Name: ______Block: ______Date: ______

How Does DNA Direct Protein Synthesis Lab?

Introduction

Protein synthesis is a complex process. In this activity you will trace the steps that are involved in protein synthesis.

Briefly define the following keywords

DNA

mRNA

tRNA

rRNA

transcription translation

amino acid

protein synthesis

Procedure

1. DNA cannot leave the nucleus with the genetic code so it serves as a template for mRNA (messenger RNA) to copy the code and transfer it to the ribosome, which 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 attaches to a ribosome and is joined by the corresponding tRNA (transfer RNA), which carries a single amino acid based on the anticodon. Recall from biochemistry amino acids are the building blocks of proteins. As tRNA carries the amino acids to the ribosome the proteins are synthesized based on the code sequence carried on the 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: ______, ______, ______, ______, ______,

______, ______, ______, ______, ______.

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? ______

Label the diagram:

A. ______

B. ______

C. ______

D. ______

E. ______

F. ______

G. ______

Online Animation:

  1. How does the cell know what protein needs to be made? ______
  2. What section of the DNA codes for the protein? ______
  3. Where is the DNA found in a eukaryotic cell? ______
  4. What two enzymes moves along the template strand of DNA to make mRNA? ______and ______
  5. Messenger RNA will form the following strand off of the template DNA:

DNA T – A – C – A – G – G – C – C – A –T –A – A – C – G – A – A – C – T

mRNA______

  1. How does the mRNA leave the nucleus? ______
  2. What three units come together at the ribosome to begin translation? ______, ______, and ______.
  3. How many bases are read at a time? ______
  4. What term is used for the three base code on mRNA? ______
  5. Tell what six amino acids are being coded for by the mRNA strand using the decoder:

______- ______- ______- ______- ______- ______

  1. What term is used for the three base code on tRNA? ______
  2. What type of bond links the amino acids together? ______
  3. Name three combinations of mRNA code that will stop the translation ______, _____, _____
  4. What is formed once the amino acids are linked together? ______
  5. Where is mRNA made? ______
  6. Where is tRNA found? ______
  7. Where is rRNA found? ______