8
votes
1answer
212 views

Finding DNA from Amino Acid sequence problem

My attempt: First I took the single letter AA codes and made them amino acids. So, the first one is Trp which is 5'-UGG-3'. From this I got the DNA sequence 3'-CCA-5'. However, the correct ...
9
votes
2answers
145 views

Why is selfishness the 'obvious' strategy?

Thinking of behaviours an organism can adapt, at the very base an action can always be either selfish or altruistic (cooperative). Usually, selfish behaviour is assumed to be the preferred choice and ...
15
votes
1answer
400 views

How fast does the rotor in ATP synthase spin?

I'm sure the exact frequency varies, but does anyone know roughly how many revolutions per minute / second the rotating center part makes?
4
votes
1answer
309 views

Finding exons in DNA problem

My attempt: I looked for the TACs because I thought this would be AUG in mRNA and ultimately Methionine (the start codon). But apparently, that's not how you do this problem. Im confused because ...
11
votes
3answers
439 views

How did the human brain evolve?

A common question posed is, "how did the eye evolve?", because the eye is so complex. However, this has been answered rather clearly and there are several examples around the world of animals in ...
10
votes
2answers
513 views

Could hydrogen replace oxygen in cellular respiration?

I was wondering what oxygen actually does in the body. I have seen a few answers to other questions that involve the electron chain and I am really not sure what that is. So I was wondering what ...
7
votes
1answer
188 views

Why is the Patellar reflex not triggered when the tendon is extended slowly?

I have been previously told that the Patellar reflex (knee-jerk-reaction) exists to prevent the hyper-extension of the patellar tendon. Yet if the impact to the tendon is delivered slowly - i.e. by ...
2
votes
0answers
237 views

Turn off multithreading in pymol [closed]

By default, pymol seems to grab the number of cores on the system for rendering. How can I force it to only use one core? Motivation: I have a large collection ...
11
votes
1answer
752 views

Is there an evolutionary advantage to crying when sad?

It seems as though the act of crying when sad does nothing to relieve that sadness. Is there an advantage to crying from an evolutionary perspective, or is it the end result of a different process? ...
12
votes
1answer
176 views

Have any mutations or genetic loci been associated with exceptional longevity in humans?

Individuals that avoid age-related diseases into later life are known as 'exceptional survivors', and have increased longevity compared to their 'controls' (those that were born at a similar time, yet ...
5
votes
2answers
7k views

What is special about the N3 buffer for Qiagen minipreps?

For those who use Qiagen miniprep columns, they may be aware that the P3 buffer is the acetic acid step to neutralize cell lysis. They may also be aware that the Qiagen P3 buffer cannot be ...
11
votes
2answers
2k views

Will humans and animals be harmed by frequencies outside their hearing range?

The human ear (for example) is sensitive to frequencies from 20Hz to 20kHz. Any sound beyond that limit would not be heard by us naturally. Will it harm us (effect our ability to hear) when we hear ...
13
votes
4answers
1k views

Could we transmit smells electronically?

We can encode sound and images in radio waves and send them, but presumably there's some physiological reason that we can't easily make a picture or video of a smell. Could we realistically break ...
16
votes
5answers
6k views

Does red light preserve your night vision?

A number of companies have started marketing LED lamps that can be switched to a red mode. The claim is that red light is less harmful to one's night vision. Given that our eyes are less sensitive to ...
19
votes
1answer
2k views

Why do stars disappear when I look at them?

I've noticed that when I'm out at night stars seem to vanish when I focus on them. I assume the reason is physiological and not astronomic. Why does this happen? I would expect that things would be ...
24
votes
4answers
1k views

Why do men have nipples?

I'd be tempted to call nipples in men vestigial, but that suggests they have no modern function. They do have a function, of course, but only in women. So why do men (and all male mammals) have them? ...
11
votes
3answers
1k views

What happens to dextrorotatory amino acids in humans?

As indicated by this question, most of the amino acids in the human body have the L-chirality. As enzymes also have handedness, what happens to the D-amino acids that end up within the human body? Are ...
7
votes
2answers
228 views

What are key factors when evaluating and comparing miniprep columns?

