From DNA to Protein - A Storyboard

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
   adenine      anti      billion      CCC      codons      conservative      Cytosine      cytosine      DNA      endoplasmic      guanine      helix      messenger      new      nucleus      phosphate      protein      replication      reticulum      ribose      ribosomes      single      start      stop      sugar      three      thymine      Thymine      transcription      transfer      translation      uracil   
DNAstructure.jpgThe genetic code of a cell is carried in , which is located in the of the cell. The DNA molecule has four nitrogenous bases, A (), T (), G () and C (). These bases pair along the inside of the "double " of the DNA molecule. The base Adenine always pairs with , and Guanine always pairs with . There are about three of these base pairs in the human genome, coding for an estimated 40,000 genes. The outside backbone of the double-stranded molecule is made up of deoxyribose molecules and charged groups.


DNA is copied by a process known as . The process is semi-, which means that in each new DNA molecule, there will be one old strand and one strand.replicationl.gif



RNA.gifSince protein production takes place in the , which are located in the cytoplasm, the genetic code must be exported there before protein can be produced. This is done in the form of RNA, also called mRNA. mRNA is made from the DNA template by a process called . There are several difference between RNA and DNA.

  1. RNA is -stranded
  2. RNA contains the sugar (instead of deoxyribose in DNA)
  3. RNA contains the base U () instead of the base Thymine



mRNA undergoes some processing and then leaves the . In the ribosomes the process of making from mRNA, called , takes place. The ribosomes read bases of mRNA at a time. The three-base sequences are called , and each "translates" to a particular amino acid. Molecules of RNA (tRNA), possessing the -codons of the mRNA, bring amino acids that build the protein chain. For instance, the mRNA codon GGG would attract a tRNA with the anti-codon . The process begins with a "" codon (AUG) which puts the amino acid methionine in place, and continues until the ribosome reaches a "" codon, at which point the process terminates. The completed protein is released into the (ER).Protein.jpg