DNA Structure

part one: DNA STRUCTURE Robert Perry Malibu High School

DNA What’s in a name ?

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eoxyribo

‌refers to the sugar molecule DEOXYRIBOSE.

N

“

ucleic ”

…an adjective referring to the NUCLEUS.

A

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” cid

…any solution with a pH lower than 7.0

DNA DEOXYRIBONUCLEIC ACID

THE HISTORIC AND FAMOUS “PHOTO 51”

Her x-ray diffraction image gave Watson & Crick the evidence that DNA was a double helix shape.

http://www.biochem.arizona.edu

1953 - Francis H. C. Crick and James D. Watson , together with Maurice Wilkins, described the double-helix structure of DNA. The chemical structure is based on x-ray crystallography of DNA done by Rosalind Franklin. Watson, Crick and Wilkins were awarded the Nobel Prize in 1962.

Ref: Watson, J.D. and F.H.C. Crick, 1953. Molecular structure of nucleic acids: a structure for deoxyribonucleic acid. Nature 171: 737-738.

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nucleotide

http://citd.scar.utoronto.ca/ANTAO1/ao1_syl.html

“THE GENETIC CODE” IS THE LINEAR SEQUENCE OF NUCLEOTIDES (A, T, C or G) RUNNING DOWN THE DNA STRAND. IN THIS CASE, THE CODE SEQUENCE WOULD BE: AAATGATCTGGC

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WEAK BONDS RUN DOWN THE MIDDLE BETWEEN THE BASES

STRONG BONDS INCLUDE ALL THE OTHER BONDS

CH2

DEOXYRIBOSE PYRIMIDINES: thymine cytosine PURINES: adenine guanine

GENOME The genome is the collective name for all of the genes in a species, such as a human being. It is a DNA blueprint which specifies how all the cells are built, how they will function and how they might divide to produce new, daughter cells. The genome is coded in a DNA molecule. The structure of DNA is built from four different nucleotide bases arranged in a linear string. The bases themselves are: adenine (a), guanine (g), cytosine (c) and thymine (t). Every cell in the organisms body contains a complete copy of the genome which was inherited from the parents.

1 ctcgaggggc ctagacattg ccctccagag agagcaccca acaccctcca ggcttgaccg 61 gccagggtgt ccccttccta ccttggagag agcagcccca gggcatcctg cagggggtgc 121 tgggacacca gctggccttc aaggtctctg cctccctcca gccaccccac tacacgctgc 181 tgggatcctg gatctcagct ccctggccga caacactggc aaactcctac tcatccacga 241 aggccctcct gggcatggtg gtccttccca gcctggcagt ctgttcctca cacaccttgt 301 tagtgcccag cccctgaggt tgcagctggg ggtgtctctg aagggctgtg agcccccagg 361 aagccctggg gaagtgcctg ccttgcctcc ccccggccct gccagcgcct ggctctgccc 421 tcctacctgg gctcccccca tccagcctcc ctccctacac actcctctca aggaggcacc 481 catgtcctct ccagctgccg ggcctcagag cactgtggcg tcctggggca gccaccgcat 541 gtcctgctgt ggcatggctc agggtggaaa gggcggaagg gaggggtcct gcagatagct 601 ggtgcccact accaaacccg ctcggggcag gagagccaaa ggctgggtgt gtgcagagcg 661 gccccgagag gttccgaggc tgaggccagg gtgggacata gggatgcgag gggccggggc 721 acaggatact ccaacctgcc tgcccccatg gtctcatcct cctgcttctg ggacctcctg 781 atcctgcccc tggtgctaag aggcaggtaa ggggctgcag gcagcagggc tcggagccca 841 tgccccctca ccatgggtca ggctggacct ccaggtgcct gttctgggga gctgggaggg 901 ccggaggggt gtaccccagg ggctcagccc agatgacact atgggggtga tggtgtcatg 961 ggacctggcc aggagagggg agatgggctc ccagaagagg agtgggggct gagagggtgc 1021 ctggggggcc aggacggagc tgggccagtg cacagcttcc cacacctgcc cacccccaga 1081 gtcctgccgc cacccccaga tcacacggaa gatgaggtcc gagtggcctg ctgaggactt 1141 gctgcttgtc cccaggtccc caggtcatgc cctccttctg ccaccctggg gagctgaggg 1201 cctcagctgg ggctgctgtc ctaaggcagg gtgggaacta ggcagccagc agggagggga 1261 cccctccctc actcccactc tcccaccccc accaccttgg cccatccatg gcggcatctt 1321 gggccatccg ggactgggga caggggtcct ggggacaggg gtccggggac agggtcctgg 1381 ggacaggggt gtggggacag gggtctgggg acaggggtgt ggggacaggg gtgtggggac 1441 aggggtctgg ggacaggggt gtggggacag gggtccgggg acaggggtgt ggggacaggg 1501 gtctggggac aggggtgtgg ggacaggggt gtggggacag gggtctgggg acaggggtgt 1561 ggggacaggg gtcctgggga caggggtgtg gggacagggg tgtggggaca ggggtgtggg 1621 gacaggggtg tggggacagg ggtcctgggg ataggggtgt ggggacaggg gtgtggggac 1681 aggggtcccg gggacagggg tgtggggaca ggggtgtggg gacaggggtc ctggggacag 1741 gggtctgagg acaggggtgt gggcacaggg gtcctgggga caggggtcct ggggacaggg 1801 gtcctgggga caggggtctg gggacagcag cgcaaagagc cccgccctgc agcctccagc 1861 tctcctggtc taatgtggaa agtggcccag ...et cetera...

