Why don’t people dying of thirst drink the sea water if it’s the only choice they have?

Updated Aug 14

It isn’t the “only choice” to drink sea water. The other choice is don’t drink it.

The problem is, the delusion that, any liquid will re-hydrate you.

The reality is a principle called “osmosis”.

Try drinking some saltwater. Really, I mean go ahead and do that. I suggest 2 heaping tablespoons of table-salt, in 2 litres of water. You will want more than 2% w/v of saline in the water. Spike it with a little orange juice to try to keep from vomiting. Try to get it down within an hour or two.

Then, you will RUN to the toilet, and rapidly dump the contents of your guts, with every meal that you had in the last several days.

You will also be dumping large amounts of water. Some people do this as a purgative/laxative process.

If your only supply was seawater, and you consumed it for several days, this can kill you.

Osmosis starts with a membrane, that allows some things through (like water) but not other things (like NaCl table salt or sea salt).

The salty water (with high concentrations/amounts of NaCl salt in it) will actually suck water out of the cells in your gut. Salty water sucks fresh water out of your body.

Some sodium may be absorbed by your gut, and your kidneys will also be working overtime, trying to get rid of the excess.

Another fun fact is that, poor hydration can happen with high-sugar liquids. Again, it is about the high amount of solutes (stuff floating around in the liquid) compared to solvent (the water). I have encountered rest-home staff who didn’t comprehend this, and didn’t care, as they shoved high-sugar juice at elderly people with weak kidneys.

Also, drinking your own urine in the desert sounds badass, but is actually a terrible idea, due to the sodium and urea in it.

What needed more energy, the secretory cell or the sensation cell?

Updated Jul 1

When a nerve cell fires, it depolarises its plasma membrane (in a wave, which is how the signal travels down the length of the cell). Then, it has to repolarise the membrane (using the sodium-potassium pump, which uses a lot of energy) before the next firing. A very large percentage of your body’s glucose is used by your brain.

On the other hand, a secretory cell is, by definition, sending out products and materials. Those products take energy to assemble, and then they are spewed out, and cannot be recycled.

A secretory cell will have a lot of carbon and carbon skeletons leaving its system, as they are assembled into final products. It will need a lot of energy (in terms of burning glucose, etc) in order to disassemble, and then reassemble, and export more of these things.

Every time a cell assembles something (down to just each residue in a peptide, or each 2-carbon unit in a fatty acid) consumes an energy unit, and burns an ATP.

Secretory cells also need a large number of Golgi stacks and other export machinery. Plus, raw materials like amino acids need to be replaced, so the cell will be using energy for importing from the environment

So it’s hard to say. Maybe it depends on how active the cells are at that particular moment.

What is the most primitive organism living today?

Updated Jun 8

If they are alive on Earth today, then none of them are primitive.

Every species currently existing is a product of billions of years of evolution.

A small, relatively simple, single-cell microbe species will be highly adapted to its particular environment. They can thrive just fine, live out their lives, create progeny, etc.

They replicate very rapidly, and, as a species or a strain, can adapt fairly rapidly to changes.

A species can even evolve by simplifying itself. If you live in an animal’s gut, you might lose the genes to make certain molecules which are plentiful in that environment. You would actually become more efficient, and thus, more evolved.

Unicellular organisms may seem “primitive” from a very basic view, but they start looking very complex when you look closely enough. This applies to individual cells, and to populations of individuals interacting with each other.

It’s very much about context.

There are plenty of single-celled bacteria and archaea which thrive in environmental conditions which would kill a human very quickly and painfully.

From humans’ perspectives, microbes may seem primitive and inferior. From some microbes’ perspectives, humans are clueless, enslaved providers of food, shelter, and transportation.

Perhaps one of the most “primitive” organisms on Earth are those zombies who devote their biological structures, processes, energy, and time, to alternately watching reality television, and then compulsively staring at their phone to scroll through FaceBook.

Why is it so taboo to support eugenics?

Updated May 4

The taboo is overtly around the issue of coercion.

If you use the word “eugenics”, some people (as seen in this discussion) have a knee-jerk reaction, and automatically think “Nazis”. They think about targeting whole ethnic groups, or killing people, or forcible sterilisation.

However, I think some of the discomfort is really about the issue of people being encouraged to make their own rational choices, and exercise thought-out, responsible control over our lives and our bodies. That doesn’t sit too well with the majority, who view having children as something that just automatically and randomly “happens” to everyone.

The truth is, humans and other animals engage in large-scale selective breeding for fitness (including intelligence) all the time. It’s perfectly normal.

Some people get nervous when there is new technology involved, and explicitly stated selection:

Genetic Counselor: “Well, Mr. and Mrs. Smith, we have tested your (alleles, single nucleotide polymorphisms, scary scientific sounding stuff, etc), and I have some bad news. If you were to have a child, there would be a 50% chance of a devastating genetic disease, with nothing but misery and pain for said child, and for you.”

Couple (in unison): ”Bummer. We better not have any kids.”

