Cells Definition and 429 Threads

What exactly is the difference between a concentration cell and galvanic/voltaic cell? How do you know what are the half reactions? Also, is the ion and electron flow the same found in voltaic cells or is it the opposite? My biggest question of electrolysis has to do with Cl species...

Hello guys, A capillary is made up of a single layer of endothelial cells right. So when blood cells pass through it, do the endothelial cells take blood cells up by endocytosis and then release it to other side. How do capillaries take up nutrients, do the endothelial cells take it up...

This is my first post here, be gentle please ^_^. I searched for answers, but nothing came up. This is not homework, it's something I've been working on after I got bored with my Arduino. I'm working on a small project in my spare time. Using just discrete transistors, I'm building an adding...

One way muscle grows is muscle hypertrophy where sarcoplasmic fluid increases inside the muscle cell. Wouldn't this burst the cell membrane, I can understand how organelles can replicate but what about the cell membrane. I know this sounds like a stupid question but please help. Thanks :smile:

Nerve and muscle tissue don't grow back much but epithelial cells in the skin grow very quickly. Why is that some tissues find it difficult to grow back and are replaced by fibrous scar tissue. Can't they do some mitosis and regrow? Thank you :smile:

The theoretical maximum efficiency of silicon solar cells is about 29%. How is this theoretical maximum efficiency derived? How can I use the working principles of a silicon solar cell to explain this?

What is your opinion of http://www.cbsnews.com/video/watch/?id=6228923n&tag=related;photovideo" segment which appeared on "60 Minutes today (February 21)? It would, if it proves out, apparently make the "fuel Cell" a feasible idea for mass use. KM

Hi guys, can you guys point to me what are the recent experimental results that show that cells can be induced to make a pluripotent cells?

Homework Statement How many cells can be in a computer`s main memory if each cell`s address can be represented by 2 hexadecimal digits? what if 4 hexadecimal digits are used? Homework Equations N/A The Attempt at a Solution ok, i tried and other people helped and i am stuck...

Hi, I was just doing some reading on semiconductors mostly with respect to photovoltaic cells. I understand that doping silicon with Boron and Phosphorus creates a good semiconductor because the extra electrons from the phosphorus jump over to the 'holes' provided by boron, and then creating...

From what i understand, the only thing that makes using fuel cells in cars versus lithium batties less desirable, is the cost of hydrogen. If hydrogen can be produced extremely cheaply, assuming the same standards for compressing and transporting and storage of hydrogen, would it be better...

Question given. Predict how the average life span of a nerve cell located in the brain differs from the average life span of a red blood cell. Provide a basis based on cellular features. I know that the average life span of a nerve cell is the life span of the organism which it lives in. The...

Does anyone know where I can get information on how particles such and quarks/lepton that form atoms, atoms to molecules and molecules to cellular life.? What area of physics is based on the area of study and can evolution of biological organism be traced?

This image confuses me a tad. We have the n-type (negative) silicon and the p-type (positive) silicon plates. We put the plates together. The electrons are in a rush to fill the positive "holes" on the p-side, and the positive holes are in a rush to to the n-side, to the electrons. Between...

Hello, Im working on a paper on solar cells and i came across the term "Fermi level". What exactly is the Fermi level in this context: "The working voltage produced by the device is the difference between the chemical potential of the titanium dioxide (Fermi level) and the redox...

Although a complete cost analysis is much more complicated, the particular question only requires the following: an energy cost estimate (in terms of $/Joule). This was directed to be done by taking volumetric or mass based costs of each fuel as well as the associated energy conent or energy...

How are plantae protists similar and different from plant cells? The Attempt at a Solution similarity: both are photosynthetic, and producers, both are paraphylitic differences: protists are unicellular whereas plants are multicellular, plants are big and complex where as protists are...

Homework Statement If the probability of any given molecule occupying any given phase cell is known, what additional information is required in order to work out the equilibrium distribution of molecular speeds in a pure gas? Homework Equations The Attempt at a Solution Since the phase...

Does anyone know or know where I could find the average mass of a single lymphocyte? Specifically, a T-cell?

Hey all, This is just a post about some questions I had regarding electrolysis and fuel cells. I know that when electricity is forced through water the water molecules split, and produce hydrogen and oxygen gas. I was wondering how things like the electrode material and how far apart they are...

How are the cells (say 2V) of a typical lead acid battery connected in series to increase voltage to 12V when all the neg. plates are connected together and all the positive plates are connected together which as I understand is the principle of connecting two batteries in parallel (pos...

Here's something I've been wondering about for some time. How long does it take a cell to produce a string of amino acids? More spesific: The duration between the DNa beginning to make the RNA string and the string of amino acids being delivered?

Solar Voltaic Cells -- converting sunlight to electricity over a given area Homework Statement Lake Mead is formed by the Hoover Dam, and while it actually changes in area and volume, consider it has an average area of 100,000 acres. Assume that 250 W/m^2 of sunlight falls on Lake Mead...

How is the energy of an excited electron sent to another adjacent molecule as in the photosystem of chloroplasts in plant cells?

