5
votes
1answer
97 views

Mammal body density

Human body density is approximately 1 kg/l (same as fresh water) - which is not surprising (at first) given that we are 70% water, and is surprising (on a second thought), given that the other 30% can ...
1
vote
1answer
68 views

5,6-dihydrouracil and 5,6-dihydroxyuracil - how they arise in DNA?

5,6-dihydrouracil can be formed from cytosine after exposure of DNA to ionizing radiation under anoxic conditions [Ref]. What are other ways by which 5,6-dihydrouracil is formed in DNA? What about ...
3
votes
1answer
33 views

Do plants have preference for the form of nitrogen as nutrient?

In the nitrogen cycle (ecology), it is usually described that plants can use nitrogen in the form of ammonium (NH4+) and nitrate (NO3-). Do plants prefer one form of nitrogen over the other?
2
votes
1answer
50 views

Why do we have two of some organs, but not all? [closed]

We have two eyes, but we don't have two hearts. Why do humans have two of some organs, but not all?
6
votes
1answer
52 views

How to search for organisms by criteria such as growth substrate and overflow metabolites?

I'm looking for a database or a systematic way to search for organisms which meet certain criteria. My criteria descending importance are: growth substrate chemolithoautotrophy (on which substrate) ...
1
vote
1answer
38 views

Speciation of humans? [duplicate]

Since we homo sapiens (and all other species) are continuously evolving, are humans undergoing speciation based on our environment? OR has there been any difference across people that could say ...
3
votes
3answers
202 views

Extreme examples of protein translation/use coupling/decoupling?

What are known extreme examples of protein translation/effect coupling/decoupling? For example, examples of proteins that are immediately used at the time the have been translated and vice versa, ...
6
votes
1answer
51 views

Number of transcription factor genes in the human genome

What is the number of the transcription factor genes present in the human genome? Does this value differ compared to Mus musculus, Drosophila melanogaster, Arabidopsis thaliana, C. elegans and S. ...
4
votes
0answers
55 views

Long-term effects of antihistamines on mind and CNS [closed]

Can maybe someone share knowledge or guesses on the following questions: Does the prolonged use of antihistamines cause long-term effects on mind or CNS? Are there any known evidences of their ...
6
votes
0answers
46 views

B cell receptor editing

If a B cell contains two mu chains and two lambda chains and is self reactive can it go back and rearrange its kappa light chains? I'm not sure if it can only try to rearrange its lambda light chains ...
6
votes
1answer
123 views

How are bones growing, if bones are not connected to the brain?

If the bones are not connected to the brain, how is their growth controlled? This question is not a duplicate of the question Mechanisms of bone growth, as this question deals with how bone growth is ...
9
votes
3answers
153 views

What causes feeling of feet falling asleep to be delayed?

This answer explains the sensation of extremities "falling asleep" as a result of sustained pressure on a nerve. The answer links to an external web page that says that the feeling "quickly goes away ...
0
votes
0answers
31 views

Deactivation of plasma cells [closed]

Is it possible to deactivate plasma cells or B-cells? So far I haven't found many answers on the Internet or in Stack Exchange. Please help! Also, please include references. So my ideas were to use ...
6
votes
1answer
109 views

Why do we still have genetic disorders that show anticipation?

Anticipation whereby symptoms of genetic disorders occur earlier and with more severity as it is passed from one generation to the next. So wouldn't these inherited diseases over a few hundred ...
3
votes
1answer
92 views

How are arms different than legs?

Ok, this is a bit of a tangent question, but it came up yesterday and I didn't know the answer: How are arms and legs defined physiologically? For example, we say humans have two arms and two legs, ...
4
votes
1answer
173 views

Body size, what are the evolutionary trade-offs?

Background Considering just the "Kingdom Animalia" branch of organisms. It is clear that bigger does not necessarily mean better - there is large variation in body size... From the 94 µm long ...
4
votes
2answers
120 views

What governs the size of animal bodies?

