All Questions

2
votes
1answer
49 views

methods for targetted deletion of genomic regions?

I would like to know what are currently used methods for targeted deletion of genomic regions in mammalian organisms or cell lines. I have heard of Zinc-Finger nucleases as a recent genetic ...
6
votes
2answers
409 views

How do cells “know” what “type” to differentiate into?

I have been reading about Townes and Holtfreter's work in 1955, in which cells are dissociated from a blastocyst in an alkaline solution then mixed together and spontaneously reaggregates based on ...
9
votes
3answers
116 views

Adipocyte Density

People who are overweight and wish to lose weight, often do so because they are concerned about looking too big. Their increased size is attributed to an increased volume of fat. When people try to ...
19
votes
3answers
22k views

If the brain has no pain receptors, how come you can get a headache?

I've read many years ago in books, that the brain has no nerves on it, and if someone was touching your brain, you couldn't feel a thing. Just two days before now, I had a very bad migraine, due to a ...
4
votes
2answers
71 views

How are there multiple varieties of the potato?

The potato appears to propagate by growing an 'eye'/'bud' which eventually grows into a new plant. So there would probably be single representative of the potato species in the world with all others ...
10
votes
1answer
152 views

Does sleep in humans re-structure based on the expected sleep time?

I've read about anecdotal evidence that human brain has a fairly good internal clock that can be used to judge the amount of time that has passed. I'm wandering if there are any mechanisms in the ...
2
votes
1answer
124 views

How stable is in vivo whole cell patch clamping?

For a head fixed animal, how stable is the current state-of-the-art whole cell recording from a cortical neuron? The animal's breathing, and heart beat must move the neuron relative to the recording ...
6
votes
3answers
1k views

Why do grapes not shrink when placed in strong sugar solution?

I tried an experiment. First, I placed grapes in pure water(hypotonic solution). The grapes burst because of endosmosis. Then, I placed new set of grapes in strong sugar solution(fully saturated) but ...
3
votes
2answers
195 views

Do Yeast Insertion constructs revert?

If I insert a new gene with a yeast integrating plasmid and select with a drop out culture once, can I assume that the newly integrated gene will stay in the strain without putting selective pressure ...
1
vote
2answers
261 views

How are different types of cells created from zygote?

In the process of mitosis that starts from zygote, how do different cells appear? What happens that some cells become one type and some another? For example, is there a cell that divides into a ...
1
vote
1answer
55 views

Arabidopsis thaliana RCSB active site gene mutant

I'm looking for an Arabidopsis thaliana gene listed in RCSB with a clear mode of function and active site. In addition it needs to have an obvious phenotype when knocked out like severely retarded ...
1
vote
3answers
85 views

Are all healthy animals more likely to defecate near the end of a rest-cycle?

Just what the title states. It stems from observation & personal experience that a person/dog/cat/monkey is more likely to relieve oneself immediately after it wakes up from the peak-sleep cycle ...
20
votes
5answers
374 views

Are there any substance that are more dangerous at low dose than at higher dose?

It is commonly admitted that The dose makes the poison which means as a person, the more I take a substance, the more risk I take for my health. There is even an indicator called LD50 (see ...
9
votes
2answers
188 views

Is there life on other planets and if so how frequent?

Some shed tears of joy as the news about the successful landing of the Mars Rover Curiosity came in. Then the most comprehensive 3D map of our observable universe was published. 2012 is literally an ...
6
votes
1answer
438 views

What causes the characteristic 'gleam' in the eye of a living being?

The title is pretty much what I seek to know. Unless the other person is play-acting, one can often make out the eye of a living person has a shine-of-life to it; a cadaver does not. Similarly the ...
6
votes
2answers
1k views

How are babies born without a brain?

In the United States, anencephaly occurs in about 1 out of every 10,000 births. There are several forms of this condition, wherein the forebrain is absent. The forebrain is host to most of the higher ...
2
votes
1answer
402 views

Are there any multi-cellular organisms out there that do not sleep?

