Biochemestry _ BDS level 3 _ Nucleic acids

1. By: Olla S. BaEissa
1
Nitrogenous Bases
Purine Pyrimidine
1 2 1 2
Guanine Adenine Cytosine Thymine Uracil
Nucleosides
In RNA In DNA
Ribonucleoside Deoxy Ribonucleosides
formed of nitrogenous base + ribose sugar formed of nitrogenous base + deoxyribose sugar
Nucleoside Nitrogenous Base Pentose sugar Nucleoside Nitrogenous Base Pentose sugar
Adenosine Adenine Ribose Deoxy Adenosine Adenine DeoxyRibose
Guanosine guanine Ribose Deoxy Guanosine guanine DeoxyRibose
Cytidine cytosine Ribose Deoxy Cytidine cytosine DeoxyRibose
Uridine uracil Ribose Deoxy Thymidine thymine DeoxyRibose
Nucleotides
In RNA In DNA
Ribonucleotides Deoxy Ribonucleotides
Nitrogenous base + ribose +
termed 5`hydroxyl Phosphate group
(usually attached to the 5th carbon of the pentose)
formed of nitrogenous base + deoxyribose +
termed 5`hydroxyl Phosphate group
(usually attached to the 5th carbon of the pentose)
Nucleotide Nitrogenous Base Pentose sugar Nucleotide Nitrogenous Base Pentose sugar
Adenylic acid
(AMP)
Adenine Ribose P Deoxy Adenylic acid
(d-AMP)
Adenine DeoxyRibose P
Guanylic acid
(GMP)
guanine Ribose P Deoxy Guanylic acid
(d-GMP)
guanine DeoxyRibose P
Cytidic acid
(CMP)
cytosine Ribose P Deoxy Cytidic acid
(d-CMP)
cytosine DeoxyRibose P
Uridic acid
(UMP)
uracil Ribose P Deoxy Thymidylic
acid (d-TMP)
thymine DeoxyRibose P

2. By: Olla S. BaEissa
2
Nucleic acids
(Polynucleotides) (polymer of nucleotides)
two main types of nucleic acids
Deoxyribonucleic acids (DNA) Ribonucleic acids (RNA)
consists of two strands of polynucleotides Responsible for storage and transfer of information needed
for production of proteins.
Nucleotides forms DNA primary structure are:
d-AMP ,d-GMP, d-CMP and d-TMP
They contain mainly four nucleotides:
AMP, GMP, CMP and UMP
- The bond and nucleotides forming the structure
of RNA are the same as in Primary DNA
- Transcription: a process which RNA are synthesized.
Structure of nucleic acids
Primary structure
(Liner structure)
Secondary structure
(Helical structure) Types of RNA
(formed and related to protein synthesis)
- Phosphodiester
bonds
- between
the 5’ hydroxyl
group of one of the
nucleotide & 3’
hydroxyl group of
the next nucleotide.
- the backbone of
DNA strand is sugar
phosphate units.
- DNA strand has
two terminal:
One end>
3`hydroxyl group
from pentose &
other end> free
phosphate group
attached to
5`hydroxyl group.
- Hydrogen bonds
- Right-handed helix.
- The two antiparallel
strands of DNA are
paired together with
complementary base
pairing nucleotides.
- one runs in the direction
5`to 3` and the other in
the direction 3`to 5
- complete turn (10 bases)
- Major groove 2.2nm
- Minor groove 1.2nm
- complete turn= 3.4 nm
- Wide 2nm
(mRNA)
Messenger RNA
(tRNA)
Transfer RNA
(rRNA)
Ribosomal RNA
form 5% of cellular
RNA.
form 15% of cellular
RNA
form 80% of cellular
RNA
- Carries codes
from the DNA in
the nucleus to the
sites of protein
synthesis in the
cytoplasm or the
ribosomes
- in the cytoplasm
mRNA binds to
tRNA anticodon
arm to read the
codon it carries
and catalyze the
assembly of amino
acids into protein
chains.
- cloverleaf
appearance
- Each tRNA binds
to a specific type of
amino acid.
- four main loops: D
Loop & tᵠC loop &
Anticodon arm &
Acceptor arm.
- Amino acids are
carried in the form
of aminoacyl group
connected to the
3`hydroxyl group of
the acceptor arm.
- Acceptor arm
terminates at tRNA
3` OH end by a
specific sequence
formed of CCA.
- average length of
75 (70-90)
- Procaryotic
Ribosome (70s):
50s & 30s
In human
- Eucaryotic
Ribosome (80s):
60s & 40s