5
votes
1answer
719 views

The genetic and physiological origins of laughter?

This Wikipedia article defines laughter in many terms, such as... "a visual expression of happiness, or an inward feeling of joy" and "a part of human behavior regulated by the brain, ...
5
votes
1answer
53 views

Why are some plants frost tender?

Why do some plants have the ability to stand frost, while others can't? Does it have to do with the size of the water vacuoles in the plant cells?
5
votes
1answer
3k views

How do SDS-PAGE gels differ in a Bis-Tris system vs. a Tris-Glycine system?

Protein migrate differently in Bis-Tris and Tris-Glycine gels. I was curious about the actual reasons why. Do certain gel systems result in a tighter resolution than others?
5
votes
1answer
1k views

What is the distinction between F' plasmid and R plasmid?

Is there a difference between an F' plasmid that has taken up a chromosomal gene that conveys antibiotic resistance, and an R plasmid? Is a bacterium containing an R plasmid and yet lacking an F+ ...
5
votes
3answers
2k views

Why does so much variation exist within species?

My last phrasing of this question did not go down well, so I will try again. The genotype of species is not always the same. If you ask yourself why not all of these possible expressions except one ...
4
votes
2answers
252 views

Can animals make their own unsaturated fatty acids?

I know that animals can't make poly-unsaturated fatty acids (PUFA) and so require them from dietary sources. For eg.Omega -3 and Omega 6 fatty acids. My questions : Can animals synthesize other ...
4
votes
1answer
128 views

Why is Homo sapiens not categorized as an invasive species?

According to Invasive Species Advisory Committee (ISAC), the definition of the invasive species is “a species that is non-native to the ecosystem under consideration and whose introduction causes or ...
4
votes
2answers
84 views

The least complex animals with ability to dream

People can dream, dogs can dream, cats probably too when they are sleeping. What about other creatures? Can a bird dream? Do rats have dreams? Are there any studies about that kind of thing? What ...
4
votes
2answers
155 views

Do animals suffer from “Human” mental disorders?

It is tragic, but apparently Killer whales and Dolphins can commit suicide too (e.g. here)... This suggests they can become depressed. I wondered whether they were "clinically" depressed like many ...
4
votes
3answers
124 views

Abnormal Prolactin Level [closed]

I want to know what makes the balance of the Prolactin abnormal. Is that related to the presence of a nodule near the pituitary?
4
votes
1answer
97 views

Is it possible to condition the body to reduce bruising?

I do combat sports, and in these sports there are a lot of hits that can cause bruising. I've found that, over time, physical conditioning can reduce and/or eliminate the bruising to the point where ...
4
votes
2answers
595 views

How to convince suspension cells to adhere more tightly?

I'm developing a cell-based assay in 96-well plates that requires adherent cells, as they need to be washed at least twice during the protocol. I'm using in-house strains of HT1080 cells (some ...
4
votes
1answer
101 views

What are some examples of scaling laws in biology?

I've seen that metabolic rate scales logarithmically as function of mass for many animals over an extremely large span of parameters. What other scaling laws exist at the individual level?
4
votes
2answers
1k views

What is the function of nodes of Ranvier in axons?

In a neuroscience class I'm taking, it was explained that myelin covers axons in sections, the uncovered sections are called nodes of Ranvier, and signals propagate much faster in the covered ...
4
votes
3answers
178 views

How does natural selection favour large body mass and size (or so it seems)

I was walking through a park this afternoon and observed a few birds having fun flying around and it got me thinking why would natural selection favour birds with flesh at all if it hinders their ...
4
votes
1answer
95 views

Difference In Telomeres Between A Thale Cress Plant And A Methuselah Tree

From what I have read and understood telomeres cap off how many times a cell can divide before it can no longer divide and that is what causes aging. A thale cress plant apparently has a life cycle ...
4
votes
1answer
190 views

How does hemoglobin-free blood transport oxygen?

