Where Does The Glucose That Is Released Into The Blood Ultimately End Up (2 Places)?

Stop Starch-induced Glucose Surges

About 35 years ago, the federal government revised their dietary guidelines to advise Americans to increase the amount of carbohydrates they consume to around 60% of their daily food intake. The objective was to achieve a healthier lifestyle.1 The latest guidelines from the Institute of Medicine recommend a daily carbohydrate intake of up to 65% of daily food intake.2 The catastrophic result has been an epidemic of life-threatening obesity, type II diabetes, metabolic syndrome, and other diseases.2 The reason is simple. Starch is one of the largest dietary sources of blood sugar and dangerous after-meal blood glucose spikes.3,4 Even if you eat so-called “healthy grains” such as whole wheat and brown rice, these all convert into sugar during digestion.5 Fortunately, researchers have uncovered a dual-action enzyme known as transglucosidase (pronounced trans-gluco-side-ace) that blocks the conversion of starch into sugar and tranforms it into beneficial fiber.6 While you can’t eliminate all starch from your diet, you can neutralize its negative impact on your body. Transglucosidase represents a novel mechanism for protecting against the harmful effects of dietary starch. Impressive laboratory studies have shown that when transglucosidase comes in contact with starchy foods and natural enzymes in the digestive tract, there’s a 31% reduction in rapidly digested starch (the kind that causes blood sugar to spike right after a meal) and an 11% increase in slowly digested starch (which gets converted to sugar more slowly, if at all).7 Together, that means approximately 40% of the starch you ingest is less likely to be rapidly absorbed into your bloodstream. Human clinical studies have confirmed the ability of transglucosidase to reduce blood glucose and insulin levels. F Continue reading >>

Research Reveals A Surprising Link Between Melatonin And Type 2 Diabetes

We typically associate the hormone melatonin with sleep. However, melatonin is actually involved in the timing and synchronization of a number of different physiological functions throughout the body. One of these functions is the regulation of blood sugar. Recent research has found that a relatively large proportion of the human population is genetically predisposed to be more sensitive to the impact of this hormone on blood sugar control. This can lead to higher blood glucose levels and ultimately greater risk of developing type 2 diabetes. Here’s how it works, and what you can do about it. The sleep hormone and the pancreas Melatonin is produced by the pineal gland in the brain in response to darkness. Levels are typically very low during the day and reach their peak at night. Like other hormones, melatonin works by binding to compatible receptors – kind of like a lock and key. These receptors are found abundantly in the eyes and the brain, and when melatonin binds to them, they signal that it’s dark outside. For humans, this darkness signal indicates that it is the period when we rest, so this timing signal contributes to and is a part of a cascade of other responses that help initiate and maintain sleep . Strangely enough, we now know that these receptors are also found in the pancreas – specifically in pancreatic beta cells. By releasing insulin, beta cells regulate glucose levels in the blood. We have also discovered that when melatonin activates these receptors, insulin secretion is decreased. Circadian physiology and glucose metabolism Prior research in animals has suggested that there is a relationship between melatonin and glucose metabolism. Mice with mutations that eliminate their melatonin receptors exhibit higher insulin secretion from their islet Continue reading >>

