CH18 - Control of Gene Expression in Eukaryotes
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
|
|
||||
|---|---|---|---|---|---|
| An enhancer is _____. | A coding region of DNA that may be located within an intron. Enhancers, which increase gene transcription, can be located upstream or downstream of the gene and within introns.
🗑
|
||||
| can eukaryotic regulatory sequences function if their 5’ to 3’ orientation is reversed? | yes
🗑
|
||||
| Why does DNase cut only transcriptionally active genes? | because DNA wrapped around histones is protected from degradation by nucleases.
🗑
|
||||
| What effect do histone deacetylases have on chromatin structure? | Histone deacetylases remove acetyl groups from histones and make them more positively charged.
🗑
|
||||
| Where is a eukaryotic promoter found and what does it contain? | Eukaryotic promoters are always found upstream of the gene and almost always contain the TATA sequence (TATAAA) to which the TATA binding protein binds.
🗑
|
||||
| Which proteins have analogous functions in eukaryotes and in E. coli? | TATA binding protein and sigma protein
🗑
|
||||
| All eukaryotic promoters are bound by which protein that is involved in the initiation of transcription of mRNA in eukaryotes? | TATA binding protein
🗑
|
||||
| What is the significance of splicing patterns in mRNA? | Splicing patterns in mRNA are critical to protein formation. Differences in post-transcriptional splicing patterns can result in the formation of different proteins or significant changes in the conformation of the protein produced.
🗑
|
||||
| In smooth and striated muscle cells the DNA for tropomyosin is the same, yet the mRNAs produced are different. Which of the following statements explains this phenomenon? | The splicing patterns of the mRNA in the two cells differ, most likely due to differing conditions within the two cell types. The presence of cell-type-specific compounds influences the splicing patterns of the mRNA.
🗑
|
||||
| The life span of an mRNA molecule can be controlled by the activities of _____. | The RISC protein complex, which binds 22bp single-stranded RNA and assists this fragment to bind to its complementary mRNA; this binding triggers another enzyme to degrade the mRNA.
🗑
|
||||
| What does p53 protein do? | It is a TUMOR SUPPRESSOR; a regulatory transcription factor that activates transcription of cell cycle control genes. It activates genes that induce apoptosis in cells with extensively damaged DNA.
🗑
|
||||
| CHROMATIN is made of what components? | DNA+proteins (histones)
🗑
|
||||
| These ___ acetylate chromatin and these ____ deacetylate chromatin. | HATs: histone acetyl transferases add negatively-charged acetyl groups to chromatin.
HDAC's: histone deacetylases: remove acetyl groups from chromatin, making it more positively charged.
🗑
|
||||
| Why is insulin is made in our pancreas and not in other cells? | Because the specific TRANSCRIPTION FACTORS for insulin production are present only in the pancreas. In pancreas cells, the DNA is "open" for the promoter to bind and transcription to begin.
🗑
|
||||
| What is BASAL TRANSCRIPTION MACHINERY and what does it do? | It is a protein complex that binds to promoter for eukaryotic TRANSCRIPTION INITIATION (Step 1)
🗑
|
||||
| What are ENHANCERS and how do they work in eukaryotic TRANSCRIPTION INITIATION? | enhancers are DNA sequences; they are regulatory elements that are far from the promoter that stimulates the activity of the promoter when t.f.s. bind to them
🗑
|
||||
| What are the DNA sequences that do the opposite of ENHANCERS? | SILENCERS: they slow down the rate of transcription when protein binds to them
🗑
|
||||
| In TRANSCRIPTION INITIATION, what happens next, after the BASAL TRANSCRIPTION MACHINERY binds do the PROMOTER? | (step 2) TATA box binding protein (TBP: "TATA box binding protein" binds to TATA box)
🗑
|
||||
| In TRANSCRIPTION INITIATION, what happens next, after TATA box binding protein binds to the TATA box? | (step 3) transcription factors (proteins): they bind to ENHANCER
🗑
|
||||
| In TRANSCRIPTION INITIATION, what happens next, after t.f.'s bind to ENHANCER? | (step 4) RNA polymerase binds to the complex of basal t.f. and promoter and starts Transcription.
🗑
|
||||
| What are the 2 domains of the REGULATORY TRANSCRIPTION FACTORS? | 1. regulatory domain: binds to other proteins in the basal t.c. complex or other proteins such as coactivators
2. recognition domain: the part of the regulatory TFs that binds to DNA (making direct contact w DNA)
🗑
|
||||
| In this level of gene expression control, the PRIMARY TRANSCRIPT undergoes splicing of various exons, resulting in a possible estimated 100K proteins from 20K human genes. | ALTERNATIVE SPLICING
🗑
|
||||
| What is miRNA? | small single-stranded RNAs called micro RNAs (miRNAs). miRNA is another way of controlling gene expression via controlling mRNA stability or the translation of mRNAs.
🗑
|
||||
| What is RNA INTERFERENCE? | It is a mechanism to control the expression (translation) of RNA. it blocks protein formation by blocking translation or making mRNA subject to degradation by other enzyme.
🗑
|
||||
| What is the RISC protein complex? | TBD
🗑
|
||||
| Define the OPERON and describe its relevance to eukaryotes. | In the OPERON, several different structural genes are under the regulation of single promoter. Is in bacteria and is rare in eukaryotes.
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
boborii
Popular Biology sets