Dark Knight Shooting-Such a Shame

[Alorael at Large]

Originally Posted By: Y? Bcaus, IDK he's on 3rd & IDC

If we're already on the subject I would be thankful if you could answer a couple more questions.
Is it true that some cell types, such as fat cells and white blood cells, don't require oxygen?

All human cells need oxygen, but there's a definite difference in how much. Generally, the more metabolically active a cell is, the more oxygen it needs. Or, put another way, cells that are just sitting around don't need much energy, so they don't need oxygen to generate that energy.

Do fat cells and leukocytes need less oxygen relative to most other cells? I don't know the answer, but I'd guess that that's false. Fat is generally quite active, producing a steady stream of hormones and building up, breaking down, and transporting fatty acids. Leukocytes are also active.

The brain is one of the most oxygen-hungry organs; that's why cardiac arrest often leads to brain damage or brain death. The heart itself is actually one of the hardiest organs (makes sense; it can't stop, no matter what), and will run quite well on little oxygen and a lot of lactic acid waste product of other cells unable to fully oxidize sugars in the absence of plentiful oxygen. Muscle in general runs anaerobically when you're exerting yourself fully for a sustained period. It's not pleasant, but you can keep it up for a long time.

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Is it true that small bodily bodies, such as enzymes, lizozomes and anti-bodies don't contain DNA (or RNA)?

Cells contain DNA in their nuclei (for eukaryotes). Eukaryotic cells also contain mitochondria, which contain their own DNA. All the other organelles, including lysosomes, Golgi, endoplasmic reticulum, and all the rest don't contain DNA.

Enzymes and antibodies are proteins. They're made from the template of DNA transcribed into RNA, but they just contain amino acids and sometimes cofactors (often vitamins or a number of minerals).

As a general rule, if it's a cell, it has DNA. If it's not a cell, it doesn't have DNA. If it's outside cells, like antibodies and a few enzymes, it doesn't have DNA. And mitochondria and chloroplasts are the exceptions, as they're essentially vestigial separate organisms that were engulfed and incorporating into distant ancestral eukaryotes.

—Alorael, who uses ancestral broadly. In fact, your ancestors almost certainly had no chloroplasts unless your family tree is more literal than most.

[Aoslare]

I'm filing this one under Fulgurous Ziggurat, Alorael.

[Erebus the Black]

By energy you mean ATP, right? (Or do you mean the combustion process in the mitochondria?)

 

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Or, put another way, cells that are just sitting around don't need much energy, so they don't need oxygen to generate that energy.

So fat cells don't require oxygen to make ATP because they have other means of producing it(or because they have another form of energy conveyers)?

 

So do animal/plant cells eaten by me reach my blood stream with their DNA intact? There's a big mix up in my head between fat cells and fat molecules, can you help me clear it up? (muscle cells don't pose such a problem because they break down into proteins and carbohydrates, but from my understanding fat remains fat).

 

Do red blood cells use the oxygen they acquired in the lungs in order to move and exist or are they all one shot cells?

 

And how do blood platelets factor in the oxygen cycle (wiki says they have no DNA)?

 

Don't be afraid to hit me with the chemistry.

[Lilith]

Originally Posted By: Y? Bcaus, IDK he's on 3rd & IDC

So fat cells don't require oxygen to make ATP because they have other means of producing it(or because they have another form of energy conveyers)?

It's not that they don't require any -- fat cells that are deprived of oxygenated blood will eventually die off. But they have lower oxygen requirements than, say, nerve cells, because they have lower energy requirements.

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So do animal/plant cells eaten by me reach my blood stream with their DNA intact? There's a big mix up in my head between fat cells and fat molecules, can you help me clear it up? (muscle cells don't pose such a problem because they break down into proteins and carbohydrates, but from my understanding fat remains fat).

Nope, DNA is way too large a molecule to easily pass across the gut wall. The pancreas secretes nucleases which break down DNA into smaller molecules that can be absorbed.

Fat cells (adipocytes) are cells that store fat molecules. Think of each fat cell as a warehouse full of ping pong balls. The balls are the fat molecules, the warehouse is the cell. When you eat fatty meat, the cells are broken down during the process of digestion and the individual molecules are released.

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Do red blood cells use the oxygen they acquired in the lungs in order to move and exist or are they all one shot cells?

Red blood cells don't actually use the oxygen they transport, since they don't have any mitochrondria: their metabolism is dependent on fermenting glucose into lactic acid to produce the ATP they need. They release the excess lactic acid into the bloodstream.

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And how do blood platelets factor in the oxygen cycle (wiki says they have no DNA)?

Platelets don't have a nucleus, but they do have mitochondria, so they can produce ATP using oxygen like most cells.

[Erebus the Black]

Originally Posted By: Lilith

Nope, DNA is way too large a molecule to easily pass across the gut wall. The pancreas secretes nucleases which break down DNA into smaller molecules that can be absorbed.

