Carbohydrates PDF

CARBOHYDRATES transport of molecules across membranes, and the synthesis of macromolecules. Functions of Carbohydrates Glycogen Storage Metabolism and Energy Production - Excess...

CARBOHYDRATES transport of molecules across membranes, and the synthesis of macromolecules. Functions of Carbohydrates Glycogen Storage Metabolism and Energy Production - Excess glucose not immediately Glycolysis required for energy is converted into - In the cytoplasm, one molecule of glycogen, a polysaccharide glucose is split into two molecules of composed of long chains of glucose pyruvate, producing a small amount molecules. Glycogen is primarily of ATP and NADPH in the process. stored in the liver and muscle tissues. In the liver, glycogen helps Kreb’s Cycle (Citric Acid Cycle) maintain blood glucose levels - In the mitochondria, pyruvate is between meals or during periods of converted into acetyl-CoA and fasting. In muscle tissue, glycogen enters the Krebs cycle where it is provides a readily available energy further broken down, generating source during physical activity. additional ATP, NADPH, and FADH2. - When glucose levels in the blood decrease or energy demands Electron Transport Chain and Oxidative increase, glycogenolysis occurs, Phosphorylation where glycogen is broken down into - NADH and FADH2 are used in the glucose to be used for ATP electron transport chain to produce a production. This mechanism ensures significant amount of ATP. Oxygen a continuous supply of energy and acts as the final electron acceptor, helps maintain metabolic balance. forming water as a byproduct. Other Functions: - When animals consume carbohydrates, the digestive system Apart from their role in energy production, breaks them down into simpler carbohydrates also contribute to various sugars, mainly glucose. physiological functions. For instance, they - Glucose then enters the are involved in the synthesis of bloodstream and is transported to glycoproteins and glycolipids, which are cells throughout the body. important for cell-cell recognition and - Inside the cells, glucose is utilized immune responses. Additionally, dietary through a series of biochemical fiber, a type of carbohydrate that cannot be processes known as cellular digested by humans, plays a significant role respiration, which occurs in the in maintaining digestive health and mitochondria. preventing certain diseases. Cellular Respiration Process: Types of Carbohydrates SIMPLE CARBOHYDRATES Basic type of carbs. Easier to handle since they are less complex and can rapidly break it down. Contains the monosaccharide and disaccharide groups. Only one sugar unit in monosaccharide–considered as the smallest carbohydrate. ATP generated through these processes e.g. (softdrinks, candy, cookies, and other serves as the primary energy carrier within sweet snacks) cells, driving various physiological functions such as muscle contractions, active COMPLEX CARBOHYDRATES Provide sustained fuel that the body needs. Often single units (monosaccharides), which are bound together. Have fairly long-lasting energy e.g. peas, beans, whole grains, and vegetables. THREE CLASSIFICATIONS Monosaccharides Cannot be hydrolyzed further to give simple units of polyhydroxy aldehyde or ketone. Contain an aldehyde group then it is Sucrose called aldos and on the other hand, if it contains a keto group then it is One of the most common called a ketose. disaccharides which on hydrolysis gives glucose and fructose. Maltose and Lactose a.k.a milk sugars Polysaccharides Glucose Contain long monosaccharides units joined together by glycosidic linkage. One of the most abundant and Act as a food storage important monosaccharides. Used by cells as an energy source. Starch: main storage polysaccharide for plants. Fructose Cellulose: one of yet polysaccharides that are mostly found in plants. a.k.a “fruit sugar” occurs naturally in many fruits It is metabolized by the liver, where it promotes the synthesis of fat. Sources of Carbohydrates Disaccharides Animals can obtain carbohydrates from: On hydrolysis, disaccharides yield PLANTS Plants store carbohydrates called two molecules of either the same or starch. different monosaccharides. Herbivores get carbohydrates from The two monosaccharides units are the plant. joined by oxide linkage which is Plants create carbohydrates from formed by the loss of water photosynthesis. molecules and this linkage is called The reaction of photosynthesis glycosidic linkage. produces glucose and oxygen. Glucose is then further stored in the form of starch in the plant, which is what animals consume