Snails... We have some kind of huge garden snails appearing lately (read since the last 10 years or so). Try as one might, it's impossible to avoid them when driving. These snails do not appear to ...
4
votes
3answers
138 views

Since Darwinian times, has there been any striking/notable effects of evolution on humans?

I understand that evolution is constant process that acts on a population in successive generations. Thus, it is obvious that evolution is happening. However, I'm curious as to the stricking examples ...
4
votes
1answer
4k views

Does mixing alcoholic drinks really make you more drunk?

There is plenty of anecdotal evidence ("beer after wine and you'll feel fine, wine after beer will make you feel queer") that mixing alcoholic drink types leads to a stronger effect, but I can't find ...
4
votes
2answers
119 views

Ultrasound during pregnancy

In a hospital I can see a long queue of pregnant women waiting for their turn for ultrasound. Is it safe to go through the ultrasound during pregnancy, especially during last few weeks? Is ...
4
votes
3answers
991 views

Is the theory of evolution being disproved by bats?

For some species the Darwin's theory evolution makes perfect sense. I can easily imagine how, for example, the giraffe has evolved to its current appearance: the natural selection was favoring ...
4
votes
1answer
160 views

Why would deers keep crossing a river full of crocodiles while some of them have been killed?

I recently watched a clip on Discovery Channel, where I saw deers crossing a river full of crocodiles, ignoring the fact that some of them would have been killed doing so. What could be an ...
4
votes
1answer
694 views

Is ovum + ovum fertilization possible for human?

In humans is it possible to fertilize a ovum with another ovum from the same female subject? I already found some works in which the ovum is fertilized by a somatic cell (see e.g. this ), but I am ...
4
votes
1answer
266 views

Human sleep cycles and dream times, what influences the timing and intensity? Sleep history included

I'm doing sleep and dreams research and have developed an iPhone application to help me track my bedtime, rise time, sleep onset and also mark dreams. The app also monitors overall activity overnight ...
4
votes
1answer
2k views

Do humans have Coelom?

Kimball Biology 5e says Coelom is the main body cavity of many animals. It is lined with an epithelium derived from mesoderm. Gilbert Embryonal Biology 9e says Coelom is the space between ...
4
votes
3answers
11k views

Does Human Female Meiosis II occur after fertilization with sperm?

I am reading the answer and I am getting confused by the sentence: At the end of meiosis I females have two daughter cells and meiosis II only occurs if and when fertilization occurs by a sperm ...
4
votes
1answer
912 views

How do caspase proteins kill a cell?

Wikipedia just says... The active effector caspases then proteolytically degrade a host of intracellular proteins to carry out the cell death program. Okay, but what parts of the cell do they ...
3
votes
1answer
17 views

What class of histone deacetylase (HDAC) inhibitor is sodium valproate (VPA)?

VPA is a known HDAC inhibitor. But I cannot find what class it is. What class is it? And is there any method of finding an answer better than floundering with Google?
3
votes
0answers
14k views

Does CPH4 exists? [closed]

I just see the film Lucy, it talks about a molecule called CPH4 which increase human capabilities. Of course it's a film and so it's not scientific facts. During an interview the producer says that ...
3
votes
1answer
45 views

How common is it to be pregnant with periods?

As you may know, some women claim that they have their period while they are pregnant. In the arab world they call it "Deer pregnancy", since when the deer gets pregnant, it still gets its' monthly ...
3
votes
2answers
82 views

How to use Autodock just for (re)scoring

I have some protein-ligand complexed that I have been docking with some other software and just want to use Autodock to evaluate those complexes. So, basically I just want to use it as a scoring ...
3
votes
2answers
86 views

Ni-NTA purification, problem with the chaperone protein

I'm trying to purify the protein by Ni-NTA affinity chromatography. It seems that my protein (size about 54 kDa) is co-purified with chaperone protein (probably GroEL - as the band is around 57kDa). ...
3
votes
1answer
70 views

Getting goosebumps at will

I can get goosebumps at will, regardless of the environment. Its mostly visible on my arms, and I can feel it on my head. It requires some level of concentration to achieve this. My questions are : ...
3
votes
2answers
246 views

How are two species with similar phenotypes identified as different?

