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12

Gluconeogenesis is not the reversal of the glycolysis, but the generation of glucose from non-carbohydrate precursors (like odd chain fatty acids and proteins). The reason why we have this process is because some organs and tissues can only use glucose as their energy source. These include the brain (although ketone bodies can be used here as well), ...


8

High intracellular glucose. Affects: all cells that do not depend on insulin to take in glucose. Examples: neurons [1], kidney cells, retina cells. Causes: high extracellular glucose (in most cases hyperglycemia) Effects: promoting necrotic cell death through $H_2O_2$ (peroxide) formation, which may participate in the development of diabetic ...


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I thought this was a great question. In particular because it hints at two questions. The first is 'why carbohydrates are used to store energy' in general. The second being 'why glucose rather than other carbohydrates?' in particular. Glucose metabolism (and glycogen storage) is a core gene pathway - its found in bacteria archaea and eukaryotes. So ...


8

The minimum requirement for E. coli and other bacteria to grow and survive is called minimal medium. It's even defined at Merriam-Webster: a medium that contains only inorganic salts, a simple carbon source (as carbon dioxide or glucose), and water Water and glucose are pretty easy, but the source of salts may often change; regardless, you really need ...


7

The question is a bit unclear, it should be reframed as suggested by AliceD. To simply answer the question, Glucose is the substrate, and in the first step it is converted to Glucose-6-phosphate. Only the Phosphate group is added which originates from ATP, your notes also are a bit misleading because it tends to suggest that Hydrogen is released, which is ...


6

Is the standard Lotka-Volterra (LV) model an exact fit for insulin-glucose (IG) dynamics? No. Can a similar model built on the same principles capture most of the essential features of the IG dynamics? Absolutely. How to capture most of the insulin-glucose dynamics using a slightly modified Lotka-Volterra model We can figure out how to change the LV ...


5

Human body is a glucose driven machine which intake carbohydrates and converts to glucose. Energy is yielded from the glucose and glucose is stored as glycogen. When the carbohydrate intake is somehow reduced then body will shift its mechanism and uses the fatty acids to produce energy. Liver synthesis ketones from fatty acids in our diet or from body fat. ...


4

Yes, but no. In other words, this quote is not probably not true in the ways you'd think. Bacteria can survive on practically nothing for long periods of time, but whether you call that life is subjective. Nitrogen is necessary for all the co-enzymes and proteins to sustain life. In order to get energy, if E coli. needs to metabolize nitrogen to waste at ...


3

Glucagon and cortisol are VERY different types of hormones, though each of them can affect glucose metabolism and effectively can increase glucose concentrations in the blood (albeit through different mechanisms). Glucagon, pictured above, is a 31 amino acid peptide hormone (i.e. PROTEIN) that is released from the alpha-cells within the pancreatic islets. ...


3

This condition is also known as "lactic acidosis" and can be pretty dangerous, since it influences the pH of the blood. When we metabolize glucose to produce ATP and NADH it is metabolized finally to pyruvate in a process called glyolysis (I am not going into detail here since this is nicely explained in the Wikipedia). Pyruvate can then be used further in ...


3

This is only a guess but I hope somewhat educated, so refute me. The establishment of glucose as nutritional molecule is mainly linked with the availability of carbohydrates in the environment, i.e. plants as nutrition. Before plants evolved however, there were only bacteria and they use glucose as one of many oligosaccharides. But more important than ...


2

Where is this occurring in the body? Almost totally in the liver. To leave the liver as a sugar, it would have had to been converted to glucose, right? Correct, but it's not a direct conversion. Fructose is metabolized almost completely in the liver in humans, and is directed toward replenishment of liver glycogen and triglyceride synthesis... ...


2

In prokaryotes the glucose transporter is always present in the cell membrane; in cells whose glucose uptake is insulin-regulated the transporter is only present in the plama membrane when hormone levels are high. GLUT4 is the isulin-regulated glucose transporter found in muscle and adipose tissue. When insulin levels are low the GLUT4 protein is in the ...


2

The glucose can react with proteins, damaging them. This is called glycation. Note that glucose is the preferred body fuel and has a 10 fold lower ability to cause glycation than fructose. http://en.wikipedia.org/wiki/Glycation


2

Excellent question... "Can you measure plasma glucose with a blood glucose meter?" Absolutely Not! In my experience, if you try to measure plasma glucose with a whole blood glucose meter the results are highly variable for a number of reasons (mentioned below). Using blood glucose meters to measure plasma glucose is dangerous. The meters are calibrated for ...


