Cells Definition and 429 Threads

  1. gracy

    Multiple fusion: daughter cells different from parent cell?

    I think in Multiple fusion daughter cells are different from parent cell.I interpreted this by looking at the image below Have I interpreted correctly?Is this image reliable?
  2. V

    Foreign cells can they survive and divide using its own dna

    If a foreign human cell is introduced into one's body by way of blood transfusion or through some other method could these foreign cells survive and take up host in their new environment ? So if a foreign nerve cell is introduced could this nerve cell take up host as a native cell where it can...
  3. V

    How to do lab testing for cells in foods

    Hello. I have no experience as a cellular biologist nor have any lab experience or knowledge. However I would like to know how would one go about finding out what is needed in order to test the following foods mostly for human cells (any kind) : 1. How can I examine the following food items...
  4. E

    Engineering Cooling Integrated Circuits with Peltier Cells

    Homework Statement Hi all, I have a question about using peltier cells for both cooling and reading temperature in the same moment. I need to cool down a couple of Integrated Circuits so I'll put put a 20mmx20mm peltier cell over them but I cannot read the cold side of the cell because it's...
  5. diracdelta

    4 balls and 4 cells probabillity

    Homework Statement Four balls are distributed randomly and independently into 4 cells. What is probability that: a) In every cell there is exactly one ball? b) All four balls be in one cell? c)Two balls in one cell ( any) , other two balls in other cell (any)? (assume that the balls are...
  6. A

    Is conditional arrangement of cells in a mxn matrix unique?

    How many ways to arrange cells of k possible values in a mxn matrix provided that sums of all rows and columns are known? For example, if we have a 5x3 matrix and 10 possible values ( from 0 to 9) that can be assigned for each cell, then how many ways to arrange cells in that matrix satisfying...
  7. S

    Ideal cells in parallel combination

    good evening to all if two ideal cells with emf 6 volt and 3 volt are connected in parellel to supply current how the net emf can be decided
  8. Sowon

    Power Source at 6.0V: Analyzing Current, Voltage, & Resistance

    Power Source at 6.0V a) Voltage drop across the parallel branch of the circuit: 0.25V b) Voltage drop across the light bulb connected in parallel: 0.25V c) Voltage drop across the light bulb connected in series: 0.5V 2) How would you measure the current through the entire circuit: By putting...
  9. E

    Efficiency calculation for solar cells

    Homework Statement Hi! I have a problem with the following problem: Calculate the efficiency of the solar cells with the characteristics given in the table below Power (28 degrees, BOL): 300 W/m2 Absorptance: <91 , emittance: >82. Reliability: 0.999 . Mass: 2 kg Homework Equations I know...
  10. patrickbotros

    Galvanic Cells and Salt Bridges

    I went to class and watched this video () but I still don't understand how salt bridges work. I think I memorized all of the details and steps but I don't understand why anything is happening at all! I know that Cu2+ gains two electrons when it touches the electrode but why? And also does the...
  11. Sayani Ghosh

    Schottky junction solar cells

    I was wondering in Schottky junction solar cells, how is the open circuit voltage dependant on the built in potential and the Schottky Barrier Height?
  12. C

    Generating Colour in Excel Cells

    Im trying to colour excel cells using (r,g,b) values. I understand its possible to do this through macros or through custom functions. Any suggestions / solutions?
  13. B

    Short Circuit Current in Solar PV Cells

    I'm reading about short circuit current in a solar PV cell and I am a little confused. The short circuit current is defined as the current across the solar cell when there is zero potential difference across the cell. At this point the short circuit current is equal to the light current. What...
  14. M

    Fuel Cells; PEMFC; Cause of Proton Movement

    Lately I've started learning about fuel cells, particularly proton exchange membrane fuel cells (PEMFC), and a fairly basic question that has been bugging me is: Since the cathode is positive, it is clear why the electrons flow through the load and to the cathode, but why do the...
  15. S

    How much improvement in probability of power cells B wrt A?

    Homework Statement The full problem statement (I just need help for part c): You are determining which model of power cell to purchase for your project. Your project requires 6 power cells, at least 4 of which must work for the project to work. You would like your project to work for at least...
  16. P

    Exciton Diffusion Length in P3HT:PCBM BHJ Cells

    Hi, I understand that an exciton must reach the D/A interface within the Exciton diffusion length to prevent recombination, however, what are the factors during device fabrication that can affect the Exciton diffusion length of a P3HT:PCBM BHJ OSC?
  17. B0b-A

    What fraction of adult human cells are not replaced over a normal lifetime ?.

    What fraction of adult human cells are not replaced over a normal lifetime ?. see ... http://en.wikipedia.org/wiki/Ship_of_Theseus / [ aka "Trigger's broom" ]. I'm guessing it's a minority : brain and heart only account for about 3% of body weight.[ skeleton is replaced every decade , but...
  18. Hijaz Aslam

    Working around with Electric Circuitry.

