5
votes
2answers
634 views

Breeding laboratory mice with cancer; how does this work?

It has recently been brought to my attention that live laboratory mice with specific cancer strains can be readily purchased for medical research. For example, the Jackson Laboratory sells mice with ...
4
votes
2answers
100 views

Burning fat transferred from one part of the body to another

While doing some research on cosmetic surgery, I discovered that there are several ways of doing breast enhancements, one of which was using body fat. While I haven't researched this method, I assume ...
7
votes
1answer
146 views

Dimensionless number for blood volume

Comments from the question How is the blood volume of a living organism measured without killing it? by @Nico discussed that the time of blood recirculation scales with the size of the organism. I was ...
3
votes
2answers
422 views

By what mechanism does an obstructed bile duct cause excess fat in the stool?

By what mechanism does an obstructed bile duct (for example gallstones) cause steatorrhoea (excess fat in the stool)?
7
votes
3answers
68 views

Why are triacylglycerols broken down before being absorbed?

So when dietary fats are in the small intestine, they are emulsified by bile salts in order for action by lipases to occur. Lipases degrade the triacylglycerols into monoacylglycerols, ...
4
votes
1answer
55 views

Why oceans are carbon sinks?

Building on this question, I understand pretty clearly why forests are carbon sinks (trees grow, and there is carbon stored in soil and biomass). What about the oceans, though? Are underwater ...
3
votes
1answer
22 views

Anopheles arabiensis lifespan and sporogony duration

What is the longest observed lifespan of a mosquito, especially of the species Anopheles arabiensis? How long does it take for Plasmodium parasites to develop and move into the salivary glands of ...
1
vote
1answer
119 views

Is Araucaria fruit toxic? [closed]

I've had an Araucaria tree in my garden for more than 30 years. Today a fruit fell off the tree. It looks just like this one: I want to know if it is toxic? Can I eat it? If so, how?
1
vote
2answers
31 views

Punnet Square for Genotype Probabilities

I'm a computational physicist by trade, and today I was working with a student that is coding a simulation that requires the interactions of different genotypes to determine which phenotype will be ...
3
votes
1answer
41 views

Math behind the Genetic Relationship Matrix

The genetic relationship matrix (GRM) can estimate the genetic relationship between two individuals (j and k) over m SNPs and i representing a specific SNP. What I dont understand from their ...
2
votes
1answer
37 views

How is the subunit molecular weight different from the native molecular weight?

I noticed that the native molecular weight for an enzyme is different from its subunit molecular weight. Why are they different? Aren't the genes needed to express the enzyme the same in the native ...
4
votes
2answers
913 views

Could we slow down life? [closed]

As far as I know there is no absolute time measurement (one that would measure time in a non-environment-dependent fashion) in any life form. Only such time measurements exist, which are dependent ...
6
votes
1answer
42 views

What is the impact of sertraline on white blood cells?

This simplified video and RT.com article discusses how the mechanics of the death of a white blood cell can be useful as an "alert mechanism" to other white blood cells of an incoming infection. Also ...
-3
votes
1answer
57 views

Normal death experience [closed]

Consider a natural cause of death (no car accidents etc) - Is it true that death is generally preceded by suffering? In other words, are we destined to experience the most severe suffering we could ...
0
votes
0answers
24 views

Is it possible that the DNA of an individual changes significantly over a period? [duplicate]

Is it possible that the DNA of an individual changes significantly over a period ?
3
votes
1answer
106 views

Restriction sites

I would like to know: how many restriction sites does a restriction enzyme use on a DNA molecule? In other words: If a sequence on a plasmid contains the following bases: ATTGCAGTCTG and I want ...
32
votes
5answers
7k views

What does the human body use oxygen for besides the final electron acceptor in the electron transport chain?

My biology teachers never explained why animals need to breathe oxygen, just that we organisms die if we don't get oxygen for too long. Maybe one of them happened to mention that its used to make ATP. ...
3
votes
0answers
24 views

How stable is linear DNA transfected in eukaryotic cells?