Looking around I see animals - ants, bees, birds, lizards, roaches all the way up to humans appear during a part of the day and not other parts. I would guess there is a sleep/recovery cycle involved. ...
4
votes
1answer
4k views

Does mixing alcoholic drinks really make you more drunk?

There is plenty of anecdotal evidence ("beer after wine and you'll feel fine, wine after beer will make you feel queer") that mixing alcoholic drink types leads to a stronger effect, but I can't find ...
11
votes
2answers
1k views

Why do neurons have only one axon?

I have just learnt about neurons. I wonder why neurons have only one axon. Can they transmit nerve impulses faster and more rapidly when they have more axons? Does having more axons help in ...
3
votes
1answer
216 views

Why do carrots spoil so fast?

The carrots we buy from a supermarkets spoil very fast, albeit giving many consumers a false sense of preservability due to their structural rigidity. The answer extends to many other vegetables many ...
5
votes
3answers
1k views

Why are antibiotics prescribed with a viral infection like a cold?

I've heard both ways; people going to the doctor for a cold and then getting a prescription for antibiotics and those that go to the doctor and told they have ride it out because it's a viral ...
4
votes
2answers
74 views

What are some of the immediate challenges to break through before finding a cure for mad cow disease?

What are the immediate challenges to break through in seeking a cure for mad cow disease? I know that mad cow disease has no treatment as of yet.
10
votes
1answer
283 views

How can an albatross stay airborne for months?

Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes. They range widely in the Southern ...
8
votes
2answers
2k views

Use of amino-acid sequences versus use of nucleotide sequences in phylogenetic analysis

Reading a paper about gene evolution, I see that they do phylogenetic analysis for bacteria using protein sequences. They take the method from another paper. I can suspect that amino-acid sequences ...
12
votes
1answer
264 views

Can DNA act as a translation substrate?

I get conflicting answers. One would think if it was true, it would be rather seminal and widely known. There are papers from Khorana[1], Holland[2], and Bretscher[3] (late 60s) that suggest that it ...
1
vote
3answers
271 views

Do Viruses produce a biomagnetic field?

From wikipedia: Biomagnetism is the phenomenon of magnetic fields produced by living organisms. The present scientific definition took form in the 1970s, when an increasing number of researchers ...
7
votes
3answers
19k views

What is the difference between an antibiotic and an antibacterial?

Concerning medicine, what are the differences between antibiotics and antibacterials?
3
votes
1answer
67 views

How can chromatin state be measured?

I have some RNA-Seq data and I'd like to align it to the physical genome and see which sections of chromatin are geometrically open and being transcribed. The data are already sequence-aligned, and ...
4
votes
1answer
357 views

Why did mammals evolve to have two testes?

What makes mammals tend to evolve to have two testes?
6
votes
2answers
494 views

Can female Drosophila melanogaster lay eggs without males?

Can female Drosophila melanogaster lay egg without males? I maintain our lab stock but find a line that seems to have all females (or all males). In the vial, I see some eggs laid, but the flies ...
7
votes
3answers
8k views

Why do I smell flowers after sneezing?

Often when I sneeze, I smell flowers for a few seconds afterwards. I've done some searching on the internet, and apparently it's something that is at least not entirely uncommon, although the exact ...
11
votes
1answer
277 views

What elements are a possible basis for life?

I've been told that life on earth is carbon-based, Then I got curious about one thing: What are the possible bases for life and under which circumstances could lifr based on other elements exist? If ...
5
votes
1answer
82 views

In which way would the yeast cell cope with the excess amount of methionine in the growth media?

I guess that when there is surplus of methionine in the cell it is incorporated in the TCA cycle as a succinyl CoA, with cysteine as a by-product. But now the cell has the surplus of cysteine. What ...
3
votes
1answer
154 views

Can a person die instantaneously from internal damage to the brain?

Given the human heart is autonomous, can a person die instantly from internal damage to the head/brain? I would expect the heart to continue to pulse until it ran out of energy ... My contention is ...
7
votes
1answer
45 views

circulating microRNAs are functional?

