3
votes
3answers
113 views

Why has grey hair evolved?

A vast majority of humans get at least some grey hair as they age. As far as I know this applies to both genders and all races. Presumably this means that at least some grey haired humans have ...
5
votes
1answer
113 views

What is the extent of the effect of Tris on E. coli?

I was a fool and dissolved my antibiotic (Kanamycin) into Tris Buffer rather than H₂O. The Kanamycin still seems to be active but a fellow labmate mentioned that Tris messes around with the membrane ...
-4
votes
2answers
71 views

How are atoms created? [closed]

From small baby to the old age, we will be grown. We are composed of bunch of atoms, multitude of atoms. When you are grown from baby to the teen age, everyone will say "he has grown!" What do you ...
6
votes
3answers
63 views

Can a single axon propagate multiple simultaneous action potentials?

I have not been able to locate any research that indicates whether a single axon of a neuron or nerve cell can conduct multiple simultaneous (i.e. spatially separate) action potentials. I am aware ...
3
votes
0answers
69 views

What are the psychodelic effects of (stellar) anise and how many people are affected?

Backstory: My girlfriend reacts heavily to chocolate and drinks containing stellar anise, in a way that seems comparable to psychodelic drugs. After consuming it, it takes approximately five minutes ...
1
vote
1answer
62 views

How to estimate the DNA density in human sperm head? [closed]

I have got an estimate of sperm head volume from internet.Like consider it as a disk of order 4-5µm. Now I wanted to find the DNA density in the sperm head. How to find that?
4
votes
3answers
84 views

What is the mechanism of oxygen uptake in E. coli?

How does E. coli uptake oxygen? Most of the literature I found is concerned with response to oxygen level supplied in the medium, as opposed to how much is actually transported inside. Can they shut ...
2
votes
1answer
214 views

Neurons with thousands of connections: where are the extra connections coming from?

If every neuron has only one Axon but can can have thousands of (or let's say, even just ten) incoming Axon connections via its dendrites, where are the extra connections coming from? It seems to ...
21
votes
3answers
2k views

What limits our healing speed?

Our bodies can repair quite a number of injuries very well. However, it takes time. For larger wounds, complete recovery can last many weeks. Why is this time so long, what is the most important ...
3
votes
1answer
31 views

Can anyone identify this caterpillar?

Can anyone identify this caterpillar we found on a cauliflower? This was the only photo we could get of it. Thanks!
0
votes
1answer
37 views

Simplest Biological Organism? [duplicate]

What is the simplest biological organism from which a DNA sample has been or could be obtained? Could the resulting DNA be processed and examined in such a way that the resulting information would ...
5
votes
0answers
73 views

Calculating additive variance, heritability, and percent of variance explained by additive effects

I've set up some dummy data in R which makes 40 genetically related lines (in this case I'm simulating hemiclones - they share one haploid copy of there genome within a line, thus additive genetic ...
3
votes
1answer
37 views

How does electrolarynx work?

I have heard that this is an effective replacement for patients who have a dysfunctional larynx, partly due to cancer. I am curious to know the inner working of this device and why such a robotic ...
5
votes
3answers
981 views

What is the relationship between sexual and and natural selection?

In http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12701.html, they say: Thus, it seems that the diverse coloration in this species is promoted by both natural and sexual selection. ...
0
votes
0answers
13 views

Why does some skin hold perfume longer than others

I was wondering my girlfriend and I used the same perfume for a while and we sprayed the same place. And after a day her skin still smells nice while mine smells normall. Will different types of ...
4
votes
1answer
91 views

What are the atmospheric requirements for large dinosaurs?

What are the atmospheric requirements for large dinosaurs? and are the atmospheric constituents for supporting large dinosaurs any different from the atmosphere today?
10
votes
7answers
3k views

How did the first self replicating organism come into existence?

