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MUSKAN.pptx

  1. 1. BIOCHEMISTRY (LIPIDS) 2022-2023 PRESENTED BY: MUSKAN PG Diploma nutrition and dietetics
  2. 2. TOPICS TO BE DISCUSSED What is biochemistry?  Objectives, scope & importance of biochemistry and its relation to nutrition.  Lipids: classification of lipids Metabolism of lipids- Biosynthesis of fatty acids Beta oxidation theory with energetic Ketosis, formation and utilization of ketone bodies.
  3. 3. BIOCHEMISTRY “Biochemistry has become the foundation for understanding all biological processes. It has provided explanations for the causes of many diseases in humans, animals and plants.” “Biochemistry is a study of the chemical substances & processes that occur in plants, animals & microorganisms & of the changes they undergo during development & life.”
  4. 4. Biochemistry is both life science and a chemical science - it explores the chemistry of living organisms and the molecular basis for the changes occurring in living cell. It uses the methods of chemistry, physics, molecular biology, and immunology to study the structure and behavior of the complex molecules found in biological material and the ways these molecules interact to form cells, tissues, and whole organisms.
  5. 5. OBJECTIVES OF BIOCHEMISTRY Study the structures and functions of biomolecules like carbohydrate, lipids, proteins minerals and DNA. Focuses on techniques used to control diseases, abnormal deficiency and treatment of deficiencies. Understand the dynamic changes of cellular systems and corresponding need of nutrients. They act as catalyst agent. Metabolic abnormalities can be studied by knowledge of biochemistry. Study of the energy transformations in living cells, organisms is another objective of study of biochemistry.
  6. 6. IMPORTANCE OF BIOCHEMISTRY • Biochemistry is thriving right now. In recent years it has become the most critical area of science. • It combines the core of biology and chemistry, which opens a new door for research from the very ground up. • Biochemistry helps us understand the medical conditions such as diabetes, jaundice, rickets, etc. with its research, and scientists are now able to find a medication that can cure them or put them in control. • Biochemistry can help us find a way to decompose our waste without harming nature successfully. • This field can also do wonders in the coming years and make us live on other planets as we study the chemical changes that happen on other planets such as mars.
  7. 7. SCOPES OF BIOCHEMISTRY Biochemistry play an important role in various fields such as; in clinical medicine, pharmacology, biotechnology, agriculture, horticulture, forestry, nursing, pathology, in physiology, and also in microbiology. BIOCHEMISTRY IN MEDICINE • Physiology • Pathology • Nursing and diagnosis
  8. 8. SCOPES OF BIOCHEMISTRY BIOCHEMISTRY IN AGRICULTURE • Prevent diseases and Enhance Yield/ growth • Adulteration SCOPES OF BIOCHEMISTRY BIOCHEMISTRY IN PHARMACY • Drug Constitution • The half-life and Drug storage • Drug metabolism
  9. 9. OTHER SCOPES • Biotechnologist • Research Scientist • Clinical Scientist • Research Associates • Chemist Microbiologist • Biomedical Scientist • Pharmacologist Laboratory Technician • Lecturer in an Educational institution
  10. 10. LIPIDS
  11. 11. LIPIDS Lipids Definition • “Lipids are organic compounds that contain hydrogen, carbon, and oxygen atoms, which form the framework for the structure and function of living cells.” These organic compounds are nonpolar molecules, which are soluble only in nonpolar solvents and insoluble in water because water is a polar molecule. In the human body, these molecules can be synthesized in the liver and are found in oil, butter, whole milk, cheese, fried foods and also in some red meats. Let us have a detailed look at the lipid structure, properties, types and classification of lipids.
  12. 12. Properties of Lipids • Lipids are a family of organic compounds, composed of fats and oils. These molecules yield high energy and are responsible for different functions within the human body. Listed below are some important characteristics of Lipids.
  13. 13. •Lipids are oily or greasy nonpolar molecules, stored in the adipose tissue of the body. Lipids are a heterogeneous group of compounds, mainly composed of hydrocarbon chains. •Lipids are energy-rich organic molecules, which provide energy for different life processes. •Lipids are a class of compounds characterised by their solubility in nonpolar solvents and insolubility in water. •Lipids are significant in biological systems as they form a mechanical barrier dividing a cell from the external environment known as the cell membrane.
