Nucleic Acids. Biotechnology

Transcription

1 Nucleic Acids Biotechnology

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3 DNA Deoxyribonucleic acid Forms the Genetic Code

4 1953 The work of four people identify the structure of DNA. This knowledge opens the floodgates of scientific discovery that have begun to shape the modern world.

5 Nature publishes James Watson's and Francis Crick's manuscript describing the double helical structure of DNA, which marks the beginning of the modern era of genetics. 1953

6 James Watson Francis Crick Maurice Wilkins The Nobel Prize in Physiology or Medicine 1962

7 2 Categories of Cells Eukaryotic Plant Animal Prokaryotic

8 The two types of cells have different arrangements and amounts of DNA:

9 Bacterial DNA Single circular chromosome. 0.5 to 5 x 10 6 bp (~1.5 mm in a 1~2 µm cell) Some small plasmids.

10 Eukaryotic DNA There is so much it is compacted into Chromatin. Then packaged into Chromosomes.

11 DNA Packaging in Eukaryotic Cells: Chromosome Chromatin DNA

12 DNA Structure A molecule of DNA is made up of millions of tiny subunits called Nucleotides. Each nucleotide consists of: 1. Phosphate group 2. Pentose sugar 3. Nitrogenous base

13 Lets look at each of the three pieces:

14 Phosphate Group Gives DNA its NEGATIVE charge.

15 Deoxyribose: Pentose Sugar Carbons are numbered from 1 to 5 clockwise around the molecule.

16 Nucleotides Four different Nitrogen Bases. Placed into 2 categories: Purines (Two Ringed): Adenine Guanine Pyramidines (One Ringed): Thymine Cytosine

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18 DNA nucleotides are linked together by covalent bonds to form a single strand. Two nucleotides can be linked together by a covalent bond between the Deoxyribose of one molecule and the Phosphate of the next molecule. More nucleotides are added in the same manner until they form a chain of molecules.

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20 DNA consists of two nucleotide chains that are arranged into a ladder-like structure called a Double Helix.

21 DNA double helix is formed using complementary base pairing & hydrogen bonds. Two strands of these nucleotide chains are bonded together into a single molecule that has a particular shape, called a DOUBLE HELIX. Hydrogen bonds link these two strands together, forming between the bases of each pair of nucleotides.

22 The 4 Bases in DNA.»Adnine (A)»Thymine (T)»Cytosine (C)»Guanine (G)

23 Nucleotides A Adenine T Thymine C Cytosine G Guanine

24 Nucleotides Each base will only bond with one other specific base. Adenine (A) Thymine (T) Form a base pair. Cytosine (C) Guanine (G) Form a base pair.

25 Complimentary Base Pairs Adenine will ONLY forms hydrogen bonds with Thymine. Cytosine ONLY forms hydrogen bonds with Guanine.

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27 Purines: 2 of the bases are made of 2 rings. These are the purines. Adenine & Guanine.

28 Pyramidines Composed of one ring. Cytosine & Thymine.

29 Nitrogen Bases

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32 Bonding: The Purine Adenine will ONLY bond with the Pyramidine Thyamine. Each of these require 2 hydrogen bonds to hold them together.

33 Bonding (2): The Purine Guanine wil ONLY bond with the pyramidine Cytosine because they both require 3 hydrogen bonds to hold them together.

34 Bonding

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37 A C T C A G T G A G T C T A

38 DNA Structure Because of this complementary base pairing, the order of the bases in one strand determines the order of the bases in the other strand.

39 Hydrogen Bonds H H H H O O H C C C C N N C Thymine H N H H N C C C C N N H N C Adenine H O N H C C C N N C Cytosine H H H N C C C C N N H N C Guanine N H O H

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41 Nucleotides The phosphate and sugar form the backbone of the DNA molecule, whereas the bases form the rungs. There are four types of nitrogenous bases.

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46 The 2 strands are Antiparallel

47 DNA Structure Key Ideas If a gene is a section of DNA that codes for a specific protein: Each unique gene has a unique sequence of bases. This unique sequence of bases will code for the production of a unique protein. It is these unique proteins and combination of proteins that give us a unique phenotype.

48 Gene DNA Protein Trait