Basically what Marie said. You usually need enzymes to cut and edit DNA. You can cut some out to stop a function of a piece of DNA or even add some in. ZFNs, TALENs are slightly 'older' technologies and CRISPR is the new technology, which is being used for the purposes above. It may be enhanced/improved in the coming years and I wouldn't be surprised if there weren't other DNA editing technologies that appear in the future too.

[removed]

I don't know what the cutoff is, but to compare animals, the most common way is to align their DNA sequence and then have a percentage of similarity. I do this as part of early research in drug discovery to have a look at how much alike some human molecules are to other species (eg monkeys, mice)

Quick correction here: transmission power falls off per the inverse square law only given an idealized isotropic antenna. Focused beams using, for instance, lasers, do not experience the same losses.

But yeah, it's cuz it's far.

It's actually pretty complicated, but in general, viruses need certain receptors on cells in order to be able to infect them. These receptors are usually specific to certain types of animals, which is why you can't just give a virus to any animal and expect it to be able to infect them. Additionally, even if a virus is able to infect a certain animal, it may not be able to replicate effectively or cause disease, which is why a lot of cross-species transmissions don't result in an outbreak. In short, it's all about the virus's ability to bind with specific receptors on host cells and replicate effectively.

Yh sounds insanely complex

First, DNA/RNA can actually enter the nucleus. Nuclear import is controlled by special amino acid sequences known as nuclear localization sequences. This, along with importin (transport protein) allows macromolecules to enter the nucleus through the nuclear pore complexes. tRNA, for example, are imported back into the nucleus, which has been shown in yeast. Plasmid DNA import has also been demonstrated.

When a cell divides, it’s nuclear envelope breaks down, so the mitotic spindle apparatus can invade and attach to the chromosomes. Then, the viral nucleic acids can interact with the hosts’. HIV, howeve, can enter the nucleus even if the cell isn’t dividing. It’s thought that the HIV genome uses the host’s cellular machinery to move into the nucleus. The HIV cDNA (result of reverse transcription) is coated with a myriad of proteins which allow it to cross into the nucleus.

Figure 1 in this paper should give you a good visualization: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3325773/

TL;DR: HIV sneaky. :( The idea of the central dogma of biology has some loopholes, with reverse transcription, and direct translation from DNA to protein. Always* exceptions to rules, that’s what makes science so amazing.

[deleted]

The answer for internal combustion engines is a little more nuanced. The simplest answer is that for a race car engine, where you want the maximum power output with the throttle wide open, you get that with cold air because the cold air has higher density (at the same pressure), and so you can get more air into the cylinder and can burn more fuel. And the efficiency goes up because the fixed losses are a smaller percentage of the overall power.

For regular internal combustion used for transportation, you rarely have the throttle all the way open and are often running with the throttle way back from wide open, creating substantial throttling losses. Lots of work on improved engine efficiency is finding ways to mitigate that problem. Variable valve timing is one example. But another is actually to deliberately heat the intake air. The lower air density will reduce the amount of mass flow of air into the cylinder, enabling scaling back the power towards the lower level that's actually needed with the throttle open more, or ideally even wide open.

So warm air can result in better efficiency given a specific engine size and a power output requirement well below its capability, because it effectively degrades the engine power without degrading its efficiency. However, if you are just operating the engine at its maximum efficiency point, with a wide open throttle, perhaps because you are using it for something other than driving a car on public roads, you'll get better efficiency with cold air.

A little more detail and links to papers with a lot more detail are on this Wikipedia page:

https://en.wikipedia.org/wiki/Warm_air_intake

[removed]

Splice-switching antisense oligonucleotide (SSOs) technology utilize modified RNA to disrupt pre-mRNA splicing. When mRNA is first transcribed from DNA, it contains regions known as introns, which do not contribute to the final protein product. These introns are removed, and the regions that do contribute to the finalized protein product, exons, are ligated together. Aberrations in pre-mRNA splicing contribute to a myriad of human diseases, such as Duchenne Muscular Dystrophy. Cryptic splice sites are when a pre-mRNA has incorrect splicing sequences in a pre-mRNA. This can be a result of a single point mutation, causing a deletion in the entire pre-mRNA, leading to a truncated protein.

SSOs are engineered to bind to these faulty pre-mRNAs, and disrupt the intron splicing machinery from binding and creating an aberrant transcript. They can modulate splicing patterns to create an mRNA that produces a “lesser of two evils (less worse)” protein.

Of course, CRISPR is likely more suited to alter single nucleotide substitution mutations, but that’s an application of RNA-based technologies that isn’t talked about as much. Splicing can be a big problem, especially with cryptic splice sites.

First off I would like to say that all you scientists are amazing. Your knowledge in the field is inspirational bc those up and coming want to be like you and just understand this block we call earth! I was looking at the mechanism of action for a retrovirus. Specifically HIV. When it enters the cell, it immediately unpacks and enzymes begin to reverse transcribe RNA to DNA. After this time it enters the nucleus of the host cell. What? That's a red flag. As far as I know, never would the cell need DNA of ANY KIND to flow INTO the nucleus. According to the central dogma, the only thing flowing OUT of the nucleus is mRNA. Wouldn't this provide a weakness. If we were to be able to prevent viral DNA which is structurally and fundamentally different from RNA from getting past the nuclear envelope, we could nip this in the bud.

[removed]

[removed]

> men tend to have a higher 1rm off of say, an 8 rep max.

What do these letters mean? Rm? Rep?

Because of the tilted axis of the earth, the sun only rises due east, and sets due west, at the spring and autumn equinoxes (around 21st March and 21st September).

The deviation from due-east / due-west at other times of the year is least near the equator and "beyond extreme" ;-) when you go beyond the arctic or antarctic circles.

https://www.timeanddate.com/astronomy/uk
Will show you lots of interesting information about the time of sunrise and sunset, and what azimuth the sun rises or sets at, for different places at different times of the year.
The link above takes you to a UK page, but you can set it to any country.

Thank you for clarifying that, I did not know (and I'm a nurse)!

This is specifically for the air supplying the combustion process. There's also a "cold side" of the heat engine, for example a steam condenser or a heat sink on a Stirling engine. If this is cooled by air, that air should be as cold as possible. (It might instead be cooled by water, in which case you want the water as cold as possible.)

Some of the individual flows happened within 50,000 years of each other. I believe the total time of the flows was 750,000 to a million years or so.

[removed]

It's been a while since I was a geology major but I learned that by the time of the K/T boundary, a lot of non -Avian dinosaurs were already extinct so it isn't like the impact killed the dinosaurs as much as it was the final blow.

Is that still accurate?

Amen to that! I will be looking forward to the status of research after 10 years. Lol and I thought I had single handedly thought of a breakthrough in modern medicine.

Proteasomes are complexes that degrade proteins rather than nucleic acids. For cleavage of nucleic acids, you’d want to look at endonuclease or exonucleases, restriction enzymes. Proteasomes typically are involved in degrading misfolded proteins (look into prions!), or proteins that are no longer needed in the cell. Just a minor correction, hope it helped. :3

Not quite the same reasons, you've also got hydrochloric acid in the mix here.

Adding to that, there are different types of nerve fibers carrying the information for different types of pain:

Fast acting A-delta fibers are responsible for that first, sharp pain one would experience after e. g. cutting their finger.

After a second or two, the usually less intense but more consistent and "dull" pain kicks in, which is carried by the slower C-type fibers.