BIO230H1 Lecture Notes - Lecture 2: Galactose, Cyclic Adenosine Monophosphate, Lac Repressor

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19 Nov 2016

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Crucial for: responses to extracellular stimuli, defining cell types (multicellular organisms) Cannot change the dna, so must change gene expression. **promotor region indicates transcription start site & contains sigma factor binding site. Rna polymerase transcribes dna: reads dna 3" 5", makes rna 5" 3". Genes can be transcribed at different efficiencies. Gene regulatory proteins (transcription factors: discovered using bacterial genetics, can turn genes on (activators, can turn genes off (repressors) Regulatory regions of dna (cis elements: coli. Multiple genes transcribed into single rna molecule. 5 genes encoding enzymes for tryptophan synthesis. Tryptophan in environment- low turn on trp operon. Tryptophan in environment- high turn off trp operon (+1) position- where 1st nucleotide is transcribed: no (0) position. Tryptophan repressor activation: rna polymerase bound- trp gene expression- on, trp repressor protein- trp gene expression off, binds to operator: dna sequence in promotor (b/w the sigma- factor binding sites) Binds to trp operon promotor- rna polymerase can"t bind.

Related Questions

1. What reaction is catalyzed by reverse transcriptase and used in the laboratory to generate cDNA?

a. transcription of RNA to DNA

b. transcription of DNA to RNA

c. conversion of ribonucleotides into deoxyribonucleotides

d. translation of RNA to DNA

e. conversion of a ribonucleotide to a DNA double helix

2. In eukaryotic cells, _________determine the amount of mRNA arising from a particular gene.

a. transcriptional-level controls

b. RNA processing-level controls

c. translational-level controls

d. replication-level controls

e. b and c

3. In eukaryotic cells, _________determine how a primary transcript is converted to mature mRNA

a. transcriptional-level controls

b. RNA processing-level controls

c. translational-level controls

d. replication-level controls

e. a and d

4. In eukaryotic cells, _________determine when a particular mRNA is actually used in protein synthesis.

a. transcriptional-level controls

b. RNA processing-level controls

c. translational-level controls

d. replication-level controls

e. None of the above because protein synthesis takes place immediately

5. Under what circumstances do cells selectively activate and suppress their genes?

a. at different stages of embryonic development

b. in different tissues

c. exposure to different types of stimuli

d. No such circumstances exist in natureâcells express all their genes throughout life.

e. a, b and c

6. Which statement about the control of gene expression is FALSE?

a. A single gene may be controlled by different transcription factors.

b. A single transcription factor may be necessary for the expression of different genes.

c. Each cell type has a characteristic pattern of gene transcription, which is determined by the particular complement of transcription factors contained in that cell.

d. Expression of protein genes is primarily controlled in nucleoli

e. Control of gene transcription is complex and influenced by various circumstances.

7. What is thought to maintain X chromosome inactivation in females?

a. DNA acetylation

b. DNA methylation

c. RNA inactivation

d. Histone methylation

e. None of the above because both X chromosomes are active in females and males.

crimsonplatypus494

Chapter 10

1.Outline the history of our knowledge on DNA up to Watson and Crick. What were the main contributions made by each researcherâs key experiment?

2.Explain the setup of the Hershey and Chase experiment, what would the results have been if protein was the genetic material?

3.Draw the structure of a DNA nucleotide, labeling each main component correctly. How does an RNA nucleotide differ?

4.If a section of double stranded DNA contains 19% Adenine, how much Thymine is present?

5.You are a researcher studying the genetic basis of heart attacks and have been working to determine the expression levels of different genes that might contribute to cancer formation. You obtain the DNA methylation status of five genes of interest (the data are shown in the table below). The plus (+) sign indicates the level of DNA methylation; more plus signs correlates with increased methylation levels.Based on this information which genes would you predict to have the highest rate of transcription?

Gene	Methylation levels
1	++
2	+++++
3	+++
4	++
5	+

What are the characteristics of the 3 main DNA forms?

Chapter 11

What are the different types of chromatin?

What are the structures and important roles for telomeres and centromeres?

What are the differences found between eukaryotic chromosomes and mitochondrial?

Chapter 12

Explain each of the different models of replication.

If you grow a culture of bacteria in media with radioactive nucleotides so that all DNA in the cells include radioactive nucleotides and then place the bacteria in new non radioactive media. After two rounds of replication what proportion of the DNA molecules will contain radioactivity?

Summarize the similarities and differences between rolling-circle replication, theta replication and linear eukaryotic replication.

What are the functions of the different DNA polymerases found in eukaryotic cells?

Draw a replication fork and include all key components and orientations. (Leading/lagging strands, DNA helicase, RNA primer and DNA gyrase)

What is the Holliday model of recombination and what are the necessary steps?

Chapter 13

What are the different types of RNA and what roles do they play?

Describe the properties and functions of each of the RNA polymerases and how they differ depending on the organism.

Describe in detail the process and mechanisms of transcription in both prokaryotes and eukaryotes.

Chapter 14

What are the primary purposes of each of the three post transcriptional modifications that occur in eukaryotic cells.

What is alternative splicing and what role does it play in the cell?

How is ribosomal RNA processed after transcription?

How do siRNA and miRNA work, describe/draw out the process in detail.

*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)

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BIO230H1 Lecture Notes - Lecture 2: Galactose, Cyclic Adenosine Monophosphate, Lac Repressor

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