All Questions

3
votes
0answers
51 views

What are polytene bands, and why are they there?

Drosophila polytene chromosomes have been particularly useful in genetic research, as it made cytogenetic gene mapping possible with very little effort. This was primarily accomplished due to polytene ...
1
vote
2answers
153 views

What gives observable light its colors? [duplicate]

I know that difference between different colors of light is difference between their wave length but I don't know what gives beautiful colors (like rainbow colors) to different wave length of ...
2
votes
2answers
271 views

What's a good and reliable database on the pharmacodynamic and pharmacokinetic data of drugs both approved and unapproved?

What's a good and reliable database for the pharmacodynamic and pharmacokinetic data of drugs both approved (in the US and elsewhere) and unapproved?
2
votes
3answers
646 views

Michaelis-Menten Kinetics: Does measuring apparent Km and Vmax take into account competing reactions?

I am learning about why it is important to measure Km and Vmax for each experimental setup because measuring the "apparent" Km and Vmax includes enzyme inhibitions of which one might not be aware. ...
3
votes
1answer
213 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 ...
2
votes
1answer
37 views

What is a good review book/source for microbiological diagnosis?

I am trying to find the diagnosis figure for different bacteria where phases are illustrated. I am using at the moment: 1) First Aid for the USMLE Step 1 2013 and 2) Medical Microbiology by Murray et ...
1
vote
0answers
41 views

What's the mechanism of action of Levomepromazine's analgesic effects?

I have absolutely no idea as to how Levomepromazine elicits its analgesic effects so please do direct me to journal articles and other credible sources with you, the answerer, making a summary of ...
2
votes
1answer
351 views

Can animals use the nitrogen in chitin to build proteins?

Fungi and insects contain chitin, which is about 6% nitrogen. Can an animal - like me - make use of this as a nitrogen source to build proteins? Are there any animals that can do this? Are there ...
1
vote
1answer
89 views

Confusion related to the use of PCA to determine the background network

I was reading this paper related to use of gene expressions for predicting the drug response. I have this confusion, the paper has used PCA on the covariance matrix formed by the genes to get what is ...
0
votes
0answers
66 views

Which receptor in particular does, “MUSCARINIC CHOLINERGIC” refer to in Goodman and Gilman?

On pg. 410 of Goodman and Gilman's The Pharmacological Basis of Therapeutics 12th Edition the term "MUSCARINIC CHOLINERGIC" is used (in the context of side effects of antidepressant agents) with ...
35
votes
3answers
2k views

Why are there no wheeled animals?

In physics, "almost everything is already discovered, and all that remains is to fill a few unimportant holes." (See Jolly.) Therefore, on Physics SE, people are veering off into different directions: ...
1
vote
1answer
114 views

Lineage selection in plasmid evolution

I've been reading through Paulsson (2002) and I am not sure what he means by "lineage selection" in the second to last section. The paper deals with plasmid replication, and mostly concentrates on the ...
2
votes
0answers
197 views

Software for counting fly eggs

Is there any software that could be used to rapidly (quicker than humans) count the eggs laid by Drosophila on a substrate by placing them under a microscope with a camera attached? The eggs are laid ...
2
votes
2answers
213 views

What type of photosynthesis is performed by phytoplankton?

I am not a biologist, but I know there exist three variants of photosynthesis, namely C3, C4 and CAM. I would like to know what type is used by the ocean's phytoplankton? It might also be that ...
9
votes
1answer
281 views

Structure of fitness landscapes in the NK model

The NK model of rugged fitness landscapes consists of $N$ sites where fitness contribution of each site depends on its state $\{0,1\}$ and is epistatically affected by $K$ other sites. When defining ...
5
votes
3answers
294 views

Tool for nucleotide alignment with all nucleotide codes (e.g. R, Y, W, S, etc.)?

I have a vector sequence and would like to find the following nucleotide sequence in it. AASYWSRA This query sequence uses several degenerate symbols, defined ...
2
votes
2answers
362 views

What would it take to recognize a deer by its photo?

