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← Concept Map 3 Returns

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Showing Revision 1 created 09/29/2013 by Cogi-Admin.

  1. Let's see how you did with the concept map for
  2. lesson three. Starting here with the human genome, there's 98%
  3. of it approximately that's non-coding. It doesn't code for anything.
  4. Then about 2% of it is protein coding. But all these
  5. regions, as part of the genome, are actually made of
  6. DNA, which we learned a lot about in lesson two. And
  7. in lesson four, we will learn more about this non-coding
  8. region. But here in lesson three, we learned about the protein
  9. coding regions of the human genome, which are
  10. divided into genes. Genes can have different sequences, so
  11. they can have different versions. They can code for
  12. different things, and we call these different versions alleles.
  13. This is the word will keep coming back to
  14. in this course. And alleles originate from mutations which
  15. we'll learn about more in lesson six. Now, a
  16. protein coding gene is composed of two major kinds
  17. of sequence: introns and exons. The introns are spliced out
  18. of the message that's going to be produced, and exons are going to be kept in
  19. the messenger RNA, or mRNA. Now the process that synthesizes mRNA from
  20. the gene DNA is transcription. And it's the first part of the central dogma.
  21. Now, once you have an mRNA transcribed
  22. from the DNA gene, it's going to be translated
  23. by ribosomes into protein. Proteins are the
  24. building blocks of cells. And the essential process
  25. of genes to RNA or DNA to RNA to protein is called the Central Dogma.
  26. Now, RNA is similar to DNA, in that
  27. it's made up of nucleotides though not deoxynucleotides.
  28. And there are four types of nitrogenous bases here. Adenine, which can base-pair
  29. with uracil. Or U, a new nitrogenous base in the
  30. RNA alphabet. And we still have guanine that compare with cytosine.
  31. Now, our mRNA transcript is actually divided into
  32. codons, which are groups of three letters of nucleotides.
  33. There are a total of 64 combinations of
  34. codons that are possible, based on this grouping of
  35. three. And these 64 combinations are interpreted as
  36. the genetic code. And in the genetic code, we
  37. have three stop codons, one start codon, and
  38. all the rest code for 20 different types of
  39. amino acids. These amino acids make up proteins,
  40. and these protiens are the building blocks of your
  41. cells that make up who you are. I hope this helps clear
  42. up some of the major concepts you learned about in lesson three.