Summary AQA ALEVEL BIOLOGY NOTES ON DNA AND RNA AS LEVEL

DNA and RNA
•
DNA ldeoxribonuele.ie acid ) is used to store
genetic information -
the instructions needed to
grow and
your
develop from a fertilised
egg
to a
fully grown adult
RNA ( rib transfer information from DNA ( in
nucleic acids is used to
genetic the the nucleus) to the ribosomes
•
.




made : RNA
•
In ribosomes ,
proteins are
they read the to make
proteins ( polypeptides) in a
process

called translation .




RNA of nucleotides
#
DNA and are
polymers
•
A nucleotide made of ( with 5 atoms)
is
up
a
pentose sugar sugar carbon ,
a
nitrogen -



containing organic
( contains carbon ) base '
and a phosphate group .




④

te nitrogen
whatisthestructureofpolynvcleoti.de
containing Nucleotides form
.
join together to
polynueleotide strands .




between
.
Nucleotides join up via a condensation reaction

sugar the phosphate group
of one nucleotide and the
sugar of

another .




so¥e .
A phosphodiester bond consists of the phosphate group and



①
two ester bonds .




of double helix forms
jahepbsind? sugar phosphate
. the DNA a -




③
.
DNA has a double -
helix structure
/
.




Tester


↳
bond . DNA molecules are
really long and are



coiled lot of
up very tightly . so a

µ information fit into a
genetic
can
/





small space in the cell nucleus .




possible bases :




-
T -

thymine
sugar C cytosine
-
-




phosphate
backbone G -


guanine


comp-lementarybasepaipolyring.IN DNA ,
the two nucleotide strands are held
together by hydrogen
bonds between two bases .




•
Adenine always pairs with thymine .
LET ) £4 IT
G)
Guanine
always pairs with cytosine
•
.
CC

⇐ ↳
Acronym :
A pk Iurns
.




=
Google crazy =

The strands antiparallel
two
polynucleotide
•

are -




they run in opposite directions .




Due to base A- % -1% ,C% G %
pairing
•
: = =

r


↳ hydrogen
bonds µ
.




30%
Usually ,



adenine
cytosine makes
makes
up 30% ; guanine makes
up
,
up
20% and
thymine makes up

20% .