1. Protein Synthesis
Mrs. Harlin

2. 3.1.2
Explain how DNA and RNA code for proteins and determine traits.

3. Protein Synthesis Transcription Translation DNA mRNA Protein Trait
Transcription and Translation
11/11/2018
Protein Synthesis
Transcription
Translation
DNA
mRNA
Protein
Trait
G. Podgorski, Biol 1010 3

4. Step 1- Transcription
Transcription makes an mRNA copy of DNA in the nucleus of the cell.
If the DNA reads:
TAC GTA GCA
The mRNA (messenger) will read:
AUG CAU CGU

5. What is the difference? DNA has T (Thymine) and RNA does not!
Instead RNA has U (Uracil).
If the DNA strand has a T you will still write an A for the RNA like you would do during DNA replication.
If the DNA strand has an A you will write a U for the RNA because RNA does not have T.

6. The Other Differences 1. So RNA has U’s, DNA has T’s.
2. RNA is single stranded; whereas, DNA is double stranded.
3. RNA is made of the sugar ribose; whereas, DNA is made of the sugar deoxyribose.

7. Step 2 Translation
The mRNA goes to a ribosome, made of rRNA, where the amino acids are brought and dropped off by a tRNA (transfer) to make the protein.
If the mRNA reads:
AUG CAU CGU
The tRNA will read:
UAC GUA GCA

8. The Protein
To figure out the sequence of amino acids the protein will have, you must use the mRNA codon chart in your textbook (pg. 211).
Look up the mRNA codons:
If the mRNA reads:
AUG CAU CGU
The amino acids will be:
Start histidine arginine

9. The Protein
The protein is formed by polypeptide chains, which are just amino acids linked by peptide bonds.
Proteins can be structural (forming part of the cells materials) or functional (hormones, enzymes, or chemicals involved in cell chemistry).