Prokaryotes and eukaryotes show differences in posttranscriptional modifications of mRNA. What are these differences, and why do eukaryotes show more modifications than prokaryotes?
What will be an ideal response?
In bacteria, the coupling of transcription and translation allows ribosomes to engage in translation of the 5? region of mRNAs whose 3? end is still under construction by RNA polymerase. Translation of the mRNA transcripts begins before transcription is complete, since there are no membrane-bound organelles to provide physical separation of the two processes. In eukaryotes, however, transcription and translation are uncoupled. Transcription takes place in the nucleus, where pre-mRNA is processed to form mature mRNA. Translation occurs in the cytoplasm after release of mature mRNA. Because the processes are physically (and temporally) separated, the mRNA receives a 5? cap and 3? tail to make the transcript stable and to help the ribosome locate
the transcript when it exits the nucleus.
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Genomic DNA sequences seem to support the idea that the first eukaryotic cell arose from within the ________ lineage.
A. bacterial B. last universal common ancestor (LUCA) C. viral D. archaeal
Now that small molecular-level deletions and subtle chromosomal rearrangements can be discovered using advanced cytogenetic techniques and microarrays, disorders whose causes had not previously been known can have their basis identified
However, since most of these are not widely publicized, being individually rare, it has been difficult to identify patients with shared chromosomal abnormalities who share phenotypic features. A new database, known as DECIPHER, is now available to search for patients with like phenotypes and/or like chromosomal abnormalities. If you are the clinical geneticist who has a patient whose data is entered into this database, suggest three or more ways using this database can benefit your patient or your field in general.
A plasma cell secretes approximately ________ antibody molecules per second over its life span of ________ days.
A) 10,000 : 4-7 B) 2000 : 7-10 C) 2000 : 4-7 D) 2000 : 10-20 E) 10,000 : 7-10
What do chloroplasts utilize light energy for?
a. to make carbohydrates b. to make proteins c. to make nucleic acids d. to make fats