Nutrients, Metabolism and Energetics

###Nutrients

• Essential elements and molecules are necessary for the body

###Metabolic Activity

• Organic molecules break down to release energy
• Energy is stored as ATP
• ATP is utilized to construct new organic molecules

###Energetics

• Energetics involves how the body maintains a balance between heat gain and heat loss

###Cellular Reaction Requirements

• Cells need oxygen to perform reactions
• Cells need organic substrates
• Cells need mineral ions
• Cells need vitamins
• Cells need water

###Metabolism

• Metabolism is the sum of all chemical and physical changes occurring in body tissues
• Metabolism consists of catabolism and anabolism

###Nutrient Pool

• The nutrient pool comprises all available nutrient molecules distributed in the blood

###Catabolism

• Converts large molecules into smaller ones
• Organic substrate breakdowns release energy to synthesize ATP

###Anabolism

• Anabolism converts small molecules into larger ones
• Organic compound synthesis is an uphill process forming new chemical bonds
• The function of anabolism is to maintain/repair structures
• The function of anabolism is to support growth
• The function of anabolism is to produce secretions
• The function of anabolism is to store nutrient reserves

###Nutrient Reserves

• Triglycerides, consisting mostly of fatty acids, are the most abundant storage lipids
• Glycogen, a branched chain of glucose molecules, is the most abundant storage carbohydrate
• Proteins are the most abundant organic components in the body and perform many vital cellular functions

###Energetics

• the study of energy flow and conversion

###Oxidation and Reduction

• Oxidation and reduction reactions are always paired
• Oxidation is the loss of hydrogen or electrons, where the electron donor is oxidized
• Reduction is the gain of hydrogen or electrons, where the electron recipient is reduced

###Oxidation and Reduction Reactions

• Electrons carry chemical energy
• Redox reactions involve energy gain by reduced atoms/molecules and energy loss by oxidized atoms/molecules
• Heat is released during oxidation and reduction reactions
• Remaining energy performs physical or chemical work like forming ATP

###Electron Transport Chain

• The electron transport chain involves protein complexes in the mitochondria
• Electrons pass through oxidation-reduction reactions
• Electrons are ultimately transferred to oxygen
• Water is formed when electrons combine with oxygen/hydrogen ions

###Coenzymes

• Coenzymes play a key role in energy by acting as intermediaries
• Coenzymes accept electrons from one molecule and transfer them to another
• NAD and FAD are example coenzymes
• NAD and FAD remove hydrogen atoms from organic molecules
• Each hydrogen atom has an electron and a proton
• Hydrogen atom acceptance reduces the coenzyme

###Coenzyme FAD

• Coenzyme FAD accepts two hydrogen atoms
• Coenzyme FAD gains two electrons, forming FADH2

###Coenzyme NAD

• Oxidized coenzyme NAD has a positive charge (NAD+)
• Coenzyme NAD accepts two hydrogen atoms and gains two electrons
• Coenzyme NAD releases one proton
• Coenzyme NAD forms NADH

###Carbohydrate Catabolism

• Carbohydrate catabolism generates ATP and high-energy compounds
• Cellular respiration consists of glucose plus oxygen which produces carbon dioxide and water
• Cellular respiration involves glycolysis, citric acid cycle, and the electron transport chain
• One glucose molecule yields a net 30-32 ATPs

###Glycolysis

• Glycolysis breaks glucose in the cytosol into smaller molecules
• Glycolysis is used by the smaller molecules to used by mitochondria
• Glycolysis doesn't require oxygen
• Glycolysis breaks 6-carbon glucose
• During glycolysis 6-carbon glucose becomes two 3-carbon pyruvic acid molecules
• The ionized form of pyruvic acid is pyruvate
• Glycolysis begins when an enzyme phosphorylates a glucose molecule, forming glucose-6-phosphate

###Glycolysis Needs

• Glycolysis needs glucose molecules
• Glycolysis needs appropriate cytosolic enzymes
• Glycolysis needs ATP and ADP
• Glycolysis needs inorganic phosphate groups
• Glycolysis needs NAD (coenzyme)

###Aerobic Metabolism

• Aerobic metabolism occurs in the mitochondria
• Aerobic metabolism requires oxygen
• Aerobic metabolism uses energy from pyruvate breakdown to make a lot of ATP
• Aerobic metabolism involves the citric acid cycle and electron transport chain

