5
votes
1answer
86 views

Why might you NOT observe a tradeoff between two life-history traits?

I have traditionally thought of and heard about life-history traits (e.g., size at first reproduction, number of offspring, size of offspring, survival, etc., etc.) as drawing from a finite pool of ...
3
votes
0answers
80 views

Can cats use ketone bodies as only source of energy?

I recall reading that much of the energy a cat produces from its food comes from proteins which I assume would produce energy via being catabolised into amino acids which in turn, if glucogenic, would ...
5
votes
2answers
114 views

There are linear and rotary molecular motors in the cells. Do any of them have a fixed or stable frequency or speed?

Are there any linear, rotary or oscillatory molecular motors in the cells which can have fixed frequeny and which can be used as a reference for elapsed time timer? This question is with relevence to ...
2
votes
1answer
100 views

How Do Acid and Base Loving Plants Get Enough PO4?

Acidic and Basic soils experience phosphate sequestration through binding with either calcium, aluminum, or iron. How do plant that thrive in acidic and basic soils obtain the necessary phosphate? ...
3
votes
0answers
104 views

What's the Mechanism of Paradoxical Excitatory Effects with Sedating Antihistamines? [closed]

I've been reading the British National Formulary 65 (BNF-65) and it mentioned that in some, especially at higher dosages, sedating (first-generation) antihistamines, can produce paradoxical excitatory ...
2
votes
2answers
2k views

Which hormones can cross the blood brain barrier?

Can hormones such as testosterone, aldosterone and estrogen cross the blood brain barrier? I looked on Wikipedia and there no mention of it in the testosterone article. Through Googling around I also ...
1
vote
1answer
387 views

Number of introns in a genome

Humans have approximately 21000 genes but they probably make more proteins than that. This has been explained by many mechanisms like alternative RNA splicing. My question is - If what we call as ...
0
votes
2answers
50 views

3 fates of this matter

When an animal eats something, it obtains matter and energy right? But, what are the 3 possible fates of the matter and 3 possible fates energy. I don't understand what they are even asking. What ...
5
votes
1answer
257 views

Variations in Genome Sizes

Why is there wide variation in genome size amongst groups of protists, insects, amphibians and plants, but less variation within groups of mammals and reptiles?
1
vote
2answers
44 views

Why don't raisins lose water when in air?

It is common that we soak raisins in water, and they acquire water by endosmosis. That means that the cells are permeable to water, right? Then why don't they lose water when kept in air? Or kept in ...
6
votes
2answers
2k views

What did we learn with Nazi human experimentation?

Was there actually any useful knowledge gained from the Nazi experiments on human test subjects? Wikipedia cites freezing and phosphine gas reactions, but I would like to know other potential results ...
2
votes
1answer
42 views

Variation in MHC in humans

What evolutionary process lead to so much variation in MHC? What is the advantage of having such variation?
6
votes
1answer
165 views

Why does radiation sickness cause hair to fall out?

As I understand it, radiation poisoning (acute radiation syndrome) is fatal because the radiation kills cells. However, why do victims experience hair loss at such an early stage in the process?
0
votes
1answer
267 views

Calcium for Humans: Supplements vs Fortified Sources

I am intolerant to meat and milk products, but purely natural foods don't contain enough calcium for the Recommended Daily Intake. Links 2 to 4 (but NOT 1) avouch a correlation between calcium ...
-2
votes
4answers
292 views

Does evolution take place universally?

Why does evolution (namely the evolution of primates into humans) take place both uniformly and universally on the earth? Why aren't there any creatures who have not taken the same evolutionary steps ...
2
votes
2answers
131 views

How did viruses learn to utilize the workings of a cell?

This is my first post here, so excuse me for its simplicity. Viruses can infiltrate a cell, overtake it and multiply. It has projecting fibers whose ends are shaped as kind of a "key" to a mobile ...
-1
votes
1answer
1k views

Female preference for males who are already in a relationship [closed]

A common saying is that women are generally more attracted towards men who are already in a relationship, and this phenomena does seem to have its own place in popular culture that is not matched by a ...
2
votes
1answer
31 views

How do processes of one osteocyte establish contact with processes of the adjacent cells within the mineralized matrix?