When people try to explain evolution, they tell me that evolution is a cumulative result of mutations & natural section of the more superior individuals of a particular species. I think I'm fairly ...
2
votes
1answer
63 views

Fatty Acid Synthesis

I have a problem in my reasoning on the fatty acid synthesis in the human body. In the synthesis process you have this homodimer. So the synthesis starts with the transfer of a acetyl group from ...
0
votes
0answers
27 views

How can cerebral vasoconstriction lead to decreased O₂ supply?

I am thinking the mechanism from hyperventilation into brain damage: hyperventilation [CO₂] decreases in plasma cerebral vasoconstriction which then decreases the oxygen supply i.e. [O₂] in the ...
10
votes
1answer
372 views

How long can a bee surive in a jar?

So, some people and I encountered an adventure game where you have a bee in a jar and need to move it from place to place before it suffocates, and someone tried to find out how long a bee would ...
0
votes
1answer
105 views

cellular respiration

What are the effects of addition of these chemicals to actively respiring cells ? Which of them would lead to INHIBITION of aerobic respiration ? Would cytochromes be actually taken up by cells ? ...
6
votes
4answers
5k views

What is the cause of muscle cramps?

According to wikipedia, muscle cramps are caused by myosin fibers not being able to break free from the actin filaments during contraction, resulting in a prolonged contraction. Obviously a lack of ...
3
votes
1answer
56 views

Hela live cell confocal laser scanning - reccommendations for good fluorophore that will show good movement

I've been doing a lot of live cell imaging lately mostly using hela cells expressing some EYFP based chimeric proteins. I'm building a video library for an art student here at the university who is ...
1
vote
3answers
224 views

What difference does it make in the organism's physiology/metabolism whether oxygen binds reversibly or not?

A follow-up to How does hemoglobin-free blood transport oxygen? I'm unsure about the use of physiology/metabolism in the title there. The question in mind is whether this reversible binding makes an ...
2
votes
1answer
153 views

Independence of Light independent reaction in photosynthesis?

Inspired by a question asked to me by a classmate, I have the following question about Light-independent (dark phase) reactions in photosynthesis:- Let us suppose an algae sample was exposed to ...
7
votes
2answers
340 views

In humans what is the last metabolic process to cease after death?

After death which of our body's metabolic processes will continue functioning for the longest?
10
votes
2answers
187 views

How did the nucleobases in the Murchison meteorite form?

The Murchison meteorite is an important piece of evidence for abiogenesis, because it contained nucleobases from extraterrestrial origin, as this Wikipedia article explains. These results ...
2
votes
2answers
197 views

What type of photosynthesis is performed by phytoplankton?

I am not a biologist, but I know there exist three variants of photosynthesis, namely C3, C4 and CAM. I would like to know what type is used by the ocean's phytoplankton? It might also be that ...
12
votes
2answers
2k views

How do insects breathe?

Do ants even breathe? If they don't, how do they stay alive? On what resources do they depend upon to stay alive? How are they different form mammals?
0
votes
0answers
19 views

Direct spread of Parvovirus B19 from blood to Brain stem and CSF

Parvovirus can spread in blood (viremia) to bone marrow. It is detected in some stages of infection in Cerebrospinal fluid (CSF). However, I am thinking if it can spread directly with facilitated ...
4
votes
3answers
1k views

Why do yeast ferment Equal sweetener

I had my students conduct a fermentation experiment manipulating sugar amounts (number of sugar packets in solution) and measuring CO₂ production via capture in a balloon and measuring circumference ...
5
votes
1answer
61 views

Shade-loving Plants

In shade-loving plants, the light compensation point is reached at low irradiance because: A. Leaves have more chlorophyll per reaction center B. These plants have greatly reduced respiration rates ...
2
votes
2answers
89 views

What is the difference between drought resistant non-succulent plants and plants that cannot be allowed to dry out?

