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

Warm-up Go to the table with the trait you have answer the following questions On a post-it answer the following questions and post on the nearest parking lot What are traits? How exactly are these traits passed? How are these characteristics are created?

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 Transcription Translation replication transcription translation 2. RNA is a link between DNA and proteins. 1. 4. 3. 5.

RNA differs from DNA in three major ways. RNA has a ribose sugar. RNA has uracil instead of thymine. RNA is a single-stranded structure.

Transcription makes three types of RNA. Transcription copies DNA to make a strand of RNA.

1. Transcription is catalyzed by RNA polymerase. RNA polymerase and other proteins form a transcription complex. The transcription complex recognizes the start of a gene and unwinds a segment of it. start site nucleotides transcription complex

RNA polymerase moves along the DNA 2. RNA polymerase reads one side of the DNA template. RNA polymerase bonds the complementary nucleotides together. The DNA helix winds again as the gene is transcribed. DNA RNA polymerase moves along the DNA

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

Transcription makes three types of RNA. 1. Messenger RNA (mRNA) carries the message that will be translated to form a protein. 2. Ribosomal RNA (rRNA) forms part of ribosomes where proteins are made. 3. Transfer RNA (tRNA) brings amino acids from the cytoplasm to a ribosome.

Check point - Practice Pass the message (2 – 3 people) Person #1 – DNA On the whiteboard copy the following DNA strand AGA GTT CTA ATC CCT Pass the board to Person #2 – mRNA Person #2 : Fill in the correct mRNA bases using the base pair rules Pass the board to Person #3 – tRNA Person #3: Fill in the correct tRNA bases using the base pair rules Find the amino acid that goes with the tRNA (use genetic code wheel

You try on your own – who can figure it out first DNA: CAG TAT GAA AUG Discussion Questions mRNA is synthesized in translation or transcription? How many codons equal one amino acid? Where does translation takes place? Where does transcription takes place?

The transcription process is similar to replication. Transcription and replication both involve complex enzymes and complementary base pairing. The two processes have different end results. Replication copies all the DNA; transcription copies a gene. Replication makes one copy; transcription can make many copies. growing RNA strands DNA one gene