introduction to dna ( d eoxyribo n ucleic a cid)
DESCRIPTION
Introduction to DNA ( D eoxyribo n ucleic a cid). What do you know?. Scientists. Phoebus Levene. 1920 – Determined the basic structure of nucleotides that make up DNA 5-carbon sugar, phosphate group, and a nitrogenous base. Erwin Chargaff. 1952 - Nitrogenous base composition - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/1.jpg)
Introduction to DNA(Deoxyribonucleic acid)
![Page 2: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/2.jpg)
What do you know?
![Page 3: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/3.jpg)
Scientists
![Page 4: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/4.jpg)
Phoebus Levene
• 1920 – Determined the basic structure of nucleotides that make up DNA
• 5-carbon sugar, phosphate group, and a nitrogenous base
![Page 5: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/5.jpg)
Erwin Chargaff
• 1952 - Nitrogenous base composition
• % of adenine is equal to % of thymine
• % of guanine is equal to % cytosine
• Composition of DNA varies from species to species
![Page 6: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/6.jpg)
Maurice Wilkins and Rosalind Franklin• 1951 - Worked with a technique called X-ray
diffraction• Determined the helical nature of DNA
![Page 7: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/7.jpg)
James Watson and Francis Crick• 1953 – Determined the structure of DNA
using Chargaff’s and Franklin’s data
A
![Page 8: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/8.jpg)
What is DNA?
![Page 9: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/9.jpg)
DNA (Deoxyribonucleic acid)
• Nucleic acid• Consists of monomers called nucleotides• Stores genetic information, determines an
organisms traits by synthesizing proteins• Each organisms genome is unique
![Page 10: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/10.jpg)
Structure of DNA
![Page 11: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/11.jpg)
Structure of DNA
• Double helix• Consists of a double strand of nucleotides• Two strands are anti-parallel– 5’ to 3’– 3’ to 5’
![Page 12: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/12.jpg)
![Page 13: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/13.jpg)
Nucleotide• Three parts of a nucleotide– 5 carbon sugar called deoxyribose–Phosphate group–A single nitrogenous base
![Page 14: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/14.jpg)
![Page 15: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/15.jpg)
Four Nitrogenous Bases
• Purines (double ring)– Adenine (A)– Guanine (G)
• Pyrimidines (single ring)– Thymine (T)– Cytosine (C)
![Page 16: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/16.jpg)
Chargaff’s Rules
• A-T (2 hydrogen bonds)
• C-G (3 hydrogen bonds)
![Page 17: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/17.jpg)
• Sides of molecule - Alternating sugars and phosphates held together by strong covalent bonds
• Center – two nitrogenous bases held together by weak hydrogen bonds
![Page 18: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/18.jpg)
DNA Structure
• Click on the hyperlink above to watch a short animation about the structure of DNA
A
![Page 19: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/19.jpg)
Genes• The sequence of nucleotides in an organisms genome
is unique• Genes consist of sequences of nucleotides
![Page 20: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/20.jpg)
Human Genome
• 3164.7 million nucleotides
• Average gene length is 3000 base pairs
• Largest gene is 2.4 million base pairs
• Approximately 20,000 – 25,000 genes
![Page 21: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/21.jpg)
DNA Replication
![Page 22: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/22.jpg)
Why is DNA replication important?
![Page 23: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/23.jpg)
Why replicate?
• Each new cell created through cell division must receive an exact copy of the original cells DNA
• Occurs in the nucleus of cells
![Page 24: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/24.jpg)
DNA Replication
• Semi-conservative – new DNA molecules have one original template strand and one new strand
• Follows complementary base pair rules
• “Leading strand” – continuously synthesized• “Lagging strand” – synthesized in fragments
A
![Page 25: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/25.jpg)
Origins of Replication
![Page 26: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/26.jpg)
![Page 27: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/27.jpg)
Steps of DNA Replication
1. DNA helicase unzips the original DNA molecules by severing hydrogen bonds between nucleotides
A
![Page 28: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/28.jpg)
2. New nucleotides are added to the template strands using DNA polymerase enzymes (complementary base pairing)
![Page 29: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/29.jpg)
3. Okazaki fragments are pieced together by DNA ligase
![Page 30: Introduction to DNA ( D eoxyribo n ucleic a cid)](https://reader036.vdocuments.mx/reader036/viewer/2022081502/5681611c550346895dd075d9/html5/thumbnails/30.jpg)
DNA Replication
C C T A A C G G T A C G A A T
A