A Brief Introduction to DNA

•What is DNA?•DNA stands for Deoxyribonucleic acid (Pagdatoon, R.). •DNA is the blue print for life (Coulter, B).• It carries all the genetic material for all living organisms.•A DNA molecule is extremely long and is tightly packed together and wrapped onto hitsones (Coulter, B).

•Who described the structure of DNA?

•Watson and Crick were the first to identify the structure of deoxyribonucleic acid (emilydonsisk)•Watson and Crick were British scientists that used tin and wire to build the first model representing the structure of DNA. •They illustrated that the DNA structure is a long double helix structure (Pagdatoon, R).

•A structure of DNA.

•Explaining the double helix.•The DNA structure is formed in a twisted ladder with the outside compiled from the sugar-backbone phosphate. • It moves in an antiparallel direction from 5’ to 3’ (Pagdatoon, R).•The complimentary bases are stabilized by hydrogen bases (guest83e221c).

•DNA•A DNA and an RNA molecule is a polymer of nucleotides.

Each nucleotide consists of:•Nitrogenous base which are Adenine, Guanine, Cytosine and Thymine which is in DNA and Uracil which is in RNA (pagdatoon, Rizha.).• Phosphate group•Sugar – DNA consists of Deoxyribose sugar and RNA consists of Ribose sugar.

(Teama, Hassan, S.).

•Understanding the nitrogenous bases.

• The nitrogenous bases are grouped according to their chemical structures (Teama, Hassan, S.).• There are two structures that the bases are grouped under.• Pyrimidine structure: this is a single ring structure. Cytosine, thymine or uracil have a pyrimidine structure (emilydonsisk).• Purine structure: this is a double ring structure. Adenine and Guanine have a double ring (emilydonsisk).

•Explaining the complimentary bases in DNA.

• In DNA Chargaff developed a rule which was:•Within a structure of DNA, the total amount of adenine will always be equal to the total number of thymine.•And the total number of guanine will always be equal to the total number of cytocine.

•DNA base pairing.• In DNA, Adenine will pair to Thymine with two hydrogen bonds pairing them.•Guanine will pair to Cytocine with three hydrogen bonds pairing them.

•Why is DNA important?•DNA is important for the following reasons:•1) It carries the genetic information that gets passed down from one generation to the next generation.•2) It contains the coding for proteins.•3) DNA is the genetic instruction guide for life and life’s processes. •4) DNA is very important by being able to replicate itself.

•Where is DNA located in the cell?

•Chromatin is a comprised of DNA and protein. • It is found in the nucleus of a eukaryotic cell.•Histones which are proteins found in the nucleus.•The DNA strand coils around histones forming a nucleosome.

•Explaining RNA in genetics.• RNA stands for ribonucleic acid• There are various RNA that are in the cell. • These include: (Teama, Hassan,S).• mRNA (messenger RNA)• tRNA (transfer RNA)• rRNA (ribosomal RNA)• cRNA (Catalytic RNA)• snRNA (small nuclear RNA)• snoRNA (small nucleolar RNA)

•Reference • Salwa Hassan Teama M.D. Molecular Biology Department / Medical Research Center Ain ShamsUniversity / Cairo / Egypt

http://www.slideshare.net/salhas/introduction-to-molecular-biology

• Pagdatoon, Rizha C. Penamante, Keysean M. AAPD2F. http://www.slideshare.net/rizhapagdatoon/dna-structure-dna-replication

• http://www.slideshare.net/emilydonsisk/dna-notes-8673498#

• http://www.slideshare.net/brucecoulter/unit-2-notes-7346764

• Biology: Concepts & Connections, sixth Edition Campbell, Reece, Taylor, Simon, and Dickey http://www.slideshare.net/guest83e221c/10-lecture-presentation