Principles Of Biochemistry/gluconeogenesis And Glycogenesis

Gluconeogenesis (abbreviated GNG) is a metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as lactate, glycerol, and glucogenic amino acids. It is one of the two main mechanisms humans and many other animals use to keep blood glucose levels from dropping too low (hypoglycemia). The other means of maintaining blood glucose levels is through the degradation of glycogen (glycogenolysis). Gluconeogenesis is a ubiquitous process, present in plants, animals, fungi, bacteria, and other microorganisms. In animals, gluconeogenesis takes place mainly in the liver and, to a lesser extent, in the cortex of kidneys. This process occurs during periods of fasting, starvation, low-carbohydrate diets, or intense exercise and is highly endergonic. For example, the pathway leading from phosphoenolpyruvate to glucose-6-phosphate requires 6 molecules of ATP. Gluconeogenesis is often associated with ketosis. Gluconeogenesis is also a target of therapy for type II diabetes, such as metformin, which inhibits glucose formation and stimulates glucose uptake by cells. Lactate is transported back to the liver where it is converted into pyruvate by the Cori cycle using the enzyme lactate dehydrogenase. Pyruvate, the first designated substrate of the gluconeogenic pathway, can then be used to generate glucose. All citric acid cycle intermediates, through conversion to oxaloacetate, amino acids other than lysine or leucine, and glycerol can also function as substrates for gluconeogenesis.Transamination or deamination of amino acids facilitates entering of their carbon skeleton into the cycle directly (as pyruvate or oxaloacetate), or indirectly via the citric acid cycle. Whether fatty acids can be converted into glucose in animals has been a longst Continue reading >>

Cell Signalling

4 Glucose metabolism: an example of integration of signalling pathways 4.1 Glucose metabolism We are now in a position to draw together the major concepts and components of signalling, and show how they operate in one well-understood system, namely the regulation of the storage or release of glucose in the human body. From this, you will be able to recognize archetypal pathways represented in specific examples, you will be able to appreciate how the same basic pathways can be stimulated by different hormones in different tissues, and you will see how opposing hormones activate separate pathways that affect the same targets but in opposite ways. Following a meal, insulin is released into the bloodstream by pancreatic β cells. The overall systemic effects of insulin are to increase uptake of blood glucose into cells, and to promote its storage as glycogen in muscle and liver cells. (Note that glycogen is a polysaccharide consisting of repeated units of glucose used for shortterm energy storage by animal cells.) A rise in the concentration of blood glucose, such as that following the consumption of food, stimulates insulin production, which signals through the insulin RTK. The insulin RTK phosphorylates various substrate proteins, which link to several key signalling pathways such as the Ras–MAP kinase pathway. There are, however, two major pathways that control glycogen synthesis and breakdown in animal cells (Figure 47). Figure 47 The control of glycogen synthesis by insulin. Several proteins bind, and are phosphorylated by, the activated insulin receptor. Cbl activates a pathway that is implicated in the translocation of the glucose transporter GLUT4 to the membrane, allowing glucose transport into the cell. Meanwhile, IRS-1 serves as a docking protein for PI 3-kinas Continue reading >>

The Difference In How Fructose And Glucose Affect Your Body

My regular readers know that I consider agave to be a BIG enemy to health and beauty- which is very high in fructose (up to 97% fructose). It truly irks me that sly marketing makes the general public think agave is a “healthy” sweetener, and that it continues to be used in “health” products purported to be better than regular baked or other goods, as well as in many restaurants. It is not. There is a myth that exists that fructose is a “healthy” sugar while glucose is bad stuff. In fact, in recent years, there has been a rise in sweeteners that contain this “healthy” sugar, such as the dreaded agave nectar. I sincerely hope that this information (please help spread it!) makes more people aware of the differences in sugar types, and makes more people know to avoid agave at all costs. S.O.S: Save Our Skin!!! Fructose Fructose is one type of sugar molecule. It occurs naturally in fresh fruits, giving them their sweetness. Because of this, many people consider fructose “natural,” and assume that all fructose products are healthier than other types of sugar. Likewise, fructose has a low glycemic index, meaning it has minimal impact on blood glucose levels. This has made it a popular sweetener with people on low-carbohydrate and low-glycemic diets, which aim to minimize blood glucose levels in order to minimize insulin release. But the glycemic index is not the sole determining factor in whether a sweetener is “healthy” or desirable to use. Because fructose is very sweet, fruit contains relatively small amounts, providing your body with just a little bit of the sugar, which is very easily handled. If people continued to eat fructose only in fruit and occasionally honey as our ancestors did, the body would easily process it without any problems. Unfortu Continue reading >>

