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Warm Up

Warm Up . In your journal write a short paragraph on discussing your feelings about cloning? Think about such things as… Is it okay to clone endangered species? How about humans? If someone in your family died, would you want them cloned? YOU HAVE 10 QUIET MINUTES!!!!!!!!!!!!!!!!!!.

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Warm Up

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  1. Warm Up In your journal write a short paragraph on discussing your feelings about cloning? Think about such things as… Is it okay to clone endangered species? How about humans? If someone in your family died, would you want them cloned? YOU HAVE 10 QUIET MINUTES!!!!!!!!!!!!!!!!!!

  2. DNA, RNA and Protein Synthesis Chapter 12

  3. PROTEIN REVIEW • Proteins are large molecules formed by smaller molecules (monomers) called amino acids. • Amino acids are known as the building blocks of proteins. • In your body, proteins aid in muscle contractions, give structure to cells and act as enzymes.

  4. Nucleic Acids Review • Both DNA and RNA are known as nucleic acids. • Just like the building block for proteins are amino acids, the building blocks for nucleic acids are NUCLEOTIDES.

  5. DNA • Deoxyribonucleic acid • Fundamental building block of all living things. • Passes on information from generation to generation by duplicating itself.

  6. The Components and Structure of DNA Long molecule made up of subunits called NUCLEOTIDES Nitrogenous base Phosphate group 5 Carbon Sugar: DEOXYRIBOSE

  7. NUCLEOTIDE • The only part that changes in a DNA molecule is the nitrogenous base! Nitrogenous base Phosphate group • ADENINE • THYMINE • GUANINE • CYTOSINE 5 Carbon Sugar: DEOXYRIBOSE

  8. NITROGENOUS BASES • Four different nitrogen bases in DNA: 1. Adenine Purines 2. Guanine 2 rings 3. Thymine Pyrimidines 4. Cytosine 1 ring

  9. The Components and Structure of DNA • DNA is shaped like a double helix. • Backbone of DNA is formed by sugar and phosphate groups from each nucleotide. • Bases stick out sideways from the chain. • Nucleotides can be joined together in any order.

  10. Who discovered DNA? • In 1953, Watson and Crick were the first to identify the structure of DNA. • Won a noble prize in 1962.

  11. Complementary Base Pairing • ONLY CERTAIN BASES CAN LINK TOGETHER. THESE BASES ARE CALLED “COMPLEMENTARY”. A always pairs with T C always pairs with G * Bases are held together by hydrogen bonds. Reason for Chargaff’s rules.

  12. Chromosomes and DNA Replication • DNA is located in the nucleus only – never found in the cytoplasm – think of it as being on house arrest. • Long molecules, in E.coli ( a very very small bacterium) there are 4,639,221 base pairs

  13. Chromosome Structure • Every nucleus of a human cell contains more than 1 meter of DNA • Chromatin- DNA that is tightly wound around proteins called histones • Histones group together to make NUCLEOSOMES which fold DNA into tiny spaces in the cells nucleus.

  14. Duplicating DNA – aka REPLICATION • Before a cell divides through mitosis, it must replicate (copy) it’s DNA. • Process of replication ensures that each new daughter cell will have a complete set of the DNA molecules.

  15. DNA Replication One DNA strand serves as a template to build the other. 1st the DNA strand “unzips” or splits down the middle. 2nd Complementary nucleotides attach to the single strands

  16. Details of REPLICATION Carried out by a series of enzymes (speed up the reaction) • The enzyme Helicase “unzips” the DNA by breaking the hydrogen bonds between the base pairs, causing the strand to “unwind” • DNA polymerase (another enzyme) joins individual nucleotides to their “partner”, after it is done it proofreads to make sure there are no mistakes. The chance in a mistake is reduced to 1 error per every billion nucleotides! replication animation

  17. Complementary Strands Fill in the blanks: One side of DNA: ACTGGCTATGC Other side : TGACCGATACG

  18. GENES • Coded DNA instructions that control the production of proteins within the cell.

  19. THE BIG PICTURE Three Important Points to Remember 1.Chromosomes are made of DNA 2.Segments of DNA code for a protein 3. Protein in turn, relates to a trait (eye color, enzymes, hormones..)

  20. FROM GENES TO PROTEINS: Decoding the information in DNA • Traits such as eye color as encoded in DNA. How are these traits passed on from generation to generation? This job takes both DNA and something called RNA.

