6
votes
1answer
3k views

What causes adenosine build up in the brain when awake?

Adenosine is an important hormone in sleep regulation. It is postulated that when a person is awake, there is a build up of adenosine in the brain, which inhibits the neurons in the brain, and ...
2
votes
1answer
47 views

Drosophila grey / yellow

I am studying biology by myself via distance-learning. I have been trying to solve the following problem for a while now and hoped you could help me. As this is "homework" I would appreciate hints ...
4
votes
2answers
2k views

No bands show up in gel electrophoresis, not even marker

I haven't seen any gel lanes in neither my PCR samples nor the marker itself when photographing them. This is not my first time performing 1.2% agarose gel electrophoresis. I see gel lanes when I ...
2
votes
1answer
129 views

“selective pressure” or “selection pressure”?

Editing a manuscript of mine, a co-author changes "selection pressure" to "selective pressure". Are those two terms interchangeable? Or are there subtle differences that I'm not aware of? The ...
3
votes
1answer
105 views

Is there a hormone combination that makes humans grumpy?

Imagine a typical situation that is likely to give rise to a bad temper within an individual: a person is awoken very early in the morning by a sound of a lawn being mowed next door. Unlike expected ...
0
votes
1answer
57 views

How many chemical species are on average in a typical plant and animal cell?

I want to know what sort of range there is on the number of different chemical species in a typical plant and animal cell. Failing that, some specific examples (with sources please). Thanks
3
votes
1answer
4k views

What is a suicide plasmid?

What is a suicide plasmid? Example: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2737453/ mentions a "suicide vector". See also ...
1
vote
0answers
37 views

Study case of the inheritance system of Oenothera

I've been told some interesting facts about oenothera. Apparently in this species some lineages have been through some translocations and in results to these translocations and in consequence, some ...
2
votes
2answers
66 views

In genome research, what is the problem in Mapping that may be caused by reads being too short?

In the following scenario: You were given short sequence reads of plant RNA obtained from a next-generation sequencing machine (fragments of 20–30 nucleotides in length). You attempt to map them back ...
0
votes
1answer
38 views

What information do microarray image convey?

OK I have read that a cell generates 4 kinds of digital (to be precise discrete) data namely DNA, RNA, Protein (sequences that can be encoded as string sequences of nucleotides/ amino acids) and micro ...
0
votes
0answers
55 views

What is the current scientific position on the issue of human race? [duplicate]

Race is perhaps one of the most controversial and sensitive issues in anthropology, biology, and other related fields. As a non-scientist, I've used google to probe the disparity between the positions ...
2
votes
1answer
301 views

Are Bovine serum albumin, Avidin, Ficoll-70 and Dextran-70 positively charged or negatively charged? [closed]

Bovine serum albumin, Avidin, Ficoll-70 and Dextran-70,are they positively charged or negatively charged ? And which other solvents can be used as a substitute to water for preparing solutions in each ...
1
vote
1answer
55 views

To diagnose osteomyelitis of vertebral column in chronic kidney failure

Assume you suspect amyloidosis because of the history of the patient: problem with vertebral column and "purulent" (serous, fibrous, or hemorrhagic) inflammation when patient very young. Now, the ...
3
votes
1answer
87 views

Is there a molecular basis to intelligence?

Is there any explanation, gene(s) or whatever detected, that are co-related or explicitly related via mechanical bio-molecular (or at any other level) models that explain the higher or lower ...
0
votes
0answers
16 views

How is the nasal secretion system of local immunity coupled with lymphatic circulation?

I started a thread about Nasal chronic Inflammation after influenza virus here. However, I do not understand enough well the structure of the nose to answer the questions there. I know that the lysed ...
2
votes
1answer
2k views

Why does hemoglobin's affinity for oxygen increase if an organism lives at a higher elevation where oxygen is lower?

