Carbohydrates PDF

PINES CITY COLLEGES COLLEGE OF MEDICAL LABORATORY SCIENCE 1st SEMESTER A.Y. 2023-2024 BIOCHEMISTRY 201...

PINES CITY COLLEGES COLLEGE OF MEDICAL LABORATORY SCIENCE 1st SEMESTER A.Y. 2023-2024 BIOCHEMISTRY 201 Lesson Number 2: CARBOHYDRATES Objectives: At the end of the module, you should be able to: 1. state the major sources of and the major functions of carbohydrates in the human body. 2. differentiate among the carbohydrate classification monosaccharide, disaccharide, oligosaccharide, and polysaccharide; be familiar with the functional groups present in carbohydrate molecules. 3. enumerate the different functions and significance of carbohydrates in the human body. 4. classify the various kinds of sugars and their corresponding functions. CARBOHYDRATES MAJOR BIOLOGICAL FUNCTIONS most abundant class of bioorganic 1. As storage from fuel molecules found in nature. o 1g when oxidized will yield 4kcal Aldehyde or ketone derivatives of of energy. polyhydroxyl alcohols composed of o G_______ ▪ Chief storage carbohydrate carbon, hydrogen, and oxygen in a ratio in animals of 1:2:1. 2. As structural elements Primary source of energy o Acid mucopolysaccharides and Functional group: Carbonyl group proteoglycans Can be reducing or non-reducing sugars ▪ Important structural o Reducing Sugars: polysaccharides in animal ▪ reduces another compound tissues. and is itself oxidized 3. Other functions ▪ act as a reducing agent due o As lubricant of skeletal joints to the presence of free o As major components of the cell aldehyde or ketone groups walls of bacteria and of the soft ▪ ____________________ cell coats in animal tissues. ____________________ o Provide adhesions between cells o Confer biological specificity in the o Non-reducing sugars surface of animal cells ▪ Do not contain an active o As the metabolism of glucose, ketone or aldehyde group they supply the precursors for the ▪ They will not reduce other compounds biosynthesis of many vital biologic ▪ ____________________ substances Property of and for the exclusive use of PCC-CMLS. Reproduction, distribution, uploading or posting online, or transmitting in any form, without prior permission of PCC-CMLS is strictly prohibited. Page 1 CLASSIFICATION OF CARBOHYDRATES General formula: _________________ 1. M__________________ D____________________ Simple sugars which cannot be Formed when two monosaccharide o hydrolyzed to a simpler form. units are joined by a glycosidic All monosaccharides and many linkage, with loss of a molecule of disaccharides are reducing agents water General formula: ___________ Example: Methods of naming: 1. Sucrose = ____________________ a. According to number of atoms o Table sugar o Diose o Found naturally in plants: sugar o Triose cane, sugar beets, honey, maple o Tetrose syrup o Pentose o Hexoses b. According to aldehyde or ketone group o Aldose 2. Lactose = ____________________ o Ketose o Primary sugar in milk and milk ▪ Generic name for ketoses is products formed by inserting he suffix -ulose (ribulose) c. Combination of alpha and beta o Aldotriose o Ketopentose 3. Maltose = ____________________ o Aldohexose o Produced when starch break down d. According to the ring structure o Used naturally in fermentation o Furanose (5 membered rings) reactions of alcohol and beer o Pyranose (6 membered rings) manufacturing Consists of six carbon atoms and it is designated as D- or L- which refers to the position of the hydroxyl group. G______________ is the only carbohydrate to be directly used for energy or stored as glycogen 3. P_____________________________ Simplest monosaccharide Contains more than 10 sugar units o Glyceraldehyde/glycerose (aldose) General formula: ______________ o Dihydroxyacetone (ketose) Classified into: a. H__________________________ 2. O______________________ o Contain only one type of sugar unit Contain 2 to 10 sugar units Property of and for the exclusive use of PCC-CMLS. Reproduction, distribution, uploading or posting online, or transmitting in any form, without prior permission of