All Questions

0
votes
0answers
7 views

When is an allele quasifixed?

Background Many models including the famous very first models derived by Ronald Fisher in his early career, assume infinite population size. In an infinite population, an allele can rise in frequency ...
0
votes
1answer
16 views

What is the difference between embryology and developmental biology?

The question is quite explanatory in it self, I used to think that both are same but then find somewhere that embryology is a part of developmental biology, can somebody please elucidate?
3
votes
4answers
70 views

What bird species is this? (Heron-like waterfowl from China)

I need help identifying this bird. (Some sort of heron?) It was seen in Wuhan, Hubei, China, in September. It is very common there. It can also swim like a duck, but I've only seen it do this once ...
0
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0answers
8 views

How many pandas should exist?

I have a degree in Biology so I'm a little embarassed that I never learned this, but... How do we know 1600 Pandas isn't enough? I know that we have historical numbers (although I couldn't find ...
0
votes
0answers
13 views

Finding appropriate research papers?

I had previously asked some question on cystic fibrosis and I had mentioned that I am a senior in high school writing a paper on gene therapy and CF. I would like to some specific paper on viral ...
0
votes
0answers
5 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 ...
3
votes
4answers
704 views

Which came first: The Chicken or the Egg? [closed]

Has there been any serious scientific inquiries into answering this age old question?
0
votes
0answers
12 views

Contaminant in DNA solution extracted from eggshell membrane

I have been extracting DNA from very old and degraded hatched eggshells inner and outer membrane. I tried some different protocols (ie Promega kit and chlorophorm extraction + ethanol precipitation). ...
2
votes
5answers
189 views

Does a neuron ever generate an action potential without stimuli?

Most accounts I read involving action potentials and synapses and the like tend to focus mostly on the action potential as a mere automatic reaction to another similar event happening upstream. From ...
3
votes
2answers
100 views

Connect the inner and outer space of cell with a wire, will there be electricity?

There is a potential difference, but ions can not go through wires, right? Though there is a electric field, but there is no electron source, I am thinking the answer is no, or will there be some ...
5
votes
1answer
581 views

Are there any effects of elevated Cysteine levels on cognitive function?

I'm looking at this diagram of homocysteine metabolism and see two distinct pathways that the amino acid may get metabolized to: with vitamin B12 it gets converted back into methionine, while with B6 ...
5
votes
1answer
84 views

In which way would the yeast cell cope with the excess amount of methionine in the growth media?

I guess that when there is surplus of methionine in the cell it is incorporated in the TCA cycle as a succinyl CoA, with cysteine as a by-product. But now the cell has the surplus of cysteine. What ...
2
votes
1answer
678 views

What is the reaction mechanism of dopamine hydroxylase converting dopamine to norepinephrine?

The reaction is basically shown below. Dopamine hydroxylase is an enzyme, so I'm not sure if we can have a theory based on organic chemistry. On the other hand, maybe there is a theory that involves ...
3
votes
1answer
130 views

What is the length of anaerobic biodigestion stages?

I have built an experimental portable batch biodigester to process organic garbage. A 50L drum filled half with garbage, half with water and with some cow dung added for inoculation, is connected from ...
12
votes
3answers
31k views

What is a coupled reaction and why do cells couple reactions?

I was wondering what exactly a coupled reaction is and why cells couple them. I read the wikipedia article as well as several others, such as life.illinois.edu but I still don't get it. Could ...
5
votes
2answers
1k views

Is wiping with RNAse Zap enough to destroy RNAse activity?

From the RNAseZap MSDS, it is an SDS at some unknown concentration, maybe with some NaOH? Some other links suggest there is some NaOH as well. The Ambion site states that RNAseZap destroys RNAse ...
11
votes
3answers
2k views

Where does the 'C' in exhaled CO₂ mostly come from?

When a human being exhales CO₂, what is, by the numbers, the main source of carbon atoms exiting the body in this way? I mean what class of cells, or which tissues are the biggest on a pie chart of ...
0
votes
1answer
45 views

What are the physiological roles of Hydrogen sulfide?

