25
votes
Accepted
Why are drug dosages so high in some mice studies?
Mice are simply different from humans; they have different metabolism, different lifespan, different body size.
Generally, for a first order approximation, one might scale simply by body weight to ...
- 47.2k
9
votes
Accepted
What are the potential dangers (if any) facing the twin girls recently born in China with their CCR5 gene modified?
Important notes:
I am not going into the ethical aspects of editing/removing CCR5 in human embryos, neither will I discuss potential effects of introducing that mutation into the human population....
- 4,401
6
votes
Accepted
Is it viable to make liquid potassium ferilizer through dissolving very small amounts of potassium chloride in water
the issue here is the chloride not the potassium. Potassium chloride is very soluble in water. but you could be killing your crops/garden when you spray it on.
Most plants do not tolerate much ...
- 28.3k
5
votes
Can one conduct “novel” research without an advanced laboratory? Has it been done by school pupils?
I can point to two published papers in which students performed useful experiments.
The present study (on the vision of bumble-bees) goes even further, since it was not only performed outside my ...
- 14.3k
4
votes
Did Mendel believe that proteins are hereditary substances?
The first person to directly indicate a linkage between the hereditary material and enzymes was Garrod in 1902, based on the observation of the hereditary enzymatic disorder alkaptonuria. This is ...
- 10.8k
4
votes
What were fed to the rodents in Calhoun's experiments?
I don't see any reason to think they were fed anything other than the standard rodent chow used in the labs at the time; the second link notes "hard pellets of food" which is the typical ...
- 47.2k
3
votes
Does beta-actin have to be consistent in Western Blots?
The long and the short of it is that your actin bands do not need to be consistent so long as you can normalize and have met the quite stringent conditions for normalization to be effective. For ...
- 13.9k
3
votes
What are the potential dangers (if any) facing the twin girls recently born in China with their CCR5 gene modified?
2019-09-29 update: the answer below is based on a scientific paper that seems to have a major flaw, see https://www.statnews.com/2019/09/27/major-error-undermines-study-suggesting-change-introduced-in-...
- 1,915
3
votes
What is a (preferably) flying carnivorous insect that hunts adult fruit flies at a rate that doesn't threaten extinction?
Biotic fruit fly pathogens / predators.
You don't need every single one for a basic project. Here are 2 types.
Parasitoid wasps
Parasitoid wasps lay eggs in larva.
Drosophila in the wild suffers ...
- 2,964
3
votes
Has there ever been a published experiment to take a viral "census" of a human subject's blood?
You wouldn’t try to isolate viruses, this being the 21st century. You’d perform metagenomics analysis, which is much more sensitive.
That’s been done several times. Two examples:
Anellovirus ...
- 14.3k
2
votes
What data would Meselson and Stahl have expected if DNA replication was dispersive rather than semiconservative?
A few baseline ideas should be understood. 1. The assumption is made that Meselson and Stahl's cell line at the start of the experiment contains DNA composed entirely of the $N_{15}$ isotope. 2. DNA ...
- 166
2
votes
Monitoring fish growth
Per your prompt, there are three new brands of fish food, but...
You have been using a standard type of food that has worked reasonably well.
I suggest you include the "standard" fish food as a ...
- 8,336
2
votes
Monitoring fish growth
This is a good experiment!
3 types of food: ok
9 tanks: ok
Apply different treatment randomly - no! You are right - no way to tell with random. It is like comparing McDonalds to vegan diet - you ...
- 2,964
2
votes
Accepted
What advantages could there be for using the unseen variant chosen by He Jiankui instead of the naturally occurring CCR5-∆ 32 mutation?
Possibly He Jiankui was using Cas9 without a template DNA. If so, this generates double-stranded breaks that are repaired through processes such as non-homologous end joining (NHEJ) that often ...
- 5,683
2
votes
Why didn't these scientists restore electrical activity in this pig's brain?
Restarting electrical activity would mean that at least parts of the brain become active again and possibly restoration of almost all cognitive functions. While this would be a tremendous scientific ...
- 4,401
2
votes
Accepted
Methods to obtain the mass distribution of an ensemble of bacteria?
Short Answer:
Flow Cytometry or Dynamic Light Scattering (DLS) might be the most "mainstream" methods out there that might give you a size or volume distribution. Then you need to do some ...
- 1,769
2
votes
Accepted
Has anyone tried the petri dish experiment with and without mask but at the side?
While I'm not sure about the petri dish experiment, I will answer the main question I think you're asking: how important is the air that escapes out of the sides/top of the mask?
This question is ...
- 3,338
2
votes
Accepted
Why is neutralizing important when carrying out the Benedict test?
Benedict's reagent is used mainly to test the presence of reducing sugars.
However, it can also be used to test non-reducing sugars indirectly. For that to happen, non-reducing sugars are first ...
2
votes
Accepted
What determines the physical appearance of a tangible amount of bacteria or viruses?
There is no one answer to this question, any more than there is a single answer to the question of what color, texture, or size a mammal is.
To get a sense of some of the diversity out there, the ...
- 6,997
2
votes
Methods to obtain the mass distribution of an ensemble of bacteria?
In addition to Markur’s answer, Coulter counters suck the cells through a small capillary (in an electrolyte solution), which also serves as a conductor in an electrical circuit. They then estimate ...
- 589
2
votes
What is the meaning of NF-kB (transcription factor) "activity"?
The word activity has at least two meanings in biochemistry. One is chemical activity as in the effective concentration of a chemical. This comes up a lot because biomolecules often behave non-ideally....
- 1,321
1
vote
Biology Experiment Algae pH & temperature help?
In general is a good idea to check the scientific literature in the subject. In the section "materials and methods" you could find how people do stuff like measuring growth or controlling pH....
- 747
1
vote
Am I reading this respirometer correctly?
No, you're misreading the scale several times. The scale divisions indicate "tenth of ten" = one, while you sometimes misread them as "tenth of one" = 0.1.
For example:
E2 is ...
- 715
1
vote
Can I imbibe seeds before sterilization?
Personal anecdote: Once I planned to sterilize seeds of Silene latifolia for tissue culture but after the first step (washing the seeds in water for an hour) I had to do other things and the seeds did ...
- 583
1
vote
Fluorescent protein tags and colocalisation
"Are protein A and B co-located?" The answer is that it depends. Since your test question included the word "necessarily", this means that the answer to the test question is no. All you have to do is ...
- 3,781
1
vote
Biology Intuition and Origin of the "facts"
Googling "landmark experiments in biology" came up with a lot of hits, what was wrong with the experiments cited in any of those works? Mendel's pea experiments should be easy enough to understand.
...
- 5,250
1
vote
How are fMRI responses to auditory stimuli measured?
I could have found this article earlier, but as things go, I didn't. But possibly it contains most of what can be said to this question:
Jonathan E. Peellej, Methodological challenges and solutions ...
1
vote
Measuring the Rate of Photosynthesis
One of the simplest measures of photosynthesis is just measuring how much your plants grow (i.e., weigh them). Of course this technique is imperfect because of other influences on growth, the amount ...
- 47.2k
1
vote
Definition of a Katal (unit of enzyme activity)
Although this is old news, as @R.M. has been good enough to provide an answer, I feel I should add my own. The reason is not that I think his answer is incorrect in any way — it is technically quite ...
- 26.6k
1
vote
Definition of a Katal (unit of enzyme activity)
A katal is indeed a specific amount of enzyme (rather than a reaction rate), but one which is measured with respect to the catalytic activity of the enzyme, rather than with respect to the number of ...
- 1,574
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