5
votes
2answers
3k views

Do octopuses have better eyes than humans?

I've read that unlike humans, octopuses have eyes "designed" the "right way", i.e. with the nerve fibers behind the retina, thus getting rid of the blind spot we humans have as well as theoretically ...
5
votes
4answers
3k views

Why Do Ruminants Require A Multi-Compartment Stomach To Digest Food?

Cows, camels, sheep, goats, etc being ruminants must chew their food repeatedly by regurgitating their food from their first stomach compartment and chewing their 'cud'. This then finer chewed ...
5
votes
1answer
989 views

If proteins have an overall charge, how do membrane proteins traverse through the hydrophobic region of the plasma membrane?

These two concepts seem almost contradictory, proteins have a net negative charge due to the amino acids in them each having a small negative charge, yet membrane proteins are able to exist traversing ...
5
votes
1answer
172 views

Free-flowing cells and those that are stuck together?

I've been thinking about the development of an embryo from the zygote stage. How is it that when cytokinesis takes place at that stage, the cells all stick together in a little ball, but later in ...
5
votes
2answers
322 views

Energy use by muscles, actual work done by muscles and more

Lately, I've started exercising in the gym and outside. I've also started to look at the details of food I eat. Food usually has a label saying the amount of energy is inside it. For example, some ...
5
votes
3answers
632 views

When to measure resting heart rate and blood pressure for following day-to-day trend?

I'd like monitor my resting heart rate and blood pressure to see how they are affected by regular cardiovascular training and other events in life. When should I take the measurements in order to ...
5
votes
2answers
565 views

What did pangolin scales evolve from?

Were they developed anew or a heritage from fish?
5
votes
1answer
2k views

How does the enzyme ATP Synthase use a proton concentration gradient to make ATP?

I understand what the enzyme ATP synthase does, but I'm not exactly sure how it does it. I've heard that it uses rotary catalysis, but how exactly does this work? How is the energy from the H+ ion ...
5
votes
2answers
323 views

When does oxidation destroy prions?

It seems like a no-brainer than oxidation, playing the, er, role it does in the universe, would destroy prions just like it destroys everything else. But when does it do that? I assume this has been ...
5
votes
1answer
83 views

Why is it always Sodium that we talk of in blood pressure?

Why is that we emphasize so much on sodium in blood pressure? I understand that it is a major extracellular ion, but, it also is tightly regulated. So when something is that tightly regulated, won't ...
5
votes
1answer
140 views

Why are mice with a single X chromosome and no Y chromosome males?

I was searching online and I read this article Mice can be male without Y chromosome and this is a part of it: The experiments demonstrate that there are multiple ways to make males, says Richard ...
5
votes
1answer
167 views

When did mouth pipetting stop becoming a way to handle liquids in a lab?

Almost all modern lab protocols have an addendum prohibiting pipetting by mouth, instead mandating that a Gilson pipette, a rubber pipette ball, or a serological Pipet-Aid be used. However, it was ...
5
votes
3answers
135 views

Why are sight and sound prerequisites for intelligence?

Edward O. Wilson, in The Diversity of Life wrote (emphasis mine): Ninety-nine percent of the animals find their way by chemical trails. […] Animals are masters of this chemical channel, ...
5
votes
3answers
86 views

Why is there a seeming dichotomy between mobility and photosynthesis?

At least among more complex organisms, I cannot think of any examples of highly mobile species (like animals) that also incorporate photosynthesis. Perhaps there are examples that I'm unaware of, but ...
5
votes
1answer
112 views

Are there terrestrial plants that thrive on sea water?

Given the existence of coastal deserts such as in the picture below, I was wondering whether terrestrial plants can survive on sea water alone? If yes, why then do coastal deserts exist, instead of ...
5
votes
1answer
78 views

Identify the plant

Can anyone tell me which plant or flower is this. I have found it in Darjeeling, West Bengal, India.
5
votes
1answer
168 views

Do humans have skin cells that trigger oxytocin release in the brain?

I was reading an article by Montgomery on the therapeutic effect of pets (Boston Globe, January 12, 2015), and I found this quote: All animals appear to have cells directly under the skin that ...
5
votes
2answers
63 views

What ways are there to determine how big genera are?

I want to look at genera as a whole, across the animal kingdom to determine the range of sizes of genera. I have examined species richness and genetic diversity (pairwise distance from sequence data ...
5
votes
2answers
439 views

Why cannot there be multiple sources for same species origins?

We often associate Africa as the geographical location of the origin of humans. Why cannot there exist multiple geographic locations of origin (given same environmental conditions)? The same ...
5
votes
1answer
126 views

Is it possible to express a mutant gene only in a specific tissue?

Imagine that someone tries to develop a knockout mouse for a gene, but this result in lethality for the homozygous. Is it possible to express that mutant gene only in a specific tissue of interest to ...
5
votes
1answer
281 views

Biological origin of shuddering during sleep

What is the biological origin of the following behavior: Sometimes, during the early, formative phase of sleep (when you have a gradually dimming consciousness of what all is happening around), you ...
5
votes
3answers
178 views

Can we knock out Caspase-9 *and* avoid breast cancer phenotype in our mouse model?

I am trying to design a wet lab experiment with no wet lab experience to name. Right now, in my dream land, it would be excellent if it were possible to create a Caspase-9 knockout mouse (damage to ...
5
votes
1answer
2k views

What is our skin made up of?