Wouldn't its affinity for oxygen decrease because the acidity of the body would increase with the lack of oxygen? The textbook said otherwise though and I don't understand.
4
votes
2answers
211 views

Do miRNA and antisense RNA do essentially the same thing?

Don't they both just disrupt RNA so it can't make a protein? If so, then what is the difference between the 2?
1
vote
1answer
71 views

Fastest and slowest action potential

When our instructor asked us about the speed of action potentials in cells, I told him that action potentials and two-wheelers travels at similar speeds. He thought that this is an 'interesting' way ...
0
votes
1answer
62 views

Enzyme kinetics [closed]

I can't understand how to study enzyme kinetics. Say I have a lipase and want to study the kinetics of this lipase using a fluorogenic substrate, how would I do this? From what I understand I would ...
1
vote
1answer
37 views

To determine no beating cardiomyocytes from ECG or video recording

I am trying to find data and some method by which I can see and say that there are some cardiomyocytes not working. I have reviewed many arrythmia data where I think I can see much cardiomyocetes ...
3
votes
1answer
152 views

How to wash the column during protein purification with GST tag?

I have been working with GST tagged proteins for the last 4 years and after loading the cell lysate into the column I was washing it with 20-30 column volumes of PBS and sometimes my proteins were ...
19
votes
3answers
45k views

What is the difference between orthologs, paralogs and homologs?

These three terms are often misused in the literature. Many researchers seem to treat them as synonyms. So, what is the definition of each of these terms and how do they differ from one another?
4
votes
1answer
591 views

Why is the mosquito a definitive host in malaria?

I thought that the definition of a definitive host was that the parasite had to sexually reproduce in that particular host. I've been told that mosquitoes are the definitive host for the plasmodium ...
2
votes
3answers
366 views

Why cancer mutations do accumulate sequentially?

According to Knudson hypothesis, cancer mutations accumulate in order. Statistics says, that cancer probability increases as sixth order of age, which may mean six consequential steps to cancer. But, ...
2
votes
1answer
37 views

Evolutionary rationale behind migration proteins

Tumor cells are able to migrate due to specific migration proteins. What is their evolutionary origin? Or are they simply deregulated?
2
votes
1answer
37 views

Protein Conformation Modeling

I'm interested in learning about computational modeling in biophysics. I have heard some amount about people modeling proteins as a network of ideal springs to examine things like conformation ...
1
vote
1answer
52 views

Is there a possibility that medicine will affect the efficiency of natural selection?

I mean, saving sick people means that they possibly can propagate something that nature does not allow. I know that there is already something that operate at genetical level producing alteration, ...
2
votes
1answer
34 views

Is a double-yolk egg capable of producing two viable chicks?

As per title: If fertilized, is a double-yolk egg capable of producing two viable chicks (that could survive to adulthood)? Have there been any reported cases of such (presumably) fraternal twins?
1
vote
1answer
160 views

What is the effect of Montelukast on the amount of IgE in blood?

I know that it decreases the amount of leucotrienes in blood. I saw a patient with high IgE altough under Montelukast medication. This suggests me that Montelukast does not affect the immunoglobulins, ...
4
votes
1answer
189 views

Evolution and the levels of selection

Reading Okasha's "Evolution and the levels of selection" he talks about "the levels of selection problem." There is a bit of a problem with this opening chapter because, while he talks about why the ...
18
votes
4answers
3k views

Why are there exactly four nucleobases in DNA?

Does someone know why DNA is composed of four nucleobases? In particular, is there an explanation for the number? Why four and not two, or eight?
7
votes
2answers
129 views

Why is there no way to remove an immune response?

We've known for a long time now how to "add a new entry to the database," as it were, of immune responses. It's called vaccination, and it's been one of the greatest success stories in the history of ...
2
votes
1answer
636 views

Why are red blood cells considered to be cells?

Wikipedia states that a cell is the basic structural, functional and biological unit of all known living organisms. Cells are the smallest unit of life that can replicate independently. It then ...
0
votes
2answers
29 views

Is process, opposite for growth, known for mammals?