What features make one plant able to withstand dry spells better than another with relatively similar structure? For instance, one of my Rudbeckias is wilting from drought at the moment, and an ...
1
vote
1answer
457 views

Breathing water vapour

Normal air consist of oxygen, CO₂ and nitrogen, with traces of water etc. Now imagine displacing all gasses except oxygen with water vapour. By water vapour I don't mean hot steam or fog. Just ...
9
votes
2answers
1k views

Does Sansevieria trifasciata really absorb Carbon Dioxide at night?

There's a claim that Sansevieria trifasciata (Mother-in-law’s Tongue) generates oxygen from carbon dioxide during the night. This seems surprising to me: that process requires energy; plants generate ...
7
votes
2answers
586 views

What effect does ambient temperature have on the cardiovascular system?

I am sorry if this is not appropriate for this site, but I think it fits so I am asking it here: I went for a run yesterday, and it was about -8⁰C. I was wearing a couple pairs of shorts, a t-shirt ...
3
votes
1answer
1k views

Does photosynthesis require only direct sunlight

I have learned throughout my basic science classes in high school that in the process of photosynthesis, plants absorb sunlight & produce food. They use carbon dioxide & water vapour. My ...
2
votes
0answers
54 views

Do humans have chemosensors for nutrients or chemicals?

I'm reading about chemoreceptors on Wikipedia, and see that the typical ones are mentioned: taste, smell, CO₂. I would like to learn more about the other kinds of chemoreceptors that humans may ...
1
vote
2answers
119 views

Plants without bacteria? is it theoretically possible?

I know from school, that all live on the Earth need bacteria as low-level "machines" that break down/extract/convert/produce chemical elements and combinations, other high-level organisms needed. But ...
1
vote
0answers
40 views

Ferredoxin synthesis pathways

I have been thinking about some alternative CO₂ fixation pathways. As almost all of them include ferredoxin reduction I started to wonder where does the ferredoxin comes from. I could not find any of ...
0
votes
2answers
90 views

How mosquitoes get their food and survive?

How mosquitoes find and get their food? For how much time they can survive without food?
0
votes
0answers
43 views

Poly Unsaturated Fatty Acid

PUFAs spontaneously oxidize, speed up the process of glycation, since too much glucose and they also decrease mitochondrial respiration - more oxygen and CO₂, less lactate and PUFA also promote ...
4
votes
2answers
128 views

Breakdown of energy expenditure at the level of a single cell

The metabolic rate measures how much energy an organism expends over a unit of time. Its breakdown for the human body in terms of its functions is well documented : so much for the heart, for the ...
13
votes
2answers
4k views

How will rising carbon dioxide levels in the troposphere affect photosynthetic producers?

Much discussion has been had about the affects of climate change on plantlife, but how will rising carbon dioxide concentrations affect the photosynthetic process itself? Since CO₂ is a reagent in ...
2
votes
2answers
47 views

Clarification on Hatch and slack pathway

The following is a minor clarification that I want to make, since it is rarely addressed directly in most of the texts I have gone through. In C₄ pathway, the chloroplasts are dimorphic, that is, ...
4
votes
2answers
262 views

Why is the floral biodiversity of grazed grassland higher than that of mown grassland?

I have collected some data to compare the biodiversity of a field in which the plagioclimax is maintained by machine mowing with a field in which the plagioclimax is maintained by sheep grazing. What ...
5
votes
3answers
231 views

Aerobic vs anaerobic respiration comparison

The following graphs compare glucose decomposition in yeasts (in anaerobic vs aerobic conditions respectively) My question is, why doesn't the first one look like a straight line as the second one ...
2
votes
2answers
103 views

Will climate change affect flower population?

There is a flower population elevated 1000 meters above sea level. If climate change causes a 12⁰C increase in temperature over the next 10 years, what will happen to the flowers?
3
votes
2answers
100 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). ...
0
votes
2answers
102 views

Why can we breathe only oxygen?

Plants has the capacity to take in both CO2 and oxygen, that's during day CO2 and at night oxygen. Why don't humans have such a capability?

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