PCC-CMLS is strictly prohibited. Page 2  o Example: Starch, glycogen, 3. D-_________________ cellulose, inulin Seldom encountered as a free b. H__________________________ monosaccharide o Contain more than one type of Synthesized from glucose in the sugar unit mammary glands o Example: Heparin, hyaluronic acid, Sometimes called “brain sugar” chondroitin sulfate Present in the chemical markers that S_________: storage of energy in plants differentiate the blood type G_________: storage of energy in 4. D-_________________ animals Most important ketohexose C_________: provides structural AKA: levulose or fruit sugar support in plants, helps in the production Dietary sugar of fibers of high tensile strength. 5. D-__________________ C_________: the principal component of Component of RNAs, DNAs and ATP the exoskeleton of arthropods (insects) 4. DERIVED CARBOHYDRATES "The beautiful thing about learning is that no one can Obtained by certain chemical reactions on take it away from you." — B.B. King sugars a. Oxidation product – sugar and acid b. Reduction product – sugar and alcohol c. Amino acid d. Deoxysugars COMPILED AND PREPARED BY: Luiza D. Botengan, RMT BIOCHEMICALLY IMPORTANT REFERENCES: MONOSACCHARIDES H. Stephen Stoker (2017). Biochemistry, 3rd edition. C&E, Publishing, Inc.: South Triangle, 1. D-Glyceraldehyde and dihydroxyacetone Quezon City Important intermediate process of glycolysis Maricris Realubin – Ubalde (2019). Biochemistry 2. D-_____________________ for Allied Health Sciences. Edric Publishing Most abundant House: Sta. Cruz, Manila Most important from a human nutritional standpoint Todd A. Swanson et al. (2010). Biochemistry, Molecular Biology, and Genetics. Lippincott Tastes sweet unlike L-Glucose which is Williams & Wilkins: Philadelphia, PA 19106 tasteless and cannot be used by the body AKA dextrose and blood sugar Google Images Property of and for the exclusive use of PCC-CMLS. Reproduction, distribution, uploading or posting online, or transmitting in any form, without prior permission of PCC-CMLS is strictly prohibited. Page 3  PINES CITY COLLEGES COLLEGE OF MEDICAL LABORATORY SCIENCE 1st SEMESTER A.Y. 2023-2024 BIOCHEMISTRY 201 Lesson Number 2B: CARBOHYDRATES Learning Objectives: At the end of the lesson, you should be able to: 1. state the clinical applications of carbohydrates. 2. state how carbohydrates are digested. 3. enumerate the enzymes and hormones that aid in carbohydrate digestion. SOME CLINICAL APPLICATIONS OF o DM, Glycogen storage disease, CARBOHYDRATES lactose intolerance, galactosemia, Glucose - the most important energy etc. source of carbohydrates to the mammals. o Bulk of dietary carbohydrate DIGESTION OF CARBOHYDRATES (starch) is digested and finally A. Dietary carbohydrates absorbed as glucose into the body 1. Starch:Contains amylose and amylopectin D____________ (or dextroglucose – 2. Sucrose: Table sugar another form of glucose) – frequently 3. Lactose: Milk sugar used in medical practice B. Digestion of dietary carbohydrates in the F_________ – abundantly found in semen mouth (Fig. 3-2) Cellulose – non-digestible carbohydrate 1. In the mouth, salivary ___________ o Decreases the intestinal cleaves starch by breaking a-1,4 linkages absorption of glucose and between glucose residues within the cholesterol chains (Fig. 3-1) o Increasing bulk of feces to avoid 2. D_____________ (linear and branched constipation oligosaccharides) are the major products S_________ and d_________ - that enter the stomach. Accumulation in the tissues may cause certain pathological conditions – cataract, nephropathy. Hyaluronic acid – serves as lubricant and shock absorbent in joints H__________ is an anticoagulant S__________ – a glycoside employed in the treatment of TB. Associated diseases: Property of and for the exclusive use of PCC-CMLS. Reproduction, distribution, uploading or posting online, or transmitting in any form, without prior permission of PCC-CMLS is strictly prohibited. Page 1  oligosaccharides containing a-1,4 and a-1,6 linkages. 