In plasma and other body fluids, miRNAs can be found. They not only originate from dying cells but also from active secretion and are usually 'packed' into vesicles/lipo-proteic structures (i.e. ...
6
votes
1answer
276 views

Why is membrane potential not zero at equilibrium?

For the squid giant axon, the membrane potential computed by the Goldman equation is -60mV. And the Nernst potentials are (the differences between the K+ and the Na+'s Nernst potential and the ...
8
votes
1answer
3k views

Do humans sneeze or cough in their sleep?

As far as I know, I've never seen anyone sneeze or cough while they're sleeping. Google wasn't very helpful either; a lot of contradicting claims. So the questions remains: do humans sneeze or cough ...
1
vote
0answers
41 views

Can we make any judgements about sleep or readiness to sleep from a heart rate metric and/or pulse oxymetry?

I'm looking at inexpensive and un-intrusive ways to quantify the state of human body/mind . One of these is Actigraphy, which is a study of human motion over time. This can be done with an iPhone ...
2
votes
0answers
262 views

Can the sleep/wake cycle be influenced by non-visible spectrum electro-magnetic radiation?

I've been reading a few papers on Melanopsin and Suprachiasmatic Nucleus (SCN), and see that the sleep/wake transition is ...
4
votes
1answer
267 views

Are there any intersections between the biochemical pathways of uracil biosynthesis (or metabolism) and methionine degradation in eukaryotes?

Is there any way in which uracil biosynthesis or metabolism could help cell in degradation of toxic levels of methionine?
0
votes
1answer
190 views

Is there sufficient evidence that human cells are not intelligent? [closed]

Being structurally composed of one or more cells, which are the basic units of life. Yet within a cell, there seems to be the same behaviors that define life: Regulation of the internal environment ...
2
votes
1answer
120 views

How are memories stored in the brain?

I've been thinking about this for a while and I can't figure out how a memory can be stored in the brain. I understand that important memories are favourably retained, such as a near death ...
4
votes
1answer
139 views

Tool use by animals: research history

I was under impression that data about quite a lot different species using different tools is a fairly modern phenomenon, i.e., all of the research is fairly recent. Around 50 years ago it was ...
3
votes
1answer
80 views

How can GMO contaminate biologic plants?

Let consider two use cases : I am the only farmer within a 200km radius. I first grow GMO plants. A few cycles later I decide to grow bio plants, so I uproot all of the GMO plants and plant fresh ...
4
votes
1answer
296 views

In the vacuum of space would death be instantaneous?

I was arguing with my colleague about this matter (I'm not going to mention which side I fall on). Would death be immediate in the vacuum of space? For example, if I was suddenly teleported into the ...
6
votes
1answer
227 views

What is the effect of garlic on intestinal flora?

Now that we can compare whole microbiomes, has there been investigations on the effect of garlic (or diallyl disulfide, its main ingredient) on intestinal flora? From the proven antimicrobial ...
4
votes
1answer
103 views

Does culling badgers restrict the spread of bovine tuberculosis?

The British government has announced that it plans a large-scale badger cull which they argue are implicated in the spread of Mycobacterium bovis - so-called bovine tuberculosis. Any cattle that ...
2
votes
1answer
81 views

How to build S16 rRNAs phylogenetic trees?

Here is what I know so far: Multiple copies are present in prokaryotes, but according to a paper by Lukjancenko el al.[1] it is enough to select the most similar ones. There are stem regions in the ...
6
votes
1answer
650 views

What is the life-span of the various organs in the human body?

It is possible for a person to donate the harvestable organs (kidneys, eyes, and such) posthumously. Let's assume for a moment that the technology exists to kill rejection, and maintain the organ in ...
3
votes
1answer
260 views

How are melatonin levels measured in humans?

I'm wondering how it is possible to measure diurnal variations of melatonin levels in humans. I keep reading that there should be a large difference in amplitude between melatonin levels measured at ...

15 30 50 per page