###Mitochondrial membranes

• The outer mitochondrial membrane contains large pores and is permeable to ions/small organic molecules like pyruvate
• The inner mitochondrial membrane contains a carrier protein that moves pyruvate into the mitochondrial matrix
• The intermembrane space separates the outer and inner membranes

###Citric Acid Cycle

• H atoms are removed from pyruvate by coenzymes acting as the primary source of energy gain
• Carbon and oxygen atoms are removed and released as CO2 during decarboxylation
• In the mitochondrion, pyruvate interacts with NAD and coenzyme A to produce CO2, NADH, and acetyl-CoA
• Acetyl-CoA consist of an acetyl group bound to CoA

###Citric Acid Cycle Details

• The acetyl group transfers to a 4-carbon oxaloacetate molecule and creates 6-carbon citric acid
• CoA is released to bind another acetyl group
• H2O molecules are tied up by several steps in the citric acid cycle
• One citric acid cycle removes two carbon atoms during regeneration of a 4-carbon chain

###Citric Acid Cycle Output

• One GTP (guanosine triphosphate) molecule is produced in one citric acid cycle
• GTP is produced through substrate-level phosphorylation
• CH3CO - CoA + 3NAD + FAD + GDP + P; + 2H2O yields CoA + 2CO2 + 3NADH + FADH2 + 2H+ + GTP

###Oxidative Phosphorylation

• Oxidative phosphorylation generates ATP through the transfer of electrons from NADH and FADH2 to oxygen
• Oxidative phosphorylation happens by a sequence of electron carriers within mitochondria
• Oxidative phosphorylation produces over 90% of the body's ATP
• Oxidative phosphorylation is based on water formation
• 2H2 + O2 → 2H2O

###Electron Transport Chain ETC

• ETC consist of protein complexes in the inner mitochondrial membrane
• The protein complexes are where key reactions of oxidative phosphorylation occur
• The ETC needs four respiratory protein complexes, coenzyme Q, and electron carriers (cytochrome molecules)
• Each cytochrome has a pigment part which contains a metal ion
• Each cytochrome has a protein part that surrounds pigment

###Oxidative Phosphorylation

• Oxidative phosphorylation provides about 95% of the ATP needed for cells to function
• Oxidative phosphorylation requires oxygen and electrons
• Oxygen and electrons availability limits the rate of ATP generation
• Cells obtain oxygen via diffusion from extracellular fluid

###Energy Yield

• The main method of generating ATP for most cells is a reaction pathway that begins with glucose and ends with carbon dioxide and water

###Glycolysis

• Glycolysis breaks down one glucose molecule into two pyruvate molecules anaerobically
• A net 2 ATP molecules is the yield of each cell in glycolysis
• Two NADH molecules pass electrons to FAD via an intermediate electron carrier in the intermembrane space, then to ETC

###Citric Acid Cycle

• Two revolutions are required in the citric acid cycle to break down two pyruvate molecules
• Each revolution in the citric acid cycle yields one ATP molecule by way of GTP
• One Citric Acid Cycle Yields an Additional gain of 2 ATP Molecules
• In the Citric Acid Cycle H Atoms Transfer to NADH and FADH2
• Electrons are Supplied to the ETC by Coenzymes
• Additional gain of 2 molecules of ATP

###Electron Transport Chain

• For each glucose molecule, 10 NADH and 2 FADH2 deliver electrons to the electron transport chain
• Each NADH yields 2.5 ATP
• Each of the eight NADH from the citric acid cycle yields 2.5 ATP and one water water molecule
• Each FADH2 yields 1.5 ATP
• The 2 FADH2 from glycolysis yield 3 ATP and two water molecules
• The total yield from the electron transport chain is 23 ATP

###ATP Production Summary

• Cells gain 30-32 ATP molecules for each processed glucose molecule
• Glycolysis produces 2 ATP molecules
• Glycolysis generated 3-5 NADH molecules
• Citric acid cycle produces 2 ATP molecules by way of GTP
• The ETC produces 23 ATP molecules
• All ATP produced in mitochondria, but 2

###Gluconeogenesis

• Synthesis of glucose from noncarbohydrate molecules
• Requires 3-carbon molecules that isn't pyruvate
• Glucose is Stored in the Liver and Skeletal muscles as glycogen