Million of years ago there lived dinosaurs up to 36 m high. About 10,000 years ago lived Machairodontinae -compared to cats today they were huge. About 400,000 years ago lived Mammuthus trogontherii: ...
0
votes
0answers
28 views

coevolution by physical interaction between RNA sequences [on hold]

There are several items that relate to the concerted evolution between pairs of sequences (especially structural) rRNA as a consequence of physical interaction in tertiary, or even quaternary ...
-1
votes
1answer
24 views

Does a snake really digest part of its heart if they don't have enough food for a long time? [on hold]

I've seen this in a book, however I couldn't believe this. Googling it told me nothing.
2
votes
3answers
84 views

fastq-dump using mkfifo to stream data

So, fastq-dump has the ability to be run on just an SRA file accession number, such that the SRA is converted to FASTQ on-the-fly, and the SRA doesn't have to be written to disk. I'm curious whether ...
5
votes
3answers
90 views

Studying effects of alcohol on cells

I am wondering about the logistics of a simple experiment with say 3 types of alcohols, and various concentrations of each, with a control(s) I would like to research the effects of alcohol on ...
6
votes
3answers
2k views

What evolutionary adaptations cause trees to grow tall?

I think there are some obvious costs for trees to grow tall. Carbon and other nutrients costs, maintenance cost, energy cost (for growing, to bring water (and nutrients) up to the higher leaves, ...
1
vote
1answer
19 views

Can plants directly use sulfuric acid?

In the explanation of the sulfur cycle, it is often said that sulfur moves from the atmosphere to the ground by acid rain in the form of sulfuric acid. Can plants directly use sulfuric acid to ...
1
vote
0answers
25 views

How does a bacterial colony, grown in a nutrient medium, change the chemical composition of that medium over time? [closed]

In order to culture cells, the nutrient medium they are grown in must contain certain chemicals and trace elements (e.g. Hams medium, for culturing human cells, and a less demanding solution for ...
3
votes
1answer
20 views

Estimating RPM to RCF in Methods from Older Papers

I'm attempting to replicate a cell biology method from a 1958 Laboratory Investigation paper. The protocol is for the isolation of an extracellular matrix protein, and a key step is a centrifugation ...
3
votes
0answers
22 views

Well to well variation in thermal cycler fluorescence?

We have an old BioRad ICycler Thermal Cycler with MyIQ single color fluorescent detector. While it's meant for RT-PCR, we've been using it for melt curves and binding assays for different types of RNA ...
-2
votes
0answers
31 views

The ethics of ACST in full blown AIDS patients [on hold]

We've always been told that a traditional Allogeneic Stem Cell Transplant (bone marrow transplant) is unsuitable as a treatment option for those living with HIV due to the mortality risks it carries ...
4
votes
1answer
90 views

Does DNA analysis allow determining amount of chromosomes?

Nowadays it is possible to sequence the DNA of extinct species, such as the Neanderthals, the Denisovans, and others. Is it possible to determine, solely from the sequenced DNA or from known bone ...
-2
votes
0answers
31 views

PCR, writing methods section for a journal, I am quite inexperienced in writing, and was just checking in if this is okay [on hold]

Touchdown PCR was performed for site directed mutagenesis in a 25ul reaction volume of 2μl of template pET15B in combining 16μl of Nuclease –free deionised with 2.5μl of 10X Standard Taq Reaction ...
3
votes
1answer
37 views

Why do small fonts strain the eyes?

I understand that too much close reading will strain the ciliary muscles of the eyes. But what about small fonts? The contraction of the ciliary muscles is dependent on the distance not font size. In ...
3
votes
1answer
168 views

Bug Identification: Is this small tubular, black bug a bed bug?

So I found this tiny bug on my wall in the bedroom of my apartment. I estimate it is about 3mm long by 1mm wide. Is it a bed bug? It does not seem to match any of the pictures I've seen online. ...
0
votes
0answers
25 views

Maximum heart rate increase/decrease while physically active [duplicate]

I'm a computer scientist and implementing a heart-rate monitor for physical exercise. While I try to improve my code, I stumbled over the question how fast the heart rate can change within a given ...
6
votes
1answer
72 views

Can rapid eye blinking induce epileptic seizures?

Photosensitive epilepsies are characterized by visually-induced seizures. Flashing-light stimuli are known to induce seizures in some (but not all) patients. My question is whether people with this ...
2
votes
2answers
2k views

Do T-cells express MHC molecules?

