1. 1 PROTEIN SYNTHESIS

2. DNA and Genes

3. DNA DNA contains genes, sequences of nucleotide bases These Genes code for polypeptides (proteins) Proteins are used to build cells and do much of the work inside cells

4. 4 Genes & Proteins  Proteins are made of amino acids linked together by peptide bonds  20 different amino acids exist

5. 5 Amino Acid Structure

6. 6 Polypeptides Amino acid chains are called polypeptides

7. 7 DNA Begins the Process DNA is found inside the nucleus Proteins, however, are made in the cytosol of cells by organelles called ribosomes Ribosomes may be free in the cytosol or attached to the surface of rough ER

8. 8 Starting with DNA DNA ‘s code must be copied and taken to the cytosolDNA ‘s code must be copied and taken to the cytosol In the cytosol, this code must be read so amino acids can be assembled to make polypeptides (proteins)In the cytosol, this code must be read so amino acids can be assembled to make polypeptides (proteins) This process is called PROTEIN SYNTHESISThis process is called PROTEIN SYNTHESIS

9. RNA

10. 10 RNA Differs from DNA RNA has a sugar riboseRNA has a sugar ribose DNA has a sugar deoxyribose

11. 11 Other Differences RNA contains the base uracil (U)RNA contains the base uracil (U) DNA has thymine (T) RNA molecule is single-strandedRNA molecule is single-stranded DNA is double- stranded DNA

12. 12 Structure of RNA

13. 13. Three Types of RNA Messenger RNA (mRNA) copies DNA’s code & carries the genetic information to the ribosomesMessenger RNA (mRNA) copies DNA’s code & carries the genetic information to the ribosomes Ribosomal RNA (rRNA), along with protein, makes up the ribosomesRibosomal RNA (rRNA), along with protein, makes up the ribosomes Transfer RNA (tRNA) transfers amino acids to the ribosomes where proteins are synthesizedTransfer RNA (tRNA) transfers amino acids to the ribosomes where proteins are synthesized

14. 14 Messenger RNA Long Straight chain of Nucleotides Made in the Nucleus Copies DNA & leaves through nuclear pores Contains the Nitrogen Bases A, G, C, U ( no T )

15. 15 Messenger RNA (mRNA) Carries the information for a specific proteinCarries the information for a specific protein Made up of 500 to 1000 nucleotides longMade up of 500 to 1000 nucleotides long Sequence of 3 bases called codonSequence of 3 bases called codon

16. 16 Ribosomal RNA (rRNA) rRNA is a single strand 100 to 3000 nucleotides longrRNA is a single strand 100 to 3000 nucleotides long Globular in shapeGlobular in shape Made inside the nucleus of a cellMade inside the nucleus of a cell Associates with proteins to form ribosomesAssociates with proteins to form ribosomes Site of protein SynthesisSite of protein Synthesis

17. 17 Transfer RNA (tRNA) Clover-leaf shape Single stranded molecule with attachment site at one end for an amino acid Opposite end has three nucleotide bases called the anticodon

18. 18 Transfer RNA amino acid attachment site UAC anticodon

19. 19 Codons and Anticodons The 3 bases of an anticodon are complementary to the 3 bases of a codon Example: Codon ACU Anticodon UGA UGA ACU

20. 20 The Genetic Code A codon designates an amino acid An amino acid may have more than one codon There are 20 amino acids, but 64 possible codons

21. 21 The Genetic Code Use the code by reading from the center to the outside Example: AUG codes for Methionine

22. 22 Name the Amino Acids GGG? UCA? CAU? GCA? AAA?

23. 23 Remember the Complementary Bases On DNA: A-T C-G On RNA: A-U C-G

24. Transcription and Translation

25. 25 Pathway to Making a Protein DNAmRNA tRNA (ribosomes) Protein

26. 26 Protein Synthesis   The production or synthesis of polypeptide chains (proteins)  Two phases: Transcription & Translation

27. 27 Transcription The process of copying the sequence of one strand of DNA, the template strand mRNA copies the template strand Requires the enzyme RNA Polymerase

28. 28 Template Strand

29. 29 Question:  What would be the complementary RNA strand for the following DNA sequence? DNA 5’-GCGTATG-3’

30. 30 Answer: DNA 5’-GCGTATG-3’DNA 5’-GCGTATG-3’ RNA 3’-CGCAUAC-5’RNA 3’-CGCAUAC-5’

31. 31 Translation Translation is the process of of decoding the mRNA into a polypeptide chain Ribosomes read mRNA three bases or 1 codon at a time and construct the proteins

32. 32 Transcription Translation

33. 33