Seager_10e_Ch22_PowerPoint.ppt Biochemistry

Biochemistry

1. Chapter 22 Nutrition and Energy for Life Seager, Slabaugh, Hansen, General, Organic, and Biochemistry, Tenth Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

2. Learning Objectives (1 of 2) Describe the difference between macronutrients and micronutrients in terms of amounts required and their functions in the body Describe the primary functions in the body of each macronutrient Distinguish between and classify vitamins as water-soluble or fat-soluble on the basis of name and behavior in the body List the primary function in the body for each major mineral Describe the major steps in the flow of energy in the biosphere

3. Learning Objectives (2 of 2) Differentiate among metabolism, anabolism, and catabolism Outline the three stages in the extraction of energy from food Explain how ATP plays a central role in the production and use of cellular energy Explain the role of coenzymes in the common catabolic pathway

4. Nutrition and Energy Macronutrients : Substances that are needed by the body in relatively large amounts Include carbohydrates, lipids, and proteins Micronutrients : Substances that are needed by the body only in small amounts Some are utilized in enzymes Classified as either vitamins or minerals Other essential nutrients Water - Constitutes 45%–75% of the human body mass Fiber - Prevents or relieves constipation by absorbing water and softening the stool for easier elimination

5. Nutrition Labeling and Education Act, 1990 Brought changes to the regulations that define what is required on a food label Daily Values (DVs) : Reference values developed by the Food and Drug Administration (FDA) specifically for use on food labels Reference Daily Intakes (RDIs) : Standards for protein, vitamins, and minerals used on food labels Daily Reference Values (DRVs) : Standards for nutrients and food components, such as fat and fiber, that have important relationships with health

6. FDA and USDA The Food and Drug Administration (FDA) Finalized the new Nutrition Facts label for packaged foods, which enables consumers to make better informed food choices Uses 2000 calories as a standard for energy intake in calculating DRVs 1 nutritional calorie is equivalent to 1 kcal of energy Reviews and revises the guidelines every five years The U.S. Department of Agriculture (USDA) Issued the MyPlate food guide to replace the MyPyramid posters with new recommendations

7. Figure 22.2 - An Example of a Food Label

8. Figure 22.3 - The Food Guide, MyPlate

9. Carbohydrates Main dietary source of energy Provide useful materials for the synthesis of cell and tissue components Considered to be fattening Excess calories are the result of high-calorie foods eaten with the carbohydrates Example - Bread is eaten with butter, a high-energy lipid

10. Classification of Dietary Carbohydrates Simple carbohydrates Include monosaccharides and disaccharides, commonly called sugars Complex carbohydrates Include the polysaccharides amylose and amylopectin, which are collectively called starch Cellulose serves a non nutritive role as fiber as it cannot be digested by humans

11. Lipids About 95% of lipids in the body and in foods are triglycerides Concentrated sources of energy Provide more than twice the energy of an equal mass of carbohydrate Contain some fat-soluble vitamins and help carry them through the body Include essential fatty acids, which cannot be synthesized in the body and must come from the diet Include polyunsaturated linoleic and linolenic acids Improve the texture of foods and absorb and retain flavors Prolong satiety as they are digested more slowly than other foods

12. Figure 22.6 - Fatty Acid Composition of Common Food Fats

13. Dietary Lipids and Health Research indicates a correlation between consumption of too much fat and the wrong type of fat and obesity and cardiovascular disease Moderate amount of fat is needed in a diet Many people consume more fat than required

14. Proteins Only macronutrients with an established RDI Used in the body to aid in: Production of new tissue as the body grows Maintenance and repair of cells Production of enzymes, hormones, and other important nitrogen-containing compounds of the body Supply of energy (4 calories/gram) Broken down to individual amino acids that are absorbed into the body's amino acid pool Classified as complete proteins if they contain all the essential amino acids in the proportions needed by the body

15. Table 22.1 - The RDI for Protein

16. Table 22.2 - The Essential Amino Acids

17. Figure 22.7 - Protein Content of Several Foods

18. Figure 22.4 - Diet Comparison

19. Vitamins Organic compounds that cannot be produced by the body in the amounts needed for good health Water-soluble vitamins Highly polar in nature Function as coenzymes, except vitamin C Excess is excreted through the kidneys Fat-soluble vitamins Have nonpolar molecular structures Function like hormones Excess accumulation in body tissues can lead to toxic effects

20. Table 22.3 - Vitamin Sources, Functions, and Deficiency Conditions (1 of 2) Vitamin Dietary Sources Functions Deficiency Conditions Water-soluble B 1 ( thiamin ) Bread, beans, nuts, milk, peas, pork, rice bran Coenzyme in decarboxylation reactions Beriberi: nausea, severe exhaustion, paralysis B 2 (riboflavin) Milk, meat, eggs, dark green vegetables, bread, beans, peas Forms the coenzymes FMN and FAD, which are hydrogen transporters Dermatitis (skin problems) Niacin Meat, whole grains, poultry, fish Forms the coenzyme NAD + , which is a hydride transporter Pellagra: weak muscles, no appetite, diarrhea , dermatitis B 6 (pyridoxine) Meat, whole grains, poultry, fish Coenzyme form carries amino and carboxyl groups Dermatitis, nervous disorders B 12 (cobalamin) Meat, fish, eggs, milk Coenzyme in amino acid Metabolism Rare except in vegetarians; pernicious anemia

