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Amino Acids Can Be Used By The Body To Make Glucose And Fatty Acids True Or False

Harvesting Energy

Harvesting Energy

Why do we humans eat food? What do we need it for, and get out of it? W O R K T O G E T H E R Cellular respiration is an: Endergonic process Exergonic process Exergonic OR endergonic process, depending on the organism. In which organelle does cellular respiration occur? Chloroplast Mitochondria Depends on whether it’s a plant or an animal. What is “food†(i.e. source of metabolic energy) for plants? Sunlight Sugar Water Oxygen Minerals cristae mitochondrion inner membrane outer membrane intermembrane space matrix Cellular respiration takes place in the mitochondria. net exergonic “downhill†reaction glucose protein amino acids CO2 + H2O + heat ADP + heat Review: ATP is produced and used in coupled reactions endergonic (ATP synthesis) exergonic (ATP breakdown) exergonic (glucose breakdown) endergonic (protein synthesis) Energy released by the exergonic breakdown of glucose is used for: The endergonic production of ATP. The exergonic production of ATP. The endergonic breakdown of ATP. The exergonic breakdown of ATP. 2 pyruvate electron transport chain (cytosol) (mitochondrion) glycolysis Krebs (citric acid) cycle 2 acetyl CoA 2 NADH Total 36 or 38 ATPs 2 ATP 6 NADH 2 FADH2 glucose 32 or 34 ATPs 2 ATP 2 NADH Overview Glycolysis splits sugar into two 3-carbon chains (pyruvate), producing 2 ATPs Cellular respiration breaks the sugar down further, producing 32-34 ATPs. NADH and FADH (derived from vitamins B3 and B2) act as electron carriers. 34 or 36 ATP in mitochondria– oxygen required in cytosol– no oxygen required glycolysis glucose fermentation pyruvate 2 ATP cellular respiration O2 if no O2 available ethanol + CO2 or lactic acid CO2 H2O fructose bisphosphate ATP ADP 1 Glucose activation in cytosol 2 Energy harvest NAD+ NADH ATP AD Continue reading >>

Nutrition Ch. 7

Nutrition Ch. 7

Front Back .Wirisformula{ margin:0 !important; padding:0 !important; vertical-align:top !important;} Metabolism The sum total of all the chemcial reactions that go on in living cells. Energy metabolism includes all the reactions by which the body obtains and spends energy from food. Example: Nutrients provide the body with FUEL and follows them through a series of reactions that release energy from their chemical bonds. As the bonds break, they release energy in a controlled version of the process by which wood burns in a fire. Energy metabolism All of the chemical reactions through which the human body acquires and spends energy from food Anabolism Small compounds joined together to make largers ones; energy must be used in order to do this Ana = up Catabolism Larger compounds BROKEN down into smaller ones; energy is RELEASED kata = down Coupled reactions Energy released from the breakdown of a large compounds is used to drive other reactions ATP Adenosine triphosphate; energy currency of the body -- produced when large compounds are broken down ATP is used to make large compounds from smaller ones. Ribosomes Cellular machinery used to make proteins Mitochondria Where energy is derived from fat, CHO, protein via TCA cycle, electron transport chain Coenzyme Complex organic molecules that work with enzymes to facilitate the enzymes' activity. Many coenzymes have B vitamins as part of their structures. co = with Cofactor The general term for substances that facilitate enzyme action is cofactors; they include both organic coenzymes such as vitamins and inorganic substances such as minerals Enzymes Protein catalysts - proteins that facilitate chemical reactions without being changed in the process Metalloenzyme Enzymes that contain one or more minerals as part of their stru Continue reading >>

