DNA Structure DNA Structure DNA Deoxyribonucleic Acid DNA
![DNA Structure DNA Structure](https://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-1.jpg)
DNA Structure
![DNA Structure • DNA – Deoxyribonucleic Acid • DNA - the thread of life DNA Structure • DNA – Deoxyribonucleic Acid • DNA - the thread of life](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-2.jpg)
DNA Structure • DNA – Deoxyribonucleic Acid • DNA - the thread of life • DNA – the genetic carrier
![Evidence for DNA: Bacterial Transformation • In 1928, F. Griffith was attempting to develop Evidence for DNA: Bacterial Transformation • In 1928, F. Griffith was attempting to develop](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-3.jpg)
Evidence for DNA: Bacterial Transformation • In 1928, F. Griffith was attempting to develop a vaccine against Streptoccocus pneumoniae he noticed 2 strains: one had a rough surface appearance, but those of the other strain appeared smooth. He designated the 2 strains R and S and used them in 4 experiments:
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![In the fourth experiment: • Live R received from dead (heat-killed) S bacteria a In the fourth experiment: • Live R received from dead (heat-killed) S bacteria a](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-5.jpg)
In the fourth experiment: • Live R received from dead (heat-killed) S bacteria a piece of DNA that caused the formation of the capsule in R bacteria. New R bacteria gained the gene of the capsule and became virulent. • Transformation: transfer a gene from one bacterium to another
![Confirmation of DNA function • View the animation ‘Hershey and Chase Experiment” in my Confirmation of DNA function • View the animation ‘Hershey and Chase Experiment” in my](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-6.jpg)
Confirmation of DNA function • View the animation ‘Hershey and Chase Experiment” in my Website. • Bacteriophages are viruses that infect bacteria. • The bacteriophage is made of a protein coat and a DNA core.
![Confirmation of DNA function • Bacteriophages inject their DNA into the bacterial cell, while Confirmation of DNA function • Bacteriophages inject their DNA into the bacterial cell, while](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-7.jpg)
Confirmation of DNA function • Bacteriophages inject their DNA into the bacterial cell, while the protein portion remains outside of the cell. • This experiment confirms that DNA, not the protein, is the genetic carrier. View “Steps in the Replication of T 4 Phage in E. coli” – animation in my Website
![DNA Structure • The basic building block of DNA is a nucleotide. • Each DNA Structure • The basic building block of DNA is a nucleotide. • Each](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-8.jpg)
DNA Structure • The basic building block of DNA is a nucleotide. • Each nucleotide is made of 3 sub-units: * Phosphate – P * Deoxyribose – R (5 -C-compoud) * One of 4 bases: A, T, C, or G (A-Adenine, TThymine, C-Cytosine, G-Guanine) * How many different nucleotides are there?
![• A DNA molecule is composed of 2 nucleotide chains (strands) oriented in • A DNA molecule is composed of 2 nucleotide chains (strands) oriented in](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-9.jpg)
• A DNA molecule is composed of 2 nucleotide chains (strands) oriented in opposite direction (antiparallel), and are twisted together (double helix) • View “DNA Structure” – animation in my Website.
![The first strand (blue) starts with five prime (5’) end, ends with three prime The first strand (blue) starts with five prime (5’) end, ends with three prime](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-10.jpg)
The first strand (blue) starts with five prime (5’) end, ends with three prime (3’)end. The second strand (red) is oriented in opposite direction Complementary base pairing: A in one strand pairs with T in the second strand (A=T pairs), and C pairs with G (C=G pairs) Example: if a sequence of bases in a strand of a DNA molecule is: 5’ A T T C G A G C T 3’ What is the sequence of bases in the second strand? 3’ T A A G C T C G A 5’
![Because of this complementary base pairing: A=T, and C=G • 1. The total amount Because of this complementary base pairing: A=T, and C=G • 1. The total amount](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-11.jpg)
Because of this complementary base pairing: A=T, and C=G • 1. The total amount of A in a DNA molecule is equal to the total amount of T • 2. The total amount of C in a DNA molecule is equal to the total amount of G • A + T + C + G =100% of a DNA molecule • Example: If A makes up 23% of a DNA molecule. C makes up what proportion? • 27%
![• In the complementary base pairing hydrogen bonds are used • In the complementary base pairing hydrogen bonds are used](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-12.jpg)
• In the complementary base pairing hydrogen bonds are used
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![DNA Replication • View “DNA Replication” and “DNA Replication Fork” animations in my Website. DNA Replication • View “DNA Replication” and “DNA Replication Fork” animations in my Website.](http://slidetodoc.com/presentation_image_h/1533e9b882a7ca3588435a0a0b845695/image-15.jpg)
DNA Replication • View “DNA Replication” and “DNA Replication Fork” animations in my Website.
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