3. Digestion by enzymes of intestinal cells a. Complexes of enzymes, produced by intestinal epithelial cells and located in their brush borders, continue the digestion of carbohydrates b. Glucoamylase (an a-glucosidase) and other maltases cleave glucose residues from the nonreducing ends of oligosaccharides and also cleave the a- 1,4 bond of maltose, releasing the two glucose residues. c. Isomaltase cleaves a-1,6 linkages, releasing glucose residues from C. Digestion of carbohydrates in the intestine branched oligosaccharides. (Fig. 3-2) d. Sucrase converts sucrose to glucose 1. The stomach contents pass into the and fructose. intestine, where bicarbonate (HCO3) e. Lactase (a b-galactosidase) converts secreted by the pancreas neutralizes lactose to glucose and galactose. the stomach acid, raising the pH into the optimal range for the action of the intestinal enzymes. 2. Digestion by pancreatic enzymes (Figure 3-2) a. The pancreas secretes an a-amylase that acts in the lumen of the small intestine and, like salivary amylase, cleaves a-1,4 linkages between D. Carbohydrates that cannot be digested glucose residues. 1. Indigestible polysaccharides are part of b. The products of pancreatic a-amylase the dietary fiber that passes through the are the disaccharides maltose and intestine into the feces. isomaltase, trisaccharides, and small Property of and for the exclusive use of PCC-CMLS. Reproduction, distribution, uploading or posting online, or transmitting in any form, without prior permission of PCC-CMLS is strictly prohibited. Page 2 E. Absorption of glucose, fructose, and G__________________& galactose A____________________________(ACTH): 1. Glucose, fructose, and galactose—the secreted by the anterior pituitary final products generated by digestion of dietary carbohydrates—can be absorbed E_______________________ by intestinal cells by two forms of secreted by the medulla of the adrenal transport: facilitated transport and glands. active transport. Stimulates glycogenolysis and lipolysis; 2. Using facilitated transport, It inhibits secretion of insulin. monosaccharides bind to transport proteins and are transported into cells C_______________________ moving down a concentration gradient. Secreted by the zona fasciculata and zona 3. Glucose also moves into cells by reticularis of the adrenal cortex secondary active transport, in which stimulates glycogenolysis, lipolysis, and sodium ions are carried along with gluconeogenesis + + glucose. An Na -K ATPase pumps Na+ into the blood, and Na+ moves down a T_____________________ concentration gradient from the blood Secreted by the thyroid gland; into the cell, bringing glucose with it. stimulates glycogenolysis and gluconeogenesis; HORMONES INVOLVED IN CARBOHYDRATE increases glucose absorption from the METABOLISM intestines 1. Hormones that increase blood glucose o Glucagon, epinephrine, cortisol, I__________________ growth hormone, thyroxine Produced by beta cells of pancreas as 2. Hormones that decrease blood glucose proinsulin. o Insulin Proinsulin is converted into insulin through 3. Regulator hormone the removal of C-peptide fragment o Somatostatin Stimulus: increase in plasma glucose causes an increase in insulin G_____________ Action: Produced by the alpha cells of pancreas. o Increases glucose entry into cells Stimulus: decrease in plasma glucose triggers o Promotes glycogenesis an increase in glucagon o Promotes lipogenesis Action: o Promotes glycolysis o Promotes glycogenolysis o Promotes synthesis of amino acids from o Promotes gluconeogenesis pyruvate Property of and for the exclusive use of PCC-CMLS. Reproduction, distribution, uploading or posting online, or transmitting in any form, without prior permission of PCC-CMLS is strictly prohibited. Page 3 S_____________________ Synthesized by delta cells of the pancreatic islets of Langerhans; inhibits secretion of insulin, glucagon, and growth hormone Getting wisdom is the wisest thing you can do! And whatever else you do, develop good judgment. - Proverbs 4:7 COMPILED AND PREPARED BY: Luiza D. Botengan