DNA (deoxyribonucleic acid) is a two stranded molecule called double helix Each strand are made of...
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Transcript of DNA (deoxyribonucleic acid) is a two stranded molecule called double helix Each strand are made of...
![Page 1: DNA (deoxyribonucleic acid) is a two stranded molecule called double helix Each strand are made of smaller parts called nucleotides The two strands.](https://reader030.fdocuments.us/reader030/viewer/2022032612/56649ee45503460f94bf31a8/html5/thumbnails/1.jpg)
DNA Structure and Replication
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DNA (deoxyribonucleic acid) is a two stranded molecule called double helix
Each strand are made of smaller parts called nucleotides
The two strands are bonded with weak hydrogen bonds
Structure of DNA
![Page 3: DNA (deoxyribonucleic acid) is a two stranded molecule called double helix Each strand are made of smaller parts called nucleotides The two strands.](https://reader030.fdocuments.us/reader030/viewer/2022032612/56649ee45503460f94bf31a8/html5/thumbnails/3.jpg)
Structure of DNA
Nucleotides have 3 parts:
• deoxyribose (sugar)• phosphate group• Nitrogenous base
(A,C,G,T)
![Page 4: DNA (deoxyribonucleic acid) is a two stranded molecule called double helix Each strand are made of smaller parts called nucleotides The two strands.](https://reader030.fdocuments.us/reader030/viewer/2022032612/56649ee45503460f94bf31a8/html5/thumbnails/4.jpg)
Nitrogenous Bases Double Rings called PURINES
• Adenine (A)• Guanine (G)
Single Ring called PYRIMIDINES• Thymine (T)• Cytosine (C)
A or G
T or C
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Base-Pairing Rules Adenine bonds with Thymine using
two hydrogen bonds
T A
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Base Pairing Rules Guanine bonds with Cytosine using
three hydrogen bonds
CG
3 H-bonds
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How did we discover this? Base-Pairing Rules (1950)
• Erwin Chargaff discovered DNA from any species had equal amounts C’s and G’s, and equal amounts A’s and T’s
• In human DNA A = 30% T = ________________ C = 20% G = ________________
![Page 8: DNA (deoxyribonucleic acid) is a two stranded molecule called double helix Each strand are made of smaller parts called nucleotides The two strands.](https://reader030.fdocuments.us/reader030/viewer/2022032612/56649ee45503460f94bf31a8/html5/thumbnails/8.jpg)
How did we discover this? Structure of DNA
(1953)• Rosalind Franklin
takes diffraction x-ray photographs of DNA
• Watson and Crick build the first model of DNA using Franklin’s pictures
![Page 10: DNA (deoxyribonucleic acid) is a two stranded molecule called double helix Each strand are made of smaller parts called nucleotides The two strands.](https://reader030.fdocuments.us/reader030/viewer/2022032612/56649ee45503460f94bf31a8/html5/thumbnails/10.jpg)
DNA Replication When a cell divides (mitosis and
meiosis) chromosomes (DNA) needs to divide to create
DNA division happens during Interphase
Carried by a series of enzymes (proteins)
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DNA Replication (in eukaryotic cells)
First, DNA is “unzipped” along the hydrogen bonds by DNA helicase
Each strand is a template to add new nucleotides
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DNA Replication DNA polymerase adds new
nucleotides Nucleotides are added using Base
Pairing Rules• A – T• C - G
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DNA Replication New DNA consists of one parent
(original) strand and one new strand of DNA
![Page 15: DNA (deoxyribonucleic acid) is a two stranded molecule called double helix Each strand are made of smaller parts called nucleotides The two strands.](https://reader030.fdocuments.us/reader030/viewer/2022032612/56649ee45503460f94bf31a8/html5/thumbnails/15.jpg)
Question What would be the complementary
DNA strand for the following DNA sequence?
Use base pairing rules• A - T• C - G
CGTATG
![Page 16: DNA (deoxyribonucleic acid) is a two stranded molecule called double helix Each strand are made of smaller parts called nucleotides The two strands.](https://reader030.fdocuments.us/reader030/viewer/2022032612/56649ee45503460f94bf31a8/html5/thumbnails/16.jpg)
Answer
Original Strand: CGTATGNew Strand:GCATAC