BIOA01H3 Lecture 25: Module 3 Lecture 25.docx
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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.
You decide to identify the CFTR mutation by analyzing the genomic DNA of your patients compared to healthy individuals. You specifically are looking to see whether a specific 3' gene truncation has occurred in the patients. You will determine this using hybridization techniques with samples from healthy and CF patients. Which of the following will allow you to accomplish this?
Using an RNA probe complementary to the region not removed by the truncation. | |
Using an RNA probe complementary to the region removed by the truncation. | |
Using an DNA probe complementary to the region not removed by the truncation. | |
Using an DNA probe complementary to the region removed by the truncation. |
To conduct the hybridization experiment, you are trying to decide between using a DNA or RNA probe. Which would be ideal to use and why?
As both are composed of nucleic acids, using either would result in identical results. | |
An RNA probe because RNA has uracil bases. | |
An RNA probe because it could also be used in a translation experiment. | |
A DNA probe because it is more stable than RNA. | |
A DNA probe because RNA cannot bind to DNA. |
Imagine Hershey/Chase had used an RNA virus (genome composed of RNA) instead of a DNA virus in their experiment. Would radioactivity still have been found in the pellet?
No, because only DNA can be labeled with radioactivity. | |
No, because the RNA genome would not enter the bacteria upon infection. | |
No, because while DNA and RNA nucleotides are similar, they are not identical. | |
Yes, because DNA and RNA nucleotides are similar. | |
Yes, because genome in any form (DNA, RNA, protein) would be labeled similarly. |
The human genome consists mostly of non-coding DNA. Which of the following are benefits of this?
Random DNA mutations generally won't affect RNA and protein function. | |
It is faster to duplicate the genome when these are present. | |
The existence of introns can lead to multiple variations of proteins encoded by a single gene. | |
It is unlikely transposons would exist in the genome if there was too much protein coding DNA. |
You accidentally add a mutant dNTP (which has an H instead of an OH connected to the 3â carbon) to a reaction where DNA is being replicated. Which of the following is true of this mutant dNTP?
It can be incorporated into DNA strand but cannot form a phosphodiester bond with an incoming wild type dNTP | |
It can be incorporated into a DNA strand but cannot base pair with a complementary nucleotide | |
It can be incorporated into a DNA strand and can form a phosphodiester bond with an incoming dNTP, but only if it is another mutant dNTP | |
It cannot be incorporated into a DNA strand. |
Andrew Murray's sister, Andrea, is adding to her brother's work on chromosomes. She is using cells that are unable to synthesize adenine (âade) and histidine (âhis). The plasmid she is currently working with consists of an origin of replication and the Ade gene.
Following her transformation of the plasmid into her yeast, what media will the cells be plated on to select for cells that have picked up the plasmid?
Media containing histidine | |
Media containing adenine | |
Media lacking adenine | |
Media lacking histidine |
Andrew Murray's sister, Andrea, is adding to her brother's work on chromosomes. She is using cells that are unable to synthesize adenine (âade) and histidine (âhis). The plasmid she is currently working with consists of an origin of replication and the Ade gene.
She starts by attempting to add the centromere DNA into a plasmid containing the origin of replication. Unfortunately, when adding the centromere sequence, the origin of replication is removed, thus leaving a plasmid with only a centromere and selection marker. Following plasmid transformation, what growth result will she see on her plates?
No colonies | |
Little colonies | |
Big colonies |
Andrew Murray's sister, Andrea, is adding to her brother's work on chromosomes. She is using cells that are unable to synthesize adenine (âade) and histidine (âhis). The plasmid she is currently working with consists of an origin of replication and the Ade gene.
She fixes the mistakes from the previous experiment and now has a complete plasmid (selection marker, origin of replication, centromere). She then inserts telomere sequences into the plasmid. How will this impact her transformation?
It will not impact her transformation | |
Her transformation will no longer work because plasmids donât require telomeres | |
She will now see much larger colonies | |
She will now see fewer but larger colonies | |
She will now see smaller colonies |
In the Meselson/Stahl experiment, E. coli were first grown in media containing heavy nitrogen, 15N, and then transferred to light nitrogen, 14N, at the beginning of the experiment.
Imagine that their data showed that replication occurs in a conservative manner instead of semi-conservative. What fraction of the DNA helices will consist of mixed DNA after 4 rounds of replication in this case?
None | |
More than 75% | |
25-50% | |
51-75% | |
Less than 25% |