I am trying to recognize a deer by its antlers or any other means. Elaborating: I was hoping to use their antlers to recognize them but I have heard that most deers shed their antlers every year so ...
1
vote
0answers
22 views

Do the antlers re-grow in the same pattern every year? [duplicate]

I am a software engineer and I am trying to develop a system to identify a deer by its photograph. Most deers lose their antlers every year. I would like to know if they re-grow in the same pattern ...
2
votes
0answers
30 views

How is the appropriately-stratified gut microbiome acquired in organisms performing horizontal transmission?

I am studying horizontal transmission of primary symbionts in insect reproduction. This reminded me of an earlier question I had asked, in which I learned that humans analogously acquired their ...
2
votes
1answer
69 views

Whence fecal E. coli (et al.) if swallowing it is dangerous?

I don't know much about medicine, and I know even less about microbiology, but I understand that there are organisms in the lower gastrointestinal tract (and in feces) of a human, like Escherichia ...
1
vote
0answers
63 views

Carrying or packaging capacity of SAD B19 dG rabies virus

I'm wondering about the carrying capacity also referred to packaging capacity or loading capacity (how many base pairs can be packed efficiently into virions) of the pseudotyped rabies virus SAD-dG as ...
2
votes
0answers
95 views

How long does Lentivirus take to express in vivo mouse neurons?

Does anyone know how long it takes for a standard Lentivirus vector to express its genes (under a strong promoter such as CAG, CB7, etc.), after injection into the brain of a mouse? By hearsay I ...
2
votes
2answers
133 views

How does your body know when it is infected so it can invoke a fever?

How does your body know when it is infected with a virus or bacteria so it can invoke a fever or ramp up the immune system?
8
votes
2answers
236 views

What is the smallest molecule that can present as an antigen to the immune system in the context of allergies?

People often claim, in a colloquial sense, that they are "allergic to everything". Is it possible to have a full-fledged IgE mediated allergic response to very small molecules? I was always under ...
3
votes
1answer
159 views

What molecular processes are involved in pseudopodial extension?

I am curious as to the processes and mechanisms involved in the extension of pseudopodia in amoeba. How does the cell know and control the direction and extent of pseudopodia formation at a molecular ...
3
votes
1answer
186 views

Are there natural selection experiments that quantitatively agree with theoretical modeling?

Has anyone ever conducted an evolution experiment and quantitatively compared it to theory? For example, has anyone ever put bacteria in a million petri dishes filled with antibiotics and calculated ...
6
votes
2answers
212 views

Is local equilibrium a reasonable assumption for evolutionary processes?

Whenever I look at discussions of fitness landscapes (in particular, Kauffman's NK model) the questions tend to resemble: The population is at a local equilibrium, but another equilibrium of ...
-4
votes
1answer
100 views

Were any brain fusion experiments ever conducted? [closed]

Did anybody ever conduct experiments on fusing living brains?
0
votes
1answer
116 views

How to classify equilibrium points [closed]

I have the two differential equations: $$\frac{dN_1}{dt} = N_1(2 - N_1 - 2N_2)$$ $$\frac{dN_2}{dt} = N_2(3 - N_2 - 3N_1).$$ I worked out the equilibrium points to be at $N_1 = 0, \frac{4}{5}$ and ...
6
votes
2answers
148 views

Would muscle fatigue still occur if aerobic conditions for a working muscle is maintained?

Put another way if the muscle is given everything it needs to contract and do work will it ever get tired or have a reduction in energy efficiency? As far as I understand muscles depend upon a ...
1
vote
0answers
147 views

How does Tianeptine work to elicit its therapeutic effects?

Tianeptine is an antidepressant and anxiolytic that has some additional analgesic properties that's used in some European countries, and the theories I've heard about how it works include the ...
7
votes
1answer
413 views

How is the exogenous DNA protected from degradation during bacterial transformation?