I am thinking why hydrogen sulfide has its effects in the body. For instance, it is one Salmonella's virulence factor. I am not sure if such a balance equations holds H2O + H2S ←→ ... Actually, I ...
6
votes
3answers
1k views

Why do grapes not shrink when placed in strong sugar solution?

I tried an experiment. First, I placed grapes in pure water(hypotonic solution). The grapes burst because of endosmosis. Then, I placed new set of grapes in strong sugar solution(fully saturated) but ...
0
votes
1answer
107 views

Pathway mediates nitroglycerin-induced relief from angina pectoris [closed]

what kind of Pathway mediates nitroglycerin-induced relief from angina pectoris,please provide some idea...
44
votes
4answers
6k views

Why 22 amino acids instead of 64?

This question got me thinking about amino acids and the ambiguity in the genetic code. With 4 nucleotides in RNA and 3 per codon, there are 64 codons. However, these 64 codons only code for 22 ...
2
votes
1answer
50 views

NMR spectroscopy detection methods for proteins

While studying, I've stumbled upon a table comparing the sensitivities of different detection methods in NMR spectroscopy: "Direct", "DEPT" and "Inverse", where "Inverse" seems to be the most ...
0
votes
2answers
38 views

How do kidney cells excrete their own wastes?

The kidney is composed of tissues, and those tissues are made up of numerous cells - so how do these cells excrete their wastes? Lastly, are there any wastes in the venous blood (renal vein), what ...
5
votes
2answers
247 views

Why haven't land animals evolved beyond urination?

It occurred to me (while urinating) that this would seem to be selected against because water is a scarce resource. Why are we constantly losing water we don't need to through urination? What is ...
2
votes
1answer
48 views

What Biology topics are linked to the Nitrogen Cycle? [closed]

What other educational topics are linked to the Nitrogen Cycle? I am a Science teacher, and I need to organise my lessons. Thanks!
3
votes
2answers
718 views

Ill effects of urea and NH₃ on metabolism

What exactly does urea do that harms our body? Does it interfere with our cellular processes or disturbs the colloidal onchotic pressure of our blood? I have heard that NH3 damages the brain. What ...
3
votes
1answer
28 views

Why is Cysteine and Tyrosine used to calculate a sequence isoelectric point?

Why are the amino acids - cysteine and tyrosine used in isoelectric point calculations for a protein sequence, yet neither of them are positively charged molecules? and are not used in net charge ...
0
votes
2answers
21 views

Is this a valid definition of independent assortment?

"Allelic combinations separate randomly. I.e. a parent might be Aa and Bb for two traits but that doesn't necessarily mean the gametes will strictly be AB or ab but any of a number of combinations. ...
1
vote
2answers
20 views

How can histidine be classified both as positively charged and hydrophobic?

I saw the chart in this post Histidine aromaticity. Since I'm not allowed to comment and post a question instead of an answer, I have to ask my question in a separate thread. How can histidine be ...
6
votes
1answer
304 views

When writing about past research should I use the species name they employed or the modern version?

I am currently writing a literature review in which I am talking about the old research on the subject. When this research was carried out the species I'm talking about were classed under a different ...
0
votes
2answers
43 views

What are non-heritable changes to genomes?

I am told that mutations are heritable changes to the genome. So this begs the question - what are non-heritable changes to genome?
0
votes
0answers
12 views

Discuss the use of NMR Spectroscopy for polymorph detection in phamaceuticals [on hold]

Need to write a 2000 word essay on this title, any help/sources would be greatly appreciated
0
votes
1answer
43 views

What impacts penetrance of Huntington's disease?

