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DNA AND RNA
Both DNA and RNA are nucleic acids, they are also known as polynucleotides made of mononucleotides.
If you are asked to `name' or `state', there is no need to put the name into a sentence.
Don't expect the same diagram to always be used to represent DNA. Remember that the molecules that link the strands
together as a key (these are the nitrogenous bases). They are attached to the sugar which in turn is attached to the
In many questions the letters A, T, C and G are used to represent the names of the nitrogenous bases, you must remember
their names in case you are asked: adenine, thymine, cytosine and guanine. ,
BASIC INFORMATION ABOUT NUCLEIC ACIDS
The monomers of DNA and RNA are nucleotides: phosphate group, pentose sugar and base. DNA and
RNA can be described as a polynucleotide
Nucleotides are joined by a bond between the phosphate and carbon that sticks out-hydrogen.
Between a sugar and base-glycosidic bond.
Between phosphate and sugar-ester bond.
Between phosphate, sugar and base-phosphodiester bond.
Bases can be categorised into purines and pyrimidine.
They have a double ring structure.
Thymine is present in DNA, uracil is present in RNA.
STRUCTURE OF DNA
It is a nucleic acid.
It is located in the nucleus.
Amount is constant in cells of the same species, except in gametes and spores.
It is a double helix.
It is a pentose sugar (deoxyribose).
It has a phosphate group.
They have a large molecular mass.
Very chemically stable.
Ratio of A and G to C and T =1.
One molecular form.
Two polynucleotide chains are joined by hydrogen bonds between the bases.
There are four nitrogenous organic bases: Adenine ,Thymine ,Cytosine
Each base has a complementary opposite shape. Adenine with Thymine, Cytosine with Guanine.
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There are two hydrogen bonds between adenine and thymine, whereas, there was three hydrogen bonds between
guanine and cytosine.
DNA's function is to carry genetic information; structurally it is very long and coiled very tightly so a lot of genetic information can
fit into the nucleus.
The double helix means that it can copy itself-this is called self-replication (information on `DNA replication') which is important in
cell division, passing genetic information to the next generation.…read more