[BIOCHEM]LAB_008_BASIC-CONCEPTS-OF-METABOLISM.pdf

(001) BASIC CONCEPTS OF METABOLISM DR. MARIA ALOIZA HADLOC | 02/23/21 be co...

(001) BASIC CONCEPTS OF METABOLISM DR. MARIA ALOIZA HADLOC | 02/23/21 be converted further into Acetyl coA which comes with a OUTLINE small amount of oxidation. The Acetyl coA that is eventually formed will now be oxidized in order to form large amounts I. METABOLISM A. 2 Classifications of Reactions for Metabolism of ATP which is the product that we want in catabolic B. Three Stages of Catabolic Reactions reaction. C. Regulation of Metabolism In the second stage, these diverse building blocks are II. BASAL METABOLIC RATE further degraded to acetyl coenzyme A (CoA) and a few A. Total Surface Area (m2) other, simple molecules. B. B. Determine BMR Some energy is captured as ATP, but the amount is III. CALORIE EXPENDITURE small compared with the energy produced during the third stage of catabolism. 3. Oxidation of acetyl CoA: The tricarboxylic acid (TCA) is the I. METABOLISM final common pathway in the oxidation of fuel molecules that Defined as the sum of all chemical reactions that take produce acetyl CoA. Oxidation of acetyl CoA generates large place in an individual. amounts of ATP via oxidative phosphorylation as electrons This abstract concept lays the foundation for understanding flow from NADH and FADH2 to oxygen. how biological systems acquire and use energy. The sum of all the chemical changes occurring in a cell, a tissue, or the body. This explains to us that for the different cells, each cell undergoes different reactions within it so we have a sequence pathway or step by step pathways inside a certain cell in order to come up with a certain product. And this product can also be used by another cell and that interaction between the different cells of the body as well as with the different tissues of the body explains to us why all this happens. A. 2 CLASSIFICATIONS OF REACTIONS FOR METABOLISM 1. Catabolic – it breaks down large molecules C. REGULATION OF METABOLISM There are two purposes why catabolic process happens: In order for metabolism to happen, each cell needs to interact with the a. to form ATP other cells so a certain cell cannot act or work on its own, interaction b. to come up with the building blocks that can be must happen. used also to form another building block Different forms of interaction: 2. Anabolic – responsible for forming dimple molecules to 1. Signals from within the cell (intracellular reaction) - we become larger compounds. can have a cell activated or inhibited by different ligands B. THREE STAGES CATABOLIC REACTIONS 2. Intercellular - meaning a signal from a certain cell can be 1. Hydrolysis of complex molecules: In the first stage, used as a signal or a ligand to the next cell in order to come complex molecules are broken down into their component up with a certain reaction. building blocks. 3. Second messenger systems – examples are: Adenyl Example cyclase and Calcium phosphatidylinositol, they are called o Proteins are degraded to amino acids, second messenger because in comparison to intracellular, poly -saccharides to monosaccharides, for example, this is the cell, you have a certain receptor and fats (triacylglycerols) to free fatty within a cell, a ligand reacts with a receptor immediately, this acids and glycerol. receptor will cause interaction within the cell - the o Protein will be hydrolyzed to its intracellular. But for second messenger, this is the cell and into its building blocks with amino acids have a receptor here, usually the G- Protein coupled o Triacylglycerol (TAG) will be hydrolyzed receptor and a second messenger, the ligand will interact to fatty acids and glycerol with the 1st receptor and eventually this receptor will cause o Glucose will be hydrolyzed to become reaction to the second messenger system, an example of monosaccharides. which is adenyl cyclase. So, this Adenyl cyclase converts 2. Conversion of building blocks to simple intermediates: ATP to Cyclic AMP. The building blocks like fatty acids and monosaccharides will Page 1 of 8 PREPARED BY: CMED 1E/1F  (001) BASIC CONCEPTS OF METABOLISM DR. MARIA ALOIZA HADLOC | 02/23/21 Second Messenger System - second messenger cyclase. Adenyl cyclase will now convert within the cell that is responsible in causing the real available ATP’s into CAMP and cyclic interaction after the ligand causes the first AMP on the other hand will activate interaction to the original receptor. The second protein kinase A and this protein kinase messenger system like the adenyl cyclase will A is the one responsible in catalyzing eventually convert ATP to cyclic AMP. transfer of phosphate from other ATP’s in Going back to the example: this is the cell, we have order to come up with end products. the 1st receptor, G- Protein coupled receptor is EXAMPLE: For the smooth muscle, cyclic AMP will also connected to a trimeric protein. Again, the act into protein kinase A in order for the muscle to first receptor is G- Protein coupled receptor and contract and cause bronchoconstriction. This is the this is the adenyl cyclase. very reason why metabolism must be regulated, it’s Once ligands or neurotransmitters or hormones not all the time that cyclic AMP must be activated interact with G-Protein