I would like to know, with references from the literature, what is the half life of a linear dsDNA transfected in a mammalian cells. For example, if I transfect human cells with a PCR product ...
9
votes
1answer
602 views

How and when did a dedicated immune system evolve?

I have recently been doing a lot of research into the interplay between the innate and adaptive immune systems in humans, and mammalian laboratory models. This has led to my reading some interesting ...
7
votes
1answer
277 views
30
votes
5answers
2k views

Why are there no organisms with metal body parts, like weapons, bones, and armour? (Or are there?)

Reading this question, Why are there no wheeled animals?, I wondered why no organisms seem to make use of the tensile and other strengths of metal, as we do in metal tools and constructions. I am ...
3
votes
1answer
32 views

What does the hominin phylogenetic tree look like?

I'm no biologist, but I'm curious what the rough phylogenetic tree looks like for Hominin. Could you create a rough sketch that includes: Homo rudolfensis Homo ergaster H. georgicus H. antecessor ...
1
vote
1answer
18 views

Any databases with AAMI ECG and ECHO?

There is no AAMI 12-lead ECG databases available online. All of them have problems. I and my friends finally finalised our tests with St Petersburg. It is not AAMI. So the next step is to search ...
6
votes
1answer
827 views

Name (and meaning of the absence) of the white semicircle at the base of the fingernail?

At the base of fingernail, there is a white semicircle (see on the first picture). But sometimes there isn't one. My questions are: what is this white semicircle on the fingernail, and what causes ...
4
votes
1answer
52 views

Modelling insecticide net efficacy loss [closed]

I am currently doing some work on modelling the effects of treated nets usage on mosquito populations. Nets do not retain their maximum efficacy forever. They lose their chemical efficacy after about ...
0
votes
1answer
40 views

What is a selectively neutral genotypic change?

I am reading the paper "Neutral evolution of mutational robustness". Because I am new to neutral evolution, I have a few questions. Firstly, from my understanding, genotypic neutrality means the ...
8
votes
3answers
164 views

Why are the organs for reproduction and urinary excretion combined?

We eat food for getting energy to our body parts, and we excrete the wastes through urine, feces, and perspiration. Why has nature combined the urinary tract with the genital system (urogenital ...
4
votes
1answer
29 views

Is there a karyotype database for human cell lines?

I'm looking for the karyotype of a specific cell line. Some karyotype are well known, such as HeLa or some carcinomas, but some are very hard to find, such as LG2 (B cells). Is there a database ...
2
votes
1answer
84 views

Lethality of a stab wound to the back

How deadly is a stab in the back? Video games, movies, and other fiction would have us believe that a backstab against a foe with a modestly-sized blade leads to immediate and certain death, having a ...
6
votes
1answer
508 views

What is this beetle and what are the strange antennae for?

I found this wonderful creature in my yard (I live in the south of France) last night: It was about 2-3cm long, with a hard carapace and wings. It also made loud hissing noises when agitated. I ...
1
vote
2answers
69 views

Can you Transfer Cancer Between People via Saliva or other Bodily Fluids?

This may sound like a strange question. But could a Cancerous cell be transferred from one person to another from Oral contact e.g. Through Saliva, or other exchange of bodily fluids? I know that ...
6
votes
2answers
483 views

Is this species a variant of a red flour beetle?

Found this little guy crawling around the back garden - South Coast of the UK. The closest things I could find online (with an admittedly weak knowledge of where to look up these things, aside a ...
7
votes
1answer
567 views

Why do pigeons kill their chicks when touched by a human?

I used to have many pigeons around the house. If by chance one of the chicks fell out of the nest, we used to put it back using gloves. Usually, if we would touch the chicks with our bare hands, ...
1
vote
2answers
66 views

Why a continuous supply of energy is needed to support a weight?