During transformation, a bacterium can take up DNA from its environment. A small fraction of bacterial species are known to be naturally competent, meaning that they can engage in this sort of ...
0
votes
1answer
117 views

Contracting muscles in humans

I study biology at school, and unfortunately for me, my program skips the muscles in humans chapter. I know (and mainly, feel) that the movement in one direction isn't created by the same muscle as ...
1
vote
0answers
95 views

How is a blood sample analyzed to give the different levels of metabolites?

How is a blood sample analyzed to give the different levels of metabolites? Are there any any procedural differences with each blood test? Thanks in advance!
3
votes
2answers
143 views

What is a bacterial biofilm?

Bacteria produce something called a biofilm. I have found a few definitions; some say it is a complex of live and dead bacteria and others say it is a layer on cell wall. What is it made of? What ...
1
vote
1answer
157 views

What is the energy balance of cooking?

If I cook some food, I get apparently several energetic advantages: thermal : the temperature of the food is closer or superior to the temperature of my body or internal organs, so I do not have to ...
2
votes
1answer
90 views

The oldest common ancesstor of all human beings

Do all human beings have a single oldest ancestor (a man and a woman), or were there were many ancestors at the same time at different places on earth? This article sheds some light. Is there another ...
4
votes
1answer
831 views

What does conditional analysis of a SNP in a GWA study entail?

I am familiar with the use of tag-SNPs in genome-wide association studies to identify gene loci involved in complex traits, but I keep seeing the term "conditional analysis" used without any ...
0
votes
2answers
203 views

Deterministic model of lambda-phage lysis/lysogeny [MATLAB] [closed]

Project 1 Base: Can someone please help me understand what I need from Project 1 Base code to do questions 1 and 2 from the first image? I'm new to MATLAB so a thorough explanation would be ...
2
votes
1answer
475 views

Manipulation of gene expression using VP16 fusion and engrailed fusion to a transcription factor?

Today, a presenter briefly mentioned that gene expression in sea urchins during development might be manipulated using VP16 and engrailed fusions. On a slide, it said that expression might be ...
1
vote
1answer
1k views

What would be the best design for spike-and-recovery and linearity-of-dilution validation experiments in one 96-well ELISA plate?

I have searched in the web for a detailed explanation of doing such validation experiment, but unfortunately couldn't find a satisfactory one. I came across the following sources: Thermo ...
1
vote
1answer
89 views

Reproductive isolation causing evolution

My course book says about reproductive isolation that it does not allow the interbreeding among the individuals of different species. It also says that it is a cause of evolution. How is this cause ...
0
votes
1answer
166 views

Why does the PR form of phytochrome exist?

I know how it gets converted because PR is more stable and when there is neither red or far red light PFR naturally converts to PR. But what is the point of it? If PFR is the biologically active one ...
1
vote
1answer
182 views

What insect is this?

I found it in Russia. Where they usually live? What they eat? Full length is approximately 2 cm.
1
vote
2answers
182 views

How long can you keep sheep eyes in formaldehyde before dissecting?

We're preparing for an experiment in our classroom and my teaching partner and I are at different points in the unit. I am concerned that the experiment will be less successful because of the ...
1
vote
1answer
2k views

Is episome a plasmid or a virus?

A plasmid is a small DNA molecule that is physically separate from, and can replicate independently of, chromosomal DNA within a cell. In general, in eukaryotes, episomes are closed circular DNA ...
2
votes
0answers
83 views

How do omega-3 fatty acids reduce cholesterol at the molecular level?

I have heard that omega-3 fatty acids found in fish are a good way to prevent/reduce cholesterol problems. My question is how do omega-3 fatty acids do that: what are they doing on a chemical level ...
0
votes
1answer
106 views

How the concentration of an antibiotic is chosen for YPD medium?

I need to prepare YPD plates containing hygromycin, but I don't know which concentration I can use. I'll select transformants of Hansenula polymorpha.
6
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
1answer
60 views

PTMs of proteins via mass spec?

I understand that mass spec is widely used to study PTMs like glycosylation of proteins, but how can mass spec determine correct PTM structure of say glycosylation if two glycan structures have the ...

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