UNIT TWO PDF - Metabolism

UNIT TWO Tuesday, August 27, 2024 7:10 PM 2A Metabolis… 2A: METABOLISM Metabolism: sum of all chemical reactions in the body ○ Catabolism: breakdown § exergonic: releases energy ○ A...

UNIT TWO Tuesday, August 27, 2024 7:10 PM 2A Metabolis… 2A: METABOLISM Metabolism: sum of all chemical reactions in the body ○ Catabolism: breakdown § exergonic: releases energy ○ Anabolism: building § Endergonic: consumes energy Interrelationship of energy ○ 1st law of thermodynamics: conservation of energy § Energy cannot be created or destroyed § What we eat directly influences what we make  Metabolic rate: how much energy their bodies using ○ Slows down with age Anabolic steroid: builds muscle We eat simple molecules we will undergo anabolic reactions to store them as complex molecules ○ Glucose --> glycogen ○ Amino acids --> proteins ○ Glycerol & Fatty acids --> triglycerides Catabolic reactions to break our stored energy into a simpler from to make ATP 2 M 2B: Metabolism of FATS 2B - Metabolis… Lipids ○ Triglycerides = glycerol + 3 fatty acids: How we store fat in our body § Storage form of fats § Monoglyceride = glycerol + 1 fatty acid ○ Phospholipids: membranes ○ Steroids: lipids that contain rings of carbon, normally make up steroid hormones ○ Fatty acids ○ Fat soluble vitamins (A, D, E, K) ○ Lipoproteins § Four classes of Lipoproteins □ Chylomicrons: transport lipids to adipose tissue □ Very-low-density lipoproteins (VLDLs): transport triglycerides from hepatocytes ® Considered bad for the cardiovascular system ® Bring fats to our liver and adipose tissue or the cells ® KEEP FAT IN OUR BODY ® We want less of these □ Low-density lipoproteins (LDLs): carry about 75% of the total cholesterol in bloo ® Considered bad for the cardiovascular system ® Bring fats to our liver and adipose tissue or the cells ® KEEP FAT IN OUR BODY ® We want less of these  Glycerol backbone to adipocytes Fatty acids tails od and deliver it to cells  Energy stores for an individual with a typical diet 1 kcal worth of energy is readily available, used up quickly 4 kcal of phosphocreatine ready to be tapped into, used up quickly The majority of our energy is coming from other sources like carbs, fats, and proteins ○ Store most energy in fats, then protein, then carbs ○ Carbs will run out 2C: Metabolism of protein Metabolism - Proteins Essential and Nonessential amino acids (AA) in humans ○ Essential: You have to consume, cannot make these § Arginine § Histidine § Isoleucine § Leucine § Lysine § Methionine § Phenylalanine § Threonine § Tryptophan § Valine ○ Non-essential: body makes these, it is not essential to be eaten § Alanine § Asparagine § Aspartate § Cysteine § Glutamate § Glutamine  STORAGE? Glycogen: skeletal muscle liver Fat: triglyceride, adipose tissue Proteins: not stored n 2D: Inte Metabo -… Fa erconversion of macronutrients olism asted or Fed? ○ Fasted (hungry) = post-absorptive state § Haven't eaten all day, relying on stored energy § CATABOLIC STATE ○ Fed (full) = absorptive state § Just eaten, body is actively absorbing the nutrients from the last meal § ANABOLIC  Interrelationship of energy ○ 1st law of thermodynamics: conservation of energy § Energy cannot be created or destroyed § What we eat directly influences what we make § ATP is like cash, lots of tissues in our body use atp, It can be spent most anywhere Energy Transfer ○ Oxidation: involves the removal of electrons from an atom or molecule § EX: conversion of lactic acid to pyruvic acid ○ Reduction: involves the addition of electrons to a molecule § EX: conversion of pyruvic acid to lactic acid ○ Oxidation and reduction are always coupled so the two reactions together are called oxidation-reduction or redox reactions § If something is reduced, something else is oxidized § The oxidation of lactic acid to pyruvic acid and the associated reduction of NAD+ may be written as: Macronutrients ○ Carbohydrate § Glycolysis: glucose breakdown to produce ATP □ Can occur with or without oxygen § Gluconeogenesis: formation of glucose from lipid or protein (non-glucose precursor) § Glycogenolysis: breakdown of glycogen into glucose § Glycogenesis: synthesis of glycogen from glucose □ Savings account Triglycerid § Monosaccharides and disaccharides are simple sugars □ Glucose □ Fructose □ Galactose □ Sucrose = glucose + fructose □ Lactose = glucose + galactose □ Maltose = glucose + glucose § Polysaccharides □ Glycogen  glycogenolysis gluconeogenesis glycolysis de hydrolysis glycogenesis Beta oxidation  ® We want less of these □ Low-density lipoproteins (LDLs): carry about 75% of the total cholesterol in bloo ® Considered bad for the cardiovascular system ® Bring fats to our liver and adipose tissue or the cells ® KEEP FAT IN OUR BODY ® We want less of these □ High-density lipoproteins (HDLs): remove excess cholesterol from body cells and transport it to the liver for elimination ® Help body to eliminate fat by lowering levels of circulating fat in the blood ® We want a lot of HDLs Lipid metabolism ○ Because most lipids are nonx (hydrophobic), they do NOT dissolve in water, require transpor blood (lipoproteins) ○ Because blood plasma is over 90% water, lipids must be transported combine w proteins pro intestines § There are lipoproteins ○ Lipids may be oxidized to produce ATP § Can ONLY be broken down when oxygen is present, COMPLETELY AEROBIC PROCESS (m enough oxygen) § If the body does not need lipids at any given time, they get stored in adipose tissue § Some are used as structural molecules or to synthesize other essential substances ○ Fates of fats § Lipid catabolism (Lipolysis): the process of splitting triglycerides into fatty acids and gly □ Step 1: triglyceride hydrolysis □ Step 2: beta oxidation (turning fatty acids into acetyl CoA) □ CHARACTERISTICS ® SLOW RATE (extremely) of ATP production ® HIGH YEILD of ATP production (~400 ATP) ® OXYGEN DEPENDENT (extremely) □ Regulation: High amounts of acetyl CoA or NADH + H+ inhibit / Decrease the rate ® Bc beta oxidation would only supply you with more acetyl coA or beta oxid ® Body needs to slow down and process the nutrients it already has § Lipid anabolism (lipogenesis): the process of synthesizing lipids from glucose or amino □ Occurs when individuals consume more calories than needed □ Forming lipids and triglycerides from glucose or amino acids □ When does it occur? Lipid anabolism occurs when the body has an excess of ene periods of calorie surplus, such as after consuming a carbohydrate-rich meal, lea fatty acids and triglycerides for storage. □ What hormone stimulates lipogenesis? ® Insulin: decreases blood sugar and increases the arrival of glucose to the c fatty acids out of the blood to make triglycerides □ What did that hormone do during glucose metabolism? ○ Ketone bodies § Result of lipid catabolism od and deliver it to cells d the blood and Lipolysis Length of FA tails vary, depends d on amount of carbon in chain Step 1: splitting glycerol and FA tails apart rter proteins to travel in ○ Glycerol goes to gluconeogenesis oduced by the liver and must be bringing in ycerol e of beta oxidation dation o acids ergy, typically during 1. Triglyceride Hydrolysis: splitting glyce ading to the synthesis of a. Green arrows show process of l b. Gluconeogenesis: takes the glyc 2. Beta oxidation: breaking down of fatt cell, take glycerol and 3. 2 carbons go into the Krebs cycle Lipogenesis: start with glycerol and fatty a nutrients  Focusing on FA tails STEP 3: Each acetyl CoA goes thru the Step 2: Body takes 2 carbons at a time krebs cycle and produces a series of and combines them with enzyme CoA energy intermediates (NADH, FADH) ○ 2 carbons + enzyme CoA makes ○ Hydrogens go on to ETC to produce acetyl CoA ATP ○ BETA OXIDATION: working down tail to make supply of acetyl CoA ○ AEROBIC, Requires oxygen erol backbone and fatty acids tails lipolysis cerol (fat) and making a carbohydrate ty acids, turns carbons into acetyl coA acids, make triglycerides, don’t need energy, stores the  § Alanine § Asparagine § Aspartate § Cysteine § Glutamate § Glutamine § Glycine Dehydration § Proline Dipeptide (fo § Serine acids to prod § Tyrosine Protein conformation Side chain: go ○ Proteins are made of amino acids each one ○ Have three main groups attached § Amino group (NH2) § Acidic carboxyl group (COOH) § Side chain (R group) Protein metabolism: ○ Digested proteins are broken down into amino acids which are oxidized to produce ATP or used to synthesize new proteins ○ LAST RESORT FOR ENERGY PRODUCTION § Functions: □ Enzymes □ Transportation □ Antibodies □ Clotting blood □ Hormones □ Muscle fibers ○ Protein catabolism (breaking down) yields amino acids which a acids, fatty acids, ketone bodies, or glucose § Cells oxidize amino acids to generate ATP via Krebs cycle § lots of ace bodies  2. Beta oxidation: breaking down of fatt cell, take glycerol and 3. 