BIO 475 Lecture Notes - Lecture 1: Messenger Rna, Polyadenylation, Ribosomal Rna

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fuchsiatrout7

8 Apr 2019

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Objective #1: rna functions: what does it mean for an rna to be designated as "coding" or "non-coding". Coding = rna in a cell that encodes a protein. Non-coding = rna in a cell that does not encode a protein: mrna is polyadenylated (poly-a tail is added as part of processing). A tail? (not in the reading; find on own. No, polyadenylation is the addition of a poly-a-tail to a messenger rna to convert it from pre-mrna to mature mrna. However, for many non-coding rnas (including trna, rrna, snrna, and snorna) polyadenylation is a way of marking the rna for degradation (at least we know this is true in yeast (eukaryotic)) Rrna is the most abundant and accounts for 80% of the total rna in a cell trna is the next abundant and accounts for 15% of the total rna in a cell.

Related Questions

1. There are viruses, called bacteriophage, that infectbacterial cells. Following viral entry, the cell begins tosynthesize viral DNA and viral proteins, leading to the productionof mature virus and the death of the bacterial cell. During thecourse of viral infection, transcription of bacterial genes isturned off so that transcription of viral genes predominates. Whichof the following is the most likely explanation for how the virusmanages to shift transcription from bacterial genes to its owngenes?

a. it synthesizes a viral RNA polymerase that recognizes onlyviral promoters

b. it synthesizes a viral DNA polymerase that recognizes onlyviral origins

c. it synthesizes a viral sigma subunit that directs thebacterial RNA polymerase to viral promoters

d. it has special viral ribosomes that only translate viralproteins

2. Unlike bacterial transcripts, eukaryotic RNA transcripts arechemically modified because:

a. Chemical groups help protect the mRNAs from degradation inthe eukaryotic cytoplasm, bacterial mRNAs are not degraded

b. Chemical groups facilitate the transport of eukaryotic RNAsfrom the nucleus to the cytoplasm, bacterial RNAs are synthesizedin the cytoplasm

c. Eukaryotic RNA polymerases cannot transcribe genes unlessthey are chemically modified, bacterial RNA polymerases transcribeunmodified genes

d. Transcripts in eukaryotic cells contain non coding regionsthat must be removed, bacterial transcripts contain only codingsequence

e. b and d

3. Termination of transcription in both E. coli and eukaryoticcells occurs because

a. there is a termination signal in the DNA following the genesequence.

b. there is a hairpin structure followed by a string of U

copperturtle968

*Please don't answer with photos, DO NOT UPLOAD PHOTO, it's hard to read.

I post this question twice, please don't answer this post if you already answer the other one, if you can answer different answer that's fine. REASON WHY I POST IT TWICE, I NEED TWO DIFFERENT VIEW.

Discussion

Hi All - this week you will learn about DNA - the molecule of life! You may think that protein-coding genes are the most important, but results from the Human Genome Project revealed that only about 2% of our DNA codes for protein - so what about the rest of the "junk DNA" (or non-protein coding portion of the genome) - is it functionally important? Yes! Scientists are learning how "the non-protein-coding portion of the genome is of crucial functional importance: for normal development and physiology and for disease". I would like you to please choose a topic with regards to the non-protein coding portion of the genome (this will introduce you to gene regulation which we will cover in chapter 11) or you may also choose to write about a topic that describes a mutation in any protein that is involved in DNA replication, transcription, or translation (we did not talk about all of the enzymes involved in those processes). Please list your reputable source - this is worth 0.5 pt (even if you use one of my sources below) and tell me WHY you chose your topic (this is worth 1 pt.) please try to briefly explain your topic to the best of your knowledge - I don't expect you to write a lot of detail about your topic - it might be hard to understand (which you are welcome to comment on in your paragraph)!