So how come some germs can pass the gut wall?

[Alorael at Large]

Originally Posted By: Y? Bcaus, IDK he's on 3rd & IDC

By energy you mean ATP, right? (Or do you mean the ombustion process in the mitochondria?)

Cells use ATP as energy. There are two ways to produce it, aerobic respiration and anaerobic respiration. Both begin with glycolysis, which produces two molecules of ATP and two of pyruvate from one molecule of glucose. It also requires two molecules of NAD that are converted into NADH.

From there, there are two options. Aerobic respiration requires oxygen, but uses the pyruvate and NADH to make another 36 molecules of ATP. Obviously, this is a lot more energy per glucose. Anaerobic respiration doesn't get any more ATP, but converts the pyruvate and NADH into various molecules and NAD so that at least more glucose can be broken down for 2 ATP apiece.

The aerobic respiration past glycolysis requires oxygen and occurs in mitochondria. For greater energy production, it's essential. For cells with either huge stores of glucose or equivalent molecules (glycogen especially) or with low energy needs, just glycolysis and lactic acid production to restore NAD works fine.

So cells need energy, which means ATP. If they don't need much, they don't need mitochondria.

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So do animal/plant cells eaten by me reach my blood stream with their DNA intact? There's a big mix up in my head between fat cells and fat molecules, can you help me clear it up? (muscle cells don't pose such a problem because they break down into proteins and carbohydrates, but from my understanding fat remains fat)./quote]
Fat cells, or adipocytes, also contain DNA and protein and carbohydrates, but mostly they contain fat globules. Importantly, those fats come in many sizes, and breaking them down and building them up and moving them is a major metabolic process (and one that, when it goes wrong, causes many diseases). But no, fat doesn't remain fat. It's digested, broken down, transported, processed, transported some more, and reprocessed. It can be turned into things other than fat.

Do red blood cells use the oxygen they acquired in the lungs in order to move and exist or are they all one shot cells?

As Lilith says, they don't require oxygen and have no way to use it. They're "one-shot" cells in the sense that they can't divide anymore: not only do they lack mitochondria, they also like nuclei and DNA. But a red blood cell will usually last 3-4 months before degrading. They're not quite disposable.

DNA is necessary for making protein, but mitochondria are necessary for oxygen-based metabolism. As long as the proteins are already made in the immature cells before the DNA and nucleus are lost, the cell can live until those proteins break down. Red blood cells last for their few months based on those proteins. Platelets do too, but they also have mitochondria, so they can use oxygen to generate more energy.

—Alorael, whose explanation of getting infected by what you eat is going to be sketchy. Your gut is a continuation of your mouth and the outside of your body. To be infected, something has to get from the inside of your gut to the inside of your body. That doesn't happen normally; you have to either have a hole somewhere or the organisms that infect you have to have some way to make one for themselves. Some other things can live happily in your gut and produce toxins that make you sick, or in the case of some parasites latch on and feed directly from you.

[Lilith]

Originally Posted By: Y? Bcaus, IDK he's on 3rd & IDC

So how come some germs can pass the gut wall?

Foodborne bacterial and parasitic infections will generally hang out in your gut rather than actually entering your body as such. Viruses that you can catch through food, like hepatitis A, have specific proteins allowing them to force their way into the cells of the gut lining and enter your bloodstream from there, basically. There are also some weird edge cases like prion diseases where nobody really knows how the infectious agent gets into the bloodstream intact.

[Prince of Kitties]

Maybe prions don't. Most of them affect the nervous system, and the gut has an incredible amount of nerve tissue. Perhaps CJD and the like get to the brain via the enteric nervous system?

[Alorael at Large]

The enteric nervous system isn't actually inside the lumen of the gut. The prions still need some way to get inside cells. And since neurons don't pass proteins, generally, there's no plausible way for prions picked up by the enteric nervous system to end up in neurons of the central nervous system.

 

—Alorael, who thinks the real mystery is the fact that proteins aren't transported from the gut into cells. They're broken down into short peptides and amino acids first. The mystery isn't how prions get in, it's how they don't get degraded first.

[Prince of Kitties]

IIRC that's not true for all proteins and all people, though. e.g. gliadin (in wheat) manages to get into the bloodstream in some people (thus Celiac disease). Or have I got that wrong?

[Dikiyoba]

Originally Posted By: Miramor

Or have I got that wrong?

A quick glance at Wikipedia makes it look like the reaction happens in the small intestine, reducing the intestine's ability to absorb nutrients. The lack of nutrients causes the symptoms that happen elsewhere in the body.

Dikiyoba.

[Lilith]

Originally Posted By: Rary's Roaring Rural Aura

—Alorael, who thinks the real mystery is the fact that proteins aren't transported from the gut into cells. They're broken down into short peptides and amino acids first. The mystery isn't how prions get in, it's how they don't get degraded first.

