Most Popular
1500 questions
14
votes
2 answers
Percentage of genome devoted to regulating gene expression
Recently I've been studying the p53 tumor suppressor gene as a model for regulation of gene expression. It's amazing how many different post-translational modifications are known to regulate p53 activity, and how many different factors are involved…
Daniel Standage
- 5,741
- 3
- 29
- 62
14
votes
2 answers
What is the morphological difference between Leydig cell in human and pig?
The pig is only an example, just an animal. Leydig cells have protein inclusions (Reinke crystals) that are mostly made of crystallised lipofuscin. They are secretory inclusions i.e. cells formed in secreting cells.
An example of Leydig cell in…
Léo Léopold Hertz 준영
- 5,149
- 6
- 40
- 90
14
votes
3 answers
How long can E. coli stocks be stored at -20°C?
I'm volunteering for a biohacker lab - biocurious in Sunnyvale. The have a pretty good set of equipment - gel boxes, incubators, but they don't have a -80°C freezer yet.
I'd like to set up some glycerol stab stocks of some E. coli strains, but…
shigeta
- 28,244
- 2
- 60
- 120
14
votes
1 answer
Why does RNA adopt an A-form helix?
RNA is known to form an A-form helix, while DNA generally forms a B-form helix under physiological conditions.
From left to right: A-form DNA, B-form DNA, Z-form DNA. Image created by Richard Wheeler
The preference of RNA for the different…
Mad Scientist
- 9,184
- 10
- 46
- 73
14
votes
2 answers
Large grey bird at creek mouth (east of Toronto)
What species of bird is this?
Spotted at the mouth of Graham Creek at Newcastle Marina (Bond Head), Lake Ontario, Canada
September 9, 2023
The bird was roughly 18 inches tall; dark grey body; light grey head and neck; yellow beak
User1974
- 852
- 6
- 23
14
votes
4 answers
Questions to ask to a panel of people that will be sequenced
Some genes have been shown to be associated with left-handedness.
Working with some clinicians, I've recommend them to ask their patients (whose genome will be sequenced) if they are "right or left-handed".
It's a simple phenotype (without any…
Pierre
- 263
- 1
- 8
14
votes
5 answers
Explaining "paraphyly" for the layperson?
I was a molecular biology major a while ago, but I never think I really understood cladistics TBH. Now reading about paraphyly, it shows this:
In this phylogenetic tree [second image], the green group is paraphyletic; it is composed of a common…
Lance
- 759
- 3
- 12
14
votes
2 answers
If I graft two trees together while young, will they grow as one plant?
If I were to graft two apple saplings together -- by bending the tops toward each other and lashing them together -- will the plants grow as one and benefit from one another, or will they be fighting each other for root space and light? If they…
J. Musser
- 3,717
- 6
- 39
- 75
14
votes
1 answer
Why do cartilaginous fishes not excrete ammonia?
My teacher taught me that bony fishes are ammonotelic while the cartilaginous fishes are ureotelic, but why does that happen? Why do cartilaginous fishes not excrete ammonia?
Voldemort
- 151
- 5
14
votes
1 answer
What do the signs +/+ +/- mean in this image?
I don't understand what this graph is supposed to explain, especially what the signs +/+ or -/- mean. I just know it characterises some rats.
Pao
- 423
- 2
- 4
- 8
14
votes
1 answer
Blood Pressure: Significance of difference between systolic and diastolic
I wanted to understand what is the difference between systolic and diastolic readings of blood pressure. I understand 120-80 to about 100-60 is considered normal but does the difference in the two values in the reading hold any significance?
I have…
user4519
- 181
- 2
- 2
- 7
14
votes
4 answers
What are the benefits of elucidating the three-dimensional structure of a protein?
I have spent months as a student working on trying to form a tricky protein crystal. But I have never actually had explained to me why the structure will be useful. Once elucidated, what can we potentially learn from the structure in terms of…
James
- 11,305
- 8
- 58
- 112
14
votes
1 answer
Owl identification. Winter in Haliburton, Ontario, Canada
Is this owl a 'Great Grey Owl' or 'Barred Owl'? I'm thinking a Great Grey because it was quite huge - about 1.5 to 2 feet tall.
OrbitRob
- 647
- 4
- 15
14
votes
1 answer
Was the Harcourt COVID-19 isolate paper ever published?
One very interesting paper concerning COVID-19 was the paper describing the first isolation of the virus by Harcourt et al. However, this paper as far as I can tell was only published as a preprint in May of 2020 describing research done in January…
Imprisoned Rhesus
- 2,300
- 1
- 20
- 34
14
votes
3 answers
Is there any reason for the variation in mitochondrial DNA size?
As my textbook An Introduction to Genetic Analysis points out, yeast mitochondrial DNA has approximately 78 kb of genetic data, while the human mitochondrial DNA contains 17 kb. Is there any evolution reason for this drastic change in size? Also,…
LanceLafontaine
- 6,705
- 8
- 36
- 78