Are the processes and canaliculi formed and contacts established after the osteocytes are embeded in the matrix or are they formed during the embedding process itself. Is there any evidence to suggest ...
3
votes
1answer
54 views

Number of MHCs in neurons

I have read that neurons have proportionately less MHC molecules than other cells of the body. What is the advantage of this?
1
vote
1answer
183 views

Expression of plasmid genes

Are plasmid genes always expressed? If so, then isn't a bacterium wasting it's resources in expressing genes (like antibiotic resistance) which are not required in "normal" conditions? If not, then ...
2
votes
1answer
46 views

How essential is vitamin B3 to the diet?

I know this might seem contradictory since by definition a vitamin is an essential part of the diet but I have read that nicotinamide, a form of vitamin B3, can be synthesised from L-tryptophan. Is it ...
1
vote
0answers
16 views

histamine inter-cellular and cytoplasmic binding site

I noticed that HRH (histamine receptor) has an inter-cellular and cytoplasmic binding site of anti-histamines which are equal in binding energy. Does anyone know what is the function of the well ...
2
votes
2answers
180 views

Accuracy of a particular genetics test

I am a newbie in biology and I am simply trying to discover the field of genomics. Consider the question - Are genetic tests accurate? I don't believe they are as the genes may not provide the ...
1
vote
2answers
2k views

Are mature RBCs prokaryotic?

Mature mammalian RBCs have all the characteristics of a eukaryotic cell except that they don't have a nucleus, they don't have any cell organelles. Does this mean that RBCs are classified as ...
7
votes
1answer
459 views

How to reduce/eliminate cell clumping in suspension CHO cells, without using an anti clumping agent?

what is the best way to eliminate clumping suspension cells used for transfection. Anti clumping agents interfere transfection and hence can't be used. Though maintaining the cell density low helps, ...
6
votes
3answers
2k views

What evolutionary adaptations cause trees to grow tall?

I think there are some obvious costs for trees to grow tall. Carbon and other nutrients costs, maintenance cost, energy cost (for growing, to bring water (and nutrients) up to the higher leaves, ...
8
votes
3answers
145 views

Which part of the brain needs to be shut down to lose conciousness?

Whether it is mechanical (trauma), chemical (anaesthesia) or electrical - which part of the brain is shut down to cause loss of consciousness?
1
vote
1answer
55 views

Adaptability in immune system

I read somewhere that recently some people are trying to use harmless bacteria that live symbiotically in humans to express some portions of antigens of the harmful ones. Some people have raised ...
6
votes
1answer
2k views

Why does the heart use lipids (and not glucose)?

Fetal hearts use glucose as their primary metabolic substrate. Adult hearts use free fatty acids, which are less efficient (require more $O_2$ to synthesize the same amount of ATP); however, during ...
3
votes
0answers
319 views

Virus titre and copy number of integration

If I need to preform a genome-wide high throughput screen using pooled shRNA library infection followed by deconvolution by deep sequencing, how would I determine the optimal infection rate at which ...
1
vote
0answers
65 views

Why is a nicotinamide-tryptophan combination used to treat affective episodes in a few older clinical trials?

At least one of the journal articles that reported on such clinical trials allured to the nicotinamide-tryptophan pathway that I assume must be related to the metabolism of tryptophan into serotonin ...
4
votes
1answer
163 views

Are the brains of any herbivorous animals capable of utilising ketone bodies as an energy source?

I ask this question because earlier today I heard from a lecturer at my university that a sheep's brain cannot utilise ketone bodies as an energy source and hence with insufficient glucose supply for ...
2
votes
1answer
575 views

Molecular Evolution: Mrbayes never stops?