  14. 14. Lipid Structure Lipids are the polymers of fatty acids that contain a long, non-polar hydrocarbon chain with a small polar region containing oxygen. The lipid structure is explained in the diagram below:
  15. 15. Classification of Lipids Lipids can be classified into two main classes: • Nonsaponifiable lipids • Saponifiable lipids Nonsaponifiable Lipids A nonsaponifiable lipid cannot be disintegrated into smaller molecules through hydrolysis. Nonsaponifiable lipids include cholesterol, prostaglandins, etc
  16. 16. Saponifiable Lipids • A saponifiable lipid comprises one or more ester groups, enabling it to undergo hydrolysis in the presence of a base, acid, or enzymes, including waxes, triglycerides, sphingolipids and phospholipids. • Further, these categories can be divided into non-polar and polar lipids. • Nonpolar lipids, namely triglycerides, are utilized as fuel and to store energy. • Polar lipids, that could form a barrier with an external water environment, are utilized in membranes. Polar lipids comprise sphingolipids and glycerophospholipids. • Fatty acids are pivotal components of all these lipids.
  17. 17. Types of Lipids Within these two major classes of lipids, there are numerous specific types of lipids, which are important to life, including fatty acids, triglycerides, glycerophospholipids, sphingolipids and steroids. These are broadly classified as simple lipids and complex lipids. Simple Lipids • Esters of fatty acids with various alcohols. • Fats: Esters of fatty acids with glycerol. Oils are fats in the liquid state • Waxes: Esters of fatty acids with higher molecular weight monohydric alcohols
  18. 18. Complex Lipids Esters of fatty acids containing groups in addition to alcohol and fatty acid. • Phospholipids: These are lipids containing, in addition to fatty acids and alcohol, phosphate group. They frequently have nitrogen-containing bases and other substituents, eg, in glycerophospholipids the alcohol is glycerol and in sphingophospholipids the alcohol is sphingosine. • Glycolipids (glycosphingolipids): Lipids containing a fatty acid, sphingosine and carbohydrate. • Other complex lipids: Lipids such as sulfolipids and amino lipids. Lipoproteins may also be placed in this category.
  19. 19. Examples of Lipids There are different types of lipids. Some examples of lipids include butter, ghee, vegetable oil, cheese, cholesterol and other steroids, waxes, phospholipids, and fat-soluble vitamins. All these compounds have similar features, i.e. insoluble in water and soluble in organic solvents, etc. Waxes • Waxes are “esters” (an organic compound made by replacing the hydrogen with acid by an alkyl or another organic group) formed from long- alcohols and long-chain carboxylic acids. • Waxes are found almost everywhere. The fruits and leaves of many plants possess waxy coatings, that can safeguard them from small predators and dehydration.
  20. 20. Phospholipids Membranes are primarily composed of phospholipids that are Phosphoacylglycerols. Triacylglycerols and phosphoacylglycerols are the same, but, the terminal OH group of the phosphoacylglycerol is esterified with phosphoric acid in place of fatty acid which results in the formation of phosphatidic acid. The name phospholipid is derived from the fact that phosphoacylglycerols are lipids containing a phosphate group.
  21. 21. Steroids • Our bodies possess chemical messengers known as hormones, which are basically organic compounds synthesized in glands and transported by the bloodstream to various tissues in order to trigger or hinder the desired process. • Steroids are a kind of hormone that is typically recognized by their tetracyclic skeleton, composed of three fused six-membered and one five-membered ring, as seen above. The four rings are assigned as A, B, C & D as observed in the shade blue, while the numbers in red indicate the carbons.
  22. 22. FATTY ACIDS • Fatty acid synthesis is the creation of fatty acids from acetyl-CoA and NADPH through the action of enzymes called fatty acid synthases. This process takes place in the cytoplasm of the cell. Most of the acetyl-CoA which is converted into fatty acids is derived from carbohydrates via the glycolytic pathway. • De novo in Latin means “from the beginning.” Thus, de novo lipogenesis is the synthesis of fatty acids, beginning with acetyl-CoA. Acetyl-CoA has to first move out of the mitochondria, where it is then converted to Malonyl-CoA (3 carbons). • Malonyl-CoA then is combined with another acetyl- CoA to form a 4 carbon fatty acid (1 carbon is given off as CO2). The addition of 2 carbons is repeated through a similar process 7 times to produce a 16 carbon fatty acid.
  23. 23. Formation of malonyl COA Malonyl-CoA is formed by carboxylating acetyl-CoA using the enzyme acetyl-CoA carboxylase. One molecule of acetyl-CoA joins with a molecule of bicarbonate, requiring energy rendered from ATP. Malonyl-CoA is utilised in fatty acid biosynthesis by the enzyme Malonyl coenzyme A. Reaction of fatty acid synthase complex While the de novo synthesis of fatty acids from acetyl-CoA occurs in the cytosol on the fatty acid synthase complex. Fatty acid synthesis is the creation of fatty acids from acetyl-CoA and NADPH through the action of enzymes called fatty acid synthases.
