1. 1
DNA
And
RNA
The illustration is a ‘model’ of the double helix forming part of a DNA molecule
(Slide 14)

2. DNA stands for deoxyribose nucleic acid
RNA stands for ribonucleic acid 2
This chemical substance is present in the nucleus
of all cells in all living organisms
DNA controls all the chemical changes which
take place in cells
The kind of cell which is formed, (muscle, blood,
nerve etc) is controlled by DNA
The kind of organism which is produced (buttercup,
giraffe, herring, human etc) is controlled by DNA

3. DNA is a very large molecule made up of a long chain of sub-units
DNA molecule 3
DNA is a very large molecule made up of a long
chain of sub-units
The sub-units are called nucleotides
Each nucleotide is made up of
a sugar called deoxyribose
a phosphate group -PO4 and
an organic base

4. Ribose is a sugar, like glucose, but with only five
Ribose & deoxyribose 4
Ribose is a sugar, like glucose, but with only five
carbon atoms in its molecule
Deoxyribose is almost the same but lacks one
oxygen atom
Both molecules may be represented by the symbol

5. Takes the place of thymine in RNA
The bases
The most common organic bases are 5
Adenine
(A)
Thymine
(T)
Cytosine
(C)
Guanine
(G)
Uracil:
Takes the place of thymine in RNA
(U)

6. Combine to form a nucleotide
Nucleotides 6
The deoxyribose,
the phosphate
and one of the bases
Combine to form a nucleotide
adenine
deoxyribose
PO4
It is the phosphate group which gives DNA its acidic properties

7. RNA Ribonucleic Acid (RNA) Sugar + Phosphate Backbone Differs from DNA
Single Stranded
Ribose Sugar
Base Pairs A-U, G-C
Are there T’s in RNA?
A, U no T’s in RNA
RNA assists DNA in manufacturing needed proteins

8. Questions Name one difference between DNA and RNA.
DNA – Double Helix, RNA – Single Stranded
DNA --- A-T, RNA ---A-U
DNA ---Deoxyribose Sugar, RNA---Ribose
What is a similarity of DNA and RNA?
G binds with C in both DNA and RNA
Both have sugar and phosphate backbone