2 carbons go into the Krebs cycle Lipogenesis: start with glycerol and fatty a nutrients wn acetyl CoA to make ne bodies for ATP, brain ta-hydroxybutyric acid blood pH (acidic blood ETA OXIDATION e cant inhibit lipolysis = l coa production) etyl coa and ketone ty acids, turns carbons into acetyl coA acids, make triglycerides, don’t need energy, stores the  ○ ribosomes Organization of Proteins ○ Primary structure: amino acid sequence § Each pearl is an amino acid, attached by peptide bonds ○ Secondary structure: twisting and folding of neighboring amino bonds § May be periods where they're twisted into a helix or fold ○ Tertiary structure: three-dimensional shape of polypeptide cha ○ Quaternary structure: arrangement of two or more polypeptide Where do proteins fit in? o acids, stabilized by hydrogen ded into a sheet ain e chains Yellow boxes are amino acids, needed for reaction to happen Lacking protein, amino acids can slow down the krebs cycle Amino acids can be used for gluconeogenesis, when glucose is needed when needs are high or you are hungry, stimulated by cortisol or glucagon, SLOW RATE ○ During the absorptive state, energy is used or stored § What fuels are involved? § In what organs are they stored? § What hormones are involved? H  We get a lot of ATP aerobically but at slower rate Proteins and fats can only be broken down aerobically, carbs are the only ones that can be broken down anaerobically or aerobically Not a lot of ATP anaerobically but at faster rate ○ Carbs power sprints 2. FO 1. GLYCOLYSIS: Starting with glucose --> pyruvic acid a a. the process whereby a 6-carbon glucose molecule is split into two 3-carbon molecules of pyruvic acid, takes place in cytosol b. Happens when you have glucose but you need ATP c. PFK rate limiting enzyme for glycolysis, hexokinsane involved in first step of glycolysis d. CHARACTERISTICS i. Rapid rate/ low yield of ATP production ii. Oxygen dependent or independent iii. INVOLVES 10 REACTIONS e. Regulation: i. Each of the following will stimulate PFK and increase the rate of glycolysis 1) Increases in ADP, AMP, Pi, decreased pH (or increased H+ ions) 2) Decreases O2 availability ii. Each of the following will inhibit PFK and decrease rate of glycolysis 1) Increases in Glucose-6-phosphate (first product) 2) Lots of ATP and citrate  3. KREB a. ORMATION OF ACETYL COENZYME A a. Formation of key enzymes i. Hexokinase: conversion of glucose to G-6-P (step 1) in glycolysis b. ii. Phosphokinase (PFK): plays a major role in regulating the rate of glycolysis c. iii. Lactate dehydrogenase (LDH): converts pyruvate to lactate iv. Pyruvate dehydrogenase (PDH): converts pyruvate to actyl-CoA d.  4. ETC a. A series of electron carriers in t BS CYCLE pass these hydrogen ions from CHARACTERISTICS i. Each carrier in the chain i. Slow ATP rate electrons ii. High ATP yield ii. Exergonic reactions relea iii. Oxygen dependent iii. This mechanism links che Happens in mitochondria, Aerobic path known as chemiosmosis Turns two times, once for each carbon from Acetyl b. Happens in space between inn CoA from one carrier to the next, h Lots of FADH2 and NADH produced and sent to ETC the ATP needed c. CHARACTERISTICS i. Slow ATP rate ii. High ATP yield iii. Oxygen dependent  the mitochondria where we lose and gain electrons as we m carrier to carrier is reduced as it picks up electrons and oxidized as it gives up ase energy used to form ATP emical reactions with the pumping of hydrogen ions and is ner and outer membrane of mitochondria, passing hydrogens hydrogens rush into intermembrane compartment, releases  Entered mitochondria between 2 & 3, m every process after is aerobic (enough 1 glucose --> 2 pyruvate 2 ATPs produced 2 NADH + 2 H+ ---> 4 or 6 ATPs in ETC GLUCOSE METABOLISM TOTAL = 36-38 ATPs p VS. LIPID METABOLISM = ~400 + ATP per molecule What are the other fates of glucose? meaning oxygen) Krebs c Form 2 Acetyl CoA S 2 NADH + 2H+ --> 6ATPs in ETC 6 2 per molecule e cycle & ETC Succinal-CoA → succinate 2 ATPs 6 NADH + 6 H+ --> 18 ATPs in ETC 2 FADH2 4 ATPs in ETC  Glycogenesis: starting w glucose, ending w glycogen ○ Facilitated by hexokinsae Glycogenolysis: start with glycogen, end with glcuose  Gluconeogenesis: Production of new glucose from lactic acid, amino a ○ Made with non-glucose precursors acids, or glycerol