Deoxyribonucleic acid (DNA)

DNA structure and base pairsDNA is the abbreviation of “Deoxyribonucleic acid”. It is the substance in the body that have information relating to genes, which are basic unit of heredity, of any organism.

DNA is a molecule of nucleic acid and is present in the form of double strand (which is twisted i.e. one end is turning in opposite direction from the other end). It is present mainly in the nuclei and mitochondria of living organisms. It is major component of chromosomes which are the rod shaped structures of the body having genes on it. It is present in all living organisms but not in some viruses.

Code is made up of four chemical bases;

1. adenine (A)

2. Guanine (G)

3. Cytosine (C)

4. Thymine (T)

is used for storage of information in DNA.

Adenine (A) always binds with Thymine (T) and Cytosine (C) always binds with Guanine (G) and this binding is referred to as pairing (Base pairing). Human DNA has about 3 billion base pairs and greater than 99% of these bases are same in all people. Information that is used for making and maintaining an organism is determined by the sequence and order of these bases.

A sugar molecule and a phosphate molecule is also attached to each base. This whole thing (complex) of base, sugar and phosphate is known as “Nucleotide”. These nucleotides are placed in the form of a spiral, in two long strands (just like a ladder), known as double helix.

DNA has the ability of forming copies of itself and this process is known as “Replication”.

Scientists related to discovery of DNA:

1. Friedrich Miescher discovered a molecule in the nuclei of white blood cells in 1869 and called it nuclein.

2. Oswald Avery and his colleagues discovered in early 1940s that DNA has genome as a map of development.

3. James Watson and Francis Crick discovered the double helical structure of DNA in 1953.

Interesting facts about DNA:

DNA is an interesting compound1. If DNA of all the cells of the body are uncoiled than it can stretch upto 10 billion miles, which is somewhat equal to the distance from the earth to the Pluto and then back.

2. Human DNA has about 3 billion base pairs but this is not the largest at this time. According to a research, Paris japonica, a flowering plant of Japan has 150 billion base pairs (the largest known base pairing at this time).

3. “Touch DNA”, belongs to that small traces of DNA, is found in fingerprints at the crime scene and can help forensic specialists in identification of criminals.

4. 50% of human genes are similar to nematodes (pinworms and hookworms) and 20% is similar to yeast.

5. Most of the mutations occur in males which is in the ratio of 2:1 in males versus females.

6. 5 million strands of DNA can be fitted in an eye of needle.

7. 3 Gigabytes of storage space is required for 3 billion base genomes.

8. 50 years will be required for a person to write the human genome, if a person writes 60 words in a minute for 8 hours a day.

9. We eat DNA everyday.

10. DNA is not only a chemical compound but also a language of instructions having not only an information molecule but also a text as well.

11. Only 3% of human DNA is found to be active and 97% is, presently, labelled as “Junk”.

12. DNA emits photons of light, like a laser without heat, in the narrow band of light that is visible.

13. DNA has crystalline properties and can work both as transmitter and receiver.

Brief overview of DNA

References and Further Reading:

Gates, R. A., Fink, R. M. Oncology Nursing Secrets. Elsevier Health Sciences. 2008.

R. J. Trent. Molecular medicine: An Introductory Text. Elsevier.

Seaward, B. L. Quiet Mind, Fearless Heart: The Taoist Path Through Stress and Spirituality. John Wiley and Sons. 2004. accessed July 16, 2011. accessed July 16, 2011. accessed July 16, 2011. accessed July 16, 2011.

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