1. 8.4 Transcription TEKS 4B, 6C, 9C The student is expected to: 4B investigate and explain cellular processes, including homeostasis, energy conversions, transport of molecules, and synthesis of new molecules; 6C explain the purpose and process of transcription and translation using models of DNA and RNA; 9C identify and investigate the role of enzymes

2. 8.4 Transcription TEKS 4B, 6C, 9C KEY CONCEPT Transcription converts a gene into a single-stranded RNA molecule.

3. 8.4 Transcription TEKS 4B, 6C, 9C RNA carries DNA’s instructions. The central dogma states that information flows in one direction from DNA to RNA to proteins.

4. 8.4 Transcription TEKS 4B, 6C, 9C The central dogma includes three processes. RNA is a link between DNA and proteins. replication transcription translation – Replication – Transcription – Translation

5. 8.4 Transcription TEKS 4B, 6C, 9C 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.

6. 8.4 Transcription TEKS 4B, 6C, 9C Transcription makes three types of RNA. Transcription copies DNA to make a strand of RNA.

7. 8.4 Transcription TEKS 4B, 6C, 9C 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

8. 8.4 Transcription TEKS 4B, 6C, 9C –RNA polymerase bonds the nucleotides together. –The DNA helix winds again as the gene is transcribed. – Nucleotides pair with one strand of the DNA. DNA RNA polymerase moves along the DNA

9. 8.4 Transcription TEKS 4B, 6C, 9C – The RNA strand detaches from the DNA once the gene is transcribed. RNA

10. 8.4 Transcription TEKS 4B, 6C, 9C Transcription makes three types of RNA. –Messenger RNA (mRNA) 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.

11. 8.4 Transcription TEKS 4B, 6C, 9C 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