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Questions tagged [glucose]

Glucose is a monosaccheride which is build up by plants during photosynthesis.

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Why does pyruvate from lactate and pyruvate from other sources follow different pathways in gluconeogenesis?

My teacher taught me in a lecture that PEP forms from Pyruvate by two ways, based on their sources, that is - 1. If the Pyruvate was from lactate (by lactate dehydrogenase action), it gets shuttled ...
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about lipid oxidation, does acid fatty transforms in glucose? [duplicate]

Lipid oxidation generates fatty acid and glycerol going into the bloodstream. Can they be converted into glucose by gluconeogenesis or are they turnd into ketone bodies?
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Glucose Carrier Proteins in Cell Membranes

I'm using Campbell's Biology textbook, and it states that certain carrier proteins transport glucose across the cell membrane much faster than would occur normally. It states that the "glucose ...
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1answer
15 views

Finding out the best concentration for my plant extract to be used as drug for diabetes

I am using plant extract of Ajuga parviflora and found out that it possess anti-diabetic properties by using alpha-amylase inhibitory assay. I used various concentration 250 µg/ml(29% inhibiton of ...
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51 views

Specific Neurons that Require Glucose

I've been doing a bit of armchair biology lately, and have been interested in the metabolic flexibility of neurons. My understanding is that, besides glucose, many neurons can metabolize lactic acid ...
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293 views

Why does GLUT2 (With a high Km), bind less glucose at a lower glucose concentration (below Km)?

A text I am reading says "GLUT2 is a low-affinity transporter in hepatocytes and pancreatic cells. After a meal, blood travels through the hepatic portal vein and GLUT 2 captures excess glucose for ...
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Insulin action on glycogen phosphorylase?

Q: What happens to glycogen phosphorylase when insulin levels are high? How exactly does insulin exert its action on the enzyme and how is this action facilitated by high glucose levels in the ...
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If glucose-6-phosphate accumulates in muscle cells after a meal, the hexokinase is inhibited; what happens to intracellular glucose level?

Let's say this situation is occuring after a meal, so that there are glucose transporter in the muscle membrane. The glucose will diffuse in the muscle cells and the hexokinase will phosphorylate it ...
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How is Glyceraldehyde 3-phosphate converted into glucose?

In the light-independent reaction of photosynthesis, one of the products is glyceraldehyde 3-phosphate, and the Wikipedia page on the light-independent reactions states that 6 of these can be used to ...
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Why only 6 water molecules are formed in the aerobic degradation of glucose?

I am studying the aerobic degradation of glucose and it seems that for every glucose molecule we should obtain $\ce{10H2O}$ molecules. However, it is known that we only obtain 6. $\ce{C6H12O6 + 6O2 -&...
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Reason for conversion of glucose to fructose in glycolysis

In glycolysis, glucose is converted to glucose 6-phosphate so it can not diffuse out of the membrane. Then it is converted to fructose 6-phosphate. Why is this? Perhaps it makes it less stable so it ...
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Why do food items expire?

Why do food items and medicines expire after sometime?
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Triosephosphate isomerase deficiency

Triose phosphate isomerase deficiency, a rare condition, is the only glycolytic enzymopathy that is lethal. This deficiency is characterized by severe hemolytic anemia and neurodegeneration. How can ...
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Why do cells not store glucose

I understand that glucose is soluble and hence it is not stored by cells but my teacher said that I also have to say that 'it would have an osmotic effect on the cell.' I don't understand what that ...
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227 views

Activation of Glycogen Synthesis by Insulin - mechanism and cellular location?

My textbook states the following... Insulin activates enzymes that convert glucose to glycogen. Does this conversion occur inside or outside the liver and muscle ...
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80 views

Why is glucose used in oral rehydration therapy?

What is mechanism of action of glucose in the intestine to reduce the watery and electrolyte secretion?
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How is the rate of gluconeogenesis controlled in the cell?