The Body’s Fuel Sources

The Body’s Fuel Sources

The Body’s Fuel Sources Our ability to run, bicycle, ski, swim, and row hinges on the capacity of the body to extract energy from ingested food. As potential fuel sources, the carbohydrate, fat, and protein in the foods that you eat follow different metabolic paths in the body, but they all ultimately yield water, carbon dioxide, and a chemical energy called adenosine triphosphate (ATP). Think of ATP molecules as high-energy compounds or batteries that store energy. Anytime you need energy—to breathe, to tie your shoes, or to cycle 100 miles (160 km)—your body uses ATP molecules. ATP, in fact, is the only molecule able to provide energy to muscle fibers to power muscle contractions. Creatine phosphate (CP), like ATP, is also stored in small amounts within cells. It’s another high-energy compound that can be rapidly mobilized to help fuel short, explosive efforts. To sustain physical activity, however, cells must constantly replenish both CP and ATP. Our daily food choices resupply the potential energy, or fuel, that the body requires to continue to function normally. This energy takes three forms: carbohydrate, fat, and protein. (See table 2.1, Estimated Energy Stores in Humans.) The body can store some of these fuels in a form that offers muscles an immediate source of energy. Carbohydrates, such as sugar and starch, for example, are readily broken down into glucose, the body’s principal energy source. Glucose can be used immediately as fuel, or can be sent to the liver and muscles and stored as glycogen. During exercise, muscle glycogen is converted back into glucose, which only the muscle fibers can use as fuel. The liver converts its glycogen back into glucose, too; however, it’s released directly into the bloodstream to maintain your blood sugar (blood Continue reading >>

Essential Amino Acid

Essential Amino Acid

See also: Protein (nutrient) An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized de novo (from scratch) by the organism, and thus must be supplied in its diet. The nine amino acids humans cannot synthesize are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine (i.e., F V T W M L I K H).[1][2] Six other amino acids are considered conditionally essential in the human diet, meaning their synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress.[2] These six are arginine, cysteine, glycine, glutamine, proline, and tyrosine (i.e., R C G Q P Y). Five amino acids are dispensable in humans, meaning they can be synthesized in the body. These five are alanine, aspartic acid, asparagine, glutamic acid and serine (i.e., A D N E S).[2] Essentiality in humans[edit] Essential Non-Essential Histidine (H) Alanine (A) Isoleucine (I) Arginine* (R) Leucine (L) Aspartic acid (D) Lysine (K) Cysteine* (C) Methionine (M) Glutamic acid (E) Phenylalanine (F) Glutamine* (Q) Threonine (T) Glycine* (G) Tryptophan (W) Proline* (P) Valine (V) Serine* (S) Tyrosine* (Y) Asparagine* (N) Selenocysteine (U) Pyrrolysine** (O) (*) Essential only in certain cases.[3][4] (**) Pyrrolysine, sometimes considered "the 22nd amino acid", is not used by humans.[5] Eukaryotes can synthesize some of the amino acids from other substrates. Consequently, only a subset of the amino acids used in protein synthesis are essential nutrients. Recommended daily intake[edit] Main article: Protein (nutrient) Estimating the daily requirement for the indispensable amino acids has proven to be difficult; these numbers have undergone considerable rev Continue reading >>

Chapter Summary

Chapter Summary

Metabolism is the sum of all the chemical and physical processes by which the body breaks down and builds up molecules. All forms of life maintain a balance between anabolic and catabolic reactions, which determines if the body achieves growth and repair or if it persists in a state of loss. Metabolic pathways are clusters of chemical reactions that occur sequentially and achieve a particular goal, such as the breakdown of glucose for energy. These pathways are carefully controlled, either turned on or off, by hormones released within the body. Condensation and hydrolysis are chemical reactions involving water, whereas phosphorylation is a chemical reaction in which phosphate is transferred. In oxidation-reduction reactions, the molecules involved exchange electrons. Enzymes, coenzymes, and cofactors increase the efficiency of metabolism. Glucose oxidation occurs in three well-defined stages: glycolysis, the TCA cycle, and oxidative phosphorylation via the electron transport chain. The end products of glucose oxidation are carbon dioxide, water, and ATP. During glycolysis, six-carbon glucose is converted into two molecules of three-carbon pyruvate. If glycolysis is anaerobic, this pyruvate is converted to lactic acid. If glycolysis is aerobic, this pyruvate is converted to acetyl CoA and enters the TCA cycle. During the TCA cycle, acetyl CoA coming from either carbohydrate,fat, or protein metabolism results in the production of GTP or ATP, NADH, and FADH2. These two final compounds go through oxidative phosphorylation (as part of the electron transport chain) to produce energy. During oxidative phosphorylation, the NADH and the FADH2 enter the electron transport chain where, through a series of reactions, ATP is produced. Triglycerides are broken down into glycerol and Continue reading >>

