22
votes
4answers
2k views

How do trees manage to grow equally in all directions?

I was walking down a road with these beautifully huge trees when this question occurred to me. Large trees with many thick branches have to grow equally in all directions, or they would tip over. Is ...
11
votes
1answer
2k views

On the genetics behind caste marriages

I am in India where it is typically a custom to marry within one's caste. Basically the caste system originated with roots in people's professions - Each of priests, carpenters, troupers, etc had a ...
34
votes
4answers
2k views

What exactly are computers used for in DNA sequencing?

I've thoroughly read the Wikipedia article on DNA sequencing and can't get one thing. There's some hardcore chemistry involved in the process that somehow splits the DNA and then isolates its parts. ...
14
votes
1answer
583 views

How fast will cells lyse under hypotonic conditions?

Routinely, lysis of cells with hypotonic solutions is carried out along with some physical (douncing) or enzymatic (lysozyme) method to break open the cells. If one were not to do any of these and ...
12
votes
1answer
8k views

What is the significance and method behind Ramachandran plots?

My PI showed a Ramachandran plot in class today with minimal explanation, but I'm interested in finding out more. I understand that the Ramachandran plot shows the relation between the omega phi and ...
5
votes
3answers
147 views

Measuring reverse transcriptase activity in E. coli

Goal: To quantify the HIV-1 reverse transcriptase (RT) activity for a number of mutated RTs. Idea: Put RT into a vector in E.coli. Deliver GFP mRNA to E.coli. RT will process the mRNA. The ...
10
votes
1answer
355 views

Foveal ganglion cell density (Tay-Sachs Disease)

I’m currently reading on Tay-Sachs disease and have stumbled upon something regarding the typical “cherry red” macula symptom. On the one hand it is mentioned that the macula is almost devoid of ...
10
votes
1answer
147 views

What determines when a virus becomes a “new strain”?

The reason we cannot find a cure for the common cold is because viruses mutate rapidly. Where do the mutations occur in the DNA/mRNA of viruses and does this have any effect on the protein level? what ...
24
votes
1answer
653 views

How did viruses come to be?

My question is out of curiosity and got me thinking. How did viruses with the head, tail and tail fibres actually evolve? These viruses look more like machines than biological entities. Are there any ...
8
votes
1answer
130 views

Is it the sphincter that flexes when a human pushes a bowel movement?

Of course the sphincter muscle is at the exit point. To use a toothpaste tube analogy, if I want to squeeze out some toothpaste, it does me little to no good to jostle the nozzle; I need to squeeze ...
8
votes
4answers
2k views

What's the aim of genetically modifying of foods/organisms?

On news, articles etc. experts talking about Genetically Modified Foods and Organisms often mentions about their disadvantages like, their potential to harm human health allergies may become more ...
12
votes
3answers
248 views

How do we know that dinosaurs were related to lizards and/or birds?

Do we clearly know what the living closest relative of the dinosaurs are? And connected to the first question, in scientific manner how do we know these relationship between extinct species and living ...
4
votes
0answers
110 views

Dimensionless number for blood volume

Comments from the question How is the blood volume of a living organism measured without killing it? by @Nico discussed that the time of blood recirculation scales with the size of the organism. I was ...
13
votes
1answer
108 views

Does a theory exist for the formation of thylakoid structure?

I'm interested in how the structure of the thylakoid forms into its characteristic highly rugose stacks of grana. What causes the thylakoid to invaginate and self-associate, albeit with what appear to ...
13
votes
2answers
582 views

Why are there N's after Sanger sequencing?

After sending a DNA sample for sequencing, the resulting sequence had N's in the beginning and end of the sequence. I know the N's mean that the computer can't tell what the base pair is, but why is ...
-1
votes
1answer
382 views

How To Avoid Macro-Evolution Confusion? [closed]

I regularly encounter students who believe humans came from amoebas and when asked why they often say Macro-Evolution has been scientifically proven. Macro-evolution is defined as evolution at or ...
3
votes
2answers
7k views

Can all mammals swim?