coupled receptors, it will because if it happens, then diseases may also cause changes within trimeric proteins that are happen. For example, Asthma, if cyclic AMP is interconnected to G-Protein coupled receptor. So continuously activated there will be continuous ideally this trimeric protein is composed of bronchoconstriction so for example the Bronchus Gamma, Beta and Alpha proteins and beneath causing now difficulty of breathing in the patient. the alpha protein is a GDP. So once the ligand This is the reason why they also have regulating interacts with the first receptor, GDP will eventually factors like: be converted into GTP. Once this happens, the 1. Dephosphorylated proteins, so these alpha domain of the trimeric protein will be dephosphorylating proteins will be released from the rest of the trimeric proteins and removing phosphate from the PKA or this Alpha + GTP will now interact with the second called the protein phosphatases in order messenger’s system - Adenylyl cyclase, so what to stop interaction within the protein will Adenyl cyclase do now? The Adenyl cyclase is kinase A. the one that will eventually cause the interaction 2. Hydrolysis of cyclic-AMP, like your within the cell. cAMP phosphodiesterase. So instead of Actually, the G-Protein coupled receptor can either cyclic-AMP being activated, they will be be stimulate or inhibit the Adenyl cyclase hydrolyzed in order for that action to depending on the hormone or the neurotransmitter finally halt. that will cause initial reaction to the receptor. These are important in clinical practice in order to Adenyl cyclase has interact, we have the 1st understand the different mechanisms of actions of different drugs. receptor and Adenyl cyclase activated by Trimeric protein. The work of Adenyl cyclase is to convert Example: available ATP to cyclic AMP. Theophylline What is the work of Cyclic AMP? The Cyclic - Given to patients with Chronic Obstructive AMP will now interact with the protein kinases. Pulmonary Disease (COPD), emphysema Protein kinases will be activated now and this is the secondary to chronic smoking one that will catalyze the transfer of phosphate - Used in order to inhibit phosphodiesterase type 3 from another ATP that is available to the Serine, and 4, which are responsible for breaking down threonine residues of protein substrate in order to cAMP in the smooth muscle, which causes finally come up with end products. bronchodilation. Because if there is no inhibitory Again, we have 1st receptor, GTP protein coupled function, there will be continuous receptor acted upon by a ligand, we have a bronchoconstriction, causing further asthma in the trimeric protein connected to the G-Protein patient. coupled receptor. So once a ligand interacts with a G-Protein coupled receptor, there will be Metabolic processes either changes within the trimeric protein. ○ use energy to build large molecules from smaller o The 1st change would be the GDP precursors (anabolism), or attached to it will be converted into GTP ○ release energy by breaking down large molecules and once that happens, the alpha into smaller products (catabolism) component of that trimeric protein will be Catabolic processes detached from the rest of the Trimeric ○ involve breaking down large biomolecules and protein in order now to interact with the capturing the energy contained within those second messenger which is the adenyl molecules for other purposes. Page 2 of 8 PREPARED BY: CMED 1E/1F  (001) BASIC CONCEPTS OF METABOLISM DR. MARIA ALOIZA HADLOC | 02/23/21 ○ Catabolic reactions serve to capture chemical The energy released is temporarily stored by the synthesis energy in the form of adenosine triphosphate of a high energy compound called ATP. (ATP) from the degradation of energy-rich fuel The energy released when ATP is broken down to ADP can molecules. be used to power many biological functions, such as muscle ○ Catabolism also allows molecules in the diet (or contraction. nutrient molecules stored in cells) to be converted Many organisms, such as yeast, can utilize the energy stored into building blocks needed for the synthesis of in glucose without using oxygen. complex molecules. Fermentation produces less ATP then cellular respiration ○ Energy generation by degradation of complex and can produce a variety of other end products. Yeast, for molecules occurs in three stages example, produce ethanol when they go through ○ Catabolic pathways are typically oxidative, and fermentation. require coenzymes such as NAD+. Anabolic processes ○ involve the synthesis of large biomolecules from smaller precursors. ○ Anabolic processes require energy while catabolic processes provide the needed energy. ○ Anabolic reactions combine small molecules, such as amino acids, to form complex molecules, such as proteins Anabolic reactions. Both anabolic and catabolic chemical reactions are ○ require energy (are endergonic), which is generally facilitated by enzymes, which are protein catalysts that provided by the breakdown of ATP to adenosine enable chemical reactions that would otherwise be unlikely diphosphate (ADP) and inorganic phosphate (Pi). to occur. Anabolic reactions often involve chemical Enzymes work by decreasing the amount of energy required reductions in which the reducing power is most