1. B8: Nucleic Acids
Alia, Raudah, Izzati

2. Intro: The role of nucleic acids.
 DNA and RNA are known as the nucleic acids.
 They are acidic molecules
 DNA is responsible for storing information of the
genetic characteristics of an organisms
 RNA enables the information stored in DNA to be
expressed
 In carrying out its functions, DNA needs to have:
i. Stable molecule
ii. Contain some ‘code’
iii. Must be able to replicate

3. B 8.1: Describe the structure of nucleotides and their
condensation polymers (nucleic acids or
polynucleotide).
 DNA & RNA = polymers
 Built from monomers known as nucleotides, so it is
polynucleotide

4. A. Nucleotides are the building blocks of nucleic
acids
 Nucleotides is made up of 3 components:
i. Pentose sugar: C5H10O5 (DNA = deoxyribose,
RNA= ribose)

5. ii. Phosphate group, PO43-

6. iii. An organic nitrogenous base (TABLE 21 – DB)
Purine bases
Pyrimidine
bases

7. A nucleotide =)

8.  Adenine, guanine, cytosine = found in DNA &
RNA
 Thymine = exclusively in DNA
 Uracil = exclusively in RNA
 Ribonucleotides are found in RNA: contain
ribose sugar and either A, G, C or U.
 Deoxyribonucleotides are found in DNA:
deoxyribose sugar and either A, G, C or T.

9. B. Nucleotides condense to form polynuleotides
 Nucleotides link together in condensation
reaction involving the phosphate at the 5’
position of one nucleotide and the –OH group
at the 3’ position of the next nucleotide.

10. Phosphodiester linkage
*nitrogenous bases do not take part in the polymerization of the nucleotides
but remain attached to C1

11. C. DNA is a double helix of two polynucleotides
 2 polynucleotide strand are coiled around the same axis
forming a double helix with sugar-phosphate backbone on the
outside and the nitrogeneous bases on the inside.

13.  10 nucleotides = one complete turn of the
helix with length of 3.4 nm
 The 2 polynucleotides strands are anti-parallel
(3’  5’ and 5’  3’)
 Base pairing: A=T , G C

14. D. RNA is a single-stranded polynucleotide molecules
 RNA differs from DNA:
- Ribose sugar instead of
deoxyribose
- The base uracil instead of
thymine
- A single stranded
structure
- Less stable than DNA
- Short-lived in the cells
- RNA is able to cross the
nuclear membrane

15. • 3 different RNA exist in
human:
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA (rRNA)
*RNA polynucleotide is
able to carries
information in its
sequence of bases