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There are two general points that should be appreciated in relation to this question: Your statement that mitochondria “have prokaryotic ribosomes” is a misleading simplification. Although mitochondria and plastids are thought to be derived from eubacteria — and their ribosomes have some similarities in antibiotic sensitivity — the structures of their ...


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Your description of it is largely correct, but the electron transport chain does not simply "dump" charged oxygen ions in the mitochondrial matrix. Instead, cytochrome C oxidase (complex IV) binds the O$_2$ molecule to one of its heme groups, and the reduction O$_2$ + 4 H$^+$ + 4 e$^-$ $\rightarrow$ 2 H$_2$O occurs at the heme group before water is released. ...


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The endosymbiotic theory states that eukaryotic mitochondria were once freely-living bacteria that somehow migrated into the cell and began a symbiotic relationship. However, just because the mitochondria within human cells have prokaryotic origins, these are distant relationships that are exceedingly old. The ribosomes of current day bacteria (on which ...


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Why Bilayer and not a Monolayer Lipid monolayer vesicles are possible as you mentioned (for example micelles). However, you have to understand that the cellular interior i.e. the cytoplasm, is aqueous and therefore a monolayer vesicle like micelles would not work. In micelles, the two compartments - interior and exterior, have to be of opposite nature for ...


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Well I'm assuming that you already have a fair idea of the structure of a leaf (of course, why else would you ask this question), so I'll just come straight to the point. The major difference between the two is that the palisade layer lies just above the spongy layer, and vice versa. That's understood. So firstly, the palisade layer consists of closely ...


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Its simple: Mass = Density * Volume = 10^3 (Kg/m3) * (10^-18 m3) = 10^-15 Kg which is equal to 10^-12 gram or 1pico gram


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The "X" you see is a chromosome. The two strands that forms the X-shaped chromosome are called chromatids. As they are bound together (by the centromer), they are called sister chromatids. Note that chromosomes look like that only during the metaphase. Note also, that not all chromosomes have a centromer that is in the middle of the chromosome as it is ...


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Human chromosomes contain certain DNA regions called telomeres. These regions are shortened on each cell division and once they are gone, the cell cannot divide. Therefore an average cell in our body can divide only about 50 times. There are indications that longer telomeres may increase lifespan, however this remains controversial. Telomeres are believed ...


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Decreasing the number of essential amino acids is frequently used as a selection marker during molecular biology experiments: An organism (usually yeast) that cannot synthesize a certain amino acid is first grown in the presence of said amino acid in the media. Then it is transfected with a gene of interest together with the gene that enables it to ...


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In a word: mutation. If you step back and think about it, multicellular organisms are really, really complex systems. Different cells have to do different kinds of things and interact with each other, they form organized tissues and organs and so on. That much is obvious. For all of this to work in concert, cells have to grow and divide (to replace dying ...


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What should be the correct reason for bilayer arrangement? I'll answer your second question first, but there is an almost identical question on this site already: Why do cells have a bilayer? There is water on the extracellular and intracellular side of the membrane. What's actually happening at a molecular dynamics level is the self-association of the ...


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Peptidoglycan is formed by the linkage of molecules of NAM ( N-acetylmuramic acid) and NAG (N-acetylglucosamine) into a polysaccharide structure. Many of these structures are then formed into a lattice by crossbridges of polypeptides. In gram + bacterial cell walls many layers of this lattice are stacked up forming a rigid structure, that is external to ...


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The bacterium always has a higher internal osmotic pressure (they contain a lot of stuff, and most of the time much more stuff than their surroundings). This pressure is contained by the membrane and cell wall, and when you destroy the cell wall the membrane alone is not strong enough, and the bacterium will spill its guts.


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Wikipedia gives quite clear and sourced answers in this case: an organelle is a specialized subunit within a cell that has a specific function. Individual organelles are usually separately enclosed within their own lipid bilayers. Under the more restricted definition of membrane-bound structures, some parts of the cell do not qualify as organelles....


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Ony a few protein kinases can phosphorylate all three amino acids — these are classified as dual-specific kinases (EC 2.7.12.1). Examples are APK1 from Arabidopsis or MEK kinases in mammals. As with other enzymes, the residues at the substrate binding site determine which substrates can be accomodated there. Structures or Ser- Thr- and Tyr-kinases are ...


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Your answers are correct, but there are more to consider: Nucleus is odd because it's the only one not directly involved in cell metabolism and has nothing to do with endosymbionts. Most cells also only have one nucleus but multiple mitochondria and chloroplasts - and multiple grana per chloroplast. Granum is odd because it's neither a eukaryotic cell ...


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I think it should be grana.. Reasons- 1. It is not a cell organelle 2. It is not having double membrane 3. It does not have its own dna or ribosomes...


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First question: B. The net gain of ATP in Photosynthesis is 0, so it cannot be A. C & D are obviously not true. Second question: B. D is not true, C is not true (it is actually the opposite- Chloroplasts absorb all BUT green, so only green would be bad). Like another commentator said, the level of CO2 only aids the rate to a point, at which the rise is ...


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I would say Nucleus is the odd one out. Chloroplast (which have Grana in them) and Mitochondria are involved in the process of creating/breaking down energy, whereas the Nucleus is, so to speak, the blue-prints of the cell. To summarize: Chloroplast is involved in Photosynthesis to create energy Grana are in the Chloroplast, which is involved in ...


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The cell wall is an organelle, but the cytoplasm is not. My guess is that the wall regulates movement (ie, active function), whereas cytoplasm is just a fluid in which the other cells are surrounded (ie, passive). http://www.edu.pe.ca/gray/class_pages/rcfleming/cells/notes.htm Note that the terms active and passive are not being used in any scientific term,...


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Cells absolutely can be considered as diffusing objects. However, the origin of the "diffusion" can be very different than for, say, a bead in water. The reason is that the thermal motion that creates the diffusion of a micron-sized bead can be much less important for a (large) cell. For instance, the diffusion coefficient due to thermal forces of a ...



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