1. DNA to Protein Transcription & Translation

2.  What are these nucleotides telling us?  Sequence of nucleotides in DNA contains information to produce proteins  Why does our body need these proteins?  Some proteins become key structures and regulators of cell functions  Others become important structures such as muscle filaments  Others, such as enzymes, control chemical functions that perform key life functions  Example: breaking down glucose in cellular respiration

3.  Amino Acids

4.  Is a nucleic acid  Double stranded  Sugar: deoxyribose  Contains 4 nitrogen bases  Is a nucleic acid  Single stranded  Sugar: Ribose  Contains 4 nitrogen bases: no thymine, instead uracil

5.  THINK: How do automobile makers build a car?  “Workers” for protein synthesis  Takes from DNA “HOW” the protein should be assembled – then – amino acid by amino acid, they assemble the protein

7.  mRNA (messenger RNA)  Brings instructions from DNA in the nucleus to the ribosome (assembly line)  rRNA (ribosomal RNA)  Makes up the ribosome  Binds to mRNA and uses the instructions to assemble the amino acids in the correct order  tRNA (transfer RNA)  Delivers amino acids to the ribosome to be assembled into a protein

8.  Summary: DNA  RNA  DNA molecule is unzipped in the nucleus to begin transcription  Enzymes use a strand of DNA as a template to produce RNA  Recall: there is NO thymine (T) in RNA; instead, thymine is replaced with Uracil (U)  Therefore: A pairs with U AND C still pairs with G  mRNA carries this information from the nucleus to the ribosome for protein production  Try transcribing the strand of DNA on your notes

9.  Nucleotide sequence transcribed from DNA to mRNA acts as the “genetic code” to build proteins  There are 20 common amino acids that make up all proteins in our body, from only 4 nitrogen bases

10.  Summary: mRNA to protein  Takes place in the cytoplasm at a ribosome  For proteins to be built, 20 different amino acids floating in the cytoplasm must be brought to the ribosome by tRNA  Each tRNA only attaches to 1 type of amino acid  Correct translation of mRNA depends upon joining each mRNA codon with the correct tRNA anticodon.  Codon: sequence of 3 mRNA bases  Anticodon: sequence of 3 complimentary tRNA bases

12.  Try translating the mRNA code on the worksheet supplied to you