2

Glycogen storage limitation is due to these additional facts also: Glycogen is a hydrophilic molecule. This means an increase in glycogen concentration will cause a proportionate increase cell weight due to water accumulation. As cells can contain only limited volume the amount of glycogen stores are limited. Lipids are hydrophobic hence can be ...


2

I think this experiment (PDF file) will help you understand the basic concept about the fate of oxygen in aerobic respiration. Basically the result is: The oxygen of respiratory carbon dioxide is in exchange equilibrium with body water. Utilized molecular oxygen is converted to body water. In respect to calculation of electrons donated to oxygen, just ...


2

Interpreting your question as "would the Lotka-Volterra predator-prey model be a good model for the glucose-insulin system?" my answer is "no". The predator-prey equations capture assumptions about how prey and predator interact with each other, and how they would fare on their own. These assumptions are not equivalent to any reasonable assumptions about the ...


2

"Is it the phosphate group, or the molecule, that is derived from ATP ?" The Phosphate group is derived from the ATP molecule (thus why Adenosine triphosphate) NOT from the molecule it would be attaching the phosphate group to. Phosphorylation - The process of taking this phosphate group and adding it to another molecule in the energy chain. I hope this ...


2

Short answer Facilitated diffusion is a passive process in which membrane channels mediate the transport of polar, or big molecules that are not solvable in the cell membrane. Co-transport, on the other hand, is active transport, as it depends on the electrochemical gradient of ions across the cell's membrane, particularly Na+. Because ATP or other energetic ...


2

It's not really possible to break it down this way. The CO2 fixated by the RUBISCO enzyme generates two phosphoglycerate (2 x 3C) molecules from one ribulose bisphophate molecule (5C), while the rest of the Calvin cycle serves to regenerate 3 ribulose bisphophate from 5 phosphoglycerate. Hence, one 3-carbon sugar (glyceraldehyde phosphate or dihydroxyacetone ...


1

No, the Lotka-Volterra model is a description of predator-prey dynamics. Although in some respects over-simplifying it is well suited for educating population dynamics and basic research. The physiology of carbohydrate homeostasis is different. Although, similar to population count in the Lotka-Volterra model, the elimination of both glucose and insulin ...


1

"Specifically, what is the difference between facilitated diffusion carrier processes (passive) and secondary active transport co-transport processes (active)?" Facilitated diffusion creates alternative paths for polar/charged substances to move down their electrochemical gradients across the hydrophobic interior of the membrane, thus greatly speeding up ...


1

Before discussing gluconeogenesis it is necessary to be clear on the following: What organism you are considering Under what physiological circumstances gluconeogenesis is occurring What is the substrate for gluconeogenesis and, if one is considering mammals: Which tissue is performing the gluconeogenesis Which tissue(s) will consume the glucose ...


1

I may have approached this problem from the wrong direction, so here's my attempt at an answer: For gluconeogenesis to function, glycolysis needs to be shut off. Glycolysis feeds the TCA cycle with Acetyl-CoA through the decarboxylation of pyruvate, and without glucose as a source, we need to look to other methods of generating OAA to make into PEP. We ...


1

Got it. The ratio of [NADH]/[NAD+] is about 100000 lower in the cytosol than it is in the mitochondria. The conversion of malate to OAA reduces a molecule of NAD+ to NADH, and that NADH can be used for the later step in gluconeogenesis: the conversion of 1,3-bisphosphoglycerate to glyceraldehyde 3-phosphate requires a molecule of NADH.


1

Glucose catabolism is a multistep process involving a series of reactions. The reaction you gave is simply the overall, balanced equation; it doesn't actually happen like that in living cells. All diatomic oxygen is converted to water in the electron transport chain, but water is also consumed and produced throughout the preceding steps, which is why the ...


1

This is not a new thing, by checking the articles about non-invasive glucose level measurement, it started in the early 90's. Near-infrared (NIR) spectra of the human inner lip were obtained by using a special optimized accessory for diffuse reflectance measurements. The partial-least squares (PLS) multivariate calibration algorithm was applied for ...


1

Too much glucose leads to the formation of advanced glycated end products, which deposit in tissues like glomerulus and cause disease like diabetic nephropathy. Also glucose is osmotically active, so when it starts appearing in urine (because of its high levels in blood), it leads to polyuria, following which the lost water is recovered from body tissues, ...


1

Glucose transports from the blood into the cells via facilitated diffusion. This means that glucose goes from higher concentrations (in the blood) to lower concentration (in the cell). Therefore, if you have super high glucose concentrations in the blood, you will have a ton of glucose in the cells. Glucose will oxidize by itself, thus it will contribute a ...



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