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What organic molecule is DNA?

What organic molecule is DNA?. Nucleic Acid. Nucleic Acid. An organic molecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus Examples: DNA ????. RNA. What differences do you see between DNA and RNA?. Differences between RNA and DNA.

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What organic molecule is DNA?

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  1. What organic molecule is DNA? • Nucleic Acid

  2. Nucleic Acid • An organic molecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus • Examples: • DNA • ???? RNA

  3. What differences do you see between DNA and RNA?

  4. Differences between RNA and DNA • 1. Sugar in RNA is ribose instead of deoxyribose. • 2. RNA is generally single stranded, not double stranded. • 3. RNA containsuracilinstead of thymine

  5. RNA Is a disposable copy of a segment of DNA FUNCTION: Main function is protein synthesis.

  6. Types of RNA Messenger RNA (mRNA) the RNA molecule that carries the copies of instructions for assembling amino acids. Ribosomal RNA (rRNA) the RNA that combined with many other proteins, make up the ribosomes that assemble proteins Transfer RNA (tRNA) carries amino acids to the ribosomes and matches them to the coded mRNA

  7. What are the 3 differences between DNA and RNA? • RNA is a single strand, DNA double • RNA has ribose sugar in it, DNA has deoxyribose sugar • RNA has the nitrogenous base uracil, • DNA has thymine

  8. How is RNA made? • By process called transcription. • Transcription – process in which segments of DNA serve as templates to produce complementary RNA molecules.

  9. Where transcription occurs • In prokaryotes it occurs in the cytoplasm • In eukaryotes it occurs in the nucleus.

  10. Transcription • The enzyme RNA polymerase attaches to DNA strand • RNA polymerase separates the DNA strands • RNA polymerase uses one strand to assemble nucleotides into RNA

  11. Where does transcription start? • The enzyme RNA polymerase binds to special regions on the DNA called promoters. • Promoters – specific base sequences on the DNA that act as signals to show RNA polymerase where to begin transcription

  12. RNA editing • Before the RNA can move on to make proteins it must be “edited.” • Pieces of the RNA are cut out. The pieces that are cut out are called introns. • The pieces remaining in the RNA are called exons.

  13. What is transcription? • The process of making RNA from a strand of DNA

  14. http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/transcription.swfhttp://www.stolaf.edu/people/giannini/flashanimat/molgenetics/transcription.swf

  15. How is RNA used to make proteins? • The nitrogenous bases act as a code for making proteins

  16. Genetic code – The language consisting of 4 letters (A, C, G, and U) that gives the instructions for building amino acids The code is read three “letters” at a time, so each “word” is three bases long

  17. codon – the three letter word that corresponds to a single amino acid

  18. There are 64 different 3 letter combinations of the 4 bases A,T,C and G (so 64 codons) • But there are only 20 amino acids. Why aren’t there 64 amino acids? Most amino acids can have more than one codon that codes for them ex. UUA, UUG, CUU, CUC, CUA and CUG all code for the amino acid tryptophan

  19. There are also codons that that code for the beginning and ending of protein synthesis. “start” codons – where the reading of the mRNA begins. (The amino acid methionine is a start codon) “stop” codon- where the reading ends.

  20. *Amino acids bond together to make a polypeptide chain. **Polypeptides- long chains of amino acids joined together.

  21. The amino acids in a polypeptide, and the order in which they are joined, determine the properties of the different proteins.

  22. What do codons “code” for? • Amino Acids

  23. Translation • After transcription the mRNA strand is ready to start the process of protein synthesis. • What part of the cell makes proteins? Ribosomes Ribosomes use the sequence of codons in mRNA to assemble amino acids into polypeptide chains.

  24. Translation- The decoding of an mRNA message into a protein (Ribosomes translate the code)

  25. Translation Translation is carried out by ribosomes in the cytoplasm. Step 1: A ribosome attaches to mRNA

  26. Translation • Step 2: As each codon passes through ribosome, tRNAs bring the proper amino acid to the ribosome.

  27. tRNA • Each tRNA molecule carries just one kind of amino acid. • Each tRNA has 3 unpaired bases called an anticodon. • Each tRNA anticodon is complementary to one mRNA codon

  28. Translation • Step 3: • The ribosomes attach the amino acids to the growing chain.

  29. Translation • Step 4: • The ribosomes helps form a peptide bond between the first and second amino acid.

  30. Translation • Step 5: • The ribosome then moves to the next codon

  31. Translation • Step 6: • Polypeptide chain continues to grow until ribosome reaches the stop codon

  32. http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/translation.swhttp://www.stolaf.edu/people/giannini/flashanimat/molgenetics/translation.sw f

  33. How are proteins related to traits? Many proteins are enzymes, which catalyze and regulate chemical reactions. Proteins regulate patterns of growth, patterns of development in humans, and they build or operate different components of a living cell.

  34. The Central Dogma • Information is transferred from DNA to RNA protein

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