Or it can go the other way:

Crackly Voice From Speaker: “Hi! Welcome to Jolly Jism Drive-Through Sperm Bank! May I take your order?”

Customer: “Yes, I’d like the Rocket Scientist with Olympic Champion… Healthy, tall, blond… Clean family history for cancer or mental illness.”

Crackly Voice From Speaker: “Excellent choice! Would you like a side order of artistic talent?”

Customer: “I’ll take the classical piano playing.”

Crackly Voice From Speaker: “Great, I’m whipping up your fresh hot sample right now! Please drive forward to the pickup window.”

And people do it in a more casual way constantly:

“Ewww, that person is stupid (or has any characteristic that repulses me), and I can barely stand to interact with them, so I certainly would never consent to having any kids with them.”

Some individuals are already pushed entirely out of the breeding pool, simply because they have characteristics which lead to being persistently rejected for sexual opportunities. They don’t have any “right” to produce children when they can’t find any willing mates.

Government force is already used to some extent, via the criminal justice system. One effect of imprisoning criminals is that it removes them from the breeding pool, either temporarily or permanently.

In the book, “Freakonomics”, the authors talked about the impact of abortion (specifically legalisation in the US) on subsequent crime rates. Maybe the reason why you weren’t mugged and killed in 1995, is because your assailant was aborted back in 1975.

I would also expect that the benefits expand, because he also won’t be using law enforcement or prison resources, or fathering another generation of low-functioning street criminals. And his sister, who was aborted a few years later, also won’t be contributing to the current generation of criminals, or to multi-generational poverty and welfare dependence, recycled by low-functioning people.

Some individuals may have an honest self-assessment that, “Me having children wouldn’t benefit anyone. It would be stupid and irresponsible, and a general, long-term disaster. So therefore, I won’t have any children.” This could range from medical history, to lacking financial resources, to simply having other priorities in life.

People who are considered conventionally “attractive” are really displaying good reproductive fitness. This can range from wide hips to get a large baby’s head through, all the way to financial status symbols. People with those characteristics will receive more attention and opportunities for mating, including with other people of high reproductive fitness.

People who get upset about all of this may just be worshipping fertility. Without caring about the suffering caused by low-functioning people producing children whom they are not equipped (mentally, behaviourally, financially) to raise in a decent manner. This includes some of those low-functioning parents actively inflicting the biological disaster by using alcohol and other drugs while pregnant.

A large portion of the people who are pumping out kids do so with exactly zero rational decision-making, self-control, or actions→consequences thinking.

And that is why the film, “Idiocracy” is gradually coming true. Mass collective bad behaviour leads to mass collective bad results, including on those of us who are not engaged in that bad behaviour. The alternative to eugenics is a default to dysgenics.

In order for phagocytes to consume pathogens, they release pseudopods to engulf the pathogen. How do phagocytes do this, do they have some kind of muscle or is it something within the cytoplasm?

Answered Jan 26

Pseudopodia are sort of like fingers that form and sort of blob out of the surface of the cell that is making them.

Inside the cell, there is always a sort of girder-like supporting structure/network called the cytoskelton. This gives the cell physical support and shape, a bit like a person’s skeleton.

However, the cytoskeleton can grow or shrink very quickly, and can be made to grow in a certain place and certain direction, as needed.

The cytoskeleton is partly made of a building block called actin. It is a protein that can be stacked into long strings. Stacking it in a certain way causes the pseudopod “fingers” to poke outwards. Kind of like growing a new arm, just because you needed one at that moment.

Later, the actin filament gets taken apart, and the pseudopod shrinks back.

In your muscle tissues (where the components are more fixed in place), actin is partnered with another protein called myosin, to do contraction (pulling). There, the strings sit there parallel to each other, and contraction is a sliding motion (the chemical and mechanical actions are somewhat complicated).

In the phagocytes, there is a further process called (strangely enough) phagocytocis, in which your cell pulls in the pathogen, and puts it into a vesicle (like a bag) where the pathogen is dissolved by enzymes. This involves proteins on the cell surface pulling a small area inwards, to form the vesicle.

Some other cells, like amoeba stages of some single-cell protozoa organisms can also use pseudopodia to reach out and pull themselves along (similar to crawling).

Could a carnivorous plant as large a Audrey II from “Little Shop of Horrors” actually evolve (non sentient, of course)?

Answered Dec 24, 2017

My guess is probably no.

A carnivorous plant that large would also need to trap large quantities of animals, which is rather difficult for an organism that is passively anchored in one place.

If it was relying on insects randomly walking into the trap structures, I expect that it wouldn’t get enough of them to add up to a sufficient total volume of food.

If it was relying on small mammals for food, there would also be a problem with both the numbers/volume issue.

Also, mice, etc, are stronger and have much more advanced perception and larger brains than insects. They would be more able to avoid the trap. They could learn from a previous near-miss (as they apparently do with regular mouse-traps). They might also develop an aversion to the scent of the plant (e.g. the pool of digestive fluid inside a “pitcher plant”).

What is the best YouTube channel to study microbiology?

