1. Transcription
1. Gene Expression
1a. All of our traits (height, eye color, and all other inherited traits) result from the activity of proteins.

2. Transcription 1b. Proteins are made of amino acids linked together.
1. Gene Expression
1b. Proteins are made of amino acids linked together.

3. Transcription
1. Gene Expression
1c. The recipe for each kind of amino acid needed for protein manufacturing is located in the DNA

4. Transcription
1. Gene Expression
1d. The information encoded within DNA must travel out of the nucleus and into the cell where the message gets expressed as a protein.
1e. This happens in 2 steps:
(1) Transcription
(2)Translation

5. Transcription
2. Transcription
2a. Transcription is the process by which part of the DNA molecule is read and copied into a molecule called ribonucleic acid (RNA).

6. Transcription 2b. Why do cells use RNA?
DNA is far too long and important to be sent out of the cell every time a protein must be made.
So the cell creates short disposable RNA molecules to carry copies of DNA’s instructions.

7. Transcription DNA RNA 2c. DNA vs. RNA 2. Transcription Double Stranded
Single Stranded
Long
Short
Stationary
Mobile
Uses Thymine
Uses Uracil
Contains deoxyribose
Contains ribose

8. Transcription
2. Transcription
Step 1
An enzyme called RNA polymerase temporarily separates the strands of a small section of DNA molecule
This exposes some of the bases of the DNA molecule.

9. Transcription
2. Transcription
Step 2
Along one strand, the RNA polymerase binds the complementary RNA nucleotides to the exposed DNA bases.
Instead of Thymine (T) RNA uses uracil (U)

10. Transcription
2. Transcription
Step 3
As the RNA polymerase moves it creates a new strand of RNA
Specifically messenger RNA (mRNA)
It is called messenger RNA because it carries DNA’s instructions out of the nucleus.

11. Transcription
2. Transcription
Step 4
When RNA polymerase is done reading the gene on the DNA, it detaches
Step 5
The separated DNA strands reconnect and the mRNA moves to the cytplasm.

12. links

13. Assignment: Homework: Transcription worksheet
AGENDA 1/14/13
Assignment:
Transcription worksheet
Homework:
Gene Expression Reading (continued…)