Examples to choose from (but not limited to) include: noncoding RNAs (snRNAs, miRNAs, siRNAs, snoRNAs, piRNAs, lincRNAs) and RNA therapeutics:

LIST:

1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4119351/ (Development of microRNA therapeutics is coming of age)

2. http://www.umassmed.edu/rti/ (RNA Therapeutics Institute)

3. http://www.genengnews.com/insight-and-intelligence/rna-based-therapeutics-and-vaccines/77900520/

4. http://genesdev.cshlp.org/content/26/21/2361.full (Biology of PIWI-Interacting RNAs: new insights into biogenesis and function inside and outside of germlines)

5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4265212/ (PIWI proteins and their interactors in piRNA biogenesis, germline development and gene expression)

6. http://www.news-medical.net/news/20121203/microRNAs-play-an-important-role-during-embryonic-development.aspx

7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4578617/ (the role of microRNAs in cell fate determination)

8. http://news.berkeley.edu/2017/01/13/scientists-reprogram-embryonic-stem-cells-to-expand-their-potential/

9. http://www.the-scientist.com/?articles.view/articleNo/40871/title/The-Second-Coming-of-RNAi/

10. http://web.mit.edu/newsoffice/2013/cardiac-development-needs-more-than-protein-coding-genes-0124.html (long non-coding RNA molecules)

11. http://www.alzforum.org/news/research-news/new-role-micrornas-torpedoes-sink-neurons(microRNAs)

12. http://ghr.nlm.nih.gov/condition/rothmund-thomson-syndrome (mutation in human helicase gene)

13. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3633371/ (mutation in mitochondrial helicase gene called TWINKLE)

14. http://sfari.org/news-and-opinion/news/2013/in-autism-related-disorders-rna-turns-out-to-be-key (RNA topoisomerase)

15. http://ghr.nlm.nih.gov/gene/TERC (dyskeratosis congenita - mutations in the TERC gene - the RNA component of telomerase)

16. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3853347/ (Top3beta is an RNA topoisomerase that works with Fragile X syndrome protein to promote synapse formation)

The following 3 articles discuss long non-coding RNAs - there are many examples in each article so you only need to talk about one example - not the whole article:

1. http://www.sciencedirect.com/science/article/pii/S2468054016300063 (mechanism of action and functional utility)

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5084630/ (dysregulated expression in ovarian cancer)

3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4736767/ (stem cells)

skyminnow948

1. The Pribnow Box is a

A. attenuator

B. enhancer

C. promoter

D. operator

2. Which of the following do not occur during post-transcriptional processing of RNA in eukaryotes?

A. the splicing of introns

B. addition of a poly-A at the 3' end

C. removal of introns

D. addition of a 7-methyl guanosine cap at the 5' end

3. In transcription, RNA polymerase binds at

A. a promoter

B. an operator

C. the oriC locus

D. an enhancer

4. The Central Dogma in genetics describes

A. the pattern of information flow in the cell

B. the pattern of chromosomal inheritance in populations

C. the role of mutations in disease

D. the role of promoters

5. Which of the following sequences of DNA could code for a stem-loop structure (only the template strand is shown)?

A. 3'--G-G-C-C-C-T-T-G-G-A-A-A-A-C-C-A-A-G-G-G-C-C--5'

B. 3'--G-G-C-C-C-T-T-G-G-A-A-A-A-G-G-T-T-C-C-C-G-G--5'

C. 3'--G-G-C-C-C-T-T-G-G-T-T-T-T-G-G-C-C-C-T-T-G-G--5'

D. none of the above

6. Removal of introns from RNA is by

A. primosomes

B. peptidases

C. galactosidases

D. spliceosomes

7. Which of the following represents the units for measuring the rate of sedimentation of a molecule/organelle in a sucrose gradient?

A. molecular weight

B. Svedberg units

C. map units

D. Daltons

8. During transcription, which strand is not read by the RNA polymerase?

A. coding strand

B. noncoding strand

C. template strand

D. terminator strand

9. The function of the rho protein is

A. to help terminate translation

B. to help RNA polymerase bind to the DNA

C. to help RNA polymerase find a promoter

D. to help terminate transcription

10. The unusual bases found in transfer RNAs

A. are added during transcription

B. are normal bases that have been modified after transcription

C. help the tRNAs to bind to DNA

D. ensure that the tRNA stays linear in solution

BIO 475 Lecture Notes - Lecture 1: Messenger Rna, Polyadenylation, Ribosomal Rna

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