From Principles of Life by H. Craig Heller, David E. Sadava, Mary V. Price: From what I understand, Huntington's disease exhibits varying degrees of penetrance depending on how many times the ...
0
votes
0answers
14 views

Which organism like to eat fat and oil? [on hold]

Fat and oil is high energy nutrient. But not so much organism utilize it as energy source. So I want to know what organism ;other than human, some carnivore that eat fatty meat; like to eat fat and ...
0
votes
1answer
13 views

Ways to measure effectiveness of a gene therapy trial?

I understand that Fluorescence in situ hybridisation can be used to measure the effectiveness of a gene therapy experiment/trial. But what are some other genetics techniques to measure the ...
-1
votes
1answer
43 views

Which (naturally selected) evolutionary process led to the development of egg-laying?

I understand that eggs were around before chickens, and therefore this age-old question isn't properly framed. But the idea still stands, there was a first egg-laying organism which modern chickens ...
-2
votes
1answer
16 views

Cells “grown in LB broth to an OD600nm” [on hold]

Cells "grown in LB broth to an OD600nm" What does the OD stand for in this?
3
votes
0answers
36 views

Does eating antacid (such as Magnesia) before meal have any impact on digestion?

During an anatomy lecture I heard of the importance of the acidity of gastric acid (e.g., killing microorganisms, dissolving food, being a factor for triggering further processes). If a healthy person ...
4
votes
3answers
69 views
+50

Why do I feel funny in my tummy when riding a virtual roller coaster?

I've ridden a virtual roller coaster on an Oculus Rift. I felt tension as I went up to the top, but more interestingly I actually felt my stomach drop when I went down the steep drop on the other ...
0
votes
1answer
41 views

What is the progressive evolutionary advantage that leads to flying?

As far as I understand, all life started as non-flying and flying came about by natural selection. What is the evolutionary advantageous "path" to flying? Or is there something else to explain this?
6
votes
4answers
490 views

If Evolution Is In Progress, Why Fight Extinction?

Natural selection is a central tenet of evolution. However, most biologists seem determined to prevent the extinction of the species that have been selected against. Why is this? Preservation of ...
2
votes
1answer
34 views

What is the difference between a phosphotransferase, a phosphatase, a phosphorylase and a kinase?

I've looked in several sources, but I'm still confused. This is what I have so far: A phosphotransferase catalyzes the addition of a phosphate group. A kinase is a type of phosphotransferase that ...
3
votes
1answer
60 views

XXY (Klinefelter's) & Trisomy 21 & X-inactivation

I read that X-inactivation doesn't tend to happen in males, but then when someone is XXY, they are a male because of the Y. However these individuals tend to live. So does that mean that ...
0
votes
1answer
32 views

What are the structual differences between DNA and RNA? [on hold]

How is the structure of DNA different from that of RNA?
2
votes
2answers
62 views

Book recommended for neurobiology

I am looking for a good explanatory book concerning Neurobiology. I am interested on how the brain works but prior to this I believe that I have to start learning things about the biology of neurons. ...
1
vote
0answers
14 views

Gene Therapy for Cystic Fibrosis Extension

Thank you everyone for answering my previous two questions on CF. I have decided to write a paper specifically on the use of viral vectors and gene therapy for cystic fibrosis. I was told by my ...
1
vote
0answers
19 views

C. elegans and nutrition

If there is ample amount of food, do C. elegans worms know when to stop eating or do they store extra energy? Could they put this extra energy to use by moving faster or putting more eggs?
3
votes
1answer
67 views

Mechanism of Muscle Growth

According to this video (sorry for the poor reference but it represents my level of understanding in physiology), muscle grow as a consequence of repairing micro-lesions. How are these micro-lesions ...
7
votes
1answer
94 views

How fast can a human run?

I'm a runner (cross country) and I'm always amazed at how fast Olympic sprinters are. There's a lot of hype about those in the 100-meter dash being the fastest in the world, and we're constantly ...
4
votes
2answers
133 views

The gender of offspring of Twins?

Given identical twin males, Michael and Douglas, Douglas and his wife have four children, all of whom are girls. Michael and his wife have only one child, a boy, and are expecting another. What are ...

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