5. The dogma is a framework for understanding the
transfer of sequence information between
information-carrying biopolymers, in the most
common or general case, in living organisms. There
are 3 major classes of such biopolymers: DNA and
RNA (both nucleic acids), and protein for
understanding the transfer
of sequence information between information-
carrying biopolymers, in the most common or
general case, in living organisms. There are 3 major
classes of such biopolymers: DNA and RNA (both
nucleic acids), and protein.
6. DNA is one of the three major macromolecules that are
essential for all known forms of life.
DNA consists of two long polymers of simple units called
nucleotides, with backbones made of sugars and phosphate
groups joined by ester bonds.
These two strands run in opposite directions to each other and
are, therefore, anti-parallel.
Attached to each sugar is one of four types of molecules called
nucleobases (informally, bases).
It is the sequence of these four nucleobases along the
backbone that encodes information.
This information is read using the genetic code, which
specifies the sequence of the amino acids within proteins.
The code is read by copying stretches of DNA into the related
nucleic acid RNA in a process called transcription.
Within cells, DNA is organized into long structures called
chromosomes.
7. NUCLIEC ACIDS
O Nucleic
acids are biopolymers, macromolecules,
essential to all known forms of life. They are
composed of nucleotides, which are the
monomeric components.
O The two main classes of nucleic acids
are deoxyribonucleic acid (DNA)
and ribonucleic acid (RNA). If
the sugar is ribose, the polymer is RNA; if the
sugar is the ribose derivative deoxyribose, the
polymer is DNA.
8.
9.
10.
11.
12. A nucleoside consists of a
nitrogenous base covalently attached to a sugar
(ribose or deoxyribose) but without the phosphate
group. A nucleotide consists of a nitrogenous base,
a sugar (ribose or deoxyribose) and one to three
phosphate groups.
Nucleoside = Sugar + Base
Nucleotide = Sugar + Base + Phosphate
13.
14. PURINES & PYRIMIDYNES
O The heterocyclic base; there are five common bases
for nucleic acids .
15.
16.
17. Nucliec acid Structure
O Chemically speaking, DNA and RNA are
very similar. Nucleic acid structure is often
divided into four different levels: primary,
secondary, tertiary, and quaternary
18. Primary structure
O Primary structure consists of a linear sequence
of nucleotides that are linked together
by phosphodiester bond. It is this linear sequence
of nucleotides that make up the primary structure
of DNA or RNA. Nucleotides consist of 3
components:
O Nitrogenous base
O Adenine
O Guanine
O Cytosine
O Thymine (present in DNA only)
O Uracil (present in RNA only)
O 5-carbon sugar which is called deoxyribose (found
in DNA) and ribose (found in RNA).
O One or more phosphate groups
19. O The nitrogen bases adenine and guanine
are purine in structure and form a glycosidic
bond between their 9 nitrogen and the 1' -OH
group of the deoxyribose. Cytosine, thymine, and
uracil are pyrimidines, hence the glycosidic bonds
form between their 1 nitrogen and the 1' -OH of the
deoxyribose. For both the purine and pyrimidine
bases, the phosphate group forms a bond with the
deoxyribose sugar through an ester bond between
one of its negatively charged oxygen groups and
the 5' -OH of the sugar.[2] The polarity in DNA and
RNA is derived from the oxygen and nitrogen
atoms in the backbone
20. O Nucleic acids are formed when nucleotides come
together through phosphodiester linkages between
the 5' and 3' carbon atoms. A nucleic acid
sequence is the order of nucleotides within a DNA
(GACT) or RNA (GACU) molecule that is determined
by a series of letters. Sequences are presented from
the 5' to 3' end and determine the covalent structure
of the entire molecule. Sequences can
be complementary to another sequence in that the
base on each position is complementary as well as in
the reverse order. An example of a complementary
sequence to AGCT is TCGA. DNA is double-stranded
containing both a sense strand and
an antisense strand. Therefore, the complementary
sequence will be to the sense strand.
