4
votes
1answer
301 views

Why do farts stink, but perfume does not?

Why is it that natural things like farts, poop, halitosis etc., from which we are always surrounded smell "bad"; whereas manufactured products, such as perfume or glue smell "good" to most of us? In ...
1
vote
1answer
66 views

How is sweetness measured?

Some time ago, I read in a newspaper--though I can't recall the details--a list of (mostly artificial) sweeteners and a list comparing how many times sweeter each was than sugar. How is relative ...
3
votes
1answer
260 views

Macroevolution vs. microevolution

Where is the line usually drawn between macroevolution and microevolution? I thought that, although similar processes govern both, the line was at the species level, with macroevolution being changes ...
1
vote
1answer
1k views

Is there any natural blue rose?

I had recently read an article that the possibility of having natural blue rose is extremely rare because of the absence of delphinidin in most roses. Are all blue roses just a product of ...
4
votes
2answers
10k views

Calculating Protein Concentration from Kilo Units (KU)

I am looking to purchase Pyruvate Kinase from the Sigma Website, they state the volume in Kilo Units (KU) i.e. 1, 5 or 25 KU. It also states there are 350-600 units / mg protein. Does this mean one ...
0
votes
0answers
48 views
1
vote
1answer
376 views

Why do you need the intrinsic pathway when you have faster extrinsic pathway?

There are two pathways in blood clot fromation; the extrinsic pathway and the intrinsic pathway. The extrinsic pathway is faster than intrinsic pathway because it has less number of steps. So, why do ...
11
votes
2answers
2k views

What is the difference between naive and adjusted p-values in a GWAS study?

What is the difference between a naive p-value and an adjusted p-value in the results of a GWAS study? See from this paper: After Bonferroni adjustment, a single gene, DCTN4 (encoding dynactin 4) ...
6
votes
3answers
370 views

Is there a hypothesis that attempts to explain patterns of species richness along all three energy-related environmental gradients?

My question is related to one of the oldest question in ecology: "What determines global patterns of species richness?". However, I want to focus on one particular part of this question, which has ...
2
votes
1answer
725 views

How many species have existed on earth? [duplicate]

I found a paper estimating the number of species currently living on earth. Now I'm wondering If anybody tried to estimate the number of species that have lived on earth. I'm familiar with problems of ...
1
vote
1answer
386 views

Question regarding Rate of Photosynthesis AP Biology Lab

We are doing a lab on the effects of light intensity/wavelength on the rate of photosynthesis in AP bio and we were asked to visit this website here: ...
2
votes
4answers
296 views

Are we inevitable in the evolution?

Suppose we wind time back to the instance when life emerged on Earth and let evolution start over again, will human beings or any other kind of self-conscious animals evolve ultimately, inevitably? ...
4
votes
1answer
73 views

Transcriptionally-mediated DNA damage

I'm researching the genetics of brain cancer, and finding a huge number of mutations in voltage-gated channels. It stands to reason that some of this DNA damage is due to the DNA being transcribed ...
3
votes
1answer
108 views

Chromatin shearing: what is it and what are the effects of high-sensitivity?

I am reading a paper which discusses a complex (MSL-DCC) involved in dosage compensation of the drosophila X-chromosome. Descriptions of the complex's structure and function are given in the papers ...
3
votes
1answer
69 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
170 views

Bacterial chromatin binding data?

I'm looking for data - maybe CHP^2 data that shows chromatin binding to a prokaryotic genome under some specific conditions. Can anyone point me to a source?
3
votes
1answer
171 views

What are centromeres *really*?

I've gathered that a centromere is a a region* where the DNA is bundles up even tighter (around protein different to Histone) and chromatids are 'joined'. However I'm still mostly in the dark ...
21
votes
1answer
544 views

Regulation of chromatin structure

Recently, I reviewed the different levels of chromatin structure. The primary level is nucleosomes, where DNA is bound to histones, and has structural similarity to "beads on a string." The secondary ...
12
votes
1answer
426 views

How are epigenetic marks transmitted during cell division?

As far as I know, this is one of the biggest questions in the epigenetic field: how are the epigenetic marks like histone modifications propagated through cell division? A lot is already known about ...
10
votes
1answer
492 views

What is the functional and structural distinction between core (H2A, H2B, H3,H4) and linker(H1/H5) histones?

Many explanations of histone biochemistry isn't quite elucidating for the undergraduate student. How does histone structure (dimers, octomers) relate to their specific functions as core or linker ...
2
votes
1answer
33 views

What signals histone methyl transferases to function?

I wanted to find out if anyone knows what stimulates histone methyltransferases to function? I know that it is a process still trying to be understood, but I can't find anything that seems to direct ...
4
votes
1answer
149 views

How does “inheritance of methylation” of DNA and/or histones work?

What are the current models/ideas describing the mechanisms explaining inheritance of methylation on DNA resp. histone level? Is there evidance of this "setup" information being really ...
11
votes
1answer
73 views

What are the mechanism binding histone code with alternative splicing?

There are some bioinformatical considerations showing that there is a significant correlation of some between histone code and alternative splicing; but what are the hypothesis about the underlying ...
2
votes
1answer
134 views

Histone marks mechanism

I am slightly confused about the mechanisms that makes histone modifications associate with gene expression. That is, H3K36me3 is believed to be present in actively transcribed genes, H3K27me3 in ...
3
votes
4answers
2k views

Can the third sex be categorized as Male or Female?

Hijra are people who have a penis (not sure if sexually active) but look much like a female (perhaps for some feminine biological property). Wikipedia says they are "physiological males who have ...
4
votes
2answers
214 views

How does the colinearity of the HOX genes determine the body plan of an organism?