I'm looking to comparing different protocols for minipreps for plasmid DNA purification. What factors should I be looking at? A few things come to mind: Cost Yield Time per step Replacement with ...
11
votes
1answer
216 views

In which order did the cells of the immune system evolve?

Thinking about how complex the interactions between different types of immune system cells (T-helpers, T-Killers, Phagocytes, B-Cells etc.) are, it's fascinating how they all combine to get the ...
6
votes
1answer
401 views

How Do Adherent Cells In Culture Attach To A Plastic Dish?

I am particularly interested in MC3T3-E1 cells (mouse fibroblasts), which are adherent cells. Are hemidesmosomes involved in anchoring the cells to the plastic dish? What (if any) other molecules are ...
13
votes
1answer
15k views

Are mosquitoes repelled by high frequency sound?

I am totally confused whether ask this question to physics or biology stackexchange. I downloaded a mobile application which claims to repel mosquitoes. This application basically produces sound from ...
18
votes
1answer
519 views

Do trees age on a microscopic level?

Most animals age via at least two mechinisms: at a "macroscopic" level, basically wear and tear to the point where (on evolutionary time scales) it's more genetically advantageous to optimize for ...
4
votes
1answer
160 views

What are minerals (other than zinc) that the human body cannot store

It is known that zinc is an essential mineral that the body cannot store. What are other minerals, especially metals, that the body cannot store? (other than water-soluble vitamins such as vitamin B ...
12
votes
3answers
30k 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 ...
15
votes
3answers
462 views

Why do some trees have a life span, while some don't?

I have heard that there is no limit on the growth of trees, but then why do some trees, such as boxelders and poplars, tend to live shorter than redwoods, for example? Some advertisements for improved ...
8
votes
2answers
241 views

What are the frequency ranges of most marine mammal vocalizations?

I am trying to determine a list of frequency ranges into which marine mammal vocalizations fall. Ideally, I would like a list showing where the most popular marine mammal vocalizations fall, followed ...
12
votes
3answers
9k views

How many agarose gel bands are typical for circularised DNA

I am aware that circular DNA can be both relaxed and super coiled. However when running an agarose gel of the circular plasmid along with singly digested plasmid with BamHI and HindIII, I see 1 band ...
2
votes
0answers
94 views

Has anybody used Evrogen's DSN-normalization protocol for cDNA normalization? [closed]

I found the link to a commercial product by Evrogen to normalise cDNA samples for gene discovery projects here: http://www.evrogen.com/technologies/normalization.shtml The most up-to-date reference ...
8
votes
1answer
864 views

Under what circumstances and why is terrific broth preferred to LB broth for E.coli growth?

Terrific Broth will result in a greater density of cells compared to LB but I have certainly seen it isn't as effective for the protein production of certain proteins compared to LB or defined media. ...
6
votes
1answer
153 views

Does muscle growth trigger angiogenesis?

So heavier people generally have more blood than lighter people (this is why heavier people generally need to take higher doses of medication for the same effect of medication). They also have more ...
6
votes
1answer
721 views

Does anyone have any TOPO directional cloning tips? [closed]

I'm just about to start working on a TOPO cloning after I couldn't get it to work with standard restriction/ligation. Does anyone have any tips for TOPO cloning?
7
votes
1answer
104 views

How can I normalize mRNA samples for sequencing?

Is there an easy, inexpensive, not too labor intensive way to normalise mRNA samples so that even though one loses information of gene expression levels, each of the transcripts in the transcriptome ...
8
votes
2answers
554 views

Is it possible to live without health problems sleeping one day and not the other?

Basically, I want to know if it would be humanely possible to sleep one day, skip the next, sleep, skip, sleep, skip, etc, with a 8 hour sleep time. If you need any extra information, let me know.
7
votes
1answer
46 views

Which functional annotations could be useful?

Analyzing a genome, for a generic gene, which functional annotations (e.g from Gene Ontology) can help understanding its meaning/function or, at least, provide helpful informations? Annotations of ...
16
votes
2answers
933 views

Why is 'Grudger' an evolutionary stable strategy?