As far as I am aware, all steps in glycolysis are readily reversible except the phosphorylation of glucose, the phosphorylation of fructose6 phosphate, and the phosphorylation of phosphoenolpyruvate ...
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51 views

How to determine the fastest metabolism ? [closed]

Which is the fastest metabolism ? Fructose metabolism or Glucose metabolism
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Why is the hexose monophosphate shunt called a direct oxidative pathway?

Why is the hexose monophosphate shunt (pentose phosphate pathway) called a direct oxidative pathway( Ref. Biochemistry by Satyanarayana , 4th edition, pg.no: 244) , even though oxygen molecule is not ...
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Source of blood glucose during starvation [closed]

During starvation there is many source for glucose such as pyruvate, lactate, amino acids (except leucine and lysine) and glycerol from triglycerides but what is the major source of blood glucose ?
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How is NAD+ used in lactic acid fermentation after it is oxidized from NADH?

I am confused with the whole process of glycolysis and the fate of the products of this reaction. So, I understand that anaerobic glycolysis results in 2 pyruvate + 2 NADH and 2 net ATP. Is the whole ...
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1answer
101 views

Is phosphofrucrokinase1 PFK1 found in the liver? [closed]

I am trying to understand glycolysis control. One thing I am stuck on is whether there is PFK1 in the liver, or only PFK2. Edit: As far as I am aware, there is no pfk2 in muscle cells, only pfk1. ...
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How do absorbance readings indicate diauxic growth of bacteria?

How is growth rate an indicator of carbohydrate use? How do absorbance readings from a spectrophotometer show growth of bacteria if the absorbance readings are taken several times over the course of a ...
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Why is GTP, not ATP, produced in Gluconeogenesis & TCA Cycle?

In both gluconeogenesis and the TCA cycle, there is a point in each that GTP is produced instead of the usual ATP. My question is why GTP and not ATP for these 2 specific steps?
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Role of the Hypothalmus in the control of Blood Sugar

In homeostatic regulation of blood glucose, the receptor and effector is the Pancreas, but how does the control centre — the Hypothalamus — connect and link into this process?
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503 views

anabolism in plants

The question is as following: Which substance has the greatest contribution to the anabolism of glucose in plants. A- Oxygen (O2). B- Water (H2O). C- carbon dioxide (CO2). The official answer given ...
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508 views

Storage of energy in muscles vs fat depos [closed]

How does the body control, where consumed energy (fat, glucose) is stored? And what is its strategy? More specific: 1) How does the body control storing glucose in muscles and not as (subcutan) fat? (...
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1answer
42 views

Physical activity in fasted state: Glucose for brain vs muscles [closed]

Let's consider this scenario: You do sports in the morning in a fasted state (i.e. without consuming any calories after waking). Your brain of course needs glucose and your liver probably still has ...
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536 views

What is the substrate for glycogenesis?

In glycogenesis (i.e. the synthesis of glycogen), are sugar phosphates the direct substrates for glycogen polymerization? I would certainly think so since glucose is phosphorylated and then stuck onto ...
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Opening and Closing of stomata

Which is the more accepted theory for the opening and Closing of stomata : the sugar concentration theory or the k+ ion theory ?
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1answer
301 views

Cellulose Branching [closed]

I understand that humans cannot digest cellulose because there are no branches to break down the polysaccharide chain. But why can cellulose not form branches?
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1answer
1k views

What's the highest glucose concentration (in mM) anywhere in the human body (tissue, capillaries, tumor microenvironment, etc.)?

Glucose blood levels are around 5mM, or 10mM after meals. In capillaries these levels can rise by about 40 %. I haven't found measurements of glucose concentration in tissues, or in extracellular ...
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Where do the four ADPs come from in the second stage of glycolysis?

In the first stage of glycolysis, the two molecules of ATP are broken down into 2 ADPs + 2 Pi through hydrolysis, then in the second stage of glycolysis they are phosphorilazed to obtain 2 ATPs. How ...
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2answers
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Starch vs Cellulose. What are the differences between Alpha and Beta glucose ring structure in them?

