scilearner

Ok I researched but I don't understand what they are saying. Transpulmonary pressure= alveolar pressure-pleural pressure= elastic recoil of the lung. How is transpulmonary pressure equal to the elastic recoil of the lung? I don't understand what you get when you substract pleural pressure from alveolar pressure. Also while I was reseaching this pneumothorax came up. It seems that elatic recoil of the lung is pushing one way and the chest wall is pushing one way. When equilibrium is reached between these two pleural space is negative. So when you puncture air fills the pleural space and becomes zero. So how does this make the lung collapse? Thank you!! Moonbear,Andy or anyone please explain!!

This is called the Hasselburgscreen illusion. http://en.wikipedia.org/wiki/Hasselburgscreen I can't believe none of you knew about this.

Is voltage the potential energy difference between source A and B in a circuit? If so in absense of resistance and the presence of a 3V battery does point A have 3V to begin with and at point B there is 0 volts. Is all potential energy converted to kinetic energy when moving from A to B? A is origin and B is the terminal end of the circuit by the way. Is that voltage drop? If what I have said is not correct and voltage doesn't drop like this does a circuit with no resistor and negligble resistance from the wires have 3V at point A and also 3V at point B? Let's say that I have a circuit like this (made it linear for ease) 3V battery--point A----------------1ohm resistor-------------pointB What is the voltage of the resistor? It is 3 right. Does that when current passes through the resistor it loses 3V. If it loses all the voltage how does it move to point B? Thanks Edit: I think I'm assuming when they say voltage drops across the 1 ohm resistor is 3, the 1 ohm resistor uses all 3V. When they say voltage drop in this case are they actually referring to voltage drop from A to B. The actual amount of energy lost due to the resistor is not really 3V. It is something less. The voltage drop across the whole thing is 3 V. Is that right?

Quite frankly I have no idea but would this equation work for it. I'm not sure wait for someone to clarify. H20<----> H+ + OH- Add acid more H+ and more water produced meaning less reaction. This is a total guess!!

Wiki-The Starling equation is an equation that illustrates the role of hydrostatic and oncotic forces (the so-called Starling forces) in the movement of fluid across capillary membranes. So is it water that moves out or do solutes dissolved in water move out as well. Simply is it water or fluid(including solutes) that move out.

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 density of electrolytes- I understand why polar molecules would find it difficult to diffuse but not ions. Why would have an ionic charge make it difficult to diffuse? I also have a question about osmosis and diffusion of ions. When water diffuses through the membrane, does the ions or anything dissolved in it diffuse as well. If so why do ions need specific protein channels for diffusion can't they just diffuse with water. Thank you very much

Thanks

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!!

Thanks a lot Mr Skeptic. I really appreciate the answer but unfortunately I find DNA replication very difficult. I researched this for the past 2 hours and I still don't get it. <-----------DNA polymerase 5'------------------------3' (1st strand) 3'------------------------5' (2nd strand) DNA polymerase----> If two DNA polymerases work at the same time in opposite direction can't you replicate DNA without lagging strands? Remember DNA polymerase can only synthesize from 5'---->3' I read this sentence a million times but I still don't get why is this relevant when you can have two polymerases. Please excuse my poor understanding!! Is it simply we only have one polymerase? Thanks

Hello everyone, Quick questions. What do they mean by different polarities in anti parallel DNA strands. Are they referring to some chemical polarity or simply the fact they run in opposite directions. I'm confused with DNA replication. DNA polymerase can only synthesize DNA in 5' to 3' direction. I don't understand how this could cause a lagging strand. For example 5'------------------------3' (1st strand) 3'------------------------5' (2nd strand) Can't two DNA polymerases work in opposite directions in DNA replication. One from 5' to 3' in the first strand(moving to the left) and the other 5 to 3 in the second strand(moving to the right) They say that RNA polymerase can only synthesize RNA from 5' to 3' direction. 5'------------------------3' (1st strand) 3'------------------------5' (2nd strand) So that makes the second strand the template strand. My question is can't RNA polymerase use the first strand as the template strand by synthesizing in the opposite direction (to the left) Thanks a lot

