scilearner

How do these machines work? I mean there is no such thing called centrifugal force in real yeah. It is basically inertia. So can anyone tell me how it can be used to separate molecules and how different masses move differently. I haven't see the machine yet so if you can explain that would be great. Thanks!!

Thanks for all the answers but I'm still confused. In a tube with water does it have 2 kind of pressure hydrostatic and what do you called the pressure created by moving molecules? Is their a name for that This is some info on Bernoulli effect "When air travels through an airway at a CONSTANT FLOW RATE, the total energy of the fluid (PE + KE) decreases because friction converts some of this energy into heat. Since the fluid is moving at a constant flow rate, the loss is in potential energy (decrease in hydrostatic pressure)." "As we move down the airway, the tubes begin to narrow. When a tube narrows, fluid velocity increases causing an increase in KE at the expense of PE (ie. a compensatory decrease in hydrostatic pressure). This is referred to as the BERNOULLI EFFECT." Ok what I like to know is that even though hydrostatic pressure is decreases is someother pressure (caused by moving molecules) increase? Thanks!!

Thanks for the answer. Do you mean that the thin pipe has less water molecules and when velocity is increased the flow rate is maintained?

Hello everyone, I have made number of topics recently I think they have all stem from my poor understanding in this matter. Ok in a gas, molecules can take up a volume and exert a pressure. Inside a fixed container when you increase the temperature pressure increases because more gas molecules are hitting the walls. Now in a liquid the molecules are close together and volume is determined by the shape of the container. So inside the container liquid molecules don't hit the walls and exert pressure some other way. What is this way. Is this called hydrostatic pressure. Also when you make the molecules move faster in a liquid somehow would that increase the pressure like in a gas. According to what I have read it actually decrease hydrostatic pressure. However I have a picture in mind more kinetic more molecules hitting the walls higher the pressure. Maybe I'm just not understanding how gases and liquids behave in a molecular level when it comes to pressure. So please help me with this. I would greatly appreciate. Thanks

Thank you both for help. So what is the pont of the bernoulli effect when it is not true. I mean when you constrict the pipe the molecules travel slower in real.

But then why does Bernoulli effect state otherwise. Why is Bernoulli effect useful when it is not true!!

What is it? I don't understand. If there is a bucket of water and you put a tube inside the bucket and blow at one end and then release water flows out of the tube. Why does this happen. Also when you raise this tube water stops. Why? This is not homework or anything.

What are air bubbles? In the typical coke can analogy. As you open the can carbon dioxide goes out as bubbles. Are bubbles created when there is a sudden change in pressure. Emphasis on sudden there. Thanks for the help

Hello, "Potential Energy (PE) + kinetic energy (KE) = Total Energy When air travels through an airway at a CONSTANT FLOW RATE, the total energy of the fluid (PE + KE) decreases because friction converts some of this energy into heat. Since the fluid is moving at a constant flow rate, the loss is in potential energy (decrease in hydrostatic pressure)." I don't understand this. Shouldn't the moving object lose K.E. Shouldn't resistance decrease speed. I think the reason for that is I don't understand what is hydrostatic pressure, I researched but I don't get it. "As we move down the airway, the tubes begin to narrow. When a tube narrows, fluid velocity increases causing an increase in KE at the expense of PE (ie. a compensatory decrease in hydrostatic pressure). This is referred to as the BERNOULLI EFFECT." How does the fluid velocity increase when the resistance also increases when the tube narrows. Is the pressure inside this tube, exerted by moving molecules (KE) or hydrostatic pressure. I don't get it.

Hello everyone, I find this so contradictory so please help to understand this. In vasoconstriction, 1. The flow of blood should increase but this would also mean higher resistance so does the flow increase or not. Normally when we constrict something we expect higher speed don't we. 2. In vasoconstriction pressure should be higher but again does the resistance decrease the pressure. My questions for vasodilations are exactly the same but vise versa. Thanks for anyone who is going to help

Thanks for the replies both of you . It was indeed very helpful. Ok I understand why I don't understand this now. I want to clarify these points. So the pressure inside the lungs is equal to the pressure outside the body. Is this because pressure outside pushes on you and lung increases the pressure by same amount to neutralize this. Please feel free to explain this more. So can lungs regulate pressure with out a tank. When you climb up a mountain does the lung regulate pressure to keep up with the low pressure outside. How does the lung do this and how does the lung neutralize the pressure acting all around your body. Thanks a lot for the help!!