From what I can gather, it looks like one of the current best guesses is that the misfolded prion might attract a coating of lipids, which both protects it from digestion and allows it to be taken into cells of the gut wall by endocytosis.

[Alorael at Large]

I didn't mean mystery quite as much as I meant first-glance oddity. Prions are very odd things, but my first question isn't so much how misfolded proteins cause problems. I can accept that. I can even accept that they somehow cause cascading misfolding. But the fact that they somehow get in, that's really what bothers me.

 

There are exceptions to pretty much everything, and yes, prolamins appear to be one of them. They increase the permeability of the intestines to allow more molecules (including themselves?) to enter circulation. From a very cursory look, it's not clear to me that this is problematic, except that then there's an inflammatory responsen in celiac disease that leads to damage to intestinal villi and malabsorption of nutrients.

 

—Alorael, who from even more cursory inspection of the literature will tentatively assert that the consensus seems to be that proteins resistant to the proteinases that would normally break them down tend to end up inducing transport across the blood-gut barrier anyway. There are some problems with that, but he lacks the expertise to explain anything at that level.

[Death Knight]

One of the things that I really just cant understand about tragedies like this is that it seems like people emulate when seeing other people do big things.

 

This relates to the fact that copy-cat joker events are coming up where people are either saying they might do something, or are doing something very much like what happened.

 

I understand that the human mind is capable of crazy things but it just seems a little bit extreme and if anything makes me wonder just how obsessed some people are with the joker character and differentiating between real life and fantasy.

[Cpt. Charles]

People have less inhibitions these days, it seems, and are saturated with violence on a daily basis. I suppose too, that some people just don't know how to control their anger or violent tendencies.

[Prince of Kitties]

I think we may actually be pretty inhibited, at least when it comes to violent impulses, compared to how we were in e.g. medieval or Renaissance Europe.

[Cpt. Charles]

I meant compared to perhaps 30 or 40 years ago.

[Sudanna]

Violent crime has been on the decline in the US for a long time. Something like thirty or forty years.

[Cpt. Charles]

Well I'm terribly misinformed. Sorry. Still, it is true that there is more violence in movies and games. Especially gory, graphic violence.

[Randomizer]

It's less that we are seeing it more and more that it's being reported and it's easier to use weapons with higher kill rates. 30 to 40 years ago handguns and knives were more common as the weapons of choice. 20 years ago you saw the rise of assault weapons and criminals wearing bullet proof vests.

 

I still remember news video of a California robbery where the thieves were armed with automatic weapons and body armor. The police broke into a gun shop to get similar weapons to respond after their issued weapons weren't enough.

[Harehunter]

Apparently, you don't need a firearm to cause multiple deaths according to CNN report.

 

I don't mean to say that one method is more or less heinous than the other. That there are people who make bad choices that cause the deaths of so many people at once is lamentable. There have been laws enacted with the purpose of preventing both of these mass murders. Yet there are still occurrences where people choose to violate those laws. So the question is this: In the wake of people who chose to break laws already in place, will more laws make us more safe?

[Goldengirl]

I hate to shift the topic from gun control, but I felt like there are more issues that deserve discussion here. This article discusses the backlash a comedian got to a joke he made about the shootings. I want to know what people here think about such jokes and how appropriate they are.

[Enraged Slith]

The purpose of comedy is to entertain, so it really comes down to whether or not your audience will appreciate the humor. In this case, most people would probably agree that it was in really bad taste (and not funny enough to justify the backlash).

[Randomizer]

People will almost always say something inappropriate. Part of it is context and placing it out of context makes it worse.

 

Arizona had an idiot lawmaker who blamed the shooting victims for not being armed and attacking the shooter. As if it helped at Fort Hood where it was soldiers being attacked. The problem seems to be that warning signs are ignored or worse deliberately ignored for other reasons.

[Lilith]

Originally Posted By: Randomizer

Arizona had an idiot lawmaker who blamed the shooting victims for not being armed and attacking the shooter. As if it helped at Fort Hood where it was soldiers being attacked. The problem seems to be that warning signs are ignored or worse deliberately ignored for other reasons.

i can see pretty much no circumstance in which more people opening fire in a dark theatre would improve the situation

[Rowen]

Originally Posted By: Lilith

i can see pretty much no circumstance in which more people opening fire in a dark theatre would improve the situation

That's a good opening for a joke, but it would be inappropriate.

[Alorael at Large]

At the risk of tastelessness, I'll suggest that if you pack a theater with exactly the right people you can guarantee a good outcome. But that would be undervaluing human life and it would be wrong.

 

—Alorael, who's envisioning time travelers depositing all the worst villains of history in a theater. Eventually the lives saved might outweigh the lives lost, but then the good utilitarians have to weigh the consequences to the timestream.