1. Reading the Code
Making more of you

2. How does DNA work to code for you?
DNA is the “blueprint”
RNA is the “contractor” to build more of you
What makes more of you?
proteins

3. RNA is like DNA
Nucleotides are monomers
Sugar is Ribose
Uracil instead of Thymine
A bonds with U (not T) in RNA

4. 3 types of RNA
Messenger RNA (mRNA)
“Working copy” of DNA
Transfer RNA (tRNA)
Transport vehicle to bring materials to the construction site
Ribosomal RNA (rRNA)
Construction site

5. 2 steps to construction
Transcription
Making the working copy of DNA
Occurs in nucleus
Translation
Reading that copy to make proteins
Occurs in cytoplasm

6. Unzip DNA at gene location
Transcription
Unzip DNA at gene location
complementary RNA nucleotides attach to exposed DNA nucleotides (A-U, C-G)

7. RNA is released when the end of the gene is reached
Transcription, cont’d
RNA is released when the end of the gene is reached
DNA zips back up
RNA can now be used

8. How do the enzymes know where to start & stop?
Promoter
Sequence of codes that says “start here”
Termination signal
Sequence of codes that says “stop”

9. mRNA is a rough draft
Rough draft of RNA needs to be cleaned up for errors and “garbage”
Introns are edited out
Exons are left to be “read”
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10. Translation, or protein synthesis
Must “translate” the gene code into protein
At construction site (Ribosome=rRNA), proteins are made from amino acids (AA)

11. DNA/RNA alphabet Every 3 letters of DNA make up CODON of RNA
Each CODON specifies a single AA
Only 20 AA make up ALL proteins
64 codons specify the 20 AA of all life

12. Turning the blueprint into the house
mRNA leaves nucleus & binds with rRNA at ribosome
tRNA picks up the correct AA in cytoplasm

13. Construction cont’d
tRNA shuttles the AA to the ribosome where its ANTICODON is complementary to the CODON on mRNA
rRNA attaches the AA together

14. AA + AA + AA makes a polypeptide, or PROTEIN (your traits)
Protein synthesis…
AA + AA + AA makes a polypeptide, or PROTEIN (your traits)

15. How does rRNA know when to start & stop?
mRNA has built-in signals
start codon (AUG)
stop codon (UAA, UAG or UGA)

16. Mutations to DNA, mutations to you
Typo’s change DNA, which change the mRNA codon, which changes the AA coded for – a different trait is formed
Point mutation
Frameshift mutation

17. Mutagens Anything that causes a mutation is a mutagen
A cancer-causing mutagen is a carcinogen

18. Random errors in replication, transcription, translation
Mutations & Cancer
Random errors in replication, transcription, translation
Environmental factors
Food & diet factors