Again, it is a basic question. What is our skin made up of? is it made up of many cells arranged in a systematic way or is it just like any layer say of a book?? what is the difference? where is the ...
5
votes
1answer
236 views

Plasmid in the nucleus and gene expression

If we insert a plasmid into a human nucleus that contains exact copy of gene and all relevant promoters to produce some human protein, will the cell create functional protein from that plasmid only ...
5
votes
1answer
66 views

How much of the weight of yoghurt is due to bacteria?

I recently started making all kinds of bacteria-processed foods by myself (such as yoghurt, but also Sauerteig and so on), and I found myself wondering how much of the weight of these products is ...
5
votes
2answers
2k views

Can the human eye distinguish colors in the periphery?

In the back of my mind I have the idea that human eyes can't notice the color of objects in the far periphery, and that any subjective perception of colors is done by the brain that tries to fill in ...
5
votes
1answer
4k views

What is the H+ gradient in mitochondria?

I would like to understand what the term H+ Gradient means. I googled this question and found terms such as chemiosmosis and ion gradient being tossed around. I am very new to biology and I do not ...
5
votes
1answer
892 views

Are fish and reptilian scales homologous?

Wikipedia: Fish scales are dermally derived, specifically in the mesoderm. This fact distinguishes them from reptile scales paleontologically. So aren't reptilia scales also dermally derived?
5
votes
1answer
193 views

Does gray/white hair turn gray/white from a normal hair? or does a gray/white hair actually grow gray/white originally?

I am really curious if hair actually tuns white/gray from default color, or does it have a defect as it is made and grows out of your head a different color?
5
votes
3answers
493 views

If someone were to die on the moon, would their body decay?

I heard that the footprints of Neil Armstrong are still there, so I was wondering if someone were to die there, would they remain preserved, too? If not how long would it take for them to decay?
5
votes
2answers
341 views
5
votes
3answers
795 views

How does strength of a pulse related to EKG(ECG)?

There are variabilities in the heart rate as well as strength of heartbeats. I want to know if one can predict which heartbeat will be strong or weak based on the corresponding EKG/ECG signal. I am ...
5
votes
1answer
10k views

Calculation of the bacterial growth rate from a spectrophotomer growth curve

Typically the microbial growth in liquid cultures is monitored by turbidity. Data is obtained with a spectrophotometer to measure optical density at 600nm. The slope of the bacterial kinetic curve in ...
5
votes
1answer
74 views

Does fasting improves immunity?

I have heard that fasting causes regeneration of memory cells(B- and T-lymphocytes) thereby improving immunity.Is this true? If yes, how?
5
votes
1answer
110 views

Can an insect poison itself with food?

Is it possible that an insect poisons itself while eating "wrong" plants/fruits/... and have symptoms like pain (may hard to measure or detect) or orientation disorder? Background: I observed a ...
5
votes
1answer
366 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 : ...
5
votes
2answers
6k views

What is the difference between transformation and transfection?

What is the difference between transformation and transfection? How do both of these methods work?
5
votes
2answers
3k views

What makes teeth feel sticky after drinking Coca-Cola?

I asked some of my friends and we all agree that teeth feel funny after drinking Coca-Cola. Other similar soft drinks also cause this effect, but this one most noticeably. It's like teeth become ...
5
votes
2answers
235 views

Can diploidy evolve in absence of sexual reproduction?

Theoretical question Can diploidy (or polyploidy) evolve from a haploid lineage in the absence of sexual reproduction ? For what theoretical reason? How can such evolution take place? Empirical ...
5
votes
2answers
136 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 ...
5
votes
1answer
128 views

How can this bird be identified? Can someone please identify this bird?

These photographs have been taken in Warora, India. Could someone please help identify this bird?
5
votes
2answers
2k views

Microscope recommendation for an amateur?

I am a mathematics student looking for a hobby and this has come up as a potential hobby. Thus I am interested in buying a high-magnification microscope that is within the limits of my budget. My ...
5
votes
2answers
15k views

Why do ladybugs have a different number of points on their backs

Everytime I see a ladybug I ask myself this question. Why does every ladybug have a different amount of points on its back? Is it because of its age? Or because of its genes? Is it inheritable?
5
votes
2answers
1k views

How do I measure bacterial growth in agar dishes (either by cell mass or by cell count)?

I am doing an experiment in which I am growing S. mutans in agar dishes, and I am not sure how I would measure the growth of the S. mutans. I am also not sure if I would do this by measuring cell mass ...
5
votes
2answers
4k views

Renin - enzyme or hormone?

Wikipedia says : The kidneys secrete a variety of hormones, including erythropoietin, and the enzyme renin. Can a substance be both an enzyme and a hormone ? Why is renin both an enzyme and a ...
5
votes
2answers
4k 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 ...
5
votes
1answer
410 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?
5
votes
1answer
14k views

What is the standard deviation of adult human heights within sexes?

The wikipedia article on human height reports mean height for many different countries by sex but it does not report standard deviations. What is the standard deviation of adult human heights within ...
5
votes
1answer
5k views

How many honeybees are there, and how has the number changed across time?

How would you begin to estimate the world population of the European Honeybee (Apis mellifera)? Would recent colony collapse disorder show up as a blip? How about the spread of A. mellifera from ...
5
votes
2answers
218 views

How does a new species survive without suffering inbreeding?

Just what the title states. The thought came from reading When has an organism evolved enough to be called a new species? I'm probably wrong but I understand new species happen sporadically rather ...

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