For example, this human DNA sequence is a fragment of the blueprint for the hormone, insulin.

When a pancreas cell activates this DNA sequence it can make insulin and secrete it into the bloodstream.

Source: http://bioserve.latrobe.edu.au/bioinf/humgen.html

1 ctcgaggggc ctagacattg ccctccagag agagcaccca acaccctcca ggcttgaccg 61 gccagggtgt ccccttccta ccttggagag agcagcccca gggcatcctg cagggggtgc 121 tgggacacca gctggccttc aaggtctctg cctccctcca gccaccccac tacacgctgc 181 tgggatcctg gatctcagct ccctggccga caacactggc aaactcctac tcatccacga 241 aggccctcct gggcatggtg gtccttccca gcctggcagt ctgttcctca cacaccttgt 301 tagtgcccag cccctgaggt tgcagctggg ggtgtctctg aagggctgtg agcccccagg 361 aagccctggg gaagtgcctg ccttgcctcc ccccggccct gccagcgcct ggctctgccc 421 tcctacctgg gctcccccca tccagcctcc ctccctacac actcctctca aggaggcacc 481 catgtcctct ccagctgccg ggcctcagag cactgtggcg tcctggggca gccaccgcat 541 gtcctgctgt ggcatggctc agggtggaaa gggcggaagg gaggggtcct gcagatagct 601 ggtgcccact accaaacccg ctcggggcag gagagccaaa ggctgggtgt gtgcagagcg 661 gccccgagag gttccgaggc tgaggccagg gtgggacata gggatgcgag gggccggggc 721 acaggatact ccaacctgcc tgcccccatg gtctcatcct cctgcttctg ggacctcctg 781 atcctgcccc tggtgctaag aggcaggtaa ggggctgcag gcagcagggc tcggagccca 841 tgccccctca ccatgggtca ggctggacct ccaggtgcct gttctgggga gctgggaggg 901 ccggaggggt gtaccccagg ggctcagccc agatgacact atgggggtga tggtgtcatg 961 ggacctggcc aggagagggg agatgggctc ccagaagagg agtgggggct gagagggtgc 1021 ctggggggcc aggacggagc tgggccagtg cacagcttcc cacacctgcc cacccccaga 1081 gtcctgccgc cacccccaga tcacacggaa gatgaggtcc gagtggcctg ctgaggactt 1141 gctgcttgtc cccaggtccc caggtcatgc cctccttctg ccaccctggg gagctgaggg 1201 cctcagctgg ggctgctgtc ctaaggcagg gtgggaacta ggcagccagc agggagggga 1261 cccctccctc actcccactc tcccaccccc accaccttgg cccatccatg gcggcatctt 1321 gggccatccg ggactgggga caggggtcct ggggacaggg gtccggggac agggtcctgg 1381 ggacaggggt gtggggacag gggtctgggg acaggggtgt ggggacaggg gtgtggggac 1441 aggggtctgg ggacaggggt gtggggacag gggtccgggg acaggggtgt ggggacaggg 1501 gtctggggac aggggtgtgg ggacaggggt gtggggacag gggtctgggg acaggggtgt 1561 ggggacaggg gtcctgggga caggggtgtg gggacagggg tgtggggaca ggggtgtggg 1621 gacaggggtg tggggacagg ggtcctgggg ataggggtgt ggggacaggg gtgtggggac 1681 aggggtcccg gggacagggg tgtggggaca ggggtgtggg gacaggggtc ctggggacag 1741 gggtctgagg acaggggtgt gggcacaggg gtcctgggga caggggtcct ggggacaggg 1801 gtcctgggga caggggtctg gggacagcag cgcaaagagc cccgccctgc agcctccagc 1861 tctcctggtc taatgtggaa agtggcccag ...et cetera...

The entire human genome, or complete list of nucleotides in our DNA sequence, consists of approximately 6 billion nucleotides, arranged in 23 pairs of chromosomes.

HOW CAN DNA 6 BILLION NUCLEOTIDES LONG FIT INTO 23 PAIRS OF TINY CHROMOSOMES ?

http://www.life.uiuc.edu/bio100/lessons/dna_and_protein_synthesis.html

DNA

histones

nucleosome

“super coil� metaphase chromosome

ma gni fied

protein scaffold

http://www.life.uiuc.edu/bio100/lessons/dna_and_protein_synthesis.html

KNOWLEDGE CHECKUP:

PART ONE

1. Which chemical inside living things carries the genetic code?

2. What do the 3 letters in question one stand for?

3. What do the 3 things in question two really mean?

4. What term is used to describe the total list of nucleotides that make up the genetic code of a species?

5. Approximately how many nucleotides are there in the “list� in question number four for the human species?

6. How many chromosome pairs do most human cells contain?

7-8-9-10: Name the four nucleotides that make up the genetic code of plants, animals, protists, fungi and bacteria.

KNOWLEDGE CHECKUP:

PART ONE

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THE END