I was recently reading about colinearity in the HOX genes that give an organism its high-level body plan (where the order of the HOX genes on the chromosome follow the head-to-tail order of body ...
2
votes
0answers
50 views

Embryo activity during seed dormancy?

What metabolic processes does a dormant embryo in a seed carry out? The newly produced seed will not germinate, either because of a lack of favourable conditions, seed hibernation, or because of a ...
0
votes
1answer
39 views

How does the body repair extracellular damage caused by glucose?

So we know that glucose is an aldehyde that can cause cell damage to the lysine and arginine residues on proteins through the Maillard Reaction (among other damaging reactions that glucose ...
9
votes
4answers
3k views

Why we have no enzyme to digest cellulose?

As we know, cellulose is the most abundant polysaccharide in nature. Why don't we have any enzyme to digest cellulose?
3
votes
1answer
51 views

How does your body ultimately recover from a cold?

Is it the eradication of the virus (assuming rhinovirus) by white blood cells? Or does your body somehow adapt to presence of the virus?
3
votes
2answers
62 views

Why are genes expressed as proteins rather than other types of bio-molecules?

I guess, we could infer that the structure of an amino acid has the same functional units as RNA is used to synthesise it. Therefore, from a logical point of view it would make sense that genes are ...
4
votes
1answer
286 views

Sexual selection in cats or other animals

I was wondering if you could answer some of my questions regarding sexual selection in cats (or any other animals). I would like to apologize beforehand for my incorrect term use. When it comes to ...
6
votes
4answers
8k views

How long can a naked human survive on Mars?

How long can a naked human survive at the surface of the Mars planet? For instance, let's say a worker's base takes fire while he sleeps, and he has to run to the emergency building 200 meters away ...
3
votes
2answers
134 views

Lactate and Diabetes

Why are lactate level high in diabetes? For example, Diabetes type II have resistance to insulin, and if they do it, their gluconeogenese should be working at high levels and, because of that, uptake ...
4
votes
2answers
117 views

What is the smallest oligocelluar organism?

What is the smallest oligocelluar organism? How many cells does it have? EDIT The question is motivated by this comment@Philosophy.SE EDIT as recommended in comments I'm looking for an example of ...
0
votes
0answers
29 views

Events after Endothelial interruption

What are the physiological events that occur after there is endothelial interruption in the blood vessel? What does endothelial interruption mean here? And what could be the physiological events?
1
vote
1answer
73 views

Linkage distance calculation

What is the map unit distance between L and S allele ? My working : If we take the normal ratio :9:3:3:1 , first one should be 9/16 = 0.5625 and then subtract 0.51 from it, we get 0.0525, ...
1
vote
1answer
81 views

Topology of protein

The domain structure of protein Z, which is composed of 180 amino acids, is shown in the upper part of the figure below. Protein Z is palmitoylated at a cysteine residue (the third amino acid) ...
1
vote
1answer
78 views

Blood group probability question

My answer ( after rounding off) is 9% -100( 0.75 X 0.25 X 0.5) but the answer given is 22 % Am I correct ?
0
votes
1answer
71 views

How does Acetaldehyde accelerate mitosis?

I read that one of the ways alcohol is carcinogenic is via accelerated mitosis due to acetaldehyde, I was wondering what pathway caused this acceleration?
1
vote
2answers
201 views

mouse gene translated to human gene

I have a list of mouse genes, but all our analysis happens for human genes. Is that possible to translate these mouse genes to human genes? and is there any tool that can help me on this? I am ...
1
vote
0answers
79 views

Cardiac ECG database with high sampling rate?

MIT-BIT arrhythmia database follows AAMI standards. It has samples of 360 sampling frequency so it can detect heart beats of 180 Hz because of Nyquist frequency. I have noted that this frequency ...
2
votes
2answers
815 views

Can more than one antibody bind the same antigen

I'd like to clear something up about antibodies that I'm not sure I've understood in the articles I've read. Looking at concepts such as "affinity maturation", "monovalent antigens" and "polyvalent ...
0
votes
1answer
54 views

Identifying mutations in a yeast strain

Cells of a triple-mutant yeast strain (leu- his- trp-) were spread either on minimal medium or on minimal medium supplemented with various combinations of histidine, leucine, or tryptophan. The ...
1
vote
1answer
24 views

Source of energy of adipocytes

Since adipocytes export fatty acids and don't use them as an energy source, which is the main source of energy for this cells?
2
votes
1answer
192 views

What does the (-) in the molecule name mean?

I'm reading some text (purchase request) that has the following line in it. (-)-Norepinephrine What does the minus sign mean in front that is in parenthesis? Is this some kind of standard way of ...
5
votes
1answer
81 views

How are Raunkiær's plant life forms viewed today?

At the beginning of the 20th century, Raunkiær proposed a typology of plant life-forms based on where they bear their buds, roughly as: cryptophytes: belowground hemicryptophytes: at the surface ...
4
votes
2answers
74 views

Do swarms show intelligence?

Can you think of collective and swarm behaviors as "intelligence"? Would such a concept apply to a) ant colonies and b) fish swarms?
2
votes
2answers
152 views

Radiation and “Safe Dose”

I've read about safe doses of radiation, briefly. Why is there such a thing a safe dose? Can't any radiation give you cancer? Why is it more and more dangerous to take in larger and larger doses? Just ...
11
votes
1answer
305 views

Deletion errors with Phusion Polymerase?

I was wondering if anyone has ever seen large deletions (~40-50 bp) occur when using phusion polymerase to clone a gene. I have recently tried using Circular Polymerase Extension cloning to clone a ...

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