For Nursing Students

1. Biochemistry
for
B.Sc.Nursing
NUCLEIC ACID
BRAINSTROMING NOTES TO PRINT

2.  Nucleic acids are biopolymers, or large
biomolecules, essential for all known forms of life.
 Nucleic acids, which include
 DNA (deoxyribonucleic acid) and
 RNA (ribonucleic acid),
 Are made from monomers known as nucleotides.
Each nucleotide has three components:
i. One 5-carbon sugar
ii. One phosphate group and
iii. One nitrogenous base.
 If the sugar is deoxyribose, the polymer is DNA.
 If the sugar is ribose, the polymer is RNA.
 When all three components are combined, they form
a nucleic acid.

3.  Both are composed of un-branched chains of units
called nucleotides, each of which contains:
(1) A nitrogenous base (either a purine or pyrimidine),
(2) A pentose, and
(3) Phosphoric acid.
 In RNA, the pentose is ribose, whereas in DNA it is 2-
deoxyribose.
 Both DNA and RNA contain the purine nitrogenous bases
adenine (A) and guanine (G) and the pyrimidine
cytosine (C), but in DNA a second pyrimidine is thymine
(T), whereas in RNA it is uracil (U).
 A number of other nitrogenous bases have been
identified in DNA and RNA, but these occur much less
frequently.
 The phosphoric acid component of each nucleotide is,
of course, chemically identical in both nucleic acids.

4. DNA RNA
Purines Adenine Adenine
Guanine Guanine
Pyrimidines Cytosine Cytsine
Thymine Uracil
Pentose 2-Deoxyribose Ribose
Phosphoric Acid Phosphoric Acid

5. 5

6.  DNA is often called the
blueprint of life.
 In simple terms, DNA
contains the instructions
for making proteins
within the cell.

7. 7
We study DNA for many
reasons, e.g.,
 its central importance
to all life on Earth,
 medical benefits such
as cures for diseases,
 better food crops.

8. 8
Our genes are on
our chromosomes.
Chromosomes are
made up of a
chemical called
DNA.

9. 9
DNA is a very long
polymer.
The basic shape is like
a twisted ladder or
zipper.
This is called a double
helix.

10. 10
The DNA
double helix
has two strands
twisted
together.

11. 11
 The backbone of the
molecule is
alternating
phosphates and
deoxyribose sugar
 The teeth are
nitrogenous bases.
phosphate
deoxyribose
bases

12. 12
C C
C
O
Phosphate
O
O -P O
O
O
O -P O
O
O
O -P O
O
O
One deoxyribose together
with its phosphate and
base make a nucleotide.
Nitrogenous
base
Deoxyribose

13. 13
 One strand of DNA is a
polymer of nucleotides.
 One strand of DNA has
many millions of
nucleotides.
nucleotide

14. 14
 Cytosine C
 Thymine T
 Adenine A
 Guanine G
DNA has four different bases:

15. 15
Pyrimidines are
single ring bases.
Purines are double
ring bases.
C
C
C
C
N
N
O
N
C
C
C
C
N
N
N
N
N
C

16. 16
 Thymine and cytosine each have one ring of
carbon and nitrogen atoms.
C
C
C
C
N
N
O
N
cytosine
C
C
C
C
N
N
O
O
thymine
C

17. 17
 Adenine and guanine each have two rings of
carbon and nitrogen atoms.
C
C
C
C
N
N
N
Adenine
N
N
C
C
C
C
C
N
N
O
N
Guanine
N
N
C

18. 18
 Remember, DNA has
two strands that fit
together something
like a zipper.
 The teeth are the
nitrogenous bases but
why do they stick
together?

19. 19
C
C
C
C
N
N
O
N
C
C
C
C
N
N
O
N
N
N
C
 The bases attract each
other because of hydrogen
bonds.
 Hydrogen bonds are weak
but there are millions and
millions of them in a
single molecule of DNA.
 The bonds between
cytosine and guanine are
shown here with dotted
lines

20. 20
 When making hydrogen
bonds, cytosine always
pairs up with guanine
 Adenine always pairs up
with thymine
 Adenine is bonded to
thymine here
C
C
C
C
N
N
O
O
C

21. 21
• Adenine and Thymine
always join together
A T
• Cytosine and Guanine
always join together
C G

23.  Ribonucleic acid (RNA) functions in converting genetic
information from genes into the amino acid sequences of
proteins.
 The three universal types of RNA include:
 Transfer RNA (tRNA),
 Messenger RNA (mRNA), and
 Ribosomal RNA (rRNA).
 Messenger RNA acts to carry genetic sequence
information between DNA and ribosomes, directing
protein synthesis.
 Ribosomal RNA is a major component of the ribosome,
and catalyzes peptide bond formation.
 Transfer RNA serves as the carrier molecule for amino
acids to be used in protein synthesis, and is responsible
for decoding the mRNA.
 In addition, many other classes of RNA are now known.

24. i. The main role of nucleic acids is to store
information that is used to make proteins.
ii. The main function of DNA is to store the
genetic information that cells in the body
need to function. RNA, on the other hand,
plays an important role in converting the
information from DNA into proteins.

25. Thank You