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1.Determine the net charge of the following peptide at PH 7.0 PKa values C00H NH3+ Side chain Valine 2.29 9.72 Aspartate 1.99 10.0 3.96 2. 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. I'm not a homework posting type person. But today I'm really running out of time and really need help. Hope you understand and help. Thank you so much

Thanks a lot Only now I realized that I have asked some very difficult questions. Thanks for the help

They can only collect and multiply when they need. They are not bone marrow Am I right?

1. Why can't antibodies enter virus infected cells. Why can't virus infected cells make their membrane permeable for antibodies. 2. Why doesn't the body create antibodies against self. What is the mechanism behind the body knowing which cells are self and non self. 3.How do memory cells increase the response second time. Do the antigens get bind to memory cells quicker and then the process activates faster. 4. How are white blood cells produced in lymph? Thank you!!

wikipedia-In biology and medicine, an epithelium is a tissue composed of cells that line the cavities and surfaces of structures throughout the body.[1] Many glands are also formed from epithelial tissue.[2] It lies on top of connective tissue, and the two layers are separated by a basement membrane.[3] When they say line the cavities and structures do the mean inside or outside. Does epithelium create a membrane outside or is it inside the membrane like villi in the intestine. What does the term line in imply. Thank you!!

"Osmolarity is the measure of solute concentration, defined as the number of osmoles of solute per liter of solution (osmol/L). " but osmole mean particles that contribute to osmotic pressue. Meaning non permeable particles But osmolarity measures non permeable and permeable particles So is this definition wrong. Thank you

Ok I searched and found this as the answer from a previous topic "The sodium potassium pump is required to maintain osmotic balance and stabilize the cells volume. If you treat an animal cell with ouabain, which inhibits the Na+/K+ pump, it will swell and often burst. Cells contain mostly negatively charged organic molecules, so they require cations for a counter charge balance: K+. This will create a large osmotic gradients, that would pull water into the cell, so it will pump out Na+. The pump is also able to generate membrane potential in nerve cells because of its electrogenic effect, but 90% of the membrane potential depends indirectly on the Na+/K+ pump." Questions I have 1. Why do cells mostly contain negative charge. If this is due to proteins. What are the proteins inside cells. 2. So my understanding is that K+ and Na+ try to neutralize the negative charge inside the cell. To reduce the solute concentration Na+ is sent out or else the cell would burst. I think this is wrong. Can someone please explain this to me. 3. For nerve cells what membrane potential do they need. Do they want the inside of the cell to be negative. Thank you very much

Thank you for the nice precise answer One question though, in general transduction the dna goes in to the capsid not the viral genome so wouldn't the bacteriophage still have its viral genome in this case.

In bacterial transduction bacteriophages contain DNA from other bacteria and infect other cells. My question is how can this occur because afer bacteriophage infects a bacteria it would die. So even if it got new bacterial DNA it would still die.

If a limiting friction of an object is 10N and the kinetic friction is 5 N. If I apply a force of 20 N continuosly would I be accelerating with a 5 N force forever.

In a non vaccum why do you need a larger force to move a larger stationary object. Is it because of the resitance forces you have to overcome. How is this resistance force created. In a non vaccum can I move a large stationary object with anyforce because there is no resistance.

Thank you everybody for your replies. I seriously have a major misunderstanding. I'll do this step by step 1. If I apply a force of 10 N to a ball inside a vaccum my understanding is ball would keep travelling at 10 N unless acted upon by an external force. Isn't this newton's first law? If I throw 10 N force for 1 m where does the force dissapear in the absence of resistance forces. Where does it go? At this point does the object reach terminal velocity? 2. When I hit an air molecule is it less than 10 N force? Merged post follows: Consecutive posts mergedOk I understand the answer for first question. 2. When I hit an air molecule is it less than 10 N force? Why is Russ Waters equation show 500 N. Thanks for your example and response though it was helpful. This is what I have trouble with. How did it become 500 N. How long does it take a ball to decelerate when hit by an air molecule. Wait it is impossible for the ball to decelerate when hit by one air molecule right it must be hit by heaps of air molecules. Did I get it. Did you get a decelerating time for the 500N question because it was a person who got hit. An air molecule would move away with any speed but a cluster of air molecules would take more. Or this is simply pushing a large object and small object right. A large object needs more force. Am I right?

