, Differences and Career Outlook

•   Bioinformatics Application in Nanotechnology

•   How Bioinformatics Handles the Biological Data?

•   Application of Bioinformatics in Medicine

•   Prenatal Diagnosis via Bioinformatics Skills

•   Applications of Bioinformatics in Agriculture

•   Next Generation Sequencing Technologies: 454 Pyrosequencing

•   GenScan: Bioinformatics Software For Structure Prediction and Analysis of Gene

•   Pairwise Sequence Alignment For Sequence Similarity

•   Applications of Bioinformatics in Biotechnology

•   Introduction to Bioinformatics: Role of Mathematics and Technology

•   Why and How of Normalization in Microarray Data Analysis

•   Steps in Microarray Data Analysis - Part I

•   Steps in Microarray Data Analysis - Part II

•   Bilirubin Metabolism And its Role in Neonatal Jaundice



Important Disclaimer: All articles on this website are for general information only and is not a professional or experts advice. We do not own any responsibility for correctness or authenticity of the information presented in this article, or any loss or injury resulting from it. We do not endorse these articles, we are neither affiliated with the authors of these articles nor responsible for their content. Please see our disclaimer section for complete terms.
Page copy protected against web site content infringement by Copyscape
Copyright © 2010 biotecharticles.com - Do not copy articles from this website.

ARTICLE CATEGORIES :
Agriculture Bioinformatics Applications Biotech Products Biotech Research
Biology Careers College/Edu DNA Environmental Biotech
Genetics Healthcare Industry News Issues Nanotechnology
Others Stem Cells Press Release Toxicology  


  |   Disclaimer/Privacy/TOS   |   Submission Guidelines   |   Contact Us