21. Table 22.3 - Vitamin Sources, Functions, and Deficiency Conditions (2 of 2) Folic acid Leafy green vegetables, peas, beans Coenzyme in methyl group transfers Anemia Pantothenic acid All plants and animals, nuts; whole-grain cereals Part of coenzyme A, acyl group carrier Anemia Biotin Found widely; egg yolk, liver, yeast, nuts Coenzyme form used in fatty acid synthesis Dermatitis, muscle Weakness C (ascorbic acid) Citrus fruits, tomatoes, green pepper, strawberries, leafy green Vegetables Synthesis of collagen for connective tissue Scurvy: tender tissues; weak, bleeding gums; swollen joints Fat-soluble A (retinol) Eggs, butter, cheese, dark green and deep orange vegetables Synthesis of visual Pigments Inflamed eye membranes, night blindness, scaliness of skin D (calciferol) Fish-liver oils, fortified milk Regulation of calcium and phosphorus Metabolism Rickets (malformation of the bones) E (tocopherol) Whole-grain cereals, margarine, vegetable oil Prevention of oxidation of vitamin A and fatty acids Breakage of red blood cells K Cabbage, potatoes, peas, leafy green vegetables Synthesis of blood-clotting substances Blood-clotting disorders

22. Minerals Metals or nonmetals used in the body in the form of ions or compounds Major minerals : Found in the body in quantities greater than 5 g Examples Ca and P - Primary inorganic structural components of bones and teeth Na, K, Cl, and Mg - Ions distributed throughout the body’s fluids Trace minerals : Found in the body in quantities less than 5 g Examples - Fe, Mn, Cu, and I Components of vitamins, enzymes, hormones, or specialized proteins

23. Figure 22.10 - Minerals in a 60-Kg Person

24. Table 22.4 - Major and Trace Mineral Sources, Functions, and Deficiency Conditions (1 of 2) Mineral Dietary Sources Functions Deficiency Conditions Major minerals Calcium Dairy foods, dark green vegetables Bone and teeth formation, blood clotting, nerve impulse transmission Stunted growth, rickets, weak and brittle bones Chlorine Table salt, seafood, meat HCl in gastric juice, acid–base balance Muscle cramps, apathy, excessive bleeding, reduced appetite Magnesium Whole-grain cereals, meat, nuts, milk, legumes Activation of enzymes, protein synthesis Inhibited growth, weakness, spasms Phosphorus Milk, cheese, meat, fish, grains, legumes, nuts Enzyme component, acid–base balance, bone and tooth formation Weakness, calcium loss, weak bones Potassium Meat, milk, many fruits, cereals, legumes Acid–base and water balance, nerve function Muscle weakness, paralysis Sodium Most foods except fruit Acid–base and water balance, nerve function Muscle cramps, apathy, reduced appetite Sulfur Protein foods Component of proteins Deficiencies are very rare

25. Table 22.4 - Major and Trace Mineral Sources, Functions, and Deficiency Conditions (2 of 2) Trace minerals Arsenic a Many foods Growth and reproduction Poor growth and reproduction Cobalt Meat, liver, dairy foods Component of vitamin B 12 Pernicious anemia ( vitamindeficiency symptom) Copper Drinking water, liver, grains, legumes, nuts Component of numerous enzymes, hemoglobin formation Anemia , fragility of arteries, low appetite, and inhibited growth Chromium Fats, vegetable oils, grains, meat Enhances insulin action Reduced ability to metabolize glucose Fluorine Drinking water, seafood, onions, spinach Maintenance of bones and teeth Higher frequency of tooth decay Iodine Iodized salt, fish, dairy products Component of thyroid hormones Hypothyroidism, goiter Iron Liver, lean meat, whole grains, dark green vegetables Component of enzymes and hemoglobin Anemia Manganese Grains, beet greens, legumes, fruit Component of enzymes Deficiencies are rare Molybdenum Legumes, cereals, organ meats, dark green vegetables Component of enzymes Deficiencies are rare Nickel Many foods Needed for health of numerous tissues Organ damage, deficiencies are rare Selenium Grains, meat, poultry, milk Component of enzymes Deficiencies are rare Silicon a Many foods Bone calcification Poor bone development, deficiencies are rare Tin a Many foods Needed for growth Poor growth Vanadium a Many foods Growth, bone development, reproduction Poor growth, bone development, and reproduction Zinc Milk, liver, shellfish, wheat bran Component of numerous enzymes Poor growth, lack of sexual maturation, loss of appetite, abnormal glucose tolerance a Need and deficiency symptoms determined for animals, probable in humans, but not yet recognized.