When I use my own data to build Bayesian phylogenetic trees using the software Mrbayes, after many generations, it never reaches stopping status (namely, the average standard deviation of split ...
9
votes
5answers
251 views
+50

Introductory biology text for an outsider

I'm a maths major and I have an interest in learning biology. I know very, very little; I know how babies are made and that's about it. Could anyone recommend a stimulating text to read for it's own ...
1
vote
1answer
263 views

L1 - L5 layers of the brain

I have read in some papers about the layers L1-L5 of the brain (e.g. in this paper). I could not find a definition of these layers. I have found information about the layers V1-V5 in the visual ...
8
votes
2answers
996 views

Free software for measuring parts of an image? [closed]

Let's say I have a picture of an insect wing and a ruler on the same image. Is there any computer program that I can use to calibrate with the ruler and then get a measurement on the wing length? ...
2
votes
1answer
179 views

Genetics problem-Height of a plant

An inbred strain of plants has a mean height of 24cm. A second strain of the same species also has a mean height of 24cm. When these plants are crossed the F1 are also 24cm in height.However, when the ...
2
votes
1answer
71 views

How correlated are proximally related CpG sites in human DNA?

Cytosine residues in DNA that can be methylated (i.e. CpG sites) are likely to be in the same methylation state if they are geographically (proximally) close together. I can only find one paper that ...
2
votes
2answers
54 views

What is the role of hippo signalling in oral squamous cells

What role do hippo signalling have on squamous cells in oral health & diseases
2
votes
1answer
63 views

Extract bacteria from compost?

I'm working on a project where I need to find certain cellulolytic bacteria. I was looking at this list : ...
1
vote
0answers
22 views

Do Total Gastrectomies leave individuals more open to infections from eating unsanitary food?

I ask this because the stomach plays a role in sterilising food and hence without one it follows that perhaps one would be more prone to getting intestinal infections.
1
vote
1answer
53 views

Does sympathetic nervous system acts bilaterally for pupil dilation or other two sided organs?

The question might seem weird. Does sympathetic nervous system acts 'bilaterally' meaning if you shout to a person's left ear a loud noise (e.g. by headphones), will it activate sympathetic system ...
1
vote
0answers
37 views

Root hair formation in Arabidopsis

In arabidopsis, 2 cell types arise in the root epidermis : root hair cells and hairless epidermal cells. The immature epidermal cells that are in contact with 2 underlying cells of root cortex ...
2
votes
3answers
196 views

Mechanical cause of loss of consciousness

Consciousness is an electrical and chemical interaction in the brain, caused by neurons firing and chemical interactions. How does a mechanical "force" cause this to stop working? i.e. How does a ...
3
votes
1answer
321 views

Are there any 6 limbed reptile fossils?

Were any 6 armed "tetrapod" fossils ever found? I've seen some lobe finned fish with two sets of shoulders in an evolutionary bio book... I'm curious because I'd like 4 limbed and 2 winged dragons to ...
3
votes
1answer
88 views

How do muscle relaxants work?

Do they act directly on the muscle and actually relax muscle tissue and ease spasms, or do they just prevent your brain from receiving signals that inform you of tight muscles? In the latter case, ...
3
votes
1answer
73 views

What's the mechanism for pain-induced swoon?

Is it true that people will pass out when subject to pain too much to bear, or there's no such threshold? What's the reason for passing out under acute pain, even if no physical injuries occur (e.g, ...
6
votes
1answer
293 views

evolutionary reason behind sharing the same path for food and air?

What is the evolutionary reason behind sharing the same path for food and air? For example, we have a nose and lungs, yet they are linked by the pharynx, which is shared with the mouth and ...
1
vote
1answer
144 views

how to clone a gene fragment in two direction as sense and antisense in vector

I have a sequence ATG GGG CCC TTT AAA TAA and want to use it as antisense RNA in my vector. How should I clone it? I am confused with the direction of my clone. I looking for the direction and ...
3
votes
1answer
173 views

Are human feces and urine merely a subset of the food and liquid we eat and drink?

In other words, does the body actually ADD ANYTHING TO urine or feces? As the food and drink makes its way from our mouth to our toilets, does the body add anything to it along the way? Or, is the ...

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