  24. 24. FATTY ACID SYNTHESIS PATHWAY • Acetyl CoA is converted to Malonyl CoA by acetyl CoA carboxylase. • Malonyl CoA is transferred to FAS. • Through a series of condensation, reduction, and dehydration reactions, the two carbons of Malonyl CoA are added to the growing fatty acyl moiety on FAS. • FAS are then recharged with another Malonyl moiety, and the cycle continues. • Each turn of the cycle results in the addition of a two-carbon group to the fatty acid moiety as well as the use of one ATP, one acetyl CoA, and two NADPH. • When the cycle has completed seven turns, the 16-carbon fatty acid (palmitate) is released from FAS.
  25. 25. Beta oxidation • Beta oxidation is a metabolic process involving multiple steps by which fatty acid molecules are broken down to produce energy. • More specifically, beta oxidation consists in breaking down long fatty acids that have been converted to acyl-CoA chains into progressively smaller fatty acyl- CoA chains. • This reaction releases acetyl-CoA, FADH2 and NADH, the three of which then enter another metabolic process called citric acid cycle or Krebs cycle, in which ATP is produced to be used as energy. • Beta oxidation goes on until two acetyl-CoA molecules are produced and the acyl-CoA chain has been completely broken down. • In eukaryotic cells, beta oxidation takes place in the mitochondria, whereas in prokaryotic cells, it happens in the cytosol.
  26. 26. Steps of β oxidation Dehydrogenation • In the first step, acyl-CoA is oxidized by the enzyme acyl CoA dehydrogenase. A double bond is formed between the second and third carbons (C2 and C3) of the acyl-CoA chain entering the beta oxidation cycle; the end product of this reaction is trans-Δ2-enoyl-CoA (trans-delta 2-enoyl CoA). • This step uses FAD and produces FADH2, which will enter the citric acid cycle and form ATP to be used as energy. (Notice in the following figure that the carbon count starts on the right side: the rightmost carbon below the oxygen atom is C1, then C2 on the left forming a double bond with C3, and so on.)
  27. 27. Steps of β oxidation 2. Hydration • In the second step, the double bond between C2 and C3 of trans-Δ2-enoyl-CoA is hydrated, forming the end product L-β-hydroxyacyl CoA, which has a hydroxyl group (OH) in C2, in place of the double bond. • This reaction is catalyzed by another enzyme: enoyl CoA hydratase. This step requires water. 3. Oxidation • In the third step, the hydroxyl group in C2 of L-β- hydroxyacyl CoA is oxidized by NAD+ in a reaction that is catalyzed by 3-hydroxyacyl-CoA dehydrogenase. • The end products are β-ketoacyl CoA and NADH + H. NADH will enter the citric acid cycle and produce ATP that will be used as energy.
  28. 28. KETOSIS • Ketosis is a process that happens when our body doesn't have enough carbohydrates to burn for energy. Instead, it burns fat and makes things called ketones, which it can use for fuel. • Ketosis is a popular low-carb weight loss program. In addition to helping you burn fat, ketosis can make you feel less hungry. • It also helps you keep muscle. A diet high in fat and protein but very low in carbs is called a ketogenic or “keto” diet. Formation of ketone bodies The compounds namely acetone, acetoacetate and β- hydroxybutyrate (or 3-hydroxy-butyrate) is known as ketone bodies. Only the first two are true ketones while β- hydroxybutyrate does not possess a keto (C=O) group. Ketone bodies are water-soluble and energy yielding. Acetone, however, is an exception, since it cannot be metabolized.
  29. 29. KETOGENESIS The synthesis of ketone bodies occurs in the liver. The enzymes for ketone body synthesis are located in the mitochondrial matrix. Acetyl CoA, formed by oxidation of fatty acids, pyruvate or some amino acids, is the precursor for ketone bodies. Ketogenesis occurs through the following reactions: 1. Two moles of acetyl CoA condense to form acetoacetyl CoA. This reaction is catalysed by thiolase, an enzyme involved in the final step of β-oxidation. Hence, acetoacetate synthesis is appropriately regarded as the reversal of thiolase reaction of fatty acid oxidation. 2. Acetoacetyl CoA combines with another molecule of acetyl CoA to produce β-hydroxy, β-methyl glutaryl CoA (HMG CoA). HMG CoA synthase, catalysing this reaction, regulates the synthesis of ketone bodies. 3. HMG CoA lyase cleaves HMG CoA to produce acetoacetate and acetyl CoA. 4. Acetoacetate can undergo spontaneous decarboxylation to form acetone. 5. Acetoacetate can be reduced by a dehydrogenase to β- hydroxybutyrate.
  30. 30. THANK YOU

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