 SOL Addressed: 2.b;3.b;4.a;5.g,h Protein Synthesis by Ranny Copenhaver

 SOL Addressed: 2.b;3.b;4.a;5.g,h ► The DNA molecule is composed of chains of nucleotides arranged in double helix shape. ► A nucleotide is made of 3 things:  A sugar- deoxyribose  A phosphate bond  A nitrogen base- ► purines: adenine guanine guanine ► Pyrimadines: cytosine thymine thymine  The nucleotides are held together by weak hydrogen bonds.  Adenine and thymine always attach.  Cytosine and guanine always attach.

 SOL Addressed: 2.b;3.b;4.a;5.g,h DNA vs. RNA

 SOL Addressed: 2.b;3.b;4.a;5.g,h Endoplasmic Reticulum and the Ribosomes: protein production machine source:

 SOL Addressed: 2.b;3.b;4.a;5.g,h DNA – The code of life 5’ end3’ end 5’ Double stranded AT – GC basepairs Right handed spiral Source: Side view: View down helix axis:

 SOL Addressed: 2.b;3.b;4.a;5.g,h Transcription 1 (making a mRNA copy of DNA) The part of the DNA molecule (the gene) that the cell wants the information from to make a protein unwinds to expose the bases. Free mRNA nucleotides in the nucleus base pair with one strand of the unwound DNA molecule.

 SOL Addressed: 2.b;3.b;4.a;5.g,h Transcription 2 The mRNA copy is made with the help of RNA polymerase. This enzyme joins up the mRNA nucleotides to make a mRNA strand. This mRNA strand is a complementary copy of the DNA (gene) The mRNA molecule leaves the nucleus via a nuclear pore into the cytoplasm

 SOL Addressed: 2.b;3.b;4.a;5.g,h Transcription (elongation) (2) /antisnse strand

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U This is a molecule of messenger RNA. It was made in the nucleus by transcription from a DNA molecule. mRNA molecule codon

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U A ribosome on the rough endoplasmic reticulum attaches to the mRNA molecule. ribosome

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U It brings an amino acid to the first three bases (codon) on the mRNA. Amino acid tRNA molecule anticodon U A C A transfer RNA molecule arrives. The three unpaired bases (anticodon) on the tRNA link up with the codon.

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U Another tRNA molecule comes into place, bringing a second amino acid. U A C C C G Its anticodon links up with the second codon on the mRNA.

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U A peptide bond forms between the two amino acids. Peptide bond C C G U A C

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U The first tRNA molecule releases its amino acid and moves off into the cytoplasm. C C G U A C

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U C C G The ribosome moves along the mRNA to the next codon.

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U Another tRNA molecule brings the next amino acid into place. C C G A A U

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U A peptide bond joins the second and third amino acids to form a polypeptide chain. C C G

 SOL Addressed: 2.b;3.b;4.a;5.g,h A U G G G C U U A A A G C A G U G C A C G U U The polypeptide chain gets longer. G U C A C G The process continues. This continues until a termination (stop) codon is reached. complete! The polypeptide is then complete!

 SOL Addressed: 2.b;3.b;4.a;5.g,h

Translation - animation

 SOL Addressed: 2.b;3.b;4.a;5.g,h

Let’s say that we look at an original strand of DNA that needs to be duplicated ► Original DNA strand: T A G G G G A G A

 SOL Addressed: 2.b;3.b;4.a;5.g,h Lets Look at the Complementary DNA ► Original DNA strand: T A G G G G A G A ► Complementary DNA: A T C C C C T C T

 SOL Addressed: 2.b;3.b;4.a;5.g,h Lets See What the mRNA Will Look Like That Is Made From the Original Strand of DNA ► Original DNA strand: T A G G G G A G A ► Complementary DNA: A T C C C C T C T ► mRNA : A U C C C C U C U The mRNA codes back to the original DNA strand. The mRNA codes back to the original DNA strand.

 SOL Addressed: 2.b;3.b;4.a;5.g,h Lets See What the tRNA Will Look Like That Is Made From the Original mRNA ► Original DNA strand: T A G G G G A G A ► Complementary DNA: A T C C C C T C T ► mRNA : A U C C C C U C U ► tRNA : U A G G G G A G A The tRNA codes back to the mRNA strand.

 SOL Addressed: 2.b;3.b;4.a;5.g,h We can use a table to find what amino acid is coded for by the mRNA. ► Original DNA strand: T A G G G G A G A ► Complementary DNA: A T C C C C T C T ► mRNA : A U C C C C U C U ► tRNA : U A G G G G A G A ► Amino Acid : Remember, 3 bases make a codon

 SOL Addressed: 2.b;3.b;4.a;5.g,h We can use a table to find what amino acid is coded for by the mRNA. ► Original DNA strand: T A G G G G A G A ► Complementary DNA: A T C C C C T C T ► mRNA : A U C C C C U C U ► tRNA : U A G G G G A G A ► Amino Acid : The AMINO ACID codes back to the mRNA strand. isoleucine proline serine

 SOL Addressed: 2.b;3.b;4.a;5.g,h

Summary of Protein Synthesis 1. DNA unwinds 2. mRNA copy is made from one of the DNA strands (in groups of 3 called codons). 3. mRNA copy moves out of nucleus into cytoplasm. 4. tRNA molecules are activated as their complementary amino acids are attached to them. 5. mRNA copy attaches to the small subunit of the ribosomes in cytoplasm. 6. A tRNA bonds complementarily with the mRNA via its anticodon. 7. A second tRNA bonds with the next three bases of the mRNA, the amino acid joins onto the amino acid of the first tRNA via a peptide bond. 8. The ribosome moves along. The first tRNA leaves the ribosome. 9. A third tRNA brings a third amino acid 10. Eventually a stop codon is reached on the mRNA. The newly synthesised polypeptide (or protein made of about 20 amino acids) leaves the ribosome.

 SOL Addressed: 2.b;3.b;4.a;5.g,hSources ► Teachnet UK, (2004). Protein synthesis. Retrieved February 13, 2009, from Teachnet UK Web site: learning%20activity.ppt#256,1,Protein synthesis ► Northallerton College, (2008). Protein synthesis. Retrieved February 13, 2009, from Northallerton College Web site: ► UC Davis School of Education, (2006). DNA and RNA and protein synthesis. Retrieved February 13, 2009, from UC Davis School of Education Web site: ► Griffitts, D. (2009). AS Biology - protein synthesis. Retrieved February 13, 2009, from World of Teaching Web site: 1 ► Driessche, Nancy (Sept 17, 2004). Introduction to biology. Retrieved February 13, 2009, from Rice University Web site: file:///F:/Classroom%20Notes%20for%20Biology%20and%20Physics/Biology/protein%20synthesis% 20in%20cell.ppt#256,1,Slide 1 ► Freimann, J. (2006). DNA part II- protein synthesis. Retrieved February 13, 2009, from Union Mine High School Web site: df