0
votes
0answers
20 views

Why do our limbs and other body parts get numb/feelingless and then they start to tickle? [duplicate]

Why do our limbs (legs, arms) get numb/feelingless when they are under prolonged pressure or when one has crossed his/her leg while sitting for a long period? After we move it to a more relaxed or ...
4
votes
1answer
158 views

Beetroot white skin mould

Does a mould make a beetroot poisonous or inedible ? Lemon's mould for instance, makes penicillin, but it's green there, and I'm allergic to penicillin, would the white mould produce penicillin too? ...
2
votes
1answer
39 views

What is mRNA expression level?

I cannot find clear explanation of what is mRNA expression level, and how to measure it. I would appreciate if someone explained it or gave a reference. Thanks!
1
vote
1answer
1k views

Evolution- Variations, adaptations and selective advantages

I am trying to understand Variations, adaptations and selective advantages and how they are all related. Feel free to add or correct me if I'm wrong- Variations are structural, functional, or ...
2
votes
0answers
54 views

Circadian rhythm in birds

Animals can use their circadian clocks to determine direction from the position of the sun. In a particular experiment conducted in Iceland, a bird, kept in a cage open to the sky, was trained ...
1
vote
1answer
3k views

What's the difference between protein and DNA behaviour during agarose gel electrophoresis?

I'm planning a science project about gel electrophoresis, and I'd like to know if there are any measurable, quantifiable (for example, things I could represent in a graph or chart) differences between ...
2
votes
1answer
293 views

Opposite results between Blomberg's K and phylogenetic signal in Phylocom (AOT)

I've been trying to test for significant phylogenetic conservatism in some plant traits. So far I used R-package picante (Blomberg's K) and AOT in Phylocom. So far these two methods yield completely ...
5
votes
1answer
338 views

Why does wood become darker when it ages?

I have lots of pieces of pine furniture which have different colours depending on how old they are. So, I just wondered why that is. I guess it has something to do with structures and chemical ...
1
vote
1answer
115 views

Can we say that microevolution and macroevolution is fundamentally the same thing over different time scales?

This Wikipedia article states: Macroevolution is evolution on a scale of separated gene pools. Macroevolutionary studies focus on change that occurs at or above the level of species, in contrast ...
2
votes
1answer
75 views

How is sweetness measured?

Some time ago, I read in a newspaper--though I can't recall the details--a list of (mostly artificial) sweeteners and a list comparing how many times sweeter each was than sugar. How is relative ...
4
votes
1answer
326 views

Why do farts stink, but perfume does not?

Why is it that natural things like farts, poop, halitosis etc., from which we are always surrounded smell "bad"; whereas manufactured products, such as perfume or glue smell "good" to most of us? In ...
1
vote
1answer
519 views

Why do you need the intrinsic pathway when you have faster extrinsic pathway?

There are two pathways in blood clot fromation; the extrinsic pathway and the intrinsic pathway. The extrinsic pathway is faster than intrinsic pathway because it has less number of steps. So, why do ...
0
votes
0answers
48 views

Is it possible for a human and another ape species to reproduce? [duplicate]

Is it possible for a human and another species to reproduce?
2
votes
1answer
324 views

recombination frequency problem

Three loci C, D and E are located on the same chromosome in this order. We found that the frequency of recombinants between C and D is 10% and that between D and E it is 20%. Assuming that ...
6
votes
3answers
407 views

Is there a hypothesis that attempts to explain patterns of species richness along all three energy-related environmental gradients?