What motivates this question is the apparent discrepancy between the concept of Work in physics and in physiology. Work in physics is defined as the dot product of the force applied to move a certain ...
6
votes
1answer
72 views

Can dolphins actually communicate linguistically?

Humans use "language." By language, I mean the thing I am using right now to talk to you. I know dolphins and orcas have very complex communication systems and also seem to process linguistic and ...
1
vote
1answer
48 views

Can all animals of the same species crossbreed?

For example, take Canis lupus, the species of dog and wolf. Within their species, can all dog and wolf types crossbreed? We can forget the logistics and assume this is all done through artificial ...
3
votes
1answer
34 views

Cause of Crease in Drupe Fruit

What causes the crease through the pericarp of a drupe fruit (peach, nectarine, olive)? It may just be in exocarp as @Ilan pointed out, but I assumed (perhaps wrongly), that the division continued ...
5
votes
3answers
133 views

How can a ligand be an integral membrane protein?

My background is in mathematics, and not biology, so please bear with me. I am currently working on a project involving the effects of Epidermal growth factor treatment (EGF) on cell migration. I am ...
1
vote
2answers
51 views

Introductory book in genetics? [duplicate]

I am working in the field of neuroscience with a background in computer science. I try to find new ways of analyzing brain imaging data (mostly MRI, EEG, MEG, fMRI) with modern machine learning ...
2
votes
1answer
33 views

Do we have evidence of heritable personality traits in chimpanzees?

I have read that chimpanizees have distinct personalities. Do we have evidence of heritable personality traits in them?
2
votes
1answer
75 views

What is the difference between Single Nucleotide Polymorphism (SNP), Mutation and Structural Variation(SV)?

This is a question which plagues many people and today I was wondering it myself while writing a grant. Indeed, I've seen many people use the terms interchangeably, but they are all very different ...
9
votes
2answers
308 views

What kind of bird species is this?

Every now and then I got a glimpse of this bird which I'm pretty sure is not native to Northern Germany where I live. There are at least three of these birds around but I usually only see something ...
3
votes
1answer
59 views

What is the optimum length of abstinence for maximum ejaculation volume in humans?

There have been papers discussing this, and whether the abstinence period should be 1 week, 2 weeks or other [1, 2]. Some think the time to maximum ejaculation volume is even longer than this. doi: ...
1
vote
1answer
43 views

Bacterial capsule vs. slime wall

I've read that the bacterial capsule protects the bacterium from phagocytes and prevents water (and nutrients, possibly?) leakage from the bacterium. A less organized and less dense version is called ...
2
votes
1answer
148 views

What is the chemical composition of an egg shell?

It ought to be some combination of C, O, and H, I presume. But really why should I care if eggshell gets in my eggs while I'm cooking?
13
votes
0answers
133 views

Was the recent “conservation hunt” of a black rhino supported by science?

CNN recently covered a sanctioned black rhino hunt in Namibia by Texan Corey Knowlton, who bid US$350,000 for the license. In the story, he claims that the hunt was actually supporting conservation of ...
1
vote
3answers
73 views

Trypsin and cell culture

I am doing an experiment where I have treat the cells with a drug and calculate their counts. I would like to know if is bad to trypsinize the cells in consecutive days i.e. twice within 48 hours. How ...
5
votes
5answers
85 views

Can an influenza virus carry other infectors with it?

This idea came to my mind when thinking about how many people become ill in many locations with similar symptoms (fever and rough cough) from Influenza. There are of course different types of ...
1
vote
0answers
30 views

Different names in paired-end sequence files

I am aligning paired end sequence reads using bwa mem and I get an error saying that ...
5
votes
3answers
92 views

Can we knock out Caspase-9 *and* avoid breast cancer phenotype in our mouse model?

I am trying to design a wet lab experiment with no wet lab experience to name. Right now, in my dream land, it would be excellent if it were possible to create a Caspase-9 knockout mouse (damage to ...

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