When I checked it seemed trivial to answer: yes, all mammals can swim. But research on the internet provided different information. I found: people and primates cannot swim, but can be taught how to ...
13
votes
2answers
1k views

How does a tree trunk sprout and grow after being cut?

After I cut trees into logs and remove the branches in winter, they start growing. They sprout out and grow completely normal looking stems and leaves and maintain them all summer. The sprouts mostly ...
5
votes
1answer
211 views

PCR primer in highly repetitive region

Is there any way to design a PCR primer if region of interest is highly repetitive (tens of kilobases only SINE's & LINE's)?
7
votes
3answers
290 views

Weighing 2 vertical halves of the human body

I had this thought while bathing: Assume a perfectly developed physical human body and anatomy in terms of size, dimensions and proportions. In theory, if I cut the body vertically into two exact ...
7
votes
3answers
532 views

Protein Biology Cheat Sheet

I'm looking find a cheat sheet for protein biology to stick on my desk to remind of some of the key principles of protein biology. I seem to remember the specific and complex principles in protein ...
4
votes
3answers
25k views

Small worm living in some kind of cocoon, what are these animals?

I am curious what animal is this. It is/lives inside some kind of cocoon, about 1 cm in length. They are attached to walls and to the ceiling, but sometimes they fall off. Inside the structure there ...
15
votes
3answers
1k views

Do probiotics survive digestion?

Pretty much this. I've been wondering if any of the yogourt and other "health" foods containing living probiotic cultures survive digestion to populate our intestines? If so, is there peer-reviewed ...
5
votes
2answers
194 views

First pass protein structure prediction

I'm working with a protein that doesn't have any homology to other proteins so it will likely require ab initio structure prediction. However, since I don't work for a structure prediction lab and I ...
5
votes
1answer
143 views

Descendants of dinosaurs

It is commonly accepted that birds are descendants of dinosaurs. It is nice that not all dinosaurs died out. Are there other animals, descendants of dinosaurs, that survived ? (Maybe not till our ...
6
votes
3answers
310 views

Compressing structural information in PDB files

There seems to be a lot of redundancy in PDB files. These files can of course be compressed with general-purpose compression programs like gzip, but I can't help but imagine that these tools are ...
6
votes
1answer
109 views

Mechanics of going from DNA sequence to metabolic network

My apologies for possibly a naive question. I'm a statistics type and have been asked to assist with analysis of metabolic pathways (and networks). However, I would like to have at least a layman's ...
24
votes
3answers
4k views

What actually happens when my leg 'falls asleep'?

Most people have experienced the temporary loss of feeling and tingling in their leg resulting from sitting in an abnormal position for a short while. Usually you get a loss of feeling in your leg ...
5
votes
1answer
114 views

How do I prepare a PDB for submission to the Protein Data Bank?

I have a couple structures that are nearly ready to be deposited in the PDB. Out of curiosity, I ran them through the ADIT's precheck tool and they failed with one error after another, as I lacked ...
7
votes
2answers
1k views

Altering the human genome

I recently had a conversation with a rather unusual gentleman who was, let's say, more than a little partial to conspiracy theories. He has this idea that governments are lowering "nanowires" from ...
20
votes
2answers
738 views

Why is rabies incurable?

I'm still not sure about the mechanics that lead to rabies being incurable. I know that it can be treated before any symptoms show up, but why is it that once symptoms show the person is a dead man ...
11
votes
4answers
285 views

What was the reason for some plant and animals to become giant in course of evolution?

The dinosaurs, mammoths, giant plants etc are known to be bigger than modern animals. I wonder why they had been lived and why they are not living now? I really don't know much but is it something ...
3
votes
2answers
389 views

Why do plants' leaves become enlarged in low light areas?

Why do almost all plants in shade have a smaller stem structure and larger leaf than that same species grown in a well lit, sunny area?
5
votes
1answer
73 views

How are the various classes of E coli genes determined?

