New answers tagged

-1

Terminology is what is holding you back. What chromosome implies depends on context, i.e. is it replicated or not. In Meiosis. Gametes arise from Germline cells that have 23 PAIRS of chromosomes. That means, that while there are 23 different chromosomes they come in doubles/pairs. This is the typical X like shape we think about when we hear chromosomes. ...


-1

I refer the honorable gentlemen to James Harriet. He reports discovering by accident by ending the pain he was in some cases able to reverse the pathology by ending the pain with anesthetic drugs, thus allowing the body's natural healing abilities to take over. He first discovered it in a sheep by accident (insufficient dose to put it down) and later used ...


0

Roller coasters release adrenaline, a chemical that is released when your body thinks it's in danger. It strengthens your body so that you could fight of flee. However, since a roller coaster is not actually dangerous, your body just feels strong and good. Your body also releases endorphins during roller coaster which makes you feel good.


2

For babies there is certainly a formula available for a complete menu for survival: formula* Here are the nutrition facts from Nestlé's "Good Start": Formula nutrition facts. source: Nestlé Comparable lists are available for people that cannot eat normally (e.g. people in a comatose state) and are fed enteral or parenteral nutrition. *. Remember ...


5

There are two different aspects to or drivers of thirst, osmolality and hypovolemia, with plasma osmolality elevation being the more potent stimulus of thirst. As stated by @arboviral (and supported by his link), not a lot is known about the mechanisms of immediate thirst satiety. Much more is known about the mechanisms causing thirst, and the mechanisms of ...


-3

I'd say the answer is easy. Since the whole body is one body all you need is the change of of water saturation in a part of you to determine / extrapolate how much water has been ingested. We all came from the water and are mostly made out of water. So it's not like water is a foreign substance and we needs special receptors in order to determine water ...


3

Satiety is divided into pre-absorption and post-absorption - the mechanism you're asking about is preabsorption satiety, which as you point out occurs long before the water can be absorbed into the bloodstream and appears to be remarkably accurate. The receptors and underlying mechanisms of pre-absorption satiety are not fully known but are thought likely to ...


0

At room temperature, Nail bed . It's not about survival. Those cells have a low growth rate. Other cells in bones may 'live' longer but harvesting bone marrow in decaying animals has not been done. If you freeze cells, they can last decades.


6

This is not an area I know well, but I'm familiar with a couple of studies that have tried to estimate the heritable (genetic) component of homosexuality in humans. A review paper by Rice et al (2012) points out that: Pedigree and twin studies indicate that homosexuality has substantial heritability in both sexes, yet concordance between identical twins ...


-2

Plants use both water and air as food using photosynthesis where water is split and recombined with carbon dioxide from air to make glucose. Overall, the chemical reaction of photosynthesis is as follows: Light energy + plant enzymes 6CO2 + 12H2O ------------------------------------------------> C6H12O6 + 6O2 + 6H2O ...which means that it takes six ...


2

You don't get energy from breaking chemical bonds, you only get energy from making chemical bonds, while breaking chemical bonds requires the input of energy. However, in practice chemical bonds are always broken as others are formed, and the net number of bonds is generally constant. Otherwise you would end up with free radicals, which are highly reactive ...


2

I am no expert in this but I had asked my doctor the same question the last time I fell sick and I'll try to paraphrase his explanation. "There is this protective lining on our respiratory tract called "Respiratory Mucosa" that acts as the first line of defense against pathogens. But when you consume cold food and beverages , this membrane gets congested or ...


2

My previous answer was to the original question which focused on red blood cells which do not contain DNA. Now the question has been revised to focus on tissue transplantation, where the cells do contain foreign DNA, my amended answer deals with a couple of the points raised, but only briefly with the question of identification. Incorporation of foreign DNA ...


0

First off, AOZ has a wonderful page about titanium alloy uses in medical applications you should read and that most of my info is coming from: Suitability of Titanium for Implant Purposes I think you're having a couple of easy to correct misconceptions. First, titanium alloys are used for medical implants and replacements because they're lightweight, ...