Hello everyone, The partial pressure of the atmosphere 33 feat benath the surface is doubled the normal amount. (2x760 mmHg). I can understand how lower you go down higher the pressure but I don't understand how you can measure atmospheric pressure under the sea. I mean under the sea you got water around you not atmosphere. Are the gases in atmosphere dissolved in this water. My question is mainly related to divers under the sea. They get double the atmospheric pressure of nitrogen and nitrogen narcosis could occur. So how do you get double the N2 in the atmosphere when you are surrounded by the sea. Also why do these effects occur when divers are using an oxygen tank. The gases inside the oxygen tank is normal atmospheric pressure right. 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 this as well increasing P02. 3. Why does the expired air have higher P02 of oxygen than alveoli? I can understand how mixing with dead space would archieve it. Does the residual volume affect it as well. Residual volume is confusing me. 4. What creates the P02 in arterial blood and why it is 95? So it is basically oxygen dissolved in blood right that causes the partial pressure of oxygen.We consider the haemoglobin bind oxygen as part of dissolved blood right? 95 is due to shunting right? 5. Why is PC02 in alveoli 40 and what creates PC02 in arterial blood? Is it 40 in alveoli because CO2 diffuses into it from the capillaries. So C02 from tissues goes to capillarie-->veins--->capillaries---->alveoli so from where does arterial PC02 come from. Your help would be greatly appreciated. Thanks Merged post follows: Consecutive posts mergedThe colour of blood for arteries and veins is mixed up in the diagram. So excuse that.

Thanks a lot for your help. So is dermatome the afferent component of that spinal nerve. I mean every never has both efferent and afferent parts right. Can you explain a bit more. Thank you!!

wiki-A dermatome is an area of skin that is mainly supplied by a single spinal nerve. There are eight cervical nerves, twelve thoracic nerves, five lumbar nerves and five sacral nerves. Each of these nerves relays sensation (including pain) from a particular region of skin to the brain. My understanding is that one spinal nerve contains bothe afferent and efferent fibers. So shouldn't a dermatome have an efferent compartment as well. Do dermatomes only have afferent fibres or is it simply that we consider only the afferent part as the dermatome of that spinal nerve. Thanks!!

I hope this is the right place to put it. Anyway when I checked wikipedia it says Protraction is the movement of an anatomical part of the body forward (anteriorly) However in the scapula protraction is movement to left and retraction to the right. It is not forward bending. Then I checked some youtube videos and they do the test like wiki. I'm confused!! Thanks

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

Thanks a lot I'm glad I asked this question and got everything cleared up. Also while we are at it can you explain how stearic hindrance destabilizes alpha helix structures. Especially proline. My understanding is that bulky side chains in proline would inhibit other things from reacting. However side groups are perpendicular to the helix so they don't react much anyway. So how does stearic hindrance affect side chains. Thanks a lot

Ok as the title suggests I want to clear up my misunderstandings on protein structure. 1. When they say primary,secondary,tertiary and quarternary structure do they mean different stages of a protein. What I mean is do all proteins have a tertiary or quarternary structure and are primary,secondary structures simply stages of them before they became a protein. Or do some proteins remain in secondary or primary structure. 2. "Myoglobin is a single-chain globular protein of 153 amino acids, containing a heme (iron-containing porphyrin) prosthetic group in the center around which the remaining apoprotein folds. It has eight alpha helices and a hydrophobic core. "(wikipedia) Does myoglobin have 8 different polypeptide helix chains joined or is it the same chain twisted to make 8 helixes. I thought one chain could only make one helix. "Collagen contains three different polypeptide helixes joined together" Does this make Collagen a quarternary structure. What is the basic difference between quaternary and tertiary structure. My understanding is that tertiary structure only has one chain twisted many ways and quaternary structure has two or more different polypeptide chains. Is this wrong? Thanks a lot for taking your time to read this. If you could help me with these basics I would be very greatful. Thank you

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!!

It is a covalent bond so aren't the atoms shared and nitrogen has give two in the diagram.

Why does nitrogen have a positive charge when all four hydrogens and nitrogen have full outer shells. There is no hydrogen without an electron here. Thanks!!

Thank you so much for your answer. I understand PKa now but I have a problem. In an amino acid there is only one molecule of SH. How can there be a large group SH molecules in one amino acid. Is the question talking about like one amino acid or mole of amino acid. I know I'm not understanding something obvious but please help Thank you!!

Just interested how this positive charge occurs. Thank you

I know how to get the answer for this question using hesselback equation but I don't understand the question. I have some questions about the questiuon. 1. The PKa value of the sulphydryl (-SH) group of cysteine is 8.33. Calculate the fraction of anion to free sulfhydryl group at PH 7.O. So is this Pka value referring to SH + H20 <---> H+ + S- reaction Why is this reaction significant. How does getting the PH of the equlibrium constant of this reaction provide any meaningful value. Also in this amino acid there is only one SH group(meaning two atoms) so how can an equilibrium reaction occur. My question is related to PKa values. I don't understand how getting the PH of the equilibrium constant can be meaningful and that two atom problem. Thank you so much