How Insulin Really Works: It Causes Fat Storage…but Doesn’t Make You Fat

Many people believe that insulin is to blame for the obesity epidemic. When you understand how it actually works, you’ll know why this is a lie. Insulin has been taking quite a beating these days. If we’re to listen to some “experts,” it’s an evil hormone whose sole goal is making us fat, type 2 diabetics. Furthermore, we’re told that carbohydrates also are in on the conspiracy. By eating carbs, we open the insulin floodgates and wreak havoc in our bodies. How true are these claims, though? Does it really make sense that our bodies would come with an insidious mechanism to punish carbohydrate intake? Let’s find out. What is Insulin, Anyway? Insulin is a hormone, which means it’s a substance the body produces to affect the functions of organs or tissues, and it’s made and released into the blood by the pancreas. Insulin’s job is a very important one: when you eat food, it’s broken down into basic nutrients (protein breaks down into amino acids; dietary fats into fatty acids; and carbohydrates into glucose), which make their way into the bloodstream. These nutrients must then be moved from the blood into muscle and fat cells for use or storage, and that’s where insulin comes into play: it helps shuttle the nutrients into cells by “telling” the cells to open up and absorb them. So, whenever you eat food, your pancreas releases insulin into the blood. As the nutrients are slowly absorbed into cells, insulin levels drop, until finally all the nutrients are absorbed, and insulin levels then remain steady at a low, “baseline” level. This cycle occurs every time you eat food: amino acids, fatty acids, and/or glucose find their way into your blood, and they’re joined by additional insulin, which ushers them into cells. Once the job is done, insu Continue reading >>

Respiration

CONCEPT Respiration is much more than just breathing; in fact, the term refers to two separate processes, only one of which is the intake and outflow of breath. At least cellular respiration, the process by which organisms convert food into chemical energy, requires oxygen; on the other hand, some forms of respiration are anaerobic, meaning that they require no oxygen. Such is the case, for instance, with some bacteria, such as those that convert ethyl alcohol to vinegar. Likewise, an anaerobic process can take place in human muscle tissue, producing lactic acid—something so painful that it feels as though vinegar itself were being poured on an open sore. HOW IT WORKS FORMS OF RESPIRATION Respiration can be defined as the process by which an organism takes in oxygen and releases carbon dioxide, one in which the circulating medium of the organism (e.g., the blood) comes into contact with air or dissolved gases. Either way, this means more or less the same thing as breathing. In some cases, this meaning of the term is extended to the transfer of oxygen from the lungs to the bloodstream and, eventually, into cells or the release of carbon dioxide from cells into the bloodstream and thence to the lungs, from whence it is expelled to the environment. Sometimes a distinction is made between external respiration, or an exchange of gases with the external environment, and internal respiration, an exchange of gases between the body's cells and the blood, in which the blood itself "bathes" the cells with oxygen and receives carbon dioxide to transfer to the environment. This is just one meaning—albeit a more familiar one—of the word respiration. Respiration also can mean cellular respiration, a series of chemical reactions within cells whereby food is "burned" in the presen Continue reading >>

