Protein Synthesis 1

Protein Synthesis 2


DNA carries the genetic "instructions", or code, to produce proteins. The code is actually the sequence of bases in DNA. For example ATAGCGA... is a code for part of a protein. The entire protein would actually require a much longer sequence of DNA bases.

Whenever a protein needs to be made, the correct DNA sequence for that protein is copied to a molecule called messenger RNA (mRNA). Since the DNA is so important, it is efficient to simply copy it's code when needed and leave the original safe in the nucleus. And lots of copies can be made at any time.

The process of copying a sequence of bases in DNA into a complementary sequence in mRNA is called Transcription. It occurs in the nucleus and is the first step in Protein Synthesis.

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A DNA sequence is shown below. The sequence is a small part of a gene that codes for a protein. Transcribe the DNA to produce the mRNA copy by placing the correct bases into position to make the mRNA transcript. Place additional symbols to fully label the process.
High school biology website with flash animations. Requires current Flash player.
  1. Which base in RNA is replaced by uracil?


  2. How many mRNA codons are illustrated above?


  3. What is the name of the enzyme that creates the mRNA copy from DNA?


  4. What is the name of the sugar in the mRNA nucleotides?


  5. What is the mRNA transcript for the DNA sequence, TTACGC


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© Copyright 2008, E. Kimmel