Given a multicellular organism, what is the theoretic minimum amount of cells it can have? Theory aside, what is the smallest known mulitcellular organism? Furthermore, anyone know of any links that show a table of organism and # of cells? Much thanks!

Homework Statement Using kirchhoff's laws, calculate the current in the 2 ohm resistor. Picture of the circuit attached. Homework Equations kirchhoff's laws, and ohms law The Attempt at a Solution i3 = i1 - i2 then i used kirchhoff's law to get: 2 - i1 = 2.i2 and 1 - 2 (...

Im try to make sure i understand something right. I have two jars on the left is oxidation takes place and on right reduction takes place. A wire connects them to allow electrons to move. electrons move from left side to right side. This makes the left side negative cause it produces electrons...

What happens when virus invades a host cell, reproduces and then leaves without destroying the host cell. Then does the immune system destroy these infected host cells? How do viruses do damage. Is it simply by leaving the host cell and destroying it?If bacteria can enter the cell without...

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?

Can anyone tell me how can I take the impedance spectra of a dye-sensitized solar cell ? Do I need to irradiate (i.e. AM 1.5, 100 mW/cm2) the solar cell during impedance measurement? or I can measure the spectra without irradiating light ? More specifically, how can I get the comparison between...

Homework Statement How exactly does connecting cells in series increase the voltage on the atomic scale? Does it speed up the electrons somehow? Explanations appreciated!

This question would perhaps be an ocean engineering question, but since we don't have a forum for that, I thought mechanical engineers would have some idea about this. My background is electrical engineering, and I have little knowledge about the mechanical issues when operating at the surface...

hi my friends I want some informations to study about gamma wave and interactions of it on humans cells.thancks alot.

Homework Statement I am doing a chemistry extended experimental investigation on the variables affecting a Daniell Cell's voltage. I am required to understand the reasoning behind voltage increase and decrease for particular conditions. I have done extensive research, but am unable to find a...

What is the mechanism by which they adhere to each other, and what stops them from sticking together when say you put your hands together?

The problem I have is just a detail I want to clarify about the voltaic cell. A standard cell is a voltaic cell in which each half-cell contains all entities shown in the half-reaction equation at SATP conditions, with a concentration of 1.0 mol/L for the aqueous solution. Referring...

Hi, Im looking for a new laptop battery. Something that's confusing me is the number of cells in a battery; what is a cell? is it a smaller battery that exists in the larger battery? If so, are the cells connected in series whose voltage sums to the voltage of the total battery? Or...

I'm using PV cells to energize an air core coil. Is there a method in which I can determine the maximum length of 32 gauge magnetic wire to use, so that I don't use too few windings and burn the coil out or too many windings limiting its' potential. I'll be using 2 PV cells that are each rated...

Imagine that it is possible to design cells of varying size. A cell is to be designed with a membrane that has a stable number of open channels. To this end, the number of channels must meet the following condition: the standard deviation of the number of open channels shall be no more than...

Bad news for those of us who like the free biscuits and the little badges but potentially good news for anyone needing a transfusion. http://www.livescience.com/health/090323-embryo-blood.html

batteries or fuel cells? hydrogen costs too much to be an effective fuel alternative? the catalyst required for the electrochemical conversion reaction is pricey platinum? Using hydrocarbons as a source for hydrogen we have more CO2 in the atmosphere? and require a high temperature...

Is it useful simulating a 3-D structure of a polymer solar cell? Is there a particular internal structure for a polymer solar cell which is most efficient?

Hello, First time post long time lurker! I've got an interesting project I am working on which involves a few MechE subjects. The overall goal (for now) is to determine the drag force of a cylindrical cone headed object in sand under various pressures. The movement of the cylinder is the tricky...

What is the approximate size of epithelia cells from the human oral cavity? And why must light intensity be low when studying them in bright field microscopy? (I know that phase contrast is better).

Is blood completely made up of blood cells, like we are completely made of atoms, or are the blood cells just suspended in the liquid we call blood?

Doing a homework crossword and this is the last problem. I can't seem to find it anywhere. An efficient grouping of cardiac muscle cells, eight letters long ending in M. Any help would be much appreciated.

Homework Statement A Doppler blood flow unit emits ultrasound at 5.0 {\rm MHz}. What is the frequency shift of the ultrasound reflected from blood moving in an artery at a speed of 0.20 m/s? What equations would I use to calculate the doppler shift? It is not in my textbook...

Hello! I performed a quick practical today using light microscopes. When looking at Epodea plant cells the chloroplasts 'retreated' to the edge of the cell; the vacuoles weren't particularly large and so didn't appear to be 'pushing' the chloroplasts an awful lot. Also, the chloroplasts at the...

http://img.exigo.com/public/1595/websites/2/images/stemenhance-label-english.pdf Sounds good and all, but I noticed that it is blue green algae. Sounds like a major scam.

Homework Statement Can someone please help A.S.A.P. I have a science assignment due tomorrow and it's 11:00 and I'm getting very frustrated. I'm about to go to bed and i'll forget about it in the morning. Ok i have 3 pictures. i tried drawing them on paint but it won't work, any ideas on how...