How are two species with similar phenotypes identified as different? Have two different individuals that were thought to be different species ever been determined to be from the same species ( or ...
3
votes
1answer
59 views

Book recommendation on selective breeding?

I am looking for a good book that gives a nice overview of the science and technics of selective breeding. I am particularly interested in the use of population genetics to support decision in this ...
3
votes
2answers
53 views

Is half-a-tablet of X a substitute for a tablet of X/2?

This may be anecdotal. At the pharmacy earlier, the prescription called for a drug with X mg of the target chemical. The pharmacy however only had stock of a higher potency of the same brand. E.g. ...
3
votes
2answers
466 views

On which strand does the promoter sit?

My book keeps giving different indicators as to whether the promoters are on the coding or template strand. It says the -35 region in prokaryotes must be on the coding strand. It also mentions, that ...
3
votes
1answer
109 views

Sporophyte and gametophyte

My textbook says that in both groups of seedless plants (vascular plants, non-vascular plants) the gametophyte is a free-living plant, independent of the sporophyte. I don't understand this statement ...
3
votes
1answer
80 views

Is there a molecular basis to intelligence?

Is there any explanation, gene(s) or whatever detected, that are co-related or explicitly related via mechanical bio-molecular (or at any other level) models that explain the higher or lower ...
3
votes
2answers
158 views

Why and how does complexity usually tends to increase through time?

The question of complexity is classic in the very first lectures of evolutionary biology where the teacher usually tries to tell the students that complexity does not necessary increases and that ...
3
votes
1answer
660 views

What is the definition of “dry weight” and “dry cell weight”?

As I understand it, the dry weight of something is its weight minus the weight of its water content. Is this the definition? What about dry cell weight?
3
votes
1answer
105 views

Evolutionary Cell Structuring

I'm a total novice when it comes to biology, and I'm really just looking for an answer to a question that has been posed to me by people who deny evolution fervently. Evolution dictates that we've ...
3
votes
1answer
48 views

Euthyrodism and goitre

I read in Tortora and Derrickson that goitre is associated with euthyrodism. How is that possible?
3
votes
1answer
135 views

Number of genes required to sustain life

Are there estimates of the minimum number of genes required to sustain life? In what I mean by life here, I don't include viruses.
3
votes
1answer
273 views

Is there an optimal composition and length for protein linkers in FRET?

I'm designing a protein that I'd like to use in FRET reporting. General idea on the shape is: FRETprotein1--Linker--CleavageSite--Linker--FRETprotein2. I would like to know what AA are best for the ...
3
votes
1answer
135 views

Identification of this fly?

So I find these flies every year in my mulch, and I've never seen them anywhere else. The mulch becomes full of their larvae, which I feed to my toad and lizards. There are so many that you can hear ...
3
votes
1answer
261 views

What hair color will result in someone inheriting both blond and ginger genes?

Both the genes for blond hair and ginger hair are recessive, so they need both parents to give the same gene for it to take affect. What happens when a person has 1 copy of a recessive gene and ...
3
votes
1answer
107 views

Are similar smells usually based on similar chemicals?

Building off of this question: Why does freshly cut grass smell like a watermelon?, is it usually the case that things that we perceive as having similar smells are, in fact, the same or a similar ...
3
votes
3answers
344 views

What is the viability of Intelligent Design as a supplement to chemical abiogenesis and Darwinian Evolution?

First of all I am not endorsing Intelligent Design (Wikipedia link); I'm asking this because I (someone who does not have a background in biology, organic chemistry, or philosophy) got into a ...
3
votes
1answer
109 views

Are any organisms known to use meiosis I to create non-identical offspring asexually?

So, there are numerous species of animals who use parthenogenesis, but to my knowledge the reproduction is clonal. That is, the offspring are identical to the mother. Are there any documented cases ...

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