###Glycogenesis

• Glycogenesis is the formation of glycogen from excess glucose
• Glycogenesis involves several steps
• Glycogenesis requires high-energy compound uridine triphosphate (UTP)

###Glycogenolysis

• Glycogenolysis involves the breakdown of glycogen to glucose monomers
• Glycogenolysis occurs quickly
• A single enzymatic step carries Out Glycogenolysis

###Lipids

• Lipids contain carbon, hydrogen, and oxygen, but in varying proportions compared to carbohydrates
• Triglycerides are the most abundant lipid in the body

###Lipid Catabolism

• Lipid catabolism (lipolysis) breaks lipids down into pieces for conversion to pyruvate or channeled directly into the citric acid cycle
• Hydrolysis splits triglycerides into one glycerol molecule and three fatty acid molecules
• Cytosol enzymes convert glycerol to pyruvate, which is then converted to acetyl-CoA for entry into the citric acid cycle

###Lipids and Energy Production

• Breaking down one 18-carbon fatty acid molecule yields 120 ATP
• Which is almost 1.3x the energy from breaking down three 6-carbon glucose molecules

###Lipid Synthesis

• Can use almost any organic substrate because lipids, amino acids, and carbohydrates can be converted to acetyl-CoA.
• Glycerol is synthesized from dihydroxyacetone phosphate (an intermediate product of glycolysis/gluconeogenesis)

###Lipid Synthesis Details

• Nonessential fatty acids and steroids are synthesized from acetyl-CoA
• Essential fatty acids cannot be synthesized in the body and must be consumed
• An example of essential fatty acids are linoleic acid and linolenic acid
• Linoleic acid and linolenic acid are 18-carbon unsaturated fatty acids in plants

###Lipid storage/use

• Lipid provide Important Energy Reserves
• Lipids yield a lot of ATP, but slowly
• Lipids are difficult for water-soluble enzymes to reach
• Lipids are Important for Cells and Steroid Hormones, which Must Reach the Target Cells

###Lipid Transport and Distribution

• Special transport mechanisms carry lipids from one region to another because most are insoluble in water
• Lipoproteins circulate most lipids through the bloodstream
• Free fatty acids make up a small percentage of total circulating lipids

###Free Fatty acids FFAs

• Free fatty acids can diffuse easily across the plasma membranes
• In blood, free fatty acids are generally bound to albumin
• Those not used in synthesis of triglycerides those that diffuse from intestinal epithelium
• Those that diffuse out of lipid reserves when triglycerides are broken down

###Free Fatty Acids

• Free Fatty Acids are important energy sources during periods of starvation
• Cells in the Liver, Cardiac/Skeletal Muscles Can Metabolize Free Fatty Acids

###Lipoproteins

• Lipoproteins are lipid-protein complexes
• Lipoproteins contain large insoluble glycerides and cholesterol
• There are four groups of lipoproteins : chylomicrons, Very low-density lipoproteins (VLDLs), low-density lipoproteins (LDLs)—“bad cholesterol" and high-density lipoproteins (HDLs)—“good cholesterol"

###Chylomicrons

• Chylomicrons are the largest lipoproteins
• Chylomicrons are produced by intestinal epithelial cells from fats in food
• Carry absorbed lipids into lymph and then into bloodstream

###Protein Metabolism

• Protein metabolism involves 100,000-140,000 different synthesized proteins
• Protein structures and function vary
• All Proteins are Built From 20 Amino Acids
• Proteins function in four ways: enzymes, hormones, structural elements, and neurotransmitters
• Very little protein is used as an energy source

###Amino Acid Catabolism

• For Proteins to Be Used as Energy, They Must Be Converted -The substances must be able to enter the citric acid cycle -This involves transamination, deamination, and the urea cycle
• Requires vitamin B6

###Transamination

• Transamination Attaches amino group of amino acid to keto acid
• Transamination Converts Keto Acid Into Amino Acid for protein synthesis
• The Product Leaves the Mitochondrion and Enters Cytosol

###Deamination

• Deamination Prepares Amino Acid for Breakdown in Citric Acid Cycle
• Deamination Generates a Toxic Ammonium Ion

###Deamination

• Deamination Generates Toxic Ammonium Ions in the Liver
• Liver Enzymes Can Synthesize