0

It's very complicated to know how a trait would have been selected for or against in the ancestral environment. Tendency to gain weight does seem to have been selected for in some populations - e.g. pacific islanders. Presumably the decreased chance of dying from starvation was enough to compensate for any increased risk of heart disease, if in fact health ...


0

I believe the answer is no. Sweat is the liquid secretion of body cells, not including the cells themselves. If the cells are secreted when sweating, then you may find some DNA in your sweat. You are right on that. Serum contains many different types of lymphocytes, the majority of them--mature red blood cells, don't have nucleus. So they don't contain DNA. ...


3

The Wikipedia page you linked says that sweat is composed of a liquid similar to blood plasma. As all DNA in humans is stored in the nucleus of a cell, it seems unlikely that the sweat itself would contain any DNA. However, when someone sweats significantly, I can't imagine that no skin cells end up in the sweat. In any case in which this occurs, then the ...


1

I believe what you're describing is referred to as ectogenesis which is essentially developing a fertilized egg inside an artificial womb until it’s able to survive outside the controlled environment. So is this possible outside of science fiction? To answer this we have to compare the stages of human reproduction and how close today's science and technology ...


10

Generally, cold suppresses sweetness. As an example, consider soft drinks that are usually served cold: they taste sweeter when warm (like you said with your examples of drinks). Our taste receptors send a stronger signal to the brain when activated by warmer substances and so the perception of sweetness, in this case, is lessened when we consume cold food ...


1

I found an article (1) which may help you understand what happened on your tongue: Light cooling from 37 to 21°C of beverages increases your sweet taste adaption, but not actual sweetness of your drink! Another article (2) states, that a certain receptor for sweet taste perception is heat-activated. So I guess there is no universal rule for any drink, you ...


2

A couple of quick google searches would tell you that the important part of sleep is the REM (Rapid Eye Movement) sleep. REM stands for rapid eye movement. During REM sleep, your eyes move quickly in different directions. That doesn't happen during non-REM sleep. Usually, REM sleep happens 90 minutes after you fall asleep. The first period of REM typically ...


3

I think the reason is primarily, that it is more quiet (the chance is very low that other people are disturbing your sleep) in the night as well as it is also dark. Keeping in mind, that the brain "gets tired" due to some proteins (melatonin) and in contrast, being more awake during the day, it seems to be just logical that the sleep in the night is ...


1

Adding to @David's answer, there has been some recent work looking at Neanderthal DNA in the context of Denisovan and modern human populations. David Reich's group [Sankararaman et al. Nature 2014] found Neanderthal-derived alleles in genes that affect skin and hair (specifically keratin filaments), as well as some that confer risk of disease. Another cool ...


1

There was a very readable piece on this topic by Chris Stringer in Nature in 2012. At that time his general conclusion was: It is not yet clear whether the archaic DNA many of us carry is tied to any visible traits. Although he added: More controversially, some of the known differences in coding DNA between Neanderthals and recent humans are ...


1

Similarities Despite major overall differences, there are some basic similarities in the two processes: Light energy excites an electron to a higher energy level. A covalent bond is broken as the electron moves elsewhere. This process is called ‘photolysis’ and is purely chemical. Differences The difference is in what happens to the excited electron ...


17

Human female cells contain most of the genetic information required to make a male, but they do not contain a critical component: The Y chromosome. This is a relatively small chromosome. Wikipedia claims we have identified around 200 genes on it to date, compared to estimates of 20,000 - 25,000 genes overall in the human genome. Importantly for your ...


2

I found this research paper (pdf) by D. Roger Illingworth, William S. Harris, and William E. Connor (Journal of the American Heart Association, 1984) that offers some help. Its abstract says: Diets rich in omega-3 fatty acids derived from fish oils lower the plasma concentrations of low density lipoproteins (LDL) and very low density lipoproteins in ...



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