1. Set up Cornell Notes on pg. 5
Topic: 8.4 Transcription
Essential Question:
What is the central dogma?
Why can an mRNA strand made during transcription, be thought of as a mirror image of the DNA strand from which it was made?
8.4 Transcription
2.1 Atoms, Ions, and Molecules
What is the central dogma?
Why can an mRNA strand made during transcription, be thought of as a mirror image of the DNA strand from which it was made?
KEY CONCEPT Transcription converts a gene into a single-stranded RNA molecule.

2. On Your OWN:
The Central Dogma
P.4
Draw fig 8.10 (pg.239)- color code
Red
Blue
Green
Make a double-bubble map comparing and contrasting DNA and RNA ( )

3. REVIEW:
rough endoplasmic reticulum Have bumps called ribosomes which link amino acids together to form proteins

4. Proteins are used for movement, eyesight, and digestion and practically everything else you do.

5. KEY CONCEPT Transcription converts a gene into a single-stranded RNA molecule.
DNA

6. Connect
Suppose you want to play skeeball at a arcade. The game only takes tokens, but you only have quarters. What do you do?
You exchange your quarters for tokens.
In a similar way, your cells cannot make proteins from DNA.
They must convert the DNA into RNA in order to make proteins
This process is known as transcription

7. RNA carries DNA’s instructions.
The central dogma states that information flows in one direction from DNA to
RNA to proteins.

8. The central dogma includes three processes.
Replication
Copies DNA
2.Transcription
Converts DNA into RNA
RNA is a link between DNA and proteins
“quarters tokens”
3.Translation
Interprets an RNA message into a string of amino acids that will make up a protein
replication
transcription
translation

9. Protein Synthesis: the process whereby biological cells generate new proteins. Includes DNA replication, transcription, and translation.

10. Location of Protein Synthesis
Prokaryotic cells: replication, transcription, and translation all occur in the cytoplasm (remember there is no nucleus), at approx the same time
In Eukaryotic cells, where DNA is located inside the nucleus, these processes are separated by location and times.
Replication and transcription occur in the nucleus
Translation occurs in the cytoplasm

11. RNA differs from DNA in three major ways.
Ribose Sugar
Deoxyribose Sugar
Uracil (U)
Thymine (T)
Single-Stranded
Double-Stranded
Please add a drawing to each side of your double-bubble map

12. RNA is similar to DNA in a few ways
Both are a chain of nucleotides
Each is made of a sugar, a phosphate group, and a nitrogen containing base
Each has A, C, & G

13. Protein Synthesis Video
Transcription 2m50s

14. Transcription copies specific genes from DNA to make a complementary strand of RNA.
Only a gene, NOT the entire DNA strand is transcribed

15. To transcribe is to make a copy of DNA into a complementary messenger RNA strand

16. Get out 3 Colors and MAKE A KEY on the top of your handout
-DNA
-RNA
- Transcription Complex (RNA Polymerase)

17. 1. RNA polymerase and other proteins, (which we call a transcription complex) recognize the start of a gene and unwind a segment of it.
start site
nucleotides
transcription complex

18. The bases must be exposed so that the DNA can be read
Why must the DNA strands unwind and separate before transcription can take place?
The bases must be exposed so that the DNA can be read
start site
nucleotides
transcription complex

19. RNA polymerase moves along the DNA
2. RNA polymerase, using the DNA as a template, strings together a “complementary” strand of RNA
Uracil bonds with Adenine U=A (no Thymine)
The DNA helix winds again as the gene is transcribed.
DNA
RNA
RNA polymerase moves along the DNA

20. RNA polymerase moves along the DNA
How does the base sequence of the RNA transcript being formed compare with the sequence on the template strand?
It is complementary
DNA
RNA
RNA polymerase moves along the DNA

21. Transcription Practice
Transcribe this DNA strand into a mRNA strand
*Remember: No Thymine. Instead use Uracil. A=U
DNA
AAA TAG GAT ATC GGA TAC AGT
RNA
UUU AUC CUA UAG CCU AUG UCA

22. 3. The RNA strand detaches from the DNA once the gene is transcribed.
The transcription complex falls apart
DNA re-zips
RNA

23. It is processed and LEAVES the nucleus, heads to the cytoplasm
Where will the RNA transcript go after it separates from the DNA in step 3?
It is processed and LEAVES the nucleus, heads to the cytoplasm
RNA

24. Transcription makes three types of RNA.
Messenger RNA (mRNA) which has been transcribed from the DNA, carries the message that will be translated to form a protein.
Ribosomal RNA (rRNA) forms part of ribosomes where proteins are made.
Transfer RNA (tRNA) brings amino acids from the cytoplasm to a ribosome.

25. Replication copies all of the DNA
Please make a Replication vs. Transcription Double Bubble (bottom of pg. 4) Pg. 242 in book
Transcription and replication are similar, but have different end results. Please create a double-bubble map comparing and contrasting the two processes.
Replication copies all of the DNA
Transcription copies a specific gene.
Replication makes one copy (only happens once)
Transcription can make many
copies (happens almost continuously)
growing RNA strands
DNA
one
gene

26. Similarities between DNA replication and Transcription?
Occur within the nucleus
Both are catalyzed by enzymes
Both unwind DNA
“complementary” base pairing
Highly regulated (very carefully done- we want NO mistakes)
Differences?
End results are different
Replication makes an identical copy of ALL of the DNA
Happens only once during the cell cycle
Transcription only makes a complementary strand of segments of DNA
Can happen over and over again at anytime

27. A T C G A A A T C G G G A T T U A G C U U U A G C C C U A A Practice
DNA
A T C G A A A T C G G G A T T
RNA
U A G C U U U A G C C C U A A