    Though I understand the basic combinations of resistors, emf and capacitors, both in parallel and series, complex circuitry questions always baffles me. I would like to know what are the key points? I mean important points to be kept in mind. What are the common mistakes? What are certain tricks...
  19. gracy

    Are All Somatic Cells Identical?

    Are all somatic cells same?As they all are product of mitosis of zygote ,all somatic cells should be identical.If yes then what makes eye cell different from say heart cell i think it is switching on and off mechanism i.e these two cells are exactly the same.They will contain same 46...
  20. J

    Why aren't drones and aircraft using hydrogen-oxygen fuel cells?

    I've heard they were much more efficient then li-ion batteries and anything else really.. and drones today are all about flight time, wouldn't hydrogen fuel cells result in a great flight time advantage? why are they not in use?
  21. M

    Electrochemical Cells (involving partial pressures and pH)

    Homework Statement A voltaic cell utilises the following reaction: 4 Fe2+(aq) + O2(g) + 4 H+(aq) ---> 4 Fe3+(aq) + 2 H2O(l) What is the emf of this cell when [Fe2+] = 1.3 M, [Fe3+] = 0.010 M, PO2 = 0.51 bar and the pH of the solution in the cathode is 3.5. The standard reduction potentials...
  22. Alain De Vos

    Blood smear , a day old, the cells show lots of bumps and bulges

    Is it because the bloodcells are dried out or because they are attacked by viruses?
  23. D

    Calculating Osmotic Pressure Of Red Blood Cells

    Homework Statement i) A human erythrocyte (red blood cell) may be approximated as a disc around 2 microns in height and with a diameter of 10 microns. If the pressure inside were to become large enough for the cell membrane to rupture, where would you expect it to fail, assuming the membrane...
  24. C

    Jumping Up and Down: Can It Affect Cells?

    Dumb question. I don't know anything about biology or physics. But with all the intricate DNA unwinding and transporting and building and whatnot going on in a cell, is that screwed up if you jump up and down? Would that actually "shake up" your cells?
  25. avito009

    How is electricity produced from solar cells?

    Is electricity produced from solar cell because light has electric and magnetic fields?
  26. T

    Verifying my understanding of solar cells and semiconductors

    My base understanding of the solar cell is as follows: Light hits metal in solar cell and emits electron via photoelectric effect. There is n-type silicon which has an overall negative charge due to excess electrons. There is also p-type silicon which has an overall positive charge due to a...
  27. B

    Finding the ratio of the emfs of two cells by a potentiometer

    I don't have a clear perception of how the following question is answered: "Two primary cells of emfs E1 and E2 respectively are joined in series with (i) the same polarity, and (ii) opposite polarities. The combination is connected through a galvanometer and a jockey to a potentiometer. The...
  28. steve_h

    Silicon carbide polytypes (large unit cells)

    Hello everyone. I am a Hungarian born Australian theoretical/applied physicist. This is my first post on the forums. I am aware that silicon carbide crystal occurs in many different crystalline forms. I was wondering if someone here could please point me to a source that catalogs the...
  29. 1

    Relevant informations about photovoltaic cells

    it's good to aim for something impossible. so... recently, i have a lot of free time (oh, I'm only in my teens), and i would like aim to be someone who makes solar cells cheap and available, that kinda thing i know physics, like general relativity, and some quantum mechanics, recently I'm hooked...
  30. D

    What is the top solar cells in market?

    What is the highest efficient solar cells out there? I heard there was one that is 80% efficient. And there is a clear solar cell but less efficient which are transparent ones.
  31. P

    Do Fuel Cell Vehicles Use Catalytic Converters?

    Homework Statement Do fuel cell vehicles have a catalytic converter? Where is it located? The attempt at a solution[/b] I am guessing that the the question qould be referring to precious metal catalyst located at anode region which breaks the fuel into protons and electrons?
  32. M

    Specialization of cells and organelles

    Hi, I just had 2 questions. 1. In multicellular organisms, are there any undifferentiated cells besides stem cells? Do they play any significant role? 2. Why is it that smooth ER does not have ribosomes attach to it but rough ER can have ribosomes come and attach? Is there a structural...
  33. Entanglement

    Understanding Galvanic Cells: Zinc and Copper Electrodes Explained"

    What I know about galvanic cells is : zinc is the anode and copper is the cathode, zinc loses electrons and it turns into ions leaving its electrons on the electrode. While copper is the cathode it also loses electrons and turns into ions leaving its electrons on the electrode, but zinc has...
  34. iamjon.smith

    Comp Sci Getting VALID range of Excel Cells in javascript

    Mod note: The OP has found an answer to his question.[/color] I am validating a text field in javascript in EXTJS 4 framework, based on the selected value of a text box: else if (record.get("type") === "CELL_VALUE" && record.get("apply_before") === true) { Ext.Msg.alert("Field...
  35. D

    Why do we need tandem solar cells?