Answered Dec 20, 2017

Thanks for the A2A.

On YouTube (or the internet in general), there isn’t just one single resource that I can recommend.

However, I have a page of links for science students (of all levels) at:

Links For Science Students

Please excuse the formatting, as I still need to work on that. However, these are the best links that I have found so far, and are somewhat categorised by field of study, with a few comments.

This page will improve in the near future, but generally, these are the links that I have appreciated, for biology, biochemistry, chemistry, mathematics, and , of course, microbiology.

What would happen if there were no plants on earth?

Answered Dec 18, 2017

I am guessing that you mean, “If all the plants disappeared right now”(?)

All humans and other terrestrial animals (e.g. livestock like cattle and chickens) would starve to death. Most people would be dead within a year, from immediate shortages, and competition/conflict over dwindling resources.

Anyone living longer would need to have stockpiles of grains, rice, canned goods, or other long-shelf-life food. They would still die when that ran out.

On a very long-term scale, the atmosphere would change, due to the lack of CO2 uptake, and the lack of O2 being pumped out.

All animals (including carnivores) are directly or indirectly dependent on plants.

On a more positive note, many of the bacteria, archaea, and fungi would still survive, although the balance of particular species would gradually change with the new environmental conditions.

What are the causes for cancer cells to behave differently from healthy ones?

Updated May 11, 2018

Basically, it tends to be a buildup of many genetic mutations, over time.

For example, you could be exposed to industrial chemicals, cigarettes, or even substances from normal cooked hamburgers, which cause mistakes when your cells divide, and are making a new copy of your DNA.

Also, you could be exposed to too much UV light (e.g. from too much time outdoors in the sun), and that can damage your DNA, causing problems with making the new copies.

Eventually, enough mutations can happen that, a cell gets out of control.

That cell can start replicating very rapidly, making more copies, with even more mistakes, because its control mechanisms are broken.

The chromosomes (with your DNA) gradually get more disorganised, due to the copying dysfunctions. A cell could end up with many more chromosomes than the usual 46, and can mix up the pieces that belong on different chromosomes. You can end up with super-large chromosomes, and even circular chromosomes.

It is kind of like taking an encyclopedia with 46 books, and then randomly changing some words, and swapping chapters and pages.

Some situations like this would just cause the cell to die, and that is the end of the matter.

With cancer, the cells have mutations that make them more efficient, in terms of growing fast. This also makes them hungry, and they can send signals to surrounding tissue to grow more blood vessels to feed to tumour. This way, a tumour can pull a lot of glucose and other nutrients towards itself, at the expense of the rest of your body, out-competing your healthy cells. This is part of how cancer can be fatal to the person. In the past, I have cared for a couple of terminal cancer patients, and it is painful for all involved (but much more painful for the dying person).

Healthy cells are “differentiated” (programmed to be a certain type), which is why some are liver cells, or skin cells, or muscle cells, or nerve cells. However cancer cells become less specific, in their genetic expression, their structure, and the substances they produce.

All of your healthy cells (except red blood cells) have a full copy of your DNA genome, but only some genes are permanently turned either on or off, depending on the type of tissue. This set of on/off switches (technical terms: C-methylation and histone-acetylation) is why your tissues and organs are different to each other. In cancer cells, the on/off mechanisms are broken.

Healthy cells tend to have a certain useful life, before they die (and are recycled by the body). Also, there is a process called “apoptosis”, which is programmed cell death, and can happen when a cell is damaged, and can stop the mutation problem right there. However, cancer cells also have this mechanism broken, and so they just keep living and replicating. As long as they have food, the right temperature, pH, etc, they are “immortal”.

Cancer cell lines used in scientific research (such as HeLa) have apparently changed significantly over time, and different variations exist. But they are still undifferentiated and immortal.

Are there any study to design bacteria so they can produce all essential nutrients by photosynthesis?

Answered Dec 15, 2017

Thanks for the A2A.

The answer is “no”, because photosynthesis is about using the energy from sunlight, to help use carbon dioxide as a building-block to put together sugar molecules, which are made of carbon, hydrogen, and oxygen. Those sugars function as energy storage (which is how plants survive every night), and also as building material, which is how plants grow new stems, leaves, etc.

Some bacteria can do photosynthesis for sugar-assembly, but there are many other essential nutrients.

If the organism has the necessary enzymes, they can use certain “carbon skeletons” (including acetyl-CoA and Krebs cycle intermediates) as building blocks for lipids and part of amino acids.

However, it still needs to get certain other, vital things from the environment (which cannot be generated by photosynthesis, either by bacteria or by plants).

It needs things like:

Nitrogen

Phosphorus

Sulphur

Iron

Magnesium

Those need to be obtained from the environment, which can be anything from the jelly-like medium in a petri dish, based on various recipes, by microbiologists (ahem), to just the regular, random soil in your backyard (different places support different microbes).

Another commentator seemed to interpret your question as being about food for humans. And the answer on that is “no”, because your food needs to get the above-listed nutrients from someplace that isn’t just photosynthesis.