Powerpoint presentation in DNA of living organisms
1.
2. Cellular composition
DNA is contained in nucleus of
cell
Phospho-lipids and proteins
combined to form cell
membrane
Lipids are fats
3. Base pairs
A=T – double hydrogen bond
G
Nucleotide (3 chemical
groups)
C – triple hydrogen bond
Sugar
– deoxyribose
contains
Phosphate
A
5 Carbon atoms
group
base (A, T, G, C)
4. DNA molecule
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
5. Ribose & deoxyribose
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
6. The bases
The most common organic bases are
Adenine
(A)
Thymine
(T)
Cytosine
(C)
Guanine
(G)
9. In fact, the DNA usually consists of a double
strand of nucleotides
The sugar-phosphate chains are on the outside
and the strands are held together by chemical
bonds between the bases
11. Bonding 1
The bases always pair up in the same way
Adenine forms a bond with Thymine
Adenine
Thymine
and Cytosine bonds with Guanine
Cytosine
Guanine
20. DNA is Dynamic
Like proteins, DNA has 3º structure
Why so many deviations from normal conformation?
Enhances responsiveness
Effects on transcription (gene expression)
May also serve in packaging
NOTE: most cellular DNA exists as protein containing supercoils
21. Denaturation of DNA
Denaturation by heating.
How observed?
A260
For dsDNA,
A260=1.0 for 50 µg/ml
For ssDNA and RNA A260=1.0 for 38
µg/ml
For ss oligos
A260=1.0 for 33 µg/ml
The T at which ½ the DNA
sample is denatured is
called the melting
temperature (Tm)
Hyperchromic shift
23. Accreditation to the following
http://www.present.udel.edu/biotech/rD
NA.html
http://www.sumanasinc.com/webcontent/anisam
ples/molecularbiology/plasmidcloning_fla.html
http://www.worldofteaching.com