T-cells recognize the MHC molecules and body's own peptides. When it doesn't, it alarms the immune system. But do T-cells express MHC molecules ? If so, how are they using it? If not, what happens ...
4
votes
4answers
225 views

Is there a PSI-BLAST for nucleotide sequences?

I understand that one can translate a nucleotide sequence and run PSI-BLAST on the protein (proteins if you take the 6 reading frames), but I'm looking for distant homology for bacterial small RNAs ...
7
votes
1answer
2k views

Why is fructose not glucose the main energy source of sperm?

The seminal fluid contains fructose as the main energy source for the sperm and not glucose. Why is fructose and not glucose the primary energy source for these sperm, since glucose is the ...
5
votes
2answers
81 views

Why deoxyribose for DNA and ribose for RNA?

Why is DNA made out of deoxyribose and RNA made of ribose? Why can't they both use ribose or deoxyribose? I think that the deoxyribose gives an advantage in storing genes, the job of DNA and ribose is ...
1
vote
0answers
26 views

FoxO gene(s) and aging [closed]

How does the FoxO gene affect aging? I read about how Hydra uses the FoxO gene to live (practically) forever... How does FoxO gene work? Currently, all I know is FoxO regulates the stem cell ...
0
votes
0answers
18 views

All cells in an embryo have the same heredity, yet they develop into different tissues and organs and organ systems. [closed]

To Remi.b All cells in an embryo have the same heredity, yet they develop into different tissues and organs and organ systems. What is the process by which this happens? THANKS :) (is it a proper ...
8
votes
2answers
355 views

More variation in proteins than genes. Why?

The Genome of a cell or organism is the same as that of the entire organism. However, the proteome of an organism is much greater than that of each cell (unless the organism is unicellular). How do ...
1
vote
0answers
15 views

What ideas have been proposed about what the first cell would have been like? [closed]

Have any researchers proposed a potential first cell (what it looks like, how it functions), and what do/would they base it on? Ubiquity of life, available ingredients? Also, in the same way protein ...
3
votes
0answers
21 views

Why are most transcription factors enhancing the expression rather than repressing?

One can classify the effects of Transcription Factors (TF) on gene expression into two types: it either enhance or repress the gene expression. I have always been told that most of transcription ...
0
votes
0answers
16 views

How can site-directed mutagenesis be used to suppress the production of anti-antibodies?

In a previous post of mine, I asked how to supress the creation of anti-antibodies in vivo. In the answer, it was mentioned that site-directed mutagenesis could be used. Currently, I can't find mcuh ...
2
votes
3answers
52 views

Anti-antibodies for preventing transplant rejection

Transplanted organs from the donor are attacked by antibodies from the recepient. So can't we construct anti-antibodies and destroy specifically those antibodies which are causing the rejections ? ...
-2
votes
0answers
69 views

Why do pregnant females still get horny? [closed]

I thought this was a good place to ask. Remembering back to when my wife was pregnant (we were both teens), I recall that she would not keep her ... hands off of me in some times. It will like she ...
4
votes
0answers
35 views

How was the cama's life expectancy computed?

A cama is a hybrid between a male dromedary camel and a female llama. The first cama was born on January 14, 1998, yet on the Wikipedia page it is said that a cama's life span is 30–40 years. How was ...
1
vote
0answers
11 views

Differential Scanning Calorimetry for bacterial membranes

I would like to study the freezing and melting of bacterial membranes and would like to use Differential Scanning Calorimetry (DSC) to obtain the glass transition temperature of the membrane. However, ...
9
votes
4answers
6k views

What is the cause of muscle cramps?

According to wikipedia, muscle cramps are caused by myosin fibers not being able to break free from the actin filaments during contraction, resulting in a prolonged contraction. Obviously a lack of ...
2
votes
0answers
32 views

Fatty Acid Synthesis of Fats Longs than 16 C

I understand that the human body when performing Fatty Acid Synthesis can synthesize only until C16 (palmitate). However the ER has desaturases and elongases. I know that desaturases are used to add ...
3
votes
1answer
58 views

How to attract spiders to my house?

I've been living in my apartment for a year now, and noticed something lately. During spring and summer I have quite a lot of midges indoors, and even now there are some. But there are no spiders! So ...

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