Deoxyribonucleic acid
DNA as a genetic material
- First extracted from, nuclei in 1870
- Named “nuclein”
- Chemical analysis: determined DNA as a weal acid and rich in Phosphorous
- Furthered named DNA, as lot of information provided by name:
Deoxyribonucleic acid
Contains sugar (deoxyribose)
Weakly acidic
Found in Nucleus
- Only four different subunits makes up DNA
- Chromosome contains less DNA than protein by weight
- Chemical structure of DNA:
- Located in the nucleus of a cell like a coiled noodle.
- Main purpose is to code genetic information.
- During Replication, it attains a structure called Chromosomes.
- DNA basically is a polymer.
- Polymer is a molecule consisting of many repeating units, which are called Monomers.
- i.e., Polymer = (monomer, monomer, monomer, monomer, monomer, monomer, monomer , monomer, monomer)
ex. Starch = (glucose, glucose, glucose, glucose, glucose, glucose)
that means,
DNA = (Nucleotides)
- Nucleotides: these are biopolymers, a DNA molecule look like a rope ladder which is made up of units: nucleotides
- Basic structure of a Nucleotide contains:
A phosphate group
Deoxyribose(5C) sugar
Nitrogenous base : Purines and Pyrimidines i.e., Adenine, Guanine, Cytosine, Thymine.
Q. how two nucleotides are joined together?
A. By Sugar-Phosphate backbone.
- Base pairing
Adenine and Thymine (double bond)
Cytosine and Guanine (triple bond)
By H-bonding
- The order of these bases is what determines DNA’s instructions, or genetic code.
- Human DNA has around 3 billion bases and more than 99% of those bases are the same in all people.
- Nucleotides are attached together to form 2 long strands that spiral to create a structure – Double helix. Its like a ladder.
- Nucleosides: N-bases + sugars
- Nucleotides: N-bases + sugars + phosphate group
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