CHAPTER 8 Summary

• Genes provide instructions to make proteins. The process of using the information in genes to make proteins is called gene expression.
• Proteins are folded chains of amino acids that make up cell structures and help cells to function properly.
• Proteins play an important role in nearly all cellular functions, from muscle movement to metabolism.
• Many drugs act on proteins in the body or are themselves proteins.
• Amino acid sequences determine the shape and function of a protein.
• A change in the DNA sequence of a gene can change the corresponding amino acid sequence, and therefore the function, of a protein.
• Different versions of the same gene, those with different nucleotide sequences, are called alleles.
• Every gene has two parts: a coding sequence and a regulatory sequence. The coding sequence determines the identity of a protein; the regulatory sequence determines where, when, and how much of the protein is produced.
• Gene expression occurs in two stages, transcription and translation, which take place in separate compartments in eukaryotic cells.
• Transcription is the first step of gene expression, copying the information stored in DNA into mRNA. Transcription occurs in the nucleus.
• Translation, the second step of gene expression, uses the information stored in mRNA to assemble a protein. Translation occurs in the cytoplasm.
• Proteins are assembled by ribosomes with the help of tRNA, which delivers amino acids to the ribosome.
• The genetic code is the set of rules by which mRNA sequences are translated into protein sequences; the code is redundant and shared by all living organisms.
• Through genetic engineering, genes from one species of organism can be inserted into the genome of another species of organism to make a transgenic organism.
• Transgenic organisms have numerous uses in biotechnology and health.

• MORE TO EXPLORE

  • Meade, H. (2012) TED Talk: Medicine from milk http://tedxboston.org/speaker/meade
  • Meade, H. M. (1997) Dairy Gene. The Sciences 37 (5):20–25.
  • Echelard, Y., et al. (2006) Production of recombinant therapeutic proteins in the milk of transgenic animals. BioPharm International 19:36–46 http://www.biopharminternational.com/biopharm/article/articleDetail.jsp?id=362005
  • Stix, G. (2005) “The land of milk and money: the first drug from a transgenic animal may be nearing approval.” Scientific American 293:102–105.
  • Center for Science in the Public Interest http://www.cspinet.org/