Protein Synthesis and Codons Practice
Protein synthesis is the process where a sequence of DNA is used to build a protein from individual amino acids. The first step in this process is called TRANSCRIPTION, where a coding region of DNA is converted to messenger RNA (mRNA). During transcription, mRNA is made from the DNA sequence following the base pair rule, except RNA does not contain the base Thymine, but instead has Uracil. The mRNA then leaves the nucleus and goes to a ribosome in the cell's cytoplasm. The ribosome reads the message three bases at a time, called a CODON. Each codon will specify a single amino acid. The amino acids are joined together and folded into a protein, a process called TRANSLATION
Key Points:
DNA is used to make a copy of mRNA (transcription)
mRNA leaves the nucleus and goes to ribosomes
3 bases = codon
1 codon = a single amino acid
A chain of amino acids = a protein
Protein synthesis is also called translation
Biologists use a codon chart or a codon wheel to determine the amino acids. Amino acids are usually abbreviated on these charts as three letter words, like Cys and Ser.
Proteins contain which of the following elements.
Protein synthesis occurs in which order?
The process of copying a gene's DNA sequence into a sequence of RNA is called:
Which process is shown in the image below?


tRNA is involved in:
What is the function of rRNA in protein synthesis?
What is a codon?
What is the role of a codon in protein synthesis?
Where does translation occur in the cell?

Use the codon chart to write the amino acid that corresponds to CCC.
Use the codon chart to write the amino acid that corresponds to CAG.
Use the codon chart to write the amino acid that corresponds to GAA.

Use the codon chart to write the amino acid that corresponds to AGU.
Use the codon chart to write the amino acid that corresponds to UAC.
Use the codon chart to write the amino acid that corresponds to CGU.


A single codon is used to signal the beginning of protein synthesis. It is commonly called the START CODON.
Locate the start codon on the chart. What are the three bases of this codon?

RNA SEQUENCE (put 1 space between each codon in all capital letters)
Amino Acid Sequence (type out with a space after each three letters).

Which amino acid would be coded first from the DNA strand being transcribed?
Use the codon chart to write the amino acid that corresponds to UUU.
Use the codon chart to write the amino acid that corresponds to CCA.
Proline
Valine
Histidine
Glycine
Phenylalanine
Arginine
There are three codons that signal the end of synthesis, these are called STOP codons.
What are the three stop codons?