Fuel For Your Body

Fuel For Your Body

Contents What fuel does your body need? What is protein? What are carbohydrates? What are vitamins and minerals? Your body is like a wonderful machine First of all it builds itself in your mother's womb. It works hard on growing bigger and stronger. It repairs itself (like healing a cut or a broken arm). It changes itself from a child to an adult. It runs all the systems needed to keep the body working. It's more complicated than the most expensive computer and it's free! To look after this amazing body machine you need to keep it supplied with the right kind of fuel. Does your family have a car? Do you go to the petrol station sometimes when mum or dad is filling the car with fuel? Have you noticed that there are different kinds of fuel? Eg petrol, diesel, LPG (liquid petroleum gas). The kind of fuel you buy depends on the kind of fuel the engine runs on. Your body runs on the fuel it gets from what you eat. If it doesn't get the right kind of fuel then it doesn't work very well or, like your car, it could break down. Protein, carbohydrates, fat, vitamins, minerals and water Your body needs all of these, but what are they? There are 20 chemicals called amino acids, which join together in different ways to make thousands of different proteins (say 'pro-teen'). Where do they come from? 11 of these amino acids are made by your body and are called 'non-essential' amino acids. The other 9 'essential' amino acids you have to get by eating the right foods. What does protein do? It is a very important nutrient because it builds up your muscles, organs and glands. It helps repair and replace them too, so that your body can keep on working. Some of the things it makes: haemoglobin (say 'heem-o-glow-bin') - which carries oxygen around the body in your blood. antibodies - to fight Continue reading >>

We Really Can Make Glucose From Fatty Acids After All! O Textbook, How Thy Biochemistry Hast Deceived Me!

We Really Can Make Glucose From Fatty Acids After All! O Textbook, How Thy Biochemistry Hast Deceived Me!

Biochemistry textbooks generally tell us that we can’t turn fatty acids into glucose. For example, on page 634 of the 2006 and 2008 editions of Biochemistry by Berg, Tymoczko, and Stryer, we find the following: Animals Cannot Convert Fatty Acids to Glucose It is important to note that animals are unable to effect the net synthesis of glucose from fatty acids. Specficially, acetyl CoA cannot be converted into pyruvate or oxaloacetate in animals. In fact this is so important that it should be written in italics and have its own bold heading! But it’s not quite right. Making glucose from fatty acids is low-paying work. It’s not the type of alchemy that would allow us to build imperial palaces out of sugar cubes or offer hourly sweet sacrifices upon the altar of the glorious god of glucose (God forbid!). But it can be done, and it’ll help pay the bills when times are tight. All Aboard the Acetyl CoA! When we’re running primarily on fatty acids, our livers break the bulk of these fatty acids down into two-carbon units called acetate. When acetate hangs out all by its lonesome like it does in a bottle of vinegar, it’s called acetic acid and it gives vinegar its characteristic smell. Our livers aren’t bottles of vinegar, however, and they do things a bit differently. They have a little shuttle called coenzyme A, or “CoA” for short, that carries acetate wherever it needs to go. When the acetate passenger is loaded onto the CoA shuttle, we refer to the whole shebang as acetyl CoA. As acetyl CoA moves its caboose along the biochemical railway, it eventually reaches a crossroads where it has to decide whether to enter the Land of Ketogenesis or traverse the TCA cycle. The Land of Ketogenesis is a quite magical place to which we’ll return in a few moments, but n Continue reading >>