I'm studying "Campbell Biology, 10th Edition" and in chapter 5 page 71 there's a statement I can't understand. according to book: In starch, all the glucose monomers are in the α configuration. ...
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1answer
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How are 6 “fixed” CO2 molecules joined toegther as glucose?

When we study calvin cycle, we study it with 6 molecules so as to form 1 glucose in a single cycle as: 6 RuBP + 6 CO2 => 12 3-PGAL => 1 Glucose + 6 RuMP But if we look deep, then we know that the ...
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In glycolysis, what is the source of the electron that makes NAD+ into NADH instead of NADH+? [closed]

I looked at the formula for the glycolysis reaction. The overall reaction seems balanced, however, I don't see anything on the left hand side of the equation that would provides the electron to ...
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30 views

Electrically facilitated active transport across a membrane

I'm trying to go back to school to do a PhD in control theory, specifically concerned with control of glucose. The glucose system can be controlled using two chemicals: insulin and glucagon. I was ...
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3answers
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What are the differences between how glucagon and cortisol work to increase blood sugar?

As I understand, both cortisol and glucagon cause an increase in blood sugar concentrations. However I don't understand how they work differently or why they work separately. I would be very grateful ...
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Is Insulin-Glucose dynamic Lotka-Volterra?

From Wikipedia: The Lotka–Volterra equations, also known as the predator–prey equations, are a pair of first-order, non-linear, differential equations frequently used to describe the dynamics of ...
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A question on glycolysis

In the first step of glycolysis, the glucose ring is phosphorylated. Phosphorylation is the process of adding a phosphate group to a molecule derived from ATP. As a result, at this point in ...
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Difference between facilitated diffusion and secondary active transport in cells

Specifically, what is the difference between facilitated diffusion carrier processes (passive transport) and secondary active transport co-transport processes (active transport)? They seem to be the ...
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When glucose production is low, the brain begins using ketoacids as energy… how does that work?

Can someone very generally describe how the brain consumes ketoacids/ketone bodies when blood glucose has been completely depleted?
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What is the purpose of gluconeogenesis?

The gluconeogenesis pathway seems quite pointless to me. I don't understand why an organism would want to spend energy to create a molecule that can then be metabolized again for less energy? The ...
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1answer
716 views

What is the role of Aspartate Transaminase in gluconeogenesis?

I know that oxaloacetate cannot cross the mitochondrial membrane, but can instead be converted to aspartate, shuttled out, and then re-converted back to oxaloacetate. What does this have to do with ...
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1answer
509 views

Why is oxaloacetate made in the mitochondria?

I'm looking at the gluconeogenic pathway: Pyruvate is shuttled into the mitochondria from the cytosol, converted to oxaloacetate by pyruvate carboxylase, converted to malate which is then shuttled ...
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2answers
472 views

Conversion and storage of glucose to glycogen

Why is excess glucose, synthesized to glycogen, stored only in limited amounts, as compared with lipids/triglycerides that are stored in our body? Why is mature glycogen arranged (polymerized) in 12 ...
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2answers
962 views

Tracking of oxygen molecules in glucose oxidation

For this reaction, found in typical biochemistry textbook: $C_6H_{12}O_6 + 6O_2 \to 6CO_2 + 6H_2O$ I am interested in where do the oxygen atoms of $6O_2$ go. I think they go to $6H_2O$, but this is ...
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1answer
351 views

How non-invasive blood glucose concentration measurement work?

Diabetes patients need to conduct the “fingerstick” a few times a day. One of the mechanisms of "fingerstick" is to take small amount of blood sample and put it onto a test strip. The enzyme on the ...
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1answer
729 views

Can you measure plasma glucose with a regular glucose meter?

I'm wondering if plasma glucose can be measured with a regular glucose meter and strips like this. I know these meters are normally used to measure whole blood glucose, but can they measure plasma ...
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4answers
4k views

Why is too much glucose harmful?

I learned the citric acid cycle in biotechnology school and how cells work; about ADP and ATP and how the Cellular respiration (C6H12O6 + 6O2 -> 6CO2+6H2O) works. I am interested in understanding why ...