Feedback Loops: Insulin And Glucagon

Name: ________________________________________ The control of blood sugar (glucose) by insulin is a good example of a negative feedback mechanism. When blood sugar rises, receptors in the body sense a change. In turn, the control center (pancreas) secretes insulin into the blood effectively lowering blood sugar levels. Once blood sugar levels reach homeostasis, the pancreas stops releasing insulin. Examine the graphic below to understand how this feedback loop works. 1. The image shows two different types of stimuli (1 and 2), but doesn't explain what the stimuli is that causes blood sugar to raise or lower. Based on clues in the graphic, what are the two stimuli? 2. What happens when your blood sugar rises? 3. What is the effect of glucagon? What cells release glucagon? 4. What is the effect of insulin? What cells release insulin? 5. What is the normal level of glucose in the blood? Why is this called a "set point." 6. What would you expect to happen if your blood sugar was 120 mg / 100 mL ? Be specific. 7. A person with diabetes cannot regulate their blood sugar, mainly because the pancreas does not release enough insulin. To treat the disease, a person must monitor their blood sugar, if their blood sugar is high, they must take an injection of insulin. How do you think they would need to treat low blood sugar? 8. In a single sentence, explain the relationship between the pancreas and homeostasis. 9. Where does the glucose that is released into the blood ultimately end up (2 places)? 10. Explain how the thermostat in your house uses a negative feedback system to maintain your home's temperature. Continue reading >>

Control Of Blood Glucose Concentration

Click here or the image below to download free resources from alevelbiology.co.uk! The liver and the pancreas have a central role in the regulation of blood glucose concentration. The cells in the pancreas secrete the hormones which tell cells to take up glucose from the blood or not take it up. On demand, glucose is made from broken down glycogen in the liver. The pancreas has alpha and beta cells. Alpha cells secrete glucagon which increases blood glucose concentration, while beta cells secrete insulin which decreases blood glucose concentration. People with type 1 diabetes have destroyed beta cells, so their lack of insulin makes them have to take it via injections. Blood Glucose is too High The pancreas detects this, so it secretes insulin. This stimulates the uptake of glucose from the blood by cells, and the storage of it in the liver once it's converted to glycogen. This reaction is called glycogenesis. The stages are: 1. Insulin attaches to receptors on target cells2. This triggers a change in how many channel proteins are included in the cell membrane3. Separately, it also stimulates the activation of enzymes involved in converting glucose into glycogen Blood Glucose is too Low The pancreas detects this too, so it secretes its masterfully antidote: glucagon. This inhibits cells from taking up any more glucose from the blood, while initiating the breakdown of glycogen in the liver to produce more glucose. The glycogen is hydrolised (broken down in the presence of water) so the term for this reaction is glycogenolysis. 1. Glucagon attaches to receptors on target cells2. This activates enzymes responsible for the conversion of glycogen into glucose3. This activates enzymes responsible for the conversion of glycerol and amino acids into glucose Another hormone invo Continue reading >>

Exocytosis

Exocytosis is the cellular process in which intracellular vesicles in the cytoplasm fuse with the plasma membrane and release or "secrete" their contents into the extracellular space. Exocytosis can be constitutive (occurring all the time) or regulated. Constitutive exocytosis is important in transporting proteins like receptors that function in the plasma membrane. Regulated exocytosis is triggered when a cell receives a signal from the outside. Many of the products that cells secrete function specifically for the tissue type in which the cells reside or are transmitted to more distant parts of the body. Most of these products are proteins that have gone through rigorous quality control and modification processes in the endoplasmic reticulum and Golgi membranes. It is in the trans -Golgi network, the "downstream" end of the Golgi apparatus, where cellular products are sorted and accumulate in exocytic vesicles. Mechanisms The mechanisms controlling regulated exocytosis were largely discovered in the 1990s. Contrary to early ideas, membranes normally do not fuse together spontaneously. This is due to the negative charges associated with the phospholipids that make up the lipid bilayer of the membranes of vesicles and organelles . Membrane fusion requires energy and the interaction of special "adaptor" molecules present on both the vesicle and plasma membrane. The adapter molecules are highly selective and only allow vesicles to fuse with membranes of particular organelles, thus preventing harm to the cell. Once the appropriate adapter molecules bind to each other (docking), energy stored and released by ATP forms a fusion pore between the vesicle membranes and plasma membrane. The contents of the vesicle are released to the exterior of the cell (or the interior of an or Continue reading >>

