Category: Science

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.

Where did the first bacteria on earth come from?

Answered Dec 16, 2017

Thanks for the A2A.

The answer is (drum-roll, please…)

Nobody knows.

It was a really, really long time ago.

Perhaps, somehow, a little bubble in the water on a beach got some amino acids and nucleic acids (specifically RNA) into it. Those molecules may have formed from water (containing various stuff dissolved in it) dripping onto a rock that heated and cooled off each day.

Perhaps it arrived, frozen in the ice of a comet or meteorite, from some other planet.

Nobody knows, and there is probably zero way for anyone to ever know.

That sounds kind of “zen”, doesn’t it?

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.

What would the earth be like if there are no bacteria to decompose animal and plant remains?

Updated Feb 6, 2018

Those are called saprophytes, although there is a wide range, and some fungi also perform this function.

If no decomposition was happening at all, then the nutrients wouldn’t be available for recycling into plants, so my guess is that all other life on earth would eventually starve. It might take awhile.

Also, partly decayed plant and animal matter is among the things consumed by worms, insects, etc, so it would disrupt the food-chain / food-web from that angle, as well.

Edited To Add: Another group of bacteria whose absence would be disastrous are the participants in the nitrogen cycle, because all plants need nitrogen in a form that is generated by those bacteria.

Edited To Add Again: I recall reading an article stating that, plant matter (fallen leaves, etc) near the Chernobyl nuclear disaster site wasn’t breaking down as normal. If true, that suggests that, the radiation has harmed a range of saprophyte bacteria and fungi. This could have a sort of secondary impact on the ecosystems there, for future plants and animals.

Could chemicals be used to mutate strains of bacteria and/or fungus and/or viruses?

Answered Dec 13, 2017

Sure, you can use certain chemicals to cause genetic mutations.

The catch is that, the mutations will be totally random, and you cannot direct it to any particular part of the genome.

You could randomly disable important genes, by causing a SNP or a frameshift error, and kill the microbe.

The keyword is, “random”.

Why do hand soaps say they clean 99.9% of bacteria and not 100% or 95.6% for instance?

Answered Dec 12, 2017

All of that is advertising hype. Don’t worry about any of it. Just use the cheapest regular soap that you can get at your local supermarket.

The whole “antibacterial” claim is rubbish.

From a microbiologist perspective, these “antibacterial” products are a bad thing. (long, scientific story).

Just buy whatever soap is the cheapest, and which your skin feels OK about.

What is the best textbook on medical microbiology?

Answered Dec 12, 2017

I have used Medical Microbiology by Murray, et. al.

With these textbook recommendation concerns, I suggest going to your university library, and looking at what they have on the shelf (or in the library catalogue). Especially see if they have multiple copies of a certain book. That will often be the one that your lecturers/professors are working with.