My question is related to one of the oldest question in ecology: "What determines global patterns of species richness?". However, I want to focus on one particular part of this question, which has ...
2
votes
1answer
997 views

How many species have existed on earth? [duplicate]

I found a paper estimating the number of species currently living on earth. Now I'm wondering If anybody tried to estimate the number of species that have lived on earth. I'm familiar with problems of ...
1
vote
1answer
408 views

Question regarding Rate of Photosynthesis AP Biology Lab

We are doing a lab on the effects of light intensity/wavelength on the rate of photosynthesis in AP bio and we were asked to visit this website here: ...
0
votes
0answers
91 views

Does our brain really “flip” images perceived by our eyes? [duplicate]

I know a similar question has been asked and this is closely related to cognitive science. However, I want to know whether is there any mechanism or structure in the visual cortex which is proved to ...
5
votes
1answer
98 views

Enlargement of thyroid gland

Why does thyroid gland enlarge both in hypothyroidism and hyperthyroidism? Hypothyroid goitre is due to lack of iodine in diet and hyperthyroid goitre (Exopthalmic goitre, Grave's disease) is due to ...
2
votes
2answers
179 views

Calcium levels and nerve hyperexcitation

Why does lower blood calcium levels (or lower calcium levels in ECF) cause nervous hyperexcitaton? Why does it cause over stimulation of nerves and muscles and spasmic contractions of muscles? This is ...
0
votes
1answer
41 views

How does the body repair extracellular damage caused by glucose?

So we know that glucose is an aldehyde that can cause cell damage to the lysine and arginine residues on proteins through the Maillard Reaction (among other damaging reactions that glucose ...
1
vote
1answer
138 views

Breathing in and out

I was reading my textbook and it says that breathing involves inhaling and exhaling but it doesn't say whether they happen simultaneously or sequentially. Also is my overall understanding of ...
3
votes
1answer
264 views

Will neurons live after the death of a human? If so, how long?

I don't know if this is correct or not, but I have heard this from a friend and I want to get a clear explanation about this.I hope there is some one who can help me.
2
votes
4answers
307 views

Are we inevitable in the evolution?

Suppose we wind time back to the instance when life emerged on Earth and let evolution start over again, will human beings or any other kind of self-conscious animals evolve ultimately, inevitably? ...
3
votes
2answers
64 views

Why are genes expressed as proteins rather than other types of bio-molecules?

I guess, we could infer that the structure of an amino acid has the same functional units as RNA is used to synthesise it. Therefore, from a logical point of view it would make sense that genes are ...
3
votes
2answers
471 views

How does sequence independent single primer amplification work?

I'm having difficulty finding an explanation of how single primer amplification of DNA works in the literature available to me, can anyone explain the methodology and what it accomplishes?
0
votes
0answers
30 views

Events after Endothelial interruption

What are the physiological events that occur after there is endothelial interruption in the blood vessel? What does endothelial interruption mean here? And what could be the physiological events?
21
votes
5answers
5k views

Do humans have enough biological differences to be grouped into races or subspecies?

After my online research on the subject, I learnt that, biologically speaking, many scientists believe that there is no such thing as a race. Homo sapiens as a species is only 200,000 years old, which ...
1
vote
1answer
90 views

Topology of protein

The domain structure of protein Z, which is composed of 180 amino acids, is shown in the upper part of the figure below. Protein Z is palmitoylated at a cysteine residue (the third amino acid) ...
6
votes
1answer
141 views

What are the lifetimes of cellular components on organelle or molecular level?

I was thinking that even though I know how generally the cell works, I don't really have a feeling of how volatile it is. I want to know what is the lifetime/turnover rate of different constituents of ...
3
votes
1answer
51 views

How does your body ultimately recover from a cold?

Is it the eradication of the virus (assuming rhinovirus) by white blood cells? Or does your body somehow adapt to presence of the virus?
1
vote
1answer
145 views

Carcinogens, how do they work?

The easiest carcinogenic thing for me to grasp is radiation, as it directly messes with DNA. Then it seems there are other compounds that simply mimic hormones, but these shouldn't necessarily cause ...
0
votes
1answer
79 views

How does Acetaldehyde accelerate mitosis?