Cellular Respiration

Index Glucose and ATP | Equation for Respiration | ATP Structure ADP to ATP | ATP-ADP Cycle | Photosynthesis and Respiration Aerobic vs Anaerobic | Glycolysis Overview Glycolysis in Detail | Glycolysis Animated | Anaerobic Respiration Lactic Acid vs Alcohol | Fermentation Animation | Anaerobic Animated Mitochondrion | Krebs Cycle | Krebs Cycle Animated | ATP Totals Hydrogen Ion Pool | Electron Transport Chain | ETS Animated Respiration Summary | Respiration Animated | Other Fuels | Quiz Use the "Go Back" buttton or "Back" menu-pulldown to return to the index at the top of this page or return to this page from any animation. Use the "refresh" button to reload any animation. Be sure your browser preferences are set to animate "gifs" and allow "looping" to see the "gif" animations. Copyright © Steve Kuensting, 2004, All Rights Reserved. This web tutorial may not be distributed by any means Introduction All living things require a constant input of energy into their cells in order to survive. This energy is needed for cell division, movement, maintenance & repair, and for building new materials. The autotrophs are organisms that can produce their own chemical (food) energy by the use of sunlight. The heterotrophs must eat chemical energy of other organisms to supply themselves with the necessary energy. Photosynthesis is the process that converts the light energy to chemical energy for a plant. The chemical energy is stored in the molecule glucose. This is the same molecule that is found in the blood of all animals. Glucose is actually a universal food molecule for all organisms. It can easily be used for energy. Plants can make the glucose, animals must eat it. Glucose and ATP Glucose can be easily used for energy. Yet, glucose is itself NOT a directly usable form of ener Continue reading >>

Environmental Biology - Ecosystems

Human vs. Natural Food Chains Overview The main concepts we are trying to get across in this section concern how energy moves through an ecosystem. If you can understand this, you are in good shape, because then you have an idea of how ecosystems are balanced, how they may be affected by human activities, and how pollutants will move through an ecosystem. If you had Biology 101, this should be review; if you had Geology 101, this is new stuff. Either way, it is pretty basic and you shouldn't have much trouble reading this material or the associated material in the text. Roles of Organisms Organisms can be either producers or consumers in terms of energy flow through an ecosystem. Producers convert energy from the environment into carbon bonds, such as those found in the sugar glucose. Plants are the most obvious examples of producers; plants take energy from sunlight and use it to convert carbon dioxide into glucose (or other sugars). Algae and cyanobacteria are also photosynthetic producers, like plants. Other producers include bacteria living around deep-sea vents. These bacteria take energy from chemicals coming from the Earth's interior and use it to make sugars. Other bacteria living deep underground can also produce sugars from such inorganic sources. Another word for producers is autotrophs. Consumers get their energy from the carbon bonds made by the producers. Another word for a consumer is a heterotroph. Based on what they eat, we can distinguish between 4 types of heterotrophs: consumer trophic level food source Herbivores primary plants Carnivores secondary or higher animals Omnivores all levels plants & animals Detritivores --------------- detritus A trophic level refers to the organisms position in the food chain. Autotrophs are at the base. Organisms that Continue reading >>

The Science Of Your Hangover

INDYEATS The science of your hangover Hangoverville is a place nobody wants to visit, but the road towards it is one many of us end up taking, especially during the party season. The telltale signs of having reached your destination are unmistakable and aptly described on a global scale. "Smacked from behind" is the literal translation of the Swedish word for hangover. Meanwhile, the Salvadoreans describe themselves as waking up "made of rubber", the French with a "wooden mouth" or a "hair ache" and the Danes with "carpenters in the forehead". "In the past, dehydration was thought to be the main cause of hangover symptoms," says Emma Derbyshire, independent nutritionist and consultant to the Natural Hydration Council. "But now, scientists believe that alcohol withdrawal, and chemicals formed in the body when our livers break down alcohol, also contribute to those dreaded symptoms." Double dose of toxins "Having any toxin hanging around in your system will get you in trouble, and alcohol is no exception," says Sneh Khemka, medical director at Bupa International. "It passes through the stomach and into the bloodstream, which distributes it throughout the body, irritating and even damaging cells and cell membranes. As if that's not bad enough, a product of alcohol metabolism that is more toxic than alcohol itself, acetaldehyde, is created when the alcohol in the liver is broken down. So in essence, you get a double whammy of toxins in the body." The good news is that acetaldehyde is automatically attacked by another enzyme and a substance called glutathione. The process works well, leaving the acetaldehyde only a short time to do its damage, but – and it's an important but – only if you stick to a few drinks. "The liver's stores of glutathione quickly run out when larg Continue reading >>

