1. Introduction to Studying DNA

2. DNA Structure and Function
Most Biotechnology Industries’ R&D is centered around two basic concepts:
The manipulation of DNA molecules within all cells (manipulation of genes).
DNA’s role in the coding of proteins. (Proteins do all the work of the cells and give cells and organisms their unique characteristics.)

3. Central Dogma of Biology
The basis of all biotechnology.
Connects the genetic code to protein production. (gene: a section of DNA on a chromosome that contains the genetic code for a specific protein)
Over 2000 different proteins synthesized by each cell.
Each cell in an organism contains the exact same DNA (genome); however, every cell does not produce the same proteins.
The more complex an organism is, the larger that organism’s genome will be.

4. Central Dogma of Biology
In Nucleus
In Cytoplasm
Replication of the DNA
Transcription
Production of mRNA, rRNA, or tRNA
Translation of the mRNA into protein

5. Central Dogma of Biology
Replication
Transcription
Translation
Tutorial Video

6. Comparisons of Genomes
Organism
# of Genes
Genome Size
(# of bp)
H. Influenza
(childhood ear infection)
1,749
1,830,137
M. Gentalium
(free-living bacteria)
470
580,070
C. Elegans
(free-living roundworm)
19,899
97,000,000
E. Coli
(intestinal bacteria)
4,377
4,639,221
H. Sapiens
(human)
40,000
3,000,000,000

7. Similarities in DNA Molecules Among All Organisms
All DNA molecules are composed of four nucleotide monomers: A C G T
Purines
(double carbon rings)
Pyrimidines
(single carbon rings)

8. Similarities in DNA Molecules Among All Organisms
DNA molecules form a double helix
Sugar-Phosphate backbone
Phosphodiester Bonds hold nucleotide to nucleotide – STRONG BONDS
A always bonds to T
C always bonds to G
Hydrogen Bonds hold base to base; therefore,
hold strand 1 to strand 2 – WEAK BONDS

9. Similarities in DNA Molecules Among All Organisms
Purine always bonds to a Pyrimidine
Therefore the rungs of the ladder are always the same width:
A T = G C

10. Similarities in DNA Molecules Among All Organisms
DNA strands are antiparallel
The 5' end of one strand pairs with the 3’ end of the opposite strand. T C G A

11. Similarities in DNA Molecules Among All Organisms
There are 10 base pairs for every complete turn of the helix.
Maintains constant shape so enzymes and regulatory proteins can work! 4 3 5 7 8 9 2 6 10 1
1 complete turn of helix

12. Similarities in DNA Molecules Among All Organisms
DNA undergoes
semiconservative replication
2 daughter strands produced from a single parent strand.
1 daughter strand goes into each daughter cell during cell division.

13. Similarities in DNA Molecules Among All Organisms: SUMMARY
All DNA molecules are composed of four nucleotide monomers (A, T, C, & G).
DNA molecules form a double helix.
Purine always bonds to a Pyrimidine.
(A T & G C)
DNA strands are antiparallel.
There are 10 base pairs for every complete turn of the helix.
DNA undergoes semiconservative replication.

14. Variations in DNA Molecules Among Organisms
The number of DNA strands (chromosomes) varies by organism.
The more complex the organism…
the more chromosomes that organism has.
Humans – 46 total chromosomes in every cell (23 pairs)
E. coli – 1 chromosomes + 2 plasmids

15. Variations in DNA Molecules Among Organisms
The length of the DNA strands varies by organism.
The more complex the organism…
the greater the number of base pairs (bp) that organism has.
Human Genome
3,000,000,000 bp
E. Coli Genome
4,639,221 bp

16. Variations in DNA Molecules Among Organisms
The number and types of genes varies by organism.
The more complex the organism…
the greater the number of genes that organism has.
Human Genome
40,000 genes
E. Coli Genome
4,377 genes

17. Variations in DNA Molecules Among Organisms
The shape of the DNA strand varies by organism.
Eukaryotes…linear chromosomes
Prokaryotes...circular chromosomes & plasmids
Eukaryotic DNA -- linear
Prokaryotic DNA -- circular

18. Variations in DNA Molecules Among All Organisms: SUMMARY
The number of DNA strands varies by organism. (more complex = more chromosomes)
The length of the DNA strand varies by organism. (more complex = more base pairs)
The number and types of genes varies by organism. (more complex = more genes)
The shape of the DNA varies by organism. (eukaryotic = linear DNA; prokaryotic = circular DNA)