Biology

Water is absorbed in the intestine. most water reabsorption take place in colon. When they water is absorbed in the first sentence, do they mean water moving out from the intestine to blood vessels. When they say reabsorption do they mean water coming into the intestine from blood vessels? The english is confusing me here. Thanks

During the early stages of earth there was no O2 atmospheric oxygen, no living things, no photosynthesis, no ozone layer etc. I have been reading that this would have allowed pure UV radiation to penetrate deep onto earth. How would this have affected the creation of adenine, amino acids etc. and the first single celled organisms? Would they have had to been sheltered in a cave? Could the UV radiation penetrate the surface of the earth? Could it penetrate down to the bottom of the ocean?

I have been recommending this YouTube video to people, which seems to be pretty well done. But I have been getting questions back, which I couldn't really answer. I have received some comments about how the hydrogen cyanide and ammonia solution would become oxidized and would not produce adenine. But the response to that is that there was no oxygen in the earth's early atmosphere. - A good video to watch is "How the earth was made" a 2 part History channel documentary. Question: In DNA and RNA, where did ester bonds come from? Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. However, accordin…

When you hear people talk about the "information" in DNA, are they referring to the ordering/sequencing of the bases(AGCT)? The bases themselves are not information, correct? It is only information or instructions, once the bases are ordered properly, so are people talking about this order information, or the information that tells the bases how to be ordered?

Hello everyone, I got some questions about diffusion. My note says that diffusion is affected by 1. Solubilty of solute- What do they mean by this. Does solubility increase or decrease the rate. Since water is the major liquid found inside the body. Are they referring to solubilty in water. If they are not soluble (non polar) can't they easily diffuse through the membrane. Or are they simply saying that less solubilty means less movement and less diffusion. 2. Concentration gradient- Atleast I understand this. 3. Number of H bonds to be broken- When dissolved in water do they have to break H bonds first before diffusing. I don't understand this. 4. Charge densi…

Ok hydrogen ion gradient drives ATP synthase. In secondary active transport the preexisting concentration gradient drives the molecules. My question is what do they mean when they say concentration gradient provides energy to do this. Is it the movement of ions like hyrdogen from high to low that results in energy. When the concentration on each side is the same why is there no energy!! Thanks!!

Ok they say that the sugar side chain signal added to proteins inside the G.A gives the protein direction when it exits through a vesicle. So how does adding a sugar side chain make the vesicle go to the right place? Thanks!!

I am trying to find out the molar concentration of Guanidinium Thiocyante in Ambions Tri Regant . Is it 2M or 4M ?

So the cells divide at a certain speed each minute, and i know it is that speed that controls aging, so when we are born our cells are going really fast right and they always go slower and slower with age. Thats how our organs get tired and we die.. so imagine if we would come up with a way to to control the speed of which the cells divide, say its going at the speed X at age 24 and instead of progressing to the speed Y at the point we are 24 we do something that will affect the cell division so it will stay at speed X and that way we will be in the same physical condition until we die in a some sort of accident/disease/cancer... Am i right? So if i´m right then please te…

Who'd have thought this creature could inspire the future of CD and DVD players (fabulous picture too) http://www.labnews.co.uk/laboratory_article.php/4991/2/2/super-shrimp-eye-inspires-cd-player-of-future

agonist/antagonist muscle pairs. Let's say agonist flexes the finger. When agonist get paralyzed why does the finger stay in an extended position? Ok I know this is obvious it is acting unopposed but my question is for the finger to stay in an extended position does the paralyzed person have to extend his finger first. What I mean is does the finger extend immediately after paralysis or does the person have to physically extend it once and then he can't flex it again so it stays that way. When my hand is at rest my fingers are flexed? What is the reason for this. How does this flexion occur auto? Thanks

Can anyone here think of a good prokaryotic microorganism that would benefit a eukaryotic organism from an intracellular symbiotic relationship? I'm thinking of halophiles, thermophiles, etc... What do you think?