for a chemical reaction to occur. This is known as activation frequently provided by the electron donor NADPH. energy. Activation energy can be visualized by thinking about the energy required for a skier to climb a hill before being able to effortlessly ski down the hill at high speeds. Enzymes decrease the activation energy required for a chemical reaction to occur. II. BASAL METABOLIC RATE This is the total number of calories that is required to maintain the vital body functions but vital bodily functions only. Thus, means that it provides the number of calories that you need when one goes jogging or walking. It means, when one is resting, when one is lying down without using any muscle of the body, then this is the basal metabolic rate as long as it maintains the vital bodily functions like breathing, pumping of the heart and that includes the basal metabolic rate. ○ They are thus intimately linked and the sum of all How much energy do you spend in a single day? these pathways is referred to as “metabolism.” Each person spends a different amount of energy (expressed in Calories) to maintain his or her bodily functions. Examine this figure to see a summary of energy and carbon flow in Basal metabolic rate (BMR) is the total number of calories metabolism. required to maintain only vital bodily functions. Source of almost all energy on the planet is the sun. ○ This number varies from person to person and is This energy is harvested by plants and some microbes and based on a number of factors including age, stored in the simple sugar glucose through a process called gender, height, weight, and aerobic fitness. photosynthesis. Different factors in order to compute for BMR: All living organisms consume glucose and combine it with a. Age oxygen to produce energy and carbon dioxide. b. Gender c. Height Page 3 of 8 PREPARED BY: CMED 1E/1F  (001) BASIC CONCEPTS OF METABOLISM DR. MARIA ALOIZA HADLOC | 02/23/21 d. Weight e. Aerobic fitness A. TOTAL SURFACE AREA (m2) The weight of the person and the height of the person in order to find within Table 1, the surface area in m2 of that certain person. From the tables provided, we will now be able to get the number of calories or basal metabolic rate as long as we know the surface area of the body. B. DETERMINE BMR 1.To determine your own BMR, you will need the following numbers: Height (in inches) = ______ Height (in centimeters) = ______ Weight (in pounds) = _____ Weight (in kilograms) = _______ 4) Calculate the number of calories you burn in 1 hour! (Calories/m2 × surface area) __________ This is your BMR! 5) Using your own words, explain what your BMR really means. For example (based from the table): Height = 167cm Weight = 69kg Total Surface Area = 1.8m2 BMR = 66.24 III. CALORIE EXPENDITURE If you were to lie in bed and not move a single muscle, except those required to keep you alive, you would burn only the number of calories you calculated in your BMR. Most of us don’t spend our time like this. For this next activity, you will calculate the number of calories you burn to do different activities. Your calculations will be based on your BMR, which you calculated in the previous part. Fill in the following chart. 2) Using the data in Table 1, calculate your total surface area (in meters squared): __________ 3) Use Table 2 to determine the number of calories your body burns per m2 of surface area per hr. Page 4 of 8 PREPARED BY: CMED 1E/1F  (001) BASIC CONCEPTS OF METABOLISM DR. MARIA ALOIZA HADLOC | 02/23/21 Based on table 3: REFERENCES For example (when playing the piano): Using BMR = 66.24 Harvey, Richard A., & Ferrier, Denise R. (2011). Lippincott Total calories burned (in 1hr.) = BMR + Activity Expenditure = 66.24 + (66.24 x 1.4) Illustrated Reviews: Biochemistry (5th ed.). Philadelphia: = 66.24 + 92.736 Wolters Kluwer = 158.976 / 158.98 Another example (climbing upstairs): Using BMR = 51 Total calories burned (in 1hr.) = BMR + Activity Expenditure = 51 + (51 x 5.8) = 51 + 295.8 = 346.8 Additional information: Body Mass Index (BMI) Formula: BMI = kg/m2 Height in m2 Weight in kg Body Mass Index range Below 18.5 Underweight 18.5 - 24.9 Normal 25 - 29.9 Overweight Above 30 Obese For example: Height = 152.4cm In order to come up with meter, divide it into 100 = 1.524m = (1.524m)2 = 2.32m2 Weight = 75kg. BMI = 75kg / 2.32m2 BMI = 32.327 TEST YOURSELF 1. What are the two reactions that make up the classification of metabolism? 2. What are the stages of catabolic reactions? 3. Different regulatory mechanisms in regulation of metabolism? 4. what is basal metabolic rate? 5. Give two factors to compute for BMR. Gender 4. Total number of calories required to maintain vital bodily functions 5. Age, 3. Intercellular, intercellular and second messenger system (adenyl cyclase) of building blocks to simple intermediates, oxidation of acetyl coA 1. Anabolic, catabolic 2. Hydrolysis of complex/large molecules, conversion Page 5 of 8 PREPARED BY: CMED 1E/1F  (001) BASIC CONCEPTS OF METABOLISM DR. MARIA ALOIZA HADLOC | 02/23/21 APPENDICES Page 6 of 8 PREPARED BY: CMED 1E/1F  (001) BASIC CONCEPTS OF METABOLISM DR. MARIA ALOIZA HADLOC | 02/23/21 Page 7 of 8 PREPARED BY: CMED 1E/1F  (001) BASIC CONCEPTS OF METABOLISM DR. MARIA ALOIZA HADLOC | 02/23/21 Page 8 of 8 PREPARED BY: CMED 1E/1F