1. THE BIG IDEA!!!!!!!

2. Transcription
From DNA to RNA

3. What is RNA?
Ribonucleic acid (RNA)

4. Structure of RNA 1 strand Phosphate group 5 carbon Sugar (ribose)
Nitrogen base

5. What are the bases?
Adenine (A)
Guanine (G)
Cytosine (C)
Uracil (U)

6. Which are purines?
Adenine and Guanine
2 rings

7. Which are pyrimidines
Cytosine and Uracil
1 ring

8. Which bases pair?
A, U
G, C
When transcribing RNA, U replaces T

9. Step one RNA polymerase binds at a promoter
A region of DNA that says start

10. Step 2
RNA polymerase unwinds the DNA
Exposes the nucleotides

11. Step 3
RNA polymerase adds complimentary RNA nucleotides

12. When is transcription finished?
RNA polymerase reaches the stop signal and detaches from the DNA
RNA is released
DNA double helix
Reforms
Watch

13. Does RNA polymerase transcribe all of the DNA?NO
Uses one part of one strand of DNA (the gene)

14. Does all the DNA transcribed code for proteins?
NO!
Introns
Long segments of “junk” DNA that have no coding info.

15. What DNA does code for proteins?
Exons
DNA that codes for proteins

16. When are the Introns removed?
Before the mRNA leaves the nucleus
An enzyme cuts out the introns & puts exons together

17. ACTIVITY
Materials: masking tape, pens or pencils (two colors), metric ruler, scissors
Procedure
Place a 15-20cm piece of masking tape on your desk. This represents a gene
Use two colors to write appropriately joined
One color represents introns, one exons
Space the letters so they take up the entire piece of tape
Lift the tape
Working from left to right cut apart the groups of letters in the same color
Stick the pieces to a piece of paper as you cut them making two strips according to color. Join the pieces in their original order.
1. Label the strand that is the intron and label the strand that is the exon.
2. Predict what might happen to a protein if an intron were not removed.
Turn into the box.