I read that one of the ways alcohol is carcinogenic is via accelerated mitosis due to acetaldehyde, I was wondering what pathway caused this acceleration?
0
votes
2answers
216 views

Rh factor and dominance of gene

"Formation of Rh antigen is controlled by dominant gene(R) and its absence by recipient gene(r).People having this antigen with genotype (RR or Rr) are called Rh positive and those whose blood ...
1
vote
2answers
263 views

mouse gene translated to human gene

I have a list of mouse genes, but all our analysis happens for human genes. Is that possible to translate these mouse genes to human genes? and is there any tool that can help me on this? I am ...
2
votes
1answer
262 views

What does the (-) in the molecule name mean?

I'm reading some text (purchase request) that has the following line in it. (-)-Norepinephrine What does the minus sign mean in front that is in parenthesis? Is this some kind of standard way of ...
1
vote
1answer
33 views

Source of energy of adipocytes

Since adipocytes export fatty acids and don't use them as an energy source, which is the main source of energy for this cells?
1
vote
1answer
84 views

Linkage distance calculation

What is the map unit distance between L and S allele ? My working : If we take the normal ratio :9:3:3:1 , first one should be 9/16 = 0.5625 and then subtract 0.51 from it, we get 0.0525, ...
1
vote
1answer
56 views

Identifying mutations in a yeast strain

Cells of a triple-mutant yeast strain (leu- his- trp-) were spread either on minimal medium or on minimal medium supplemented with various combinations of histidine, leucine, or tryptophan. The ...
2
votes
0answers
75 views

What is the biochemical pathway of fluoride?

Fluoride is a common active ingredient in tooth paste to prevent dental caries. It is also added or removed from the water supply in some communities for the same reason, but in children only. My ...
1
vote
1answer
88 views

Blood group probability question

My answer ( after rounding off) is 9% -100( 0.75 X 0.25 X 0.5) but the answer given is 22 % Am I correct ?
2
votes
2answers
170 views

Radiation and “Safe Dose”

I've read about safe doses of radiation, briefly. Why is there such a thing a safe dose? Can't any radiation give you cancer? Why is it more and more dangerous to take in larger and larger doses? Just ...
4
votes
1answer
322 views

Sexual selection in cats or other animals

I was wondering if you could answer some of my questions regarding sexual selection in cats (or any other animals). I would like to apologize beforehand for my incorrect term use. When it comes to ...
5
votes
2answers
301 views

poor RNA quality from zebrafish embryos

Does anyone routinely do RNA isolation from zebrafish embryos? I have embryos from different stages but all below 24hpf. This is the protocol I follow: Take 10-20 embryos Wash once with milliQ ...
2
votes
2answers
1k views

Are humans an eusocial species?

In the evolution of sociality among animals, different degrees are acknowledged. Some species present overlapping generations, some division of labor, and the minority present reproductive division. ...
5
votes
1answer
85 views

How are Raunkiær's plant life forms viewed today?

At the beginning of the 20th century, Raunkiær proposed a typology of plant life-forms based on where they bear their buds, roughly as: cryptophytes: belowground hemicryptophytes: at the surface ...
1
vote
0answers
15 views

Are there any good reviews on the mouse and human conservation in coding and gene regulatory module regions?

I was looking for reviews that deal with conservation between mouse and human of proteins, noncoding RNAs, gene regulatory module (such as promoters and enhancers), gene regulatory networks post the ...
4
votes
1answer
433 views

Effect of single nucleotide deletion or insertion on primer annealing

How is primer annealing, and, consequently, PCR amplification affected by single nucleotide deletion or insertion inside the primer ? Imagine a primer like this: GCGTCATAAAGGGGACGTG (primer) and ...
2
votes
1answer
50 views

Citing species in a biology article

My question concern the abbreviation of the genus of a species. I talk about two species: Amphiprion clarkii and Amphiprion perideraion. Question 1 Let's assume I haven't said a word about these ...
2
votes
3answers
121 views

Can antibiotic resistant bacteria compete with normal one in an antibiotic free environment?

The question is based on an intuition that antibiotic resistance can't come along. This mutation will probably make bacteria less tenacious. Is there any research how AR bacteria compete with normal ...

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