Looking at some more detailed codon usage tables, genes may be further clustered into three gene classes: Metabolic genes, highly expressed genes during exponential growth, and horizontal gene ...
10
votes
1answer
160 views

Were dinosaurs 'hot-blooded' or 'cold-blooded'?

Were dinosaurs hot-blooded or cold-blooded? NOTE: The popular term 'hot-blooded' means having an internally maintained average body temperature, which is generally more than that of the surroundings, ...
13
votes
5answers
355 views

Can species back-evolve?

One of the tenets of Darwin's theory is the survival of the fittest, ie adaptation of features that allow a species to adapt better to its surrounding environment. I am wondering that given the right ...
17
votes
3answers
338 views

How is the blood volume of a living organism measured without killing it?

How is the blood-volume of an organism measured without killing it? NOTE: The blood-volume of an organism is defined as the total volume of blood present inside that organism.
22
votes
1answer
361 views

Phagemid display

If I'm using a bacteriophage for phage display and I'm trying to avoid avidity effects by using a helper phage what would be the best way to maintain a large library size while keeping everything ...
7
votes
1answer
181 views

What is the fastest way to build an alanine scanning library?

For interfacial studies, I would like to build an alanine scanning library for one of my proteins examining 20 sites. I will ultimately express the gene using E.coli cell-free protein synthesis. I ...
7
votes
1answer
215 views

What is the difference between copy number changes with and without allelic imbalance?

I require some clarification on copy number aberrations (structural gain and loss in chromosomes). From what I understand, gain/loss per se can be divided into two types. Consider two alleles, A and ...
5
votes
4answers
5k views

RNA or ribosome, which one moves during translation?

During translation ribosomes decode the genetic information present in the mRNA and protein synthesis takes place. During this process which of those two does move, the ribosome or the mRNA?
9
votes
1answer
834 views

How does population stability evolve?

The number of individuals constituting a population is called population size. Over time population size does not remain constant, it fluctuates to different extent over generations because of ...
13
votes
1answer
205 views

How straightforward is in vitro compartmentalization?

in vitro compartmentalization (IVC) is one of those technologies that everyone knows about, talks about, but never actual does due to the rather technical difficulties in setting the system up. I was ...
11
votes
2answers
182 views

protocol for pulldown of DNA breakpoints?

Is there any method to do pulldown enrichment of DNA breakpoints from a cell? I have found this paper reporting a method to enrich for the DNA single-strand breakpoints from meiotic recombination ...
3
votes
2answers
1k views

Neutralizing TCA washes

Trichloroacetic Acid (TCA) is commonly used for protein precipitation but the wash waste needs to be neutralized prior to disposal. What exactly is required to effectively neutralize TCA waste? Do I ...
5
votes
2answers
409 views

What does the 34/70 in Saccharomyces pastorianus Weihenstephan 34/70 stand for?

I've searched everywhere. No Wikipedia page. No information on NCBI. I searched all occurrences of 34/70 in some primary research articles! The best I've found is this brewery forum where someone ...
28
votes
3answers
14k views

Why do eukaryotic organisms have introns in their DNA?

We touched on introns and exons in my bio class, but unfortunately we didn't really talk about why Eukaryotes have introns. It would seem they would have to have some purpose since prokaryotes do not ...
5
votes
1answer
317 views

How long does it take to stain cells?

I'm never going to run these type of experiments but I do need to have a good idea of their timescale. After I fix my cells, if I stained my cells with histology stains like DAPI, Fluorescein, and ...
6
votes
1answer
152 views

What temperature should mammalian B-Cells be stored at outside of the incubator?

I'm working with murine B-cells. The general protocol is to keep cells on ice to keep them from dying but I've noticed that it makes these cells aggregate and precipitate out. I've heard suggestions ...
8
votes
2answers
9k views

Glomerular Filtration Rate

In practice, when you have vasoconstriction of the glomerular capillaries and subsequently an increase in blood pressure, glomerular filtration rate increases. However, this seems counterintuitive to ...

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