Every animal born small, then grow larger and larger. The same is true for parts of the animal bodies. Is there any cases, when body or part of the body diminishes in size and mass, while staying ...
1
vote
2answers
739 views

What actually are the blood groups for human being?

We all know that, Human blood groups are of 4 types with Negative and Positive of each types. The Wikipedia article also states so. But according to this forum thread there are some other types too: ...
7
votes
1answer
134 views

Identification of species found in fly lab

I just found this in my Drosophila lab (within a closed vial) - unfortunately it was dead having been frozen for two weeks. Can anyone help id what it is, and whether it poses a risk to my flies (like ...
8
votes
1answer
713 views

Why does it hurt more when you touch a nerve directly?

I am not a biologist nor know much about biology (so please explain in layman's terms) however I have always been curious as to why this is. What causes the difference in pain between touching an ...
0
votes
1answer
58 views

Curious about Brazzein

What is in compound "Brazzein" that it makes it 2000 times more sweeter than sugar? Can anyone please explain the science behind it?
-4
votes
1answer
15k views

What is the difference between the Ureter and Urethra? also between the Renal papilla and Renal pelvis? [closed]

Differentiate between the following: Ureter and Urethra Renal papilla and Renal pelvis It is not given in my book. Please help.
4
votes
2answers
113 views

Detecting food fraud

There's undoubtedly more than one way to do this, but if a DIY biologist were to attempt to detect food fraud (e.g. as done by students from Stanford University and Trinity School, Manhattan with ...
4
votes
2answers
107 views

Is it possible to be (briefly) aware you had been decapitated?

If a person's head was cleanly and rapidly decapitated by a sharp blade slicing through the neck, such as would happen on the guillotine, could that person remain conscious? If so for how long? Long ...
14
votes
3answers
948 views

What evolutionary explanations are there for death?

I know death and cancer doesn't hurt humans' reproductive success. It's not helping either. Why do we die? Why dying humans (all of us) are common? What's the point of dying?
5
votes
1answer
57 views

What limits our ability to grow enamel rods?

From what I've understood from what I've read (which might be wrong), enamel rods extend away from the dentin in our teeth. As young people grow, the rods are thickened. What are the technical ...
3
votes
1answer
533 views

What types of light can't a plant photosynthesize in?

I have a plant on my desk, and it got me to wondering: Can my plant use the light from my monitors to photosynthesize? If so, what light (apart from green light, to a degree) can't plants use to ...
4
votes
3answers
1k views

Polymorphism in cnidarians?

To me, the phenomenon of polymorphism in cnidarians is particularly troubling. I gather that it essentially refers to existence of various different forms or kinds of individuals, i.e. zooids and ...
4
votes
1answer
81 views

Why humans have the temperature they have?

It is obviously very onerous to generate heat at all, although it has advantages. We don't have to lie on the sun like a crocodile to get warmer. And we avoid the freezing of our body water by out own ...
3
votes
1answer
148 views

Biological meaning/interpretation of clustering coefficience

I have been looking for some time to find an answer to the following question. I would be grateful for any help/advice or directions. I work very frequently with large number of proteins and assess ...
4
votes
1answer
345 views

Hypotonic or Hypertonic solution and why?

A doctor needed to administer 5% albumin to a patient. Albumin is normally administered dissolved in 0.9% saline solution. Since the physician did not have any 5% albumin solution, he diluted 25% ...
7
votes
1answer
697 views

Why do people sleep with their eyes open?

It's a fact that some people sleep with their eyes open, but why does that happen? Is it normal behavior, not a symptom of any sort of disorder? Are there any (dis)advantages to sleeping with eyes ...
0
votes
1answer
101 views

How does Oedipus complex fit in the evolutionary theory? [closed]

This is somthing that really makes me curious. How is posible that trough a evolution process the best posible candidate is the one that falls in love whith his progenitor?

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