IntertwinedJoey Goldman

DNA

• DNA stands for Deoxyribonucleic Acid

• DNA hold all the heredity information that passes down from generation to generation

• DNA is used when a cell divides

• DNA is in every cell

• It was Frederick Griffith that discovered that “transformation property” by doing experiments with mice. He found that when a mouse was injected with a dead S strain, that usually killed the mouse when the strain was alive, and an alive R strain, which did not kill the rat, eventually killed the rat. It did this because the R stain transformed into the S strain and killed the mouse.

• Hershey and Chase discovered that it was the DNA that passed on the genetic information instead of protein. In his experiment, he put protein in one container and DNA in the other. He killed both the protein and the DNA, so DNA did not evolve into a new cell because of the lack of information.

Nucleotides

• Nucleotides are organic molecules that are the monomers for nucleic acids like DNA and RNA. • They also serve to carry packets of energy, in the form of ATP,

within the cell• DNA is made of repeating units called nucleotides.• Oswald Avery discovered through his experiments, based off

of Griffith’s, concluded that it was nucleic acid that made up DNA

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Nucleotides

• Nucleotides are composed of a nitrogenous base, a five-carbon sugar of either ribose or deoxyribose, and at least one phosphate group.

http://dnarnanews.blogspot.com/2013/04/what-is-three-parts-of-nucleotide.html

Deoxyribose

• Deoxyribose is a monosaccharide with the formula H---(CHOH)₃-H. • Its name indicates that it is a deoxy sugar, meaning

that it is derived from the sugar ribose by loss of an oxygen atom.• It’s a pentose sugar obtained by the hydrolysis of DNA• The sugar in DNA is called deoxyribose

http://www.daviddarling.info/encyclopedia/D/deoxyribose.html

Nitrogenous bases

• A nitrogenous base is a nitrogen containing molecule that has the same chemical properties as a base.• The four nucleotides in DNA are adenine, cytosine, guanine and

thymine.• The nitrogenous bases are either pyrimidines or purines. • In pyrimidines, there are cytosine, thymine, and uracil. • In purines, there are adenine and guanine.

http://www.visionlearning.com/en/library/Biology/2/DNA-II/160

A single strand of DNA

• Nucleotides can only make a connection by joining phosphates to sugars, so the bases• The phosphate end is referred to as the 5' (5-prime) end, and the

sugar end is referred to as the 3' (3-prime) end. The bonds between a phosphate and two sugar molecules in a nucleotide strand are collectively called a phosphodiester bond. This is a fancy way of saying that two sugars are linked together by a phosphate in between.

http://www.littletree.com.au/dna.htm

Chargaff’s Rule

• An experiment by Erwin Chargaff allowed him to understand that, in the DNA structure, Adenine binds with Thymine, and Guanine binds with cytosine, and that this pairing was constant and Adenine never paired with Guanine or Cytosine and Thymine did not either.• He saw that the same nucleotides do not repeat in the same order, as

proposed by Levene. • Chargaff's rules state that DNA from any cell of all organisms should

have a 1:1 ratio of pyrimidine and purine bases and that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine

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Chargaff’s Rule

https://legacy.etap.org/demo/biology1/lesson5/instruction2tutor.html

Double Helix• Each strand has a backbone made up of sugar molecules linked together by phosphate groups.

• The bases wind up parallel to each other and the sugars and phosphates run perpendicular to the stack of bases. A long strand of nucleotides put together in this way is called a polynucleotide strand.

• The 3' C of a sugar molecule is connected through a phosphate group to the 5' C of the next sugar.

• This linkage is also called 3'-5' phosphodiester linkage. All DNA strands are read from the 5' to the 3' end where the 5' end terminates in a phosphate group and the 3' end terminates in a sugar molecule.

• After DNA was placed in an x-ray crystallography, Rosalind Franklin took a picture of the DNA structure, but was unaware of what do with it. Two men named Watson and Crick based their observations on that photo she took and found that the structure of DNA was in fact a double Helix.

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Double Helix

http://tigger.uic.edu/classes/phys/phys461/phys450/ANJUM04/ http://www.elmhurst.edu/~chm/vchembook/582dnadoublehelix.html

DNA Replication

• There are three steps to DNA replication• The first step is initiation. In initiation, the double helix is

“unzipped” by an enzyme called helicase, which breaks down the hydrogen bonds holding the two strand of the DNA together.• The two strands are broken apart and serve as template

strands for the new strands being made

DNA Replication

• The next step is Elongation• A protein called DNA polymerase comes and breaks down the nucleotide

section by section, reads the codes, and then pulls the complementary nucleotides to the original strand, to create a new strand.• The Polymerase attaches itself and reads the old strand, adding one base

pair at a time to a new strand• New bases are added, creating a new strand, complementary to the

original one• The enzyme then proofreads its work• Polymerase can only read the DNA strand from 3’ to 5’ and can only read

5’ to 3’ in fragments.

DNA Replication

• The next and final step is Termination• In this step, the new complementary strand and an old strand

are fused together• Two “identical” DNA molecules are formed from the two new

and two old strands• Only the new strand and the old strand come together, not the

two old ones or two new ones

Work Cited• http://en.wikipedia.org/wiki/Nucleotide• http://en.wikipedia.org/wiki/Deoxyribose• http://www.thefreedictionary.com/deoxyribose • http://education-portal.com/academy/lesson/nitrogenous-base-defin

ition-pairs-quiz.html• http://www.dummies.com/how-to/content/assembling-the-double-h

elix-the-structure-of-dna.html • http://tigger.uic.edu/classes/phys/phys461/phys450/ANJUM04/ • Notes in class on your PowerPoint

Images Cited

• http://dnarnanews.blogspot.com/2013/04/what-is-three-parts-of-nucleotide.html• https://legacy.etap.org/demo/biology1/lesson5/instruction2tutor.html • http://www.littletree.com.au/dna.htm • http://tigger.uic.edu/classes/phys/phys461/phys450/ANJUM04/ • http://www.visionlearning.com/en/library/Biology/2/DNA-II/160• http://www.elmhurst.edu/~chm/vchembook/582dnadoublehelix.html • http://

www.extremetech.com/extreme/134672-harvard-cracks-dna-storage-crams-700-terabytes-of-data-into-a-single-gram