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

Classic :D:D:D:D @Yousuf masseter trapezius pectoralis major deltoid lattisimus dorsi biceps brachii triceps brachii rectus abdominis external obliques gluteus maximus quadriceps femoris biceps femoris gastronemeous Shouldn't wikipedia tell you where these are. Trapezius starts from neck, pec major is like your chest, deltoid covers shoulder, lattismus dorsi is in the lower region of your trunk from behind. Biceps in the front of your arm, triceps in the back of your arm. This is just few things I can think of. If you know origin insertiob for each muscle that would give you the location. http://www.getbodysmart.com http://www.innerbody.com/htm/body.html These should help.

Hello everyone, 1. As you increase alkalinity of the solution open chain form of monosaccharides increase. I like to know the chemical reason behind this. 2. Aldehydes oxidize things more than Ketones. I know that this is due to the hyrdogen atom but how does that make aldehydes more reactive. Isn't oxygen in ketone a strong oxidizing agent? 3. What happens to monosaccharides in the presence of acid? Thanks for the help

Thanks Bruce Centripetal force is bit different to normal linear force right. I mean the acceleration is determined by velocity in c.f as opposed to mass right.

Hey thanks. This is unique to centripetal force right? I mean a linear single force can not give a constant acceleration. If you don't mind can you show me how centripetal force formula is derived. Thanks

Ok I got it Thanks everyone!! Only one question remain the centripetal force in a centrifuge machine. Why is the centripetal force equal to the equation of gravity in this case. Thanks!!

Thanks for the replies. So between the two masses what is the direction of gravity. Does the big mass exert 9.8 ms2 on small mass or vise versa. Do they both exert this force on each other. If they do why doens't earth get attracted by the smaller mass? Rechecking the formula I think the bigger mass has less g when you make F=gM. Ok I think I got it now but how is that centripetal force from a centrifuge act as gravity.Basically how come this formula is applicable to that as well.

How is the acceleration due to gravity created? What makes it 9.8 m/s2. I think I'm not understanding gravity properly. My understanding of gravity is that it is the force that attracts 2 objects. If one object is lesss heavy that object would move towards the heavier one at a faster rate(earth). So here isn't the mass affecting acceleration?

Ok this makes sense but pressure inside an airway is determined by hydrostatic pressure and when air moves fast hydrostaic pressure is decreased and converted to kinetic energy. So this collapses the airway. My question is doesn't kinetic energy of moving molecules exert a pressure on the walls of the airways. Why is it that only hyrdostatic pressure determines the pressure inside an airway? Thanks!!

Thanks but you predetermined the acceleration. Isn't the acceleration determined by the mass of the object. If earth exerts gravity on an object and that object exerts gravity on earth. The earth would move less due to mass. So doesn't mass affect acceleration?

Thanks for the answer. So in a centifuge with 3g centripetal force does heavy molecules in a test tube move with 3 times 9.8 m/s2 acceleration in the absense of resistance. How can you give an constant acceleration like that. Doesn't mass change acceleration?

Hello everyone, Normally if there is 1 kg object and I apply 10 N force it would accelerate at 10m/s. Here the acceleration is determined by the mass of object. How does gravity in the absense of resistance make objects travel at a fixed acceleration? In a centrifuge a force equivalent to double or triple gravity is used. Does this force give a constant acceleration (9.8m/s2) like gravity too. How is that done? Thanks!!

lol what an analogy!! Thanks a lot I did understand everything you said so it worked. Now my question is how is this related to Bernoulli's equation. Do you mean the reason velocity increases is that unrestricted branches get more flow. That is true but isn't bernoulli referring to one pipe!! Basically in real life is bernoulli's equation useless because resistance is too great!!

In starling forces only hydrostatic pressure is taken into account. I don't understand if blood is moving through a capillary don't they have to take velocity pressure of blood as well? Thanks!!