2
votes
1answer
47 views

Similarities Between Cells?

Which of the following are usually identical between a lung cell and a brain cell, from the same person, assuming that they are normal (non-cancerous) cells? Circle your choice(s). ...
3
votes
2answers
3k views

Is there an evolutionary reason for the 5 electron transport complexes in plants and animals?

The electron transport chains of both the light reactions of photosynthesis (in plants) and oxidative phosphorylation (in animals) both contain 5 complexes including ATP synthase, as shown below. ...
2
votes
2answers
335 views

Translate DNA to Protein

Assuming the sequence shown is read left to right, what is the sequence of the protein produced? sequence: 5’-ATGTACTTCCATCTGGAATAG-3’ MY ATTEMPT: I know RNA is synthesized 5 to 3. This is ...
2
votes
2answers
118 views

Is it more likely that the very first living organisms had a linear genome?

Is it right to assume that the first living organisms on earth had a linear genome? I base this on the fact that linear macromolecules are clearly much more common in nature that circular ones. To be ...
4
votes
1answer
37 views

Are there any strictly chloroplast/mitochondrion-residing ribozymes?

A simple question that had occurred to me. Considering the small doubt of transcribed genes in both organelles, I would doubt it, but are there any known ribozymes strictly found in either ...
2
votes
1answer
57 views

Preserved alpha complementation over evolutionary time?

Has the result of alpha-complementation ever happened via mutation through evolutionary time, and been preserved in modern day organisms? In other words, has a functional gene product ever been split ...
5
votes
1answer
252 views

Which way to run BLAST?

I have a set of scaffolds from a genome assembly, and I want to align a collection of proteins from various species to it. I can do this using BLAST in two ways: Create a BLAST database of the ...
6
votes
1answer
189 views

Is it possible to increase lifespan through controlled evolution?

A few years back when I was reading The Selfish Gene by Richard Dawkins, there's this short passage where he theorizes about a way to achieve an increased lifespan through controlled evolution. The ...
5
votes
1answer
2k views

Multi-nucleated cells: advantages and examples?

This question arises because I saw that monocytes and leukocytes are commonly called 'mononuclear cells' in the scientific literature. The implication of course being that other immune sub-types are ...
5
votes
1answer
156 views

Why was polyploidy not lethal in certain octodontid rodents?

As discussed in Why is polyploidy lethal for some organisms while for others is not?, polyploidy is normally lethal in mammals. However, two species of Octodontidae (South American rodents), are ...
3
votes
1answer
67 views

Brain response frequencies while sleeping

I'm not sure if this is the right place to ask this but Biology seemed to fit best. I'm trying to find out what frequencies the brain responds to best while sleeping. The reason for this is recently ...
2
votes
1answer
51 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
549 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
126 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 ...
22
votes
3answers
27k 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
75 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
162 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
131 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
228 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 ...
2
votes
2answers
319 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
58 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
89 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 ...
23
votes
5answers
557 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
212 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
481 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
501 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
5k 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 ...
12
votes
2answers
2k 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
231 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
2k 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
78 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
318 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
304 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
300 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 ...
8
votes
3answers
23k views

What is the difference between an antibiotic and an antibacterial?

Concerning medicine, what are the differences between antibiotics and antibacterials?
3
votes
1answer
68 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
395 views

Why did mammals evolve to have two testes?

What makes mammals tend to evolve to have two testes?
6
votes
2answers
590 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
9k 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
294 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
88 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
168 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
47 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
295 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
8k 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
44 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
310 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 ...

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