|
DNA
|
RNA
|
|
Deoxyribonucleic Acid
|
Ribonucleic Acid
|
|
DNA replicates and stores genetic
information. It is a blueprint for all genetic information contained within
an organism
|
RNA converts the genetic
information contained within DNA to a format used to build proteins, and then
moves it to ribosomal protein factories.
|
|
DNA consists of two strands,
arranged in a double helix. These strands are made up of subunits called
nucleotides. Each nucleotide contains a phosphate, a 5-carbon sugar molecule
and a nitrogenous base.
|
RNA only has one strand, but like
DNA, is made up of nucleotides. RNA strands are shorter than DNA strands. RNA
sometimes forms a secondary double helix structure, but only
intermittently.
|
|
DNA is a much longer polymer than
RNA. A chromosome, for example, is a single, long DNA molecule, which would
be several centimetres in length when unravelled.
|
RNA molecules are variable in
length, but much shorter than long DNA polymers. A large RNA molecule might
only be a few thousand base pairs long.
|
|
The sugar in DNA is deoxyribose,
which contains one less hydroxyl group than RNA’s ribose.
|
RNA contains ribose sugar
molecules, without the hydroxyl modifications of deoxyribose.
|
|
The bases in DNA are Adenine (‘A’),
Thymine (‘T’), Guanine (‘G’) and Cytosine (‘C’).
|
RNA shares Adenine (‘A’), Guanine
(‘G’) and Cytosine (‘C’) with DNA, but contains Uracil (‘U’) rather than
Thymine.
|
|
Adenine and Thymine pair (A-T)
Cytosine and Guanine pair
(C-G)
|
Adenine and Uracil pair (A-U)
Cytosine and Guanine pair
(C-G)
|
|
DNA is found in the nucleus, with a
small amount of DNA also present in mitochondria.
|
RNA forms in the nucleolus, and
then moves to specialised regions of the cytoplasm depending on the type of
RNA formed.
|
|
Due to its deoxyribose sugar, which
contains one less oxygen-containing hydroxyl group, DNA is a more stable
molecule than RNA, which is useful for a molecule which has the task of
keeping genetic information safe.
|
RNA, containing a ribose sugar, is
more reactive than DNA and is not stable in alkaline conditions. RNA’s larger
helical grooves mean it is more easily subject to attack by enzymes.
|
|
DNA is vulnerable to damage by
ultraviolet light.
|
RNA is more resistant to damage
from UV light than DNA.
|
