Set up Cornell Notes on pg. 5 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? 8.4 Transcription 2.1 Atoms, Ions, and Molecules 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.

On Your OWN: The Central Dogma P.4 Draw fig 8.10 (pg.239)- color code Red Blue Green Make a double-bubble map comparing and contrasting DNA and RNA (239-240)

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

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

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

Connect Suppose you want to play skeeball at a arcade. The game only takes tokens, but you only have quarters. What do you do? You exchange your quarters for tokens. In a similar way, your cells cannot make proteins from DNA. They must convert the DNA into RNA in order to make proteins This process is known as transcription

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

The central dogma includes three processes. Replication Copies DNA 2.Transcription Converts DNA into RNA RNA is a link between DNA and proteins “quarters tokens” 3.Translation Interprets an RNA message into a string of amino acids that will make up a protein replication transcription translation

Protein Synthesis: the process whereby biological cells generate new proteins. Includes DNA replication, transcription, and translation.

Location of Protein Synthesis Prokaryotic cells: replication, transcription, and translation all occur in the cytoplasm (remember there is no nucleus), at approx the same time In Eukaryotic cells, where DNA is located inside the nucleus, these processes are separated by location and times. Replication and transcription occur in the nucleus Translation occurs in the cytoplasm

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

RNA is similar to DNA in a few ways Both are a chain of nucleotides Each is made of a sugar, a phosphate group, and a nitrogen containing base Each has A, C, & G

Protein Synthesis Video Transcription 2m50s

Transcription copies specific genes from DNA to make a complementary strand of RNA. Only a gene, NOT the entire DNA strand is transcribed

To transcribe is to make a copy of DNA into a complementary messenger RNA strand

Get out 3 Colors and MAKE A KEY on the top of your handout -DNA -RNA - Transcription Complex (RNA Polymerase)

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

The bases must be exposed so that the DNA can be read Why must the DNA strands unwind and separate before transcription can take place? The bases must be exposed so that the DNA can be read start site nucleotides transcription complex

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. DNA RNA RNA polymerase moves along the DNA

RNA polymerase moves along the DNA How does the base sequence of the RNA transcript being formed compare with the sequence on the template strand? It is complementary DNA RNA RNA polymerase moves along the DNA

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

3. The RNA strand detaches from the DNA once the gene is transcribed. The transcription complex falls apart DNA re-zips RNA

It is processed and LEAVES the nucleus, heads to the cytoplasm Where will the RNA transcript go after it separates from the DNA in step 3? It is processed and LEAVES the nucleus, heads to the cytoplasm RNA

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.

Replication copies all of the DNA Please make a Replication vs. Transcription Double Bubble (bottom of pg. 4) 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) growing RNA strands DNA one gene

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) Differences? End results are different Replication makes an identical copy of ALL of the DNA Happens only once during the cell cycle Transcription only makes a complementary strand of segments of DNA Can happen over and over again at anytime

A T C G A A A T C G G G A T T U A G C U U U A G C C C U A A 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