to get carbohydrates. ANIMALS Carnivorous animals: their prey is the main source of carbohydrates. Monogastrics Tissues of the prey that they Carbohydrate Digestion: consume provide an indirect source of carbohydrates. Enzymatic Breakdown: - In the small intestine, carbohydrates Glycogen: a type of stored glucose that is (like starch) are broken down by found mainly in muscle tissues and skeletal amylase (from the saliva and muscles. pancreas) into maltose, which is Gluconeogenesis: a process by further broken down into glucose by carnivorous animals in which they are able maltase and other enzymes. to synthesize glucose from some amino carbohydrates>maltose>glucose acids in meat using their liver. amylase> maltase> Glucose Absorption: Digestibility and Utilization - Glucose is then absorbed into the bloodstream via the intestinal lining. Ruminants Carbohydrate Digestion: Utilization: Microbial Fermentation: Glucose: primary energy source for monogastric animals. - The rumen contains microbes It is readily used by cells for ATP (bacteria, protozoa, and fungi) production. - Microbes ferment carbohydrates (cellulose and hemicellulose) Excess Glucose: stored as glycogen in the liver and muscles or converted to fat. Volatile Fatty Acids (VFAs): - Microbes break down cellulose into Hindgut Fermenter VFA (acetate, propionate, butyrate Carbohydrate Digestion: acid) which are absorbed by the rumen and utilized as the primary Enzymatic Digestion: energy source for the animal. - In the foregut, carbohydrates are digested enzymatically. Limited Glucose Digestion: Microbial Fermentation: - Ruminants do not rely heavily on - In the cecum and colon, microbes glucose from diet; ferment fiber (mainly cellulose) into - Propionate is converted to glucose VFAs. in the liver via gluconeogenesis. Utilization: Utilization: VFAs are absorbed from the hindgut and VFAs produced are absorbed into the used as energy. bloodstream and used for energy. Hindgut fermenters can also absorb glucose directly from the small intestine, so they rely Ruminants rely less on direct glucose on both glucose and VFAs for energy. absorption and more on VFAs for energy. Acetate and Butyrate Carbohydrate Deficiency - Serve as energy sources for cells. Overall Performance Propionate - Is converted to glucose Starvation is one of the first signs to be observed when there's a lack of carbohydrate intake. There will be a decrease in production of milk from lactating animals such as pigs, ruminants, and horses because of the lack of carbohydrates. Weight loss, lethargy, and reduced growth rate will be visible to these animals due to lowered sources of nutrients. Microbial Imbalance Ruminal Acidosis Carbohydrates provide substrate for Caused by excessive intake of growth of microbes and production forage high in starch and sugar of microbial proteins. content that are rapidly fermented Lack of these fibrous carbohydrates in the rumen. results in impairment of It produces high levels of lactic acid gastrointestinal function. that lowers the pH of the rumen. Ruminants that rely on microbial Due to the faster production rate of fermentation in the rumen will be acid that it can be absorbed by the unable to break down fibrous plant animal, ruminants may experience material into volatile fatty acids digestive discomfort, diarrhea, (VFAs). dehydration, and even death. Hindgut fermenters will feel pain in their colons due to the lack of fermentable carbohydrates that disrupts their normal gut microfauna, leading to gut impaction. Ketosis Long-term carbohydrate inadequacy results in increased production of organic compounds called ketones. The excess amount of ketones in blood and tissues, also known as “hypoglycemia.” Occurs mostly in ruminants in peak Colic lactation and in late pregnancies. Acetone-like breath Colic refers to the abdominal pain that most commonly affects horses. Abrupt increase in the diet of carbohydrates can upset gut bacteria and cause gas buildup in the hind gut. It usually occurs because of excessive production of gas from the forage and hard feeds with high sugar or starch content Colic can lead to intestinal blockage, and in severe cases, become displaced and twisted (volvulus). Excessive Carbohydrates Insulin Resistance Overconsumption of carbohydrates, especially simple sugars, affects the ability of the body to manage blood sugar (glucose) levels. It happens more often in monogastrics, but can also be experienced by ruminants and hindgut fermenters. Forages and diet high in sugar causes large spikes in blood sugar levels, thus pancreas release insulin to absorb this glucose