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  1. Classwork • On pg. 6 of your notebooks- Split page into 3 sections: • Top1/3- Draw fig 8.10 (pg.239)- color code • Middle 1/3 - Make a double-bubble map comparing and contrasting DNA and RNA (239-240)

  2. 8.4 Transcription 2.1 Atoms, Ions, and Molecules • Set up Cornell Notes on pg. 7 • Topic: 8.4 Transcription • Essential Question: • What is the central dogma? • Why can an mRNA strand made during transcription, be thought of as a mirror image of the DNA strand from which it was made? KEY CONCEPT Transcription converts a gene into a single-stranded RNA molecule.

  3. rough endoplasmicreticulum Have bumps called ribosomeswhich link amino acids together to form proteins REVIEW:

  4. Proteins are used for movement, eyesight, and digestionand practically everything else you do.

  5. nucleotide unzips Review: Replication nucleotides Helicase

  6. nucleotide new strand DNA polymerase • 2. DNA polymerase (pol-uh-mer-ase) enzymes bond the nucleotides together to form the new double helix. complementary

  7. new strand original strand Two molecules of DNA 3. Two new molecules of DNA are formed, each with an original “parent” strand and a complementary newly formed “daughter” strand. complementary Why do we call the new “daughter” strand a complementary strand and not an identical strand?

  8. KEY CONCEPT Transcription converts a gene into a single-stranded RNA molecule. RNA DNA

  9. RNA carries DNA’s instructions. • The central dogma states that information flows in one direction from DNA to RNA to proteins.

  10. replication transcription translation • The central dogma includes three processes. • 1. Replication • 2.Transcription • 3.Translation • RNA is a link between DNA and proteins.

  11. RNA differs from DNA in three major ways. RNA Ribose Sugar Uracil (U) Single-Stranded DNA Deoxyribose Sugar Thymine (T) Double-Stranded Please add a drawing to each side of your double-bubble map

  12. Protein Synthesis Video • Replication 1m40s • Transcription 2m50s

  13. Transcriptioncopies specific genes from DNA to make a strand of RNA.

  14. To transcribe is to make or translate a copy of DNA into RNA

  15. transcription complex start site nucleotides • 1. RNA polymerase and other proteins, (which we call a transcription complex) recognize the start of a gene and unwind a segment of it.

  16. transcription complex start site nucleotides Transcription Complex START nucleotides

  17. DNA RNA polymerase moves along the DNA • 2. RNA polymerase, using the DNA as a template, strings together a “complementary” strand of RNA • Uracil bonds with Adenine U=A (no Thymine) • The DNA helix winds again as the gene is transcribed. Will the RNA be a identical copy of the DNA or a complementary strand? RNA

  18. Transcription Practice Transcribe this DNA strand into a mRNA strand *Remember: No Thymine. Instead use Uracil. A=U DNA AAA TAG GAT ATC GGA TAC AGT RNA UUU AUC CUA UAG CCU AUG UCA

  19. RNA • 3. The RNA strand detaches from the DNA once the gene is transcribed. • DNA rezips

  20. Transcription makes three types of RNA. • Messenger RNA (mRNA) which has been transcribed from the DNA, carries the message that will be translated to form a protein. • Ribosomal RNA (rRNA) forms part of ribosomes where proteins are made. • Transfer RNA (tRNA) brings amino acids from the cytoplasm to a ribosome.

  21. one gene growing RNA strands DNA Replication vs. Transcription Double Bubble ( bottom of pg. 6 ) Pg. 242 in book • Transcription and replication are similar, but have different end results. Please create a double-bubble map comparing and contrasting the two processes. • Replication copiesall of the DNA • Transcription copiesa specific gene. • Replication makesone copy (only happens once) • Transcription can make many copies (happens almost continuously)

  22. Similarities between DNA replication and Transcription? • Occur within the nucleus • Both are catalyzed by enzymes • Both unwind DNA • “complementary” base pairing • Highly regulated (very carefully done- we want NO mistakes)