26. Energy in the Biosphere (1 of 2) The sun is the ultimate source of energy used in all biological processes Enormous energy output results from the fusion of hydrogen atoms into helium atoms Portion of the liberated energy reaches the Earth’s surface and is absorbed by chlorophyll pigments in the plants Photosynthesis converts CO 2 and H 2 O into glucose, and then into starch, triglycerides, and other storage forms of energy

27. Energy in the Biosphere (2 of 2) Energy stored in plants is obtained by all animals directly or indirectly Cellular respiration Plants and animals combine energy-rich compounds with oxygen from the air to produce CO 2 and H 2 O and release energy Portion of energy released is captured within cells in the form of adenosine triphosphate (ATP) Remainder of the energy is liberated as heat

28. Figure 22.11 - Energy Flow in the Biosphere

29. Carbon Cycle Respiration process is the reverse of the photosynthetic process Some of Earth’s carbon compounds are repeatedly recycled by living organisms

30. Metabolism Sum of all reactions involved in maintaining a living cell Categories Catabolism : All reactions that lead to the breakdown of biomolecules Reactions release energy Anabolism : All reactions involved in the synthesis of biomolecules Reactions require energy Metabolic pathway : Sequence of reactions used to produce one product or accomplish one process Examples - Citric acid cycle and electron transport cha

31. Catabolism of Food (1 of 2) Stage I - Large, complex molecules are digested into simpler ones via hydrolysis Stage II - Small molecules are broken down into simpler units, primarily the two-carbon acetyl portion of acetyl coenzyme A (acetyl CoA)

32. Catabolism of Food (2 of 2) Stage III - C ommon catabolic pathway Reactions of the citric acid cycle plus those of the electron transport chain and oxidative phosphorylation Purpose is to convert chemical energy in foods to ATP molecules

33. Figure 22.13 - Three Stages in the Extraction of Energy from Food

34. Structure of ATP Adenosine portion consists of a heterocyclic base, adenine, bonded to ribose Triphosphate portion is bonded to the ribose to give ATP ATP molecule has a charge of –4 At the cell pH of 7.4, all protons of the triphosphate group are ionized ATP is complexed with Mg 2+ in a 1:1 ratio Net charge of complex is –2 Triphosphate end is essential in the transfer of biochemical energy

35. Figure 22.16 - The Structure of ATP

36. Hydrolysis of ATP in Water (1 of 2) Results in the transfer of a phosphoryl group (—PO 3 2– ) from ATP to water Products are adenosine diphosphate (ADP) and an inorganic phosphate, P i

37. Hydrolysis of ATP in Water (2 of 2) Accompanied by the release of free energy ( Δ G ), which is used in cellular processes that require input of energy Δ G has a positive value when energy is absorbed and a negative value when energy is released Represented when measured under standard conditions Represented by when measured at body conditions ATP is a high-energy compound Liberates a great amount of free energy on hydrolysis

38. Figure 22.17 - Schematic Representation of the Lowering of Energy

39. Table 22.6 - Hydrolases of Some ATP-Related Compounds Reaction Δ G ° 9 (kcal/mol) ATP + H 2 O ⟶ ADP + P i +H + −7.3 ATP + H 2 O ⟶ AMP + PP i + 2H + −10.9 PP i + H 2 O ⟶ 2P i −4.6 ADP + H 2 O ⟶ AMP + P i + H + −7.3

40. The ATP–ADP Cycle Plays a central role in linking energy production with energy utilization

41. Mitochondria Cellular organelles where reactions of the common catabolic pathway occur Known as cellular power stations Contain both inner and outer membranes Folds of the inner membrane are called cristae Gel-filled space that surrounds the cristae is called the matrix

42. Coenzyme A (CoA) (1 of 2) Central compound in metabolism and is a part of acetyl CoA Derived from the B vitamin pantothenic acid (B 5 ) Contains: Phosphate derivative of ADP b - mercaptoethylamine Reactive sulfhydryl group (—SH)

43. Coenzyme A (CoA) (2 of 2) Transfers acyl groups Acyl groups are linked to CoA via the sulfur atom in a thioester bond

44. Nicotinamide Adenine Dinucleotide (NAD + ) (1 of 3) Derivative of ADP and the vitamin nicotinamide Reactive site is located in the nicotinamide portion

45. Nicotinamide Adenine Dinucleotide (NAD + ) (2 of 3) Acts as an electron acceptor Nicotinamide ring accepts two electrons and one proton during oxidation of a substrate, which forms the reduced coenzyme NADH

46. Nicotinamide Adenine Dinucleotide (NAD + ) (3 of 3) General reaction: Concise manner of representing the general reaction:

47. Flavin Adenine Dinucleotide (FAD) (1 of 2) Derived from ADP and the vitamin riboflavin Reactive site is located within the riboflavin ring system

48. Flavin Adenine Dinucleotide (FAD) (2 of 2) Substrates of enzymes that use FAD as the coenzyme give up two electrons FAD accepts both the H atoms Involved in the reactions in which a —CH 2 —CH 2 — portion of the substrate is oxidized to a double bond