Anatomy And Function Of The Liver

Anatomy of the liver The liver is located in the upper right-hand portion of the abdominal cavity, beneath the diaphragm and on top of the stomach, right kidney, and intestines. The liver, a dark reddish-brown organ, has multiple functions. There are two distinct sources that supply blood to the liver: Oxygenated blood flows in from the hepatic artery. Nutrient-rich blood flows in from the hepatic portal vein. The liver consists of two main lobes, both of which are made up of 8 segments. The segments are made up of a thousand lobules. The lobules are connected to small ducts that connect with larger ducts to ultimately form the common hepatic duct. The common hepatic duct transports bile produced by the liver cells to the gallbladder and duodenum (the first part of the small intestine). What are the functions of the liver? The liver regulates most chemical levels in the blood and excretes a product called bile. Bile helps to break down fats, preparing them for further digestion and absorption. All of the blood leaving the stomach and intestines passes through the liver. The liver processes this blood and breaks down, balances, and creates nutrients for the body to use. It also metabolized drugs in the blood into forms that are easier for the body to use. Many vital functions have been identified with the liver. Some of the more well-known functions include the following: Production of bile, which helps carry away waste and break down fats in the small intestine during digestion Production of certain proteins for blood plasma Production of cholesterol and special proteins to help carry fats through the body Store and release glucose as needed Processing of hemoglobin for use of its iron content (the liver stores iron) Conversion of harmful ammonia to urea (urea is one of Continue reading >>

Section 16.1oxidation Of Glucose And Fatty Acids To Co2

The complete aerobic oxidation of glucose is coupled to the synthesis of as many as 36 molecules of ATP: Glycolysis, the initial stage of glucose metabolism, takes place in the cytosol and does not involve molecular O. It produces a small amount of ATP and the three-carbon compound pyruvate. In aerobic cells, pyruvate formed in glycolysis is transported into the mitochondria, where it is oxidized by O to CO. Via chemiosmotic coupling, the oxidation of pyruvate in the mitochondria generates the bulk of the ATP produced during the conversion of glucose to CO. In this section, we discuss the biochemical pathways that oxidize glucose and fatty acids to CO and HO; the fate of the released electrons is described in the next section. Go to: Cytosolic Enzymes Convert Glucose to Pyruvate A set of 10 enzymes catalyze the reactions, constituting the glycolytic pathway, that degrade one molecule of glucose to two molecules of pyruvate (Figure 16-3). All the metabolic intermediates between glucose and pyruvate are watersoluble phosphorylated compounds. Four molecules of ATP are formed from ADP in glycolysis (reactions 6 and 9). However, two ATP molecules are consumed during earlier steps of this pathway: the first by the addition of a phosphate residue to glucose in the reaction catalyzed by hexokinase (reaction 1), and the second by the addition of a second phosphate to fructose 6-phosphate in the reaction catalyzed by phosphofructokinase-1 (reaction 3). Thus there is a net gain of two ATP molecules. The balanced chemical equation for the conversion of glucose to pyruvate shows that four hydrogen atoms (four protons and four electrons) are also formed: (For convenience, we show pyruvate in its un-ionized form, pyruvic acid, although at physiological pH it would be largely dissociat Continue reading >>