Does anyone knows the location and function of each of the muscles masseter trapezius pectoralis major deltoid lattisimus dorsi biceps brachii triceps brachii rectus abdominis external obliques gluteus maximus quadriceps femoris biceps femoris gastronemeous

How does the body know what it wants or needs to eat? Whether it wants piza, a hamburger or a steak? How does the body know it is missing those things or whether it's lacking certain vitamins or minerals found in certain foods?

ENCOUNTER This evening I watched Encounters at the End of the World(1), a program about Antarctica and the McMurdo research station, the largest research station in Antarctica. Here 1000 men and women live together in close quarters risking their lives and their sanity in search of cutting-edge science. In this TV program viewers listen to Werner Herzog the first outsider and filmmaker to be admitted. He is accompanied only by his cameraman. This rare access to the raw beauty and raw humanity of the ultimate 'down under' was fascinating and led me to write this prose-poem.-Ron Price with thanks to (1)Encounters at the End of the World, SBS TV, 10 November, 10:00-11:…

How does the brain form a full-color mental image of an object, person or event when the relevant object, event, or scene is not actually present to the senses?

In the event of a natural disaster, or some other event that left you stranded without access to food. Is there any one thing in the natural environment that you could live on for months on end? Preying Mantuses? Grasshoppers? Sap/Zap from a tree? Would it be logistically possible? ie: would you be able to find enough of the particular source of nutrition?

Restricitive air way disease is the loss of lung compliance. So this would make it harder for the lung to expand causing inspiration difficult. My questioon is why can't this make exhaling difficult. Losing the elasticity of the lung would make both recoil and expansion difficult right. This might sound funny but let's say the lung was in expanded position and then suddenly lost its elasticity, wouldn't this make exhaling difficult. Is barrel chest restricive or obstructive air way disease. Thanks a lot for your help in advance

Hi Guys I want to discuss the bone formation of a fetus. There are many links out there describing what happens to the major organs/features on a week to week basis but there is little info out there for us laymen which describes bone/musculoskeletal formation on a week to week basis. Is is possible if someone could dwell into this? It would be nice to know..

Hello all, I was wondering if anyone knows of a good non-commercial resource for gathering information about fluorescent organelle labels for microscopy? I want to start compiling an easy-to-use resource for our microscope users but don't want it biased to a particular company. Any help would be much appreciated!

in coral species which have a partnership with algae, how does the coral recieve the products of photosynthesis from the algae?

Hey, just wondering if someone was to fall into a pool of liquid nitrogen and become completely frozen, what would be tissue damage and would it be possible to bring him/her back to life?

Ok when staying in the same posture for a long time I feel numbness in my legs. I can understand how veins would find it difficult to travel up when I'm not using my muscles that much. My question is but if arteries are working well wouldn't my leg and nerve get good blood supply. Isn't arteries the main thing here. Where have I gone wrong. If veins have reduced flow does that affect the arteries as well. Thanks!! EDIT: When I re read my post it seems like I'm having a numbness problem and seeking medical advice. I don't have a numbness problem I'm rather interested in how it occurs. Thanks!!

Hello everyone, Ok to understand the respiratory system, proper understanding of this diagram is essential. Something I don't have, so if anyone can help me with these questions I would be very greatful. Thanks 1. Anatomic dead space and residual volume? I know what anatomic dead space is but residual volume is confusing me. Is it in the conducting zone as well and non technically isn't it like some kind of anatomic dead space. 2. Why does the alveoli have less partial pressure of oxygen than inspired air? I can understand how addition of water vapour can reduce it but residual volume just confused me. Does oxygen from residual volume get mixed with thi…

War City riots Video games television martial arts Since the beginning of recorded history (and maybe before that; we don't know), mankind has craved violence. Television and video games show that violence doesn't need a motive, that people are naturally motivated to commit, or spectate, acts of violence, not out of the dreams of power, money, or territory, but simply by nature of the violence itself. This is likely because of adrenaline. However, adrenaline is supposed to be a survival hormone. If it's designed to help you survive, then how come it feels so good that people will hurle themselves into life-threatening situations, or initiate violence agains…