DNA Structure

Category: Education

Presentation Description

The students will learn the basic structure of DNA.


Presentation Transcript

DNA (Deoxyribonucleic Acid):

DNA (Deoxyribonucleic Acid) http://www.youtube.com/watch?v=qy8dk5iS1f0

Genetic material of cells…:

Genetic material of cells… GENES – units of genetic material that CODES FOR A SPECIFIC TRAIT Called NUCLEIC ACIDS DNA is made up of repeating molecules called NUCLEOTIDES

DNA Nucleotide:

DNA Nucleotide O O=P-O O Phosphate Group N Nitrogenous base (A, G, C, or T) CH2 O C 1 C 4 C 3 C 2 5 Sugar (deoxyribose)


A HISTORY OF DNA Discovery of the DNA double helix A. Frederick Griffith – Discovers that a factor in diseased bacteria can transform harmless bacteria into deadly bacteria (1928) B. Rosalind Franklin - X-ray photo of DNA. (1952) C. Watson and Crick - described the DNA molecule from Franklin’s X-ray. (1953) SEE p. 292-293

Watson & Crick proposed…:

Watson & Crick proposed… DNA had specific pairing between the nitrogen bases: ADENINE – THYMINE CYTOSINE - GUANINE DNA was made of 2 long stands of nucleotides arranged in a specific way called the “Complementary Rule”

DNA Double Helix:

DNA Double Helix Nitrogenous Base (A,T,G or C) “Rungs of ladder” “Legs of ladder” Phosphate & Sugar Backbone

DNA Double Helix:

DNA Double Helix P P P O O O 1 2 3 4 5 5 3 3 5 P P P O O O 1 2 3 4 5 5 3 5 3 G C T A

Nitrogenous Bases:

Nitrogenous Bases PURINES 1. Adenine (A) 2. Guanine (G) PYRIMIDINES 3. Thymine (T) 4. Cytosine (C) T or C A or G

Chargaff’s Rule:

Chargaff’s Rule Adenine must pair with Thymine Guanine must pair with Cytosine Their amounts in a given DNA molecule will be about the same . G C T A



Genetic Diversity…:

Genetic Diversity… Different arrangements of NUCLEOTIDES in a nucleic acid (DNA) provides the key to DIVERSITY among living organisms.

The Code of Life…:

The Code of Life… The “code” of the chromosome is the SPECIFIC ORDER that bases occur. Can you find this code in our DNA model? A T C G T A T G C G G …

DNA is wrapped tightly around histones and coiled tightly to form chromosomes :

DNA is wrapped tightly around histones and coiled tightly to form chromosomes See p. 297

DNA Fingerprinting:

DNA Fingerprinting The Process of Making a DNA Fingerprint http://www.dailymotion.com/video/x4o0ak_dna-fingerprinting_tech The Case: “It Takes a Lickin” http://www.pbs.org/wgbh/nova/sheppard/lab01.html

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