How Fat Cells Work

How Fat Cells Work

In the last section, we learned how fat in the body is broken down and rebuilt into chylomicrons, which enter the bloodstream by way of the lymphatic system. Chylomicrons do not last long in the bloodstream -- only about eight minutes -- because enzymes called lipoprotein lipases break the fats into fatty acids. Lipoprotein lipases are found in the walls of blood vessels in fat tissue, muscle tissue and heart muscle. Insulin When you eat a candy bar or a meal, the presence of glucose, amino acids or fatty acids in the intestine stimulates the pancreas to secrete a hormone called insulin. Insulin acts on many cells in your body, especially those in the liver, muscle and fat tissue. Insulin tells the cells to do the following: The activity of lipoprotein lipases depends upon the levels of insulin in the body. If insulin is high, then the lipases are highly active; if insulin is low, the lipases are inactive. The fatty acids are then absorbed from the blood into fat cells, muscle cells and liver cells. In these cells, under stimulation by insulin, fatty acids are made into fat molecules and stored as fat droplets. It is also possible for fat cells to take up glucose and amino acids, which have been absorbed into the bloodstream after a meal, and convert those into fat molecules. The conversion of carbohydrates or protein into fat is 10 times less efficient than simply storing fat in a fat cell, but the body can do it. If you have 100 extra calories in fat (about 11 grams) floating in your bloodstream, fat cells can store it using only 2.5 calories of energy. On the other hand, if you have 100 extra calories in glucose (about 25 grams) floating in your bloodstream, it takes 23 calories of energy to convert the glucose into fat and then store it. Given a choice, a fat cell w Continue reading >>

Nutrition Review Exam2

Nutrition Review Exam2

1. Nutrition 101Exam 2 Review Session TAs: Helen Corless and Delma Betancourt 2. Chapter 6Protein: Amino Acids 3. Which of the following atoms is not a component of carbohydrate or fat?a) Hydrogenb) Nitrogenc) Oxygend) Carbon 4. Which of the following atoms is not a component of carbohydrate or fat?a) Hydrogenb) Nitrogenc) Oxygend) Carbon 5. Carbohydrates, lipids, and proteins are all composed of carbon, hydrogen and oxygen in various arrangementsBut…protein is unique in that it also contains nitrogen 6. Which of the following differentiates amino acids from each other?a) Number of carbon-carbon double bondsb) The side groupc) The amino groupd) Hydrogenation 7. Which of the following differentiates amino acids from each other?a) Number of carbon-carbon double bondsb) The side groupc) The amino groupd) Hydrogenation 8. There are 20 different amino acids, eachwith its own unique side group 9. An amino acid that the body can synthesize is called:a) Indispensableb) Essentialc) Conditionally essentiald) Non-essential 10. An amino acid that the body can synthesize is called:a) Indispensableb) Essentialc) Conditionally essentiald) Non-essential 11. Most amino acids are nonessential, meaning the body can synthesize them for itself (as long as building blocks are available)Essential amino acids must come from the diet, because the body cannot make these in sufficient quantities (indispensable)Conditionally essential: normally nonessential but must be supplied by diet under special circumstances (e.g. PKU -> tyrosine) 12. Proteins form when _______ bonds join amino acids in a ________ reaction.a) Carbon; hydrolysisb) Carbon; anabolicc) Peptide; condensationd) Peptide; catabolic 13. Proteins form when _______ bonds join amino acids in a ________ reaction.a) Carbon; hydrolysisb) Continue reading >>

