-KeyModel 1- Transcription
1. A) Nucleus
B) Nucleus
2. A) mRNA
B) Nucleotides, in the nucleus
3. RNA polymerase
4. A) A: U, C: G
B) A: T, C: G (uracil replaces thymine in RNA)
5. Template (reading) strand
6. A) 31 -> 51
C) 51 -> 31
7. Transcription is copying… the DNA is being copied to RNA
8. RNA polymerase and transcription factors
9. Promoter
10. No, cells only transcribe the genes that they need.
11. No. A cell only transcribes the genes that it needs. A skin cell would not transcribe brain cell
genes, for example.
Model 2- mRNA Processing
12. A) Introns
B) Methyl cap on 5’ end poly-A tail on 3’ end
13. Nuclear pore
14. AUG (start codon)
15. It carries the code for a protein from the nucleus to the cytoplasm (where proteins are made)
16. Different sections can be removed to make different proteins; i.e., different exons remain in
the final mRNA.
17. To prevent the exonucleases from destroying coding sections of mRNA.
18. Longer tail means the mRNA will last longer, allowing it to be used more times.
19. – pre-mRNA made from template strand of DNA, starting at the promoter
- Introns removed
- Methyl cap & poly-A tail added
20. Protein (enzyme)
21. They are recycled when other mRNAs are broken down. They move from the cytoplasm to
nucleus.
22. All species use same nucleotides & basic mechanism. The more differences, the less related
the organisms.