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The main difference is that memory B cells start an immune reaction much more effective and faster than naive B cells. The reaction is also specific towards the antigen. The memory B cell has a specific membrane receptor for an antigen. It produces specific antibodies only when exposed to the antigen. References: Tangye SG, Avery DT, Deenick EK, Hodgkin ...


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My first thought was this: According to Wikipedia (citation provided) Between 50 and 70 billion cells die each day due to apoptosis in the average human adult. For an average child between the ages of 8 and 14, approximately 20 billion to 30 billion cells die a day. For every cell that dies a new one must be born, so there must be at least between 50 ...


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Many cell components are not simply hydrophobic or hydrophilic, but have dual affinities. Proteins typically have structures which result in the interior of the protein being hydrophobic and the exterior, which is exposed to the water in the cytosol, being hydrophilic. Thus, differences in polarity between different regions allow proteins to be dissolved in ...


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Some thoughts on this. First of all, the positive-inside rule, proposed by Gunnar von Heijne, is an empirical rule based upon observations, not one derived from theoretical considerations, so any explanation is simply an attempt at a rationalisation. Having said that, here are three of those rationalisations: the membrane potential is usually negative ...


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MitoSOX looks pretty cool. I've never used it myself, but I'm sure you could see some cool mitochondrial dynamics going on. Its a bit pricey though, but all dyes are going to be. Even at only 8 hours you should probably be able to see a few divisions, which would be cool with hoechst.


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groups of cells A normal light microscope. 4x-20x magnification individual cell Lo resolution: Light microscope with 40x magnification. High resolution: Confocal microscope with 40-100x magnification. cell organelles Low resolution: Confocal microscope with >=60x magnification. Note: some organelles are easier to visualize while others ...


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Because cells are not only characterized by by their genetic material and other interior components, but also by the genes they express. Cells have to fulfill multiple different functions to be able to build complex multicellular organisms. Differently expressed genes lead to different proteins made in the cell, which leads to different morphology, shape or ...


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Cyclin dependent kinase is the answer for the first question. Cyclin concentration increases during m phase and falls in g1 s and g2 phase as it is degraded. Cdk is always present in the cell but gets activated during m phase, when cyclin is present. (cyclin dependent) Cancer cells do not require growth factors to stimulate cell division. They have ...


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My understanding is that telomeres are linked to cell senescence, which is not necessarily the same thing as organism senescence. So even if you could track down a method to slow cell division, it would more likely mess with organ function now rather than extend life. Here's a nice summary of cell senescence: ...


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Your hypothesis is incorrect. You must be assuming that lactamase destroys the antibiotic with perfect efficiency. This is incorrect. You must be assuming that the population will remain genetically stable. This is doubly incorrect. Firstly the penicillin will select highly resistant bacteria which suffer a greater fitness burden from expressing the ...


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activation energy - there is an energy barrier that must be crossed by supplying energy for a chemical reaction to proceed - enzymes bring substrates and reagents into close proximity so the amount of energy needed to initiate, sustain and complete the reaction is reduced in the process.


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There is a wide continuum from "cancer" in the sense of uncontrolled cell division (this could include even things like 2-3 extra cells making an imperceptible, microscopic bulge in your colon) to cancer in the sense of huge lumps of meat growing on your body and killing you painfully within X months. For the latter kind, many "stages" of "evolution" must be ...


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This answer doesn't add anything to the others, but is an attempt to explain using different language. "my question is why the water of cytosol doesn't dissolve the ionic part of the lipid bilayer" In a sense, it does. See my diagram below The bilayer is composed of phospholipids, classic amphiphiles with a polar head group and a nonpolar tail group. The ...


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ADDENDUM Water can disrupt the intramolecular hydrogen bonds by bonding to the donors/acceptors. However, water in many cases can also act like a bridge and stabilize the protein structures. As already pointed out by jarlemag, the hydrophobic residues can push the water out of the pockets where intramolecular hydrogen bonds are to be formed. You may notice ...


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After fertilisation the zygote has two copies of each of the chromosomes (not worrying about sex chromosomes). When each of these is replicated the cells will have chromosome pairs, which will then divide in mitosis. The classical chromosome image of pairs of X-shaped chromosomes relates to the situation at mitotic metaphase when each of the chromosomes has ...



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