Adipose Tissue

Adipose Tissue

Ann L. Albright and Judith S. Stern Department of Nutrition and Internal Medicine University of California at Davis Davis, CA USA Morphology and Development of Adipose TissueAdipose-Tissue MetabolismAdipose Tissue DistributionDefinition and Causes of ObesityFurther Reading Albright, A.L. and Stern, J.S. (1998). Adipose tissue. In: Encyclopedia of Sports Medicine and Science, T.D.Fahey (Editor). Internet Society for Sport Science: 30 May 1998. Adipose tissue is specialized connective tissue that functions as the major storage site for fat in the form of triglycerides. Adipose tissue is found in mammals in two different forms: white adipose tissue and brown adipose tissue. The presence, amount, and distribution of each varies depending upon the species. Most adipose tissue is white, the focus of this review. White adipose tissue serves three functions: heat insulation, mechanical cushion, and most importantly, a source of energy. Subcutaneous adipose tissue, found directly below the skin, is an especially important heat insulator in the body, because it conducts heat only one third as readily as other tissues. The degree of insulation is dependent upon the thickness of this fat layer. For example, a person with a 2-mm layer of subcutaneous fat will feel as comfortable at 15°C as a person with a 1-mm layer at 16°C. Adipose tissue also surrounds internal organs and provides some protection for these organs from jarring. As the major form of energy storage, fat provides a buffer for energy imbalances when energy intake is not equal to energy output. It is an efficient way to store excess energy, because it is stored with very little water. Consequently, more energy can be derived per gram of fat (9 kcal.gm-1) than per gram of carbohydrate (4 kcal.gm-1) or protein (4 kcal.g Continue reading >>

Can Amino Acids Be Used By The Body To Make Glucose & Fatty Acids?

Can Amino Acids Be Used By The Body To Make Glucose & Fatty Acids?

Amino acids are nitrogen-containing molecules that are the building blocks of all proteins in food and in the body. They can be used as energy, yielding about 4 calories per gram, but their primary purpose is the synthesis and maintenance of body proteins including, but not limited to, muscle mass. Video of the Day During normal protein metabolism, a certain number of amino acids are pushed aside each day. When these amino acids are disproportionate to other amino acids for the synthesis of new protein, your liver and kidneys dispose of the nitrogen as urea, and the rest of the molecule is used as energy in a variety of ways. Then certain amino acids -- minus their nitrogen -- can enter the citric acid cycle -- the biochemical pathway that converts food into energy. Others can be converted to glucose or fat. This process may be enhanced when you take in more protein than you need. Your body relies on a continuous supply of glucose and fatty acids for energy for physical activity and cellular needs during rest. When you exercise, your body relies still more on glucose because fat is slower to metabolize. The higher your exercise intensity is, the more your body requires quicker-burning glucose. Some glucose is stored as glycogen in the liver and muscles and can be recruited when blood glucose is used up. When glycogen becomes depleted, the process of gluconeogenesis can take over -- the creation of new glucose from another source. The usual source for gluconeogenesis is amino acids. Healthy people store adequate body fat to cover their energy needs. Although certain amino acids can be converted to fatty acids, there should be no need for this to occur in order to supply energy. But if a very high protein intake adds substantially more calories, theoretically those extra Continue reading >>

Macronutrients

Macronutrients

Overview Carbohydrates, fats and proteins are macronutrients. We require them in relatively large amounts for normal function and good health. These are also energy-yielding nutrients, meaning these nutrients provide calories. On This Page: What are Carbohydrates? Carbohydrates Understanding Carbohydrates Every few years, carbohydrates are vilified as public enemy number one and are accused of being the root of obesity, diabetes, heart disease and more. Carb-bashers shun yogurt and fruit and fill up on bun-less cheeseburgers. Instead of beans, they eat bacon. They dine on the tops of pizza and toss the crusts into the trash. They so vehemently avoid carbs and spout off a list of their evils that they may have you fearing your food. Rest assured, you can and should eat carbohydrates. In fact, much of the world relies on carbohydrates as their major source of energy. Rice, for instance, is a staple in Southeast Asia. The carbohydrate-rich potato was so important to the people of Ireland that when the blight devastated the potato crop in the mid 1800s, much of the population was wiped out. What are Carbohydrates? The basic structure of carbohydrates is a sugar molecule, and they are classified by how many sugar molecules they contain. Simple carbohydrates, usually referred to as sugars, are naturally present in fruit, milk and other unprocessed foods. Plant carbohydrates can be refined into table sugar and syrups, which are then added to foods such as sodas, desserts, sweetened yogurts and more. Simple carbohydrates may be single sugar molecules called monosaccharides or two monosaccharides joined together called disaccharides. Glucose, a monosaccharide, is the most abundant sugar molecule and is the preferred energy source for the brain. It is a part of all disaccharides Continue reading >>