REFERENCES: Bishop, M. L., Fody, E.P., Schoeff, L.E. (2018). Clinical Chemistry: Principles, Techniques and Correlations. (8th ed.) Philadelphia: Lippincott Williams & Wilkins, Baltimore, Maryland. H. Stephen Stoker (2017). Biochemistry, 3rd edition. C&E, Publishing, Inc.: South Triangle, Quezon City Maricris Realubin – Ubalde (2019). Biochemistry for Allied Health Sciences. Edric Publishing House: Sta. Cruz, Manila Todd A. Swanson et al. (2010). Biochemistry, Molecular Biology, and Genetics. Lippincott Williams & Wilkins: Philadelphia, PA 19106 Google Images Property of and for the exclusive use of PCC-CMLS. Reproduction, distribution, uploading or posting online, or transmitting in any form, without prior permission of PCC-CMLS is strictly prohibited. Page 4  PINES CITY COLLEGES COLLEGE OF MEDICAL LABORATORY SCIENCE 1st SEMESTER A.Y. 2023-2024 BIOCHEMISTRY 201 Lesson Number 2C: CARBOHYDRATES Learning Objectives: At the end of the lesson, you should be able to: 1. state how glucose is regulated and digested. 2. differentiate glycolysis, gluconeogenesis, glycogenolysis, glycogenesis, lipogenesis, and lipolysis. 3. differentiate the different pathways involved in glucose metabolism and enumerate the enzymes involved. 4. enumerate the diseases involved in glucose metabolism and how they are diagnosed. REGULATION OF GLUCOSE CONCENTRATION IN THE BLOOD LIPOGENESIS o Conversion of carbohydrates to GLYCOLYSIS fatty acids o Metabolism of glucose to o Decreases glucose since pyruvate or lactate to energy carbohydrates are converted into o Decreases blood glucose since fatty acids and stored as fats glucose is consumed to produce LIPOLYSIS lactate/pyruvate o Breakdown of fats GLUCONEOGENESIS o Increases glucose because fats o Formation of glucose-6-phosphate are converted into consumable from non-carbohydrate sources glucose o Increases blood glucose GLYCOGENOLYSIS HORMONES INVOLVED IN CARBOHYDRATE o Breakdown of glycogen to glucose METABOLISM for use as energy 1. Hormones that increase blood glucose o Increases glucose since glycogen o Glucagon, epinephrine, cortisol, is degraded into glucose growth hormone, thyroxine molecules 2. Hormones that decrease blood glucose GLYCOGENESIS o Insulin o Conversion of glucose to glycogen 3. Regulator hormone for storage o Somatostatin o Decreases glucose since excess glucose in the body is stored in “You don’t have to be great to start, the liver and skeletal muscle as but you have to start to be great.” glycogen –Unknown Property of and for the exclusive use of PCC-CMLS. Reproduction, distribution, uploading or posting online, or transmitting in any form, without prior permission of PCC-CMLS is strictly prohibited. Page 1  FATE OF GLUCOSE 1. Embden-Meyerhof pathway (EMP)/ Glycolysis 2. Hexose Monophosphate (HMP) Shunt 3. Glycogenesis 1. EMBDEN-MEYERHOF PATHWAY (Fig. 1) Glucose is broken down into 2, 3-carbon molecules of pyruvic acid that can enter the tricarboxylic acid cycle (TCA cycle) on conversion to acetyl-coenzyme A (acetyl-CoA) which deliver the acetyl group to the citric acid cycle/Krebs cycle (Fig. 2) to be oxidized for energy production. Aerobic pathway and Anaerobic Pathway Occurs in the cytoplasm 2. HEXOSE MONOPHOSPHATE (HMP) SHUNT Fig. 1. EMP (Fig. 3) AKA: Pentose phosphate pathway A detour of glucose-6-phosphate from the glycolytic pathway to become 6- phosphogluconic acid. This oxidized product permits the formation of ribose-5-phosphate adenine dinucleotide phosphate (NADPH) Permits pentoses, such as ribose, to enter the glycolytic pathway. Occurs in the cytoplasm Fig. 2. Krebs Cycle Property of and for the exclusive use of PCC-CMLS. Reproduction, distribution, uploading or posting online, or transmitting in any form, without prior permission of PCC-CMLS is strictly prohibited. Page 2  Fig. 3. HMP Shunt 3. GLYCOGENESIS (Fig. 4) Glucose-6-phosphate is converted to glucose-1-phosphate, which is then CATEGORIES OF FASTING PLASMA converted to uridine diphosphoglucose/ GLUCOSE UDP-Glucose and then to glycogen by Normal fasting glucose: glycogen synthase.