T RANSCRIPTION

B ELLWORK O BJ : S IMULATE THE PROCESS OF TRANSCRIPTION HW: F INISH T RANSCRIPTION PROBLEMS 1. What is the “central dogma or big idea” of biology? 2. What are the 3 kinds of RNA? 3. Describe the function of each type of RNA 4. Give at least 2 reasons why making proteins is such an important process 5. When you are finished, write down as many things as you can remember about the similarities & differences between DNA & RNA

VIDEO CLIP: CHEFS E

S O HOW DOES RNA MAKE PROTEINS ??? DNA RNA Protein DNA stores information to run cell Proteins actually DO the work in the cell RNA’s function is to make proteins!

P ROTEIN S YNTHESIS To get from a DNA gene to a protein, the cell has to perform protein synthesis. It requires 3 types of RNA: mRNA rRNA tRNA It happens in 2 parts: Transcription Translation

T RANSCRIPTION Transcription is the process of making an mRNA copy of the DNA instructions (recipe for a protein). Occurs in the nucleus.

T RANSCRIPTION VIDEO CLIP Basic_withFX.html

T RANSCRIPTION - S TEP 1 S IGNAL Transcription begins when the cell receives a message to make a certain quantity of a specific protein.

E XAMPLE After drinking milk, your cells receive a signal to begin making more LACTASE- the enzyme that breaks down lactose (milk sugar) What other example can you think of that would signal cells to make a protein?

RNA Polymerase “unzips” the DNA so it can get to the gene (recipe for the protein) on a single strand T RANSCRIPTION - S TEP 2 U NZIPPING

What kind of molecule is RNA polymerase (hint- look at the ending of the word)?

RNA polymerase binds to the promoter or starter DNA sequence (usually “TATA”) and begins making the complementary mRNA copy T RANSCRIPTION - S TEP 3 B INDING & R EADING

P RACTICE Try #1 on your transcription worksheet G C C T G A C A C G T C A T C C C G A G T A A A _ _ _ _ _ _ _ _ _ _ _ _ #2- Circle promoter (TATA) GACCTATAGTCTAGCTATAATGCTACACTGAGCTGCG CAGGATATCAGATCGATATTACGATGTGACTCGACGC GTCGAACGTATACGGGTGCATGATCCTGTATCGATCGAAATATCGATCGTTA CAGCTTGCATATGCCCACGTACTAGGACATAGCTAGCTTTATAGCTAGCAAT #3- Underline the sequence that will be copied into mRNA C G G A C UG U G C A G U A G G G C U C A U U U

P RACTICE Circle the promoter, underline the sequence to be made into mRNA, make the complementary mRNA underneath T G C A T A T G G G A T G T G C T G A T C G A T T G A G T G A A C G T A T A C C C T A C A C G A C T A G C T A A C T C A C T mRNA: G G G A U G U G C U G A U C G A U U G A G U G A

After gene is transcribed, DNA zips back up (closes) T RANSCRIPTION - S TEP 4 DNA CLOSES

T AKE YOUR H ANDOUT Fold it correctly to reveal the hidden picture!

mRNA is spliced Segments called introns are removed (not part of the recipe) Segments called exons are kept (final recipe) T RANSCRIPTION - S TEP 5 M RNA S PLICING

T ALK TO YOUR NEIGHBOR How did the Harry Potter fold-in model the process of mRNA splicing? Explain introns vs exons.

B ELLWORK 1. Explain the analogy of the cake making. What is the Recipe book? What is the copy of the recipe? What is the recipe? What is the ‘name’ of the recipe that alerts you to it’s presence What is the cook who ‘reads’ the recipe? What are the ingredients called?

P RACTICE Circle the promoter, underline the sequence to be made into mRNA, make the complementary mRNA underneath T G C A T A T G G G A T G T G C T G A T C G A T T G A G T G A A C G T A T A C C C T A C A C G A C T A G C T A A C T C A C T mRNA: G G G A U G U G C T G A U C G A U U G A G U G A Boxed-in parts = introns Remove introns: G G G A U G U G C T G A A U U U G A Mature mRNA: G G G A U G U G C T G A A U U U G A

The mature mRNA leaves the nucleus to find a ribosome T RANSCRIPTION - S TEP 6 M RNA LEAVES NUCLEUS

T RANSCRIPTION VIDEO CLIP - ONE MORE TIME Basic_withFX.html

T RANSCRIPTION SUMMARY - S UMMARIZE TRANSCRIPTION TO YOUR NEIGHBOR

T RANSCRIPTION A CTIVITY 1. You and your partner will receive a “signal” in the cytoplasm (lab table) to begin transcription of a specific protein 2. Go into the nucleus (desk-side) & find the appropriate gene on the DNA molecule to transcribe mRNA from 3. Record the mRNA on your worksheet 4. Splice the mRNA according to instructions 5. Take your mature mRNA out of the nucleus & into the cytoplasm to (double check it with the answer key at your lab table) 6. Move to the next lab table to get a new signal & repeat **If you finish early, begin the HW problems

C LOSURE Write a note to a student who was absent explaining what they need to know about transcription. **If you finish early, begin the HW problems