Metabolism

Metabolism

Home > Preview pairs of chemical reactions in which some of the energy released from the breakdown of one compound is used to create a bond in the formation of another compound 1-Glycolytic System via A-Glycolytic System B-Lactic Acid Pathway 2-Aerobic or Oxidative System A-Pyruvate to Acetyl Co B-Kreb Cycle C-ETC 1-ATP is used to start glycolysis 2-glucose is converted into two 3-carbon comp 3-ATP is produced 4-Coenzymes take H and electrons to ETC 5-ATP is produced 6-3-carbon compound convert to Pyruvates true Pyruvate does not need oxygen for a quick short energy demand such as a sprint true this can occur is the cells don't have enough oxygen or lack a sufficient number of mitochondria true Once the pyruvate is converted to Acetyl CoA the carbon group from pyruvate becomes carbon dioxide which is expelled out of the body through the lungs Author: nando54321 ID: 228380 Filename: Metabolism Updated: March 3, 5877521 Tags: bio45 Folders: Description: Test 3 Show Answers: Continue reading >>

Protein

Protein

All animals must eat protein regularly to survive, because we cannot make protein out of fat or carbohydrate or cholesterol. Proteins form enzymes, muscles, hormones, and other vital bodily components. How much protein do we need, and does it matter where we get it from? What is protein? Proteins are complicated molecules of many different shapes and sizes that are essential to all forms of life. Proteins are intimately involved in virtually everything that happens inside our cells and are infinitely more diverse and complex than carbohydrates and fats. Below are just a few examples of important bodily proteins: Enzymes (to run chemical reactions) Peptide hormones (example: insulin) Antibodies (immune system molecules) Muscle fibers Neurotransmitters (examples: serotonin, adrenaline, dopamine, nitrous oxide, and histamine) Blood carrier proteins (examples: hemoglobin, albumin) Hair, skin, and nails Melanin (skin pigment) Below are some examples of important molecules that cannot be built without proteins: DNA and RNA Glutathione (a critical antioxidant) Creatine (supplies energy to muscles) Why do we have to eat protein? Carbohydrates, fats and cholesterol are made of carbon, hydrogen and oxygen, but proteins are unique because they also contain nitrogen. This is why the body cannot make protein out of carbohydrate, fat, or cholesterol. We can make carbohydrate (from protein), and can store some extra as glycogen. We can make cholesterol out of anything, and can recycle excess cholesterol in the bile. We can make most fats out of anything, and can store huge amounts of extra fat. We can live a whole lifetime (after infancy) without eating any carbohydrate, and we can live for 6 months or more without eating any fat, depending on how much fat we have on our bodies to beg Continue reading >>

Chemistry Ii: Water And Organic Molecules

Chemistry Ii: Water And Organic Molecules

Table of Contents It can be quite correctly argued that life exists on Earth because of the abundant liquid water. Other planets have water, but they either have it as a gas (Venus) or ice (Mars). This relationship is shown in Figure 1. Recent studies of Mars reveal the presence sometime in the past of running fluid, possibly water. The chemical nature of water is thus one we must examine as it permeates living systems: water is a universal solvent, and can be too much of a good thing for some cells to deal with. Figure 1. Water can exist in all three states of matter on Earth, while only in one state on our two nearest neighboring planets. The above graph is from Water is polar covalently bonded within the molecule. This unequal sharing of the electrons results in a slightly positive and a slightly negative side of the molecule. Other molecules, such as Ethane, are nonpolar, having neither a positive nor a negative side, as shown in Figure 2. Figure 2. The difference between a polar (water) and nonpolar (ethane) molecule is due to the unequal sharing of electrons within the polar molecule. Nonpolar molecules have electrons equally shared within their covalent bonds. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission. These link up by the hydrogen bond discussed earlier. Consequently, water has a great interconnectivity of individual molecules, which is caused by the individually weak hydrogen bonds, shown in Figure 3, that can be quite strong when taken by the billions. Figure 3. Formation of a hydrogen bond between the hydrogen side of one water molecule and the oxygen side of another water molecule. Image from Purves et al., Life: The Science of Biology, Continue reading >>

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