8.4 Transcription 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 ( )

8.4 Transcription Set up Cornell Notes on pg. 7 Topic: 8.4 Transcription Essential Question: 1.What is the central dogma? 2.Why can an mRNA strand made during transcription, be thought of as a mirror image of the DNA strand from which it was made? 2.1 Atoms, Ions, and Molecules 8.4 Transcription KEY CONCEPT Transcription converts a gene into a single- stranded RNA molecule.

3.2 Cell Organelles rough endoplasmic reticulum Have bumps called ribosomes which link amino acids together to form proteins REVIEW:

8.4 Transcription Proteins are used for movement, eyesight, and digestion and practically everything else you do.

8.4 Transcription nucleotide unzips nucleotides Review: Replication Helicase

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

8.4 Transcription original strand new 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?

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

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

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

8.4 Transcription 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

8.4 Transcription Protein Synthesis Video Replication 1m40s Transcription 2m50s

8.4 Transcription Transcription copies specific genes from DNA to make a strand of RNA.

8.4 Transcription To transcribe is to make or translate a copy of DNA into RNA

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

8.4 Transcription start site nucleotides transcription complex START Transcription Complex nucleotides

8.4 Transcription 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. DNA RNA polymerase moves along the DNA RNA Will the RNA be a identical copy of the DNA or a complementary strand?

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

8.4 Transcription 3. The RNA strand detaches from the DNA once the gene is transcribed. DNA rezips RNA

8.4 Transcription 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.

8.4 Transcription growing RNA strands DNA one gene 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 copies all of the DNA –Transcription copies a specific gene. –Replication makes one copy (only happens once) –Transcription can make many copies (happens almost continuously)

8.4 Transcription 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)

8.4 Transcription Practice DNA A T C G A A A T C G G G A T T RNA U A G C U U U A G C C C U A A