The Structure of DNA

Diposkan oleh OM Kris On 9:09 AM
The Structure of DNA
Figure 1 (a) DNA is shaped like a spiraling ladder with two sugar-phosphate strands as the “sides” of the ladder and paired bases as the “rungs.” (b) This photograph of DNA shows that it is a double helix. (Adapted from Campbell, Reece, Simon, Essential Biology with Physiology, © 2004.)
Now that we know where the genes are, let’s look more closely at what genes aremade of, at DNA it self. What does DNA look like? A molecule of deoxy ribonucleic acid, or DNA, consists of two strands that, when put together, resemble a spiraling ladder with two “sides” and a series of regularly spaced “rungs” (Figure 1). Because DNA consists of two strands twisted into a spiral or helix, it is often described as a double helix. Let’s examine a single strand of DNA, and then consider how the two strands fit together.
Each DNA strand has a backbone (or a “side” of the ladder) that is made up of alternating molecules of deoxyribose sugar and phosphate. Attached to this backbone is a series of nitrogenous bases (each represents one half of a “rung”). Only four different nitrogenous bases are used in DNA—adenine (A), guanine (G), cytosine (C), and thymine (T). A single nitrogenous base bound to a single molecule of sugar and a single phosphate is called a nucleotide. So, a strand of DNA can also be described as a string of nucleotides.
Now let’s put the two strands of DNA together. Each base binds with a base on the opposite strand using hydrogen bonds. The binding occurs in a very specific way—adenine always pairs with thymine (A–T), and guanine always pairs with cytosine (G–C).

3 Responses to 'The Structure of DNA'

  1. http://krisscience.blogspot.com/2012/04/structure-of-dna.html?showComment=1348570540177#c7346326294770400327'> September 25, 2012 at 3:55 AM

    This comment has been removed by the author.

     

  2. DNA Testing said...
    http://krisscience.blogspot.com/2012/04/structure-of-dna.html?showComment=1348570634792#c3468573851344050789'> September 25, 2012 at 3:57 AM

    As day by day people are more aware about DNA,as for its demand has been also more and more.Now a days DNA testing and Forensic Science are in great demand as the are one of the best way of finding out truth and hidden things.DNA for Immigration

     

  3. Sonal said...
    http://krisscience.blogspot.com/2012/04/structure-of-dna.html?showComment=1489229281630#c4604001158613343782'> March 11, 2017 at 2:48 AM

    Insightful information posted. One can also get the admission in architecture colleges in maharashtra ranking only at SMMCA Nagpur. Thanks for sharing.

     

Post a Comment

ARCHIVE BLOG

Loading...

Traffic

Bloggers - Meet Millions of Bloggers free counters