Name: ________________________________________________Block: ______ Date: _________
How Does DNA Direct Protein Synthesis?
Introduction
Protein synthesis is a complex process. In this activity you will trace the steps that are involved in protein synthesis.
Keywords
DNA
mRNA
tRNA
rRNA
transcription
translation
amino acid
protein synthesis
Procedure
1. DNA is too large to leave the nucleus through the nuclear pores. Instead, it serves as a template for messenger RNA
(mRNA) to copy the code and transfer it to the ribosome. This process is called transcription. Write the sequence of
mRNA codons that would result from the transcription of this portion of DNA.
DNA:
TAC ATA TAG CTT TTG ACG GGG AAC CCC ATT
mRNA:
____ ____ ____ ____ ____ ____ ____ ____ ____ ____
2. After transcription, mRNA leaves the nucleus and attaches to a ribosome. The ribosome helps to join the corresponding
transfer RNA (tRNA), which carries a single amino acid determined by the anticodon. Recall from biochemistry amino
acids are the building blocks of proteins. As tRNA carries the amino acids to the ribosome the polypeptides are
synthesized based on the code sequence carried on on mRNA. This process is called translation. The tables show the
mRNA codons and the amino acids for which they code. For example, if you were given the mRNA codon AGA, you can
see on the table that these bases code for the amino acid Arginine. Use the mRNA sequence above to write the sequence
of amino acids carried by the tRNA.
Amino Acids: __________, __________ , __________ , __________ , __________,
__________, __________ , __________ , __________ , __________.
Questions
1. How many amino acids make up the portion of the newly synthesized protein from the above question? ____________
2. What is the purpose of the UAA codon?
3. What do the letters RNA stand for? __________________________________________________________________
4. How is mRNA different from DNA? ___________________________________________________________________
_________________________________________________________________________________________________
5. On mRNA, what nitrogen base binds with the DNA base:
A?______
G?_____
T?______
C? ______
6. Where in the cell is mRNA made? ___________________________________________________________________
7. What enzymes are used in the process of transcription? __________________________________________________
8. What carries the amino acids to the ribosome where it joins with the mRNA? __________________________________
9. How are mRNA and tRNA alike? ____________________________________________________________________
_________________________________________________________________________________________________
10. How are mRNA and tRNA different? ________________________________________________________________
_________________________________________________________________________________________________
11. What determines what proteins are made? ___________________________________________________________
Label the diagram:
A. _________________
B. _________________
C. _________________
D. _________________
E. _________________
F. _________________
G. _________________
Online Animations & Videos:
Sign up, log in and click on the RNA Protein Synthesis Links and explore transcription and translation.

Web Page 1: Read, think about the diagrams and study the process.
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
http://www.wisc-online.com/objects/ViewObject.aspx?ID=ap1302
Web Page 2: Practice the process of protein synthesis. Be sure to read the bold text below the
diagram for instructions on what to do! It does not take long so you might want to try a couple of
times to be sure you know how to transcribe and translate the DNA sequence into a protein.
o

http://learn.genetics.utah.edu/content/begin/dna/transcribe/
Web Page 3: Khan Academy has updated a lot of their lessons and videos. Check this one out to help
you further understand this complicated process.
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https://www.khanacademy.org/partner-content/nova/rnawondermolecule/v/proteinsynthesis