I am currently reading 'The Selfish Gene' by Richard Dawkins, which I am sure many here have read. The topic are evolutionary stable strategies (ESS) regarding cooperation. I apologise for the long ...
5
votes
2answers
169 views

Why do the brains of cocaine-users shrink faster than the brains of non-cocaine users?

http://news.sciencemag.org/sciencenow/2012/04/cocaine-may-age-the-brain.html?rss=1 Cocaine-dependent individuals showed a significantly greater-than-normal age-related decline in gray matter in ...
5
votes
1answer
194 views

How do plants intake minerals through their leaves?

How do plants intake the fertilizer when it is sprayed all over the leaf surface as a foliar feed?
14
votes
2answers
152 views

Relationship between our microbiome and personalized nutrition

Recently, it has been asked whether there are 'metabolic types' between humans that can benefit from a sort of personalized nutrition. One answer suggested that one discerning factor could be the ...
9
votes
2answers
5k views

Why is PEG important for efficient yeast transformation?

One way to do an yeast transformation is by using lithium acetate, a single-stranded carrier DNA, and PEG (1). I was wondering why is the polyethylene glycol important for the efficient ...
8
votes
2answers
136 views

Why are melodies/harmonies perceived as pleasurable by humans?

Is there any evolutionary advantage to finding melodies or harmonies pleasurable? Does the ear pick up these particular oscillating waves differently from other sounds, and if so, how does that affect ...
6
votes
3answers
199 views

Genetic effects on personality

It is said that genes are partly responsible for the choices we make in our life; our genes help to create our environment, and then that environment can influence our personality. So, beside genes, ...
6
votes
2answers
227 views

Is there such thing as a generic “metabolic type”?

A while ago I picked up a book called "Eat right for your metabolic type". The book discussed the effects of the endocrine system on the overall shape and the speed of metabolism. The book outlined ...
6
votes
1answer
674 views

What happens to a human body once a sugary snack is consumed?

I'm looking to understand the effects of sugary snacks and/or drinks on a human body. I'm particularly interested in the timing of the ingestion versus various hormonal levels that may be circadian in ...
10
votes
2answers
244 views

What can the timing of human urination tell about the human's physical condition and circadian rhythms?

I've noticed a peculiar phenomenon. A subject drinks 400 ml of water, then observes time until the urge to urinate is felt. The time is 15 minutes. The subject releases water. 14 minutes later another ...
19
votes
4answers
6k views

How many genes do we share with our mother?

Somewhere I have read we share more than 99% of our genes with every other other person and 98% of our genes with chimpanzees. What does this mean? Don't we share 50% of our genes with our mother and ...
4
votes
1answer
176 views

From inflammation to sickness and depression: when the immune system subjugates the brain

Recently, some research, for example this article has proposed that inflammation can cause innate immune cells to produce pro-inflammatory cytokines that act on the brain to cause sickness behaviour. ...
7
votes
1answer
3k views

Why is Hydrofluoric Acid so dangerous if its a weak acid?

I've read that Hydrofluoric acid (HF) is extremely dangerous to touch, but what exactly makes it so toxic? It's weak acid ($K_a = 7.2 \times 10^{–4}$) and dissociates approximately 1/1000 as much as ...
8
votes
1answer
1k views

Does the use of “var”, “x”, and/or “ssp” in a scientific name provide specific information?

What exactly does it mean when a plant has a scientific name that specifies a vairety, for example Nothofagus solandri var. cliffortioides, or when the name includes an "x", as in Populus ...
19
votes
4answers
3k views

Do trees really get a large share of their mass from the carbon in the air?

I remember hearing that trees and other plants actually obtain a large amount of their mass from the carbon floating in the air, not the ground beneath them. Does the makeup of air actually contain ...
8
votes
0answers
79 views

Using the IMGT/GENE-DB service to find RSS

I'm trying to get the data for the Human and Mouse 12 and 23 Recomination Signal Sequences (RSS), to run a classification algorithm on it. I'm not a biologist, so I apologise in advance for my ...

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