  21. FROM GENES TO PROTEINS: RNA • Like DNA, RNA is a nucleic acid, ribonucleic acid. • RNA differs from DNA in 3 ways. • Allows for the ability to copy a single DNA sequence

  22. RNA • Most RNA molecules are involved in protein synthesis (the making of proteins) • Three different types of RNA 1. mRNA - messenger 2. tRNA - transfer 3. rRNA - ribosomal

  23. Messenger RNA • Carry copies of instructions • Serve as messengers from DNA to the rest of the cell (because DNA cannot leave the nucleus)

  24. Ribosomal RNA • Proteins are assembled on ribosomes • Ribosomes are made up of proteins and RNA.

  25. Transfer RNA • Transfers each amino acid to the ribosome as it is coded by messages in mRNA. • Needed for the last step of synthesis production

  26. FROM GENES TO PROTEINS: Uracil instead of Thymine • No thymine bases are found in RNA, instead uracil pairs with adenine. DNARNA A-T A-U C-G C-G

  27. From DNA to RNA Original DNA strand ATTACGAAGGCTA UAAUGCUUCCGAU New RNA strand

  28. FROM GENES TO PROTEINS: The Big Picture • 2 STEP PROCESS: 1st. TRANSCRIPTION- from DNA to RNA 2nd. TRANSLATION - from RNA to proteins.

  29. FROM GENES TO PROTEINS: Transfer of Information, From DNA to RNA • TRANSCRIPTION 1. Enzyme RNA polymerase unzips the DNA strand located in the nucleus. 2. Uses one strand of the DNA as a template to assemble a single strand of RNA RESULT OF TRANSCRIPTION – ONE SINGLE STRAND OF RNA ****THIS IS NOT THE SAME AS DNA REPLICATION****

  30. Promoters • How does RNA polymerase know where to start unzipping the DNA strand? • Enzyme binds to DNA in specific regions known as promoters. • Act as a signal telling RNA polymerase where to start and stop.

  31. Transcription vs. Replication

  32. RNA Editing – Introns vs. Exons • INTRONS – part of the DNA molecule NOT involved in protein synthesis • EXONS – part of DNA that is involved or “expressed” in protein synthesis • After RNA transcribes the DNA strand it must cut out the introns while it is still in the nucleus. The remaining exons are then spliced back together to form the final mRNA.

  33. Why do we need mRNA? • Remember, DNA is only found in the nucleus of the cell. • mRNA is needed to carry information out of the nucleus to other parts of the cell. For example, Imagine that your name is DNA and you are on house arrest. If you need McDonalds you must send someone else with your message (order) to McDonalds.

  34. translation

  35. The Genetic Code • Language of mRNA is called the genetic code. • Code is written using the four letters AUCG

  36. FROM GENES TO PROTEINS: The Genetic Code, Codons • The mRNA instructions are written as three nucleotide sequences called CODONS. • Each nucleotide triplet in mRNA specifies for a particular amino acid. • Each codon along the mRNA strand corresponds with a specific amino acid. AUC GGA UUA CCC CODON CODON CODON CODON

  37. mRNA codes for Specific Amino Acids mRNA AUC GGA UUA CCC CODON CODON CODON CODON Isoleucine Glycine Leucine Proline

  38. Now you try…………… • UAA • Stop • UGU • Cysteine • GAU • Aspartic acid

  39. FROM GENES TO PROTEINS: RNA’s Roles in Translation • Takes place in the cytoplasm at the ribosomes. In order for translation to occur, mRNA must migrate to the ribosomes. • tRNA and ribosomes help in the synthesis of proteins. Proteins are made from mRNA. • The mRNA moves out of the nucleus to the ribosomes. There tRNA carries the amino acid to it’s correct codon. The sequence is then converted into an amino acid sequence.

  40. FROM GENES TO PROTEINS: Translation • tRNA consists of a single strand of RNA with an amino acid linked to the end. • Each tRNA contains an anticodon – three nucleotide sequence that is complementary to an mRNA codon.

  41. From DNA mRNA tRNA Proteins DNA Strand ATCGATCCG mRNA Strand UAGCUAGGC codons tRNA Strand AUCGAUCCG anti-codons Proteins Isoleucine, etc

  42. Break it down...

  43. What happens when there is a mistake? • Normally process is very accurate, but occassionaly they make a mistake known as a mutation. ex. THE DOG BIT THE CAT THE DOG BIT THE CAR **One change can make a huge difference!

  44. 3 Types of Mutations • Point mutation – only a single nucleotide changes. (Only changes one protein) ATCGAA Serine, Arginine ATGGAA Stop, Arginine • Deletion mutation – base is removed or entire segments. THE CAT ATE THE ATA TE

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