1. 12.3
KEY CONCEPT Transcription converts DNA into a single-stranded RNA molecule. DNA can not leave nucleus..RNA CAN!

2. The Central Dogma includes three processes. Replication Transcription
12.3
The Central Dogma includes three processes.
Replication
Transcription
Translation
replication
transcription
translation
RNA is the link between DNA and making the proteins. 2. 1. 3. 4. 5.

3. DNA
DNA has a deoxyribose sugar.
DNA has A, T, C and G as bases.
DNA is a double-stranded structure.

4. RNA differs from DNA in three major ways.
12.3
RNA differs from DNA in three major ways.
RNA has a ribose sugar.
RNA has uracil instead of thymine.
RNA is a single-stranded structure.

5. Job of Transcription is to copy DNA to make a strand of RNA.
12.3
Job of Transcription is to copy DNA to make a strand of RNA.
It does this in 3 major steps

6. 1. RNA polymerase unzips a specific gene in the segment of DNA needed.
12.3
1. RNA polymerase unzips a specific gene in the segment of DNA needed.
start site
nucleotides
RNA Polymerase

7. RNA polymerase moves along the DNA
12.3 2.
RNA polymerase bonds complementary
nucleotides with one strand of DNA
DNA
5. nucleotides
4. DNA strand
RNA polymerase moves along the DNA
6. mrna
7. RNA polymerase

8. The DNA helix winds back up again.
12.3 3.
The mRNA strand detaches from the DNA once the gene is transcribed and travels out of nucleus to ribosome (rRNA).
The DNA helix winds back up again.
RNA

9. Transcription makes three types of RNA.
12.3
Transcription makes three types of RNA.
Messenger RNA (mRNA) 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.
Remember:
Amino acids are building blocks of a protein

10. The transcription process is similar to replication.
12.3
The transcription process is similar to replication.
Transcription and replication both involve complex enzymes and complementary base pairing.
The two processes have different end results.
Replication copies all the DNA in cell; transcription copies a specific gene on a strand of DNA.
Replication makes one copy of DNA; transcription can make many copies.
growing RNA strands
DNA
one
gene