Yes it did Thanks I'm only confused with the ball question now. If I throw a ball at 10 N and someone stands on the way wouldn't he get hit by 10N in the absenses of resistance forces. Now I'm comparing this person to an air molecule. So if the airmolecule get hit with 10 N it would exert 10 N back(air resistance force) neutralizing the force. That is my question Thanks a lot for help so far

Thanks a lot for the answers so far When I hit a ball onto a concrete floor why does the ball move back. Is it due to absense of resistance forces and the ball moves back as the reaction force.Is this a clear example of newton's third law. Also in the stone question if a stone falls at 10N (due to gravity). Does the earth under the water move towards the stone as the reaction force. Why does it only move a bit and how come the ball doesn't move up because of this. What do you exactly mean by earth moving up. If I throw a ball at 10 N. Why wouldn't it hit an air molecule at 10N and then cause neutralization of the force. Why is however in real air resistance less than 10 N Thanks a lot for the help so far

Hello, Few questions about these things.This is not homework!! 1. Is Newton's 3rd law caused by conservation of momentum? 2. If I drop a stone into a pond. The stone would exert a force on the water and the water would exert a force on the stone. So why doesn't the stone move up!! 3. Is air resistance caused by collisions with air particles. How come it takes time neutralize the force. I mean if I hit a air molecule with 10N force it would exert 10N back. So If I threw something at 10N why wouldn't it immediately stop after hitting an air molecule. I know these questions demonstrate a very poor understanding but please help me so I can improve!!Thank you!!

Due to colloid osmotic pressure reabsorption occurs but only water is absorbed. So how do they absorb ions and other solutes. Are they mixed in water? Thank you!!

Hello, In science there are so many equilibrium concepts. Pressure, electricity ,concentration..... Everything seems to be moving from high to low to reach equilibrium My questions are 1. Why does everything try to reach equilibrium? (Extremes are generally harmful and for survival of this word equilibrium is required is that the reason) 2. From where do the particles get energy to move from high to low and how do they know they have to move from high to low to reach equilibrium. Thank you very much!!

Hello, Ok I researched it but I don't understand. What I understand is that when one molecule normally diffuses(high to low) another molecule from a (low to high gradient) attaches to the carrier protein. How does this molecule attach without ATP? I don't get it. Any help would be appreciated. I'm talking about membrane transport of course!!

Hello everyone, How does an electric field create a magnetic field. If we move at the same speed in the direction of the electric field would we see a magnetic field. Would we still see it because it is perpendicular but we would see the electric field not moving so not sure. Thanks!!

Hello, Quick question. This is a light wave This is another light wave Why doesn't this graph have another perpendicular graph. Are they talking about the particles in the magnetic field or electric field here or both. Simply how do they make one wave out of a light wave that has two waves

1.Can cholestrol be stored in adipoctytes or is it only stored in liver? 2. If it only stored in liver how does choletrol turn into vitamin d when exposed to sunlight? 3. How does exercise increase HDL? 4. What exactly is HDL and LDL. I researched about this but I don't get it. How are they created?

------> Boat going at 10m/s ------> Sea going at 5m/s What is boats speed relative to the sea. If I use vectors it would BS= BG+GB =15-5=10m/s But the answer must be five and BG=15m/s(A person in the ground would see the boat travelling at 15m/s) Where have I gone wrong?

Does the immune system neutralise the toxin created by the bacteria or does it only neutralise the bacteria. Or is it both? Thank you

Hello everyone, I just started biology and I have lots of clarifications If red blood cells are created in the bone marrow how do they enter the circulatory system. Do they permeate through the blood vessels?

Thanks for the reply Captain Panic even though I got confused Thanks for the reply I know the ideal gas law so in this case let's say I want to know the density of gas molecules near the red area in the picture. Do I take the volume as the blue box or the yellow box. Thanks