Do Now 3.8:

Objective:Describe how the

nucleotide sequence of nucleic acids store

information.Task: Decipher the

coded message:

EOB jt b dpef

DNA Basics• DNA is a chemical polymer made of

nucleotides.

• The order of nucleotides in a DNA molecule are instructions for making proteins.

• A gene is a piece of DNA for making 1 protein*

Codes• There’s a code that allows

people to say and write whatever they want – it’s called the alphabet.

• Each “bit” is a letter that “codes for” a specific sound. Certain sounds in a specific order make up a word, and a number of words is used to make a sentence.

DOG

bit

Computer Codes

• Computer (binary) code is another example. “32-bit” means that every computer “word” has 32 digits, all of which are 1s or 0s (on / off).

• Computers are just really fast calculators with special programs.

• 00000000000000000000000000000001 = 1• 00000000000000000000000000000010 = 2• 00000000000000000000000000000011 = 3• 00000000000000000000000000000100 = 4• 00000000000000000000000000000101 = 5• 00000000000000000000000000000110 = 6• 00000000000000000000000000000111 = 7

Programs

• Program (n): “a planned, coordinated group of activities, procedures, etc., often for a specific purpose.“

• DNA is a programming code for cells!

There are 4 bases in DNA: A,T,G, & C• Computers use a 2 “letter” code: 0 and 1

• The English language is a “base 26” code – there are 26 possible values for each piece of information

• DNA is a “base 4” code – every “bit” of information is a single A, T, G, or C in the DNA sequence.

The 4 “letters” of DNA : Nucleotide Bases

Let’s take a Look

This is a map of

chromosome #6.

How many copies of

chromosome 6 are in each of your cells?

Close Up of Chromosome

#6

This is a single gene called GUSBL1.

We’ll call it Gus for short.

What Does a Gene Look Like?A Coded Message of DNA!!!

1 ggagcgcgcc agagactggc gggcagctcc gcccgcggcc gggatgcact aggcaaagcc61 agctgggctc ctgagtccgg tgggtacttg gagaacttat tacgtctagc tggaggattg 121 taaatgcacc aatcagcatg ctgtgtctag ctcaagattt tctccatccc cttattttgg 181 gccagtggct gtcattacat atgagaactc aagctccatg aggagatgtt tcattgtcaa 241 gagcagtcat gatggcctgc actccacaca atgcaacaga gtgaaggagc aggttctggt 301 tctttggtgt agtcctgaag cttcctaaga aagttcacat caggtgatgg ataggagcaa 361 ccctgtaaaa ccagccttag actatttttc aaacaggctg gtgaattacc agatctccgt 421 caagtgcagt aaccagttca agttggaagt gtgtcttttg aatgcagaaa acaaagtcgt 481 ggacaaccag gctgggaccc agggccagct gaaggtgctg ggtgccaacc tctggtggcc 541 gtacctgatg cacgaacacc ccgcctacct gtactcgtgg gaggatggtg attgctcaca 601 ccaaagcctt ggacccctcc cagcctgtga cctttgtgac caactccacc tacgcagcag 661 acaagggggc tctgtatgtg gatgtgatcc gtgtgaacag ctactactct tggtatcgca 721 actacgggca cctggagttg attcagctgc agctgcccgc ccagtttgag aattggtgta 781 agacatcaca atcccattat tcagagcgcg tatggagtgg aaacgcttat agggtttcac 841 caggatccac ctctgatgtt cagtgaagag taccagaaaa gtctgctaga gcagtaccat 901 ctgggtctgg atcaaaaacg cagaaaatac gtggttggag agctcatctg gaattttgcc 961 gatttcatga ctaaccagt

OK, but

What IS it?

Sugar-PhosphateBackbone

Complimentary Base-pairing

Hydrogen Bonds

Each Nucleotide has 3 Parts

Complimentary Base-Pairing

• The 2 strands of a DNA molecule are held together by HYDROGEN BONDS between nucleotides

• Because they have different shapes, A and T stick together, as do G and C.

• A is always across from T and G is always across from C in a DNA molecule

• Practice…

What We’ve Learned About DNA Already:

• DNA is a chemical polymer made up of many subunits called…

Nucleotides

• A gene (made of DNA) is a “program,” or instructions a cell uses to make a…

Protein

Why Scientists Study DNA• HEALTH: certain forms of genes can cause diseases,

like cancer. Some genes can even predispose a person to diseases like alcoholism.

• BIOTECHNOLOGY: by manipulating the genetic program of organisms, many useful drugs and therapies have been developed (insulin, HgH, etc.).

• EVOLUTION: Changes in DNA sequences between species indicate how the sequences have changed over time.

• IDENTIFICATION: Every organism has a unique DNA sequence (exceptions: identical twins, clones)

Think Quick!

• A scientist breaks a DNA molecule down into its individual subunits. These subunits are called:

A. monosaccharides

B. amino acids

C. lipids

D. nucleotides

• The nucleotides from the last question are broken down even more. Which of the following will NOT be produced as a result?

A. Phosphate

B. Sugar

C. Proteins

D. Nitrogen Bases

HOMEWORK

• Read “The Structure of DNA” pp. 185-187

• SR # 1-3 p. 189