Moving another question will save thus ! responseQuauieleoQuestion 16Pomezprotein that inhibits EZF, transcription factor that activates several genes involved cell...

A particular E2F transcription factor recognizes the sequence TTTCGCGC in the promoter of its target gene. A temperature-sensitive mutation in the gene encoding this $\mathrm{E} 2 \mathrm{F}$ transcription factor alters the ability of its protein product to activate transcription; at $25^{\circ} \mathrm{C}$ the mutant protein activates transcription normally, but at $35^{\circ} \mathrm{C}$, it fails to activate transcription at all. However, the ability of the protein to recognize its target DNA sequence is not impaired at either temperature. Would cells heterozygous for this temperature-sensitive mutation be expected to divide normally at $25^{\circ} \mathrm{C}$ ? at $35^{\circ} \mathrm{C}$ ? Would your answers change if the $\mathrm{E} 2 \mathrm{F}$ protein functions as a homodimer?

In this question that we are looking at two potential situations. First we have protein A which activates its own Jean. It's the transcription activator. Then we also have protein are which represses itself. So we have a is a positive feedback loop and our is a negative feedback loop. And our question is, which of these is going to be remembered by the daughter cells and why? So for this we're looking at how long lived for response is if we have a look at our it's a negative feedback loop, we're going to have a very short lived response. This is a transient response. You get some of our it represses itself. You lose our whereas if you look at A it is a positive feedback loop. A. We get high concentrations of a in the cell, and some of these are going to go to the daughter cells. Some will be passed into each daughter cell, and because it activates itself, it will then activate the copy of a in each daughter, and so it will be spread along for generations. So descendants inherit activation. US

If each of these proteins were missing, what would happen during the DNA replication process? What do you need? A plan raises very useful because the unipolar makes replaces the primer. The already primary with DNA. And more importantly, it actually lays down the base pairs. So if it was missing, they would have to find their own way to lay down, um, than individual nucleotides for Indian A like a slight case, um, connects the two strands of DNA together, um, groups connects the oak Okazaki uh, fragments. Let's keep going. Um, we have sliding clap for D N A primaries. This allows the DNA polymerase from disassociating with the templates trend. Otherwise, you could simply disconnect, So it prevents memories from DNA primaries from disconnecting from from the template. Next we have the d is the nucleus that removes the irony primers. Well, this is very important because it can cleave the double stranded breaks in the target molecules, and this is very useful for DNA repair. Um, so it's kind of like the proof reading before the DNA. Well, one of the farms of proof reading, Um, and let's finally get t e. So e is the oldest one more. So this is a DNA helix case. Hilly case is a charge of end zipping the DNA at the beginning at the point of for application at the point off replication. So, um, if if it was missing, they would have to find a different way to unzip that DNA from double helix structure. And let's finally get to f f is primaries prime misleads down the Arnie primer, um, which allows for the DNA playmates to hop on. So if there was no our promise, the cell would have to find some other way that allows the d. N a plan may still hop on and start replication. So thank you for watching, and I hope this help.

Here we are looking at different transcription factors. So these are going to be different proteins that are going to attach to your DNA strand, allowing for the action of your different preliminaries enzymes in order to read a certain gene sequence. So your transcription factors will consist of several different protein groups and will allow for that attachment of your preliminaries and its proper reading function. So here you can imagine you have your transcription factors on top and you can have the binding of the poem arrays which will be initiated by these transcription factors. So if we remove these transcription factors, there is no longer going to be any way for the preliminaries to attach to that gene as well. So if there's a mutation in just a single one of these transcription factors, it's going to have less affinity to binding as this complex and too binding to DNA. So if you decrease the rate at which your transcription factors bind, you're going to decrease the rate at which your proliferates enzymes buying, and when that occurs, the basic overall transcription function of the cell is going to decrease as well. So here, the best answer choice is going to be a that a mutation in these transcription factors are going to lower the overall transcription capability of the cell, your other phone, your other proteins, such as repressors and activators may also rely on this, but all processes will be inhibited somewhat equally due to this. So here you should take answer choice A.

Question here asked how imitation that results in a non functional RB protein. Rather, I'm contributes to cancer. So we know that our be here is going to be a tumor suppressor, acting at the G one slash synthesis checkpoint to prevent cells from beginning DNA replication. So without a functional copy of RV here, cells or more prone to begin a round of cell division.