    I have a general question about tandem solar cells. So tandem solar cells are solar cells with multiple p-n junctions in them. However, why can't we have a single junction solar cell with multiple wavelength absorbers in them? That is to say, why do tandem solar cells need to be split...
  36. G

    Optimizing Solar Panel Efficiency: Calculating Sunlight for Maximum Power"

    How can I calculate the total diffused and incident light of the sun?Edit I am doing this project with solar panels. I thought, watching as well several youtube videos, that I could improve the panels with mirrors, and looking at some plants, I realized that some of their leaves bended towards...
  37. J

    Is a Sun-Solar Cell System Truly Equivalent to a Carnot Engine?

    I have undertaken a course on Semiconductors. My professor told us that a sun-solar cell system can be taken as a Carnot Engine. He assumed that the surface temperature of sun is 6000k and that of solar cell is 300k.And then he found out the efficiency by (1-T1/T2), which came out close to be...
  38. J

    Creating Cells with Household Materials: Ideas?

    I'm hoping to make (or model) these little cells on my own, but I'm not entirely sure how it can be done with household materials. I've seen a few videos of it being done but there's not much on how to create them. Any ideas? Thanks
  39. B

    Using a Catalyst With Fuel Cells: Benefits and Challenges

    With galvanic cells, we assume that the redox reaction is kinetically inhibited so that equilibrium takes a long time to reach, so we can make a good measurement of the potential difference V. I thought fuel cells were the same originally, except that we recycle in reactants and products to make...
  40. B

    Ionization of Zinc in galvanic cells

    what exactly ionizes zinc in the galvanic cell or the daniell cell ? i mean zinc atoms in the galvanic cell are ionized into Zn ++ and 2 e- . then the electrons move through the conductor to the copper bar , my question is why does zinc ionize when connected in a battery ? when the circuit...
  41. Mohamad&Issa

    Bone Marrow Stem Cells: Biology School Project

    Hello... For my biology school project, I was searching throw internet about Stem Cells in the bone marrow, that are responsible for the renewal of blood cell. I found that the bone marrow stem cells transform into red blood cells, white blood cells, monocytes... My question is how can this...
  42. Q

    How to Calculate the Density of Aluminum in a Face-Centered Cubic Unit Cell

    (Skip to the bottom for my questions). I'm just sounding off my thoughts above. Homework Statement Find the density of aluminum, which crystallizes in a face-centered cubic unit cell. The atomic radius is 143 pm. Homework Equations edge length of FCC is (4/sqrt2)r. The Attempt at a...
  43. P

    Which virtual cells look the same as the basic cell?

    Homework Statement Above is the basic cell drawn with an object inside of it. You look in top view of the basic cell and the space around it filled with virtual cells. You can see the top view of a basic cell (the square [that is marked blue] formed by the four real mirrors with a...
  44. P

    Virtual cells of mirror reflections

    Homework Statement Please note that this is an extension of this question here: https://www.physicsforums.com/showthread.php?p=4571995#post4571995**Questions** Mirrors A and B with the space between them, including the bird, are part of the real world. Those are all a part of a basic cell...
  45. H

    What Is the Newest Generation of Solar Cells?

    Dose anyone know that what is the newest generation of solar cells?
  46. B

    What is the current in a circuit with two cells?

    Homework Statement What is the current in this circuit: http://img802.imageshack.us/img802/4646/8ekh.png Homework Equations All potential differences in a closed portion of a circuit must add to 0. Terminal Voltage = EMF - I x internal resistance. The Attempt at a Solution I do not know how...
  47. O

    Biology How did they measure total cells? (genetics of bacteria)

    1. About how many cells were plated to count His+ revertant colonies? How was total cell number determined? I know that the mutation freq was out of 10^7 survivors. So they had to measure the total cell number and come up with 10^7 survivors? But I'm not sure how they got this...
  48. O

    Proton Concentration Cell: Finding Original pH with Initial EMF

    Proton concentration cell is made by connecting with Pt wire two acid-base solutions and measuring emf. but wire allows redox reaction, changing conc of H+ in each solution. how is original pH found- with initial emf reading?
  49. O

    Deduce Half-Cell Reactions from Galvanic Cell Representation

    Please tell me how to deduce reliably from galvanic cell representation, the half-cell reactions, for any cell, or vice versa. Pt(s) | H2(g) | HCl(aq) | Cl2(g) | Pt(s) Pb(s) | PbCl2(s) | HCl(aq) | H2(g) | Pt(s) Pb(s) | PbSO4(s) | K2SO4(aq) || KNO3(aq) || KCl(aq) | PbCl2(s) | Pb(s)...
  50. N

    Why Do Cells and Organisms Suddenly Die?

    I'm a high school student in AP Biology, and we are learning about how cells can absorb nutrients they need through the plasma membrane, as well as break down glucose into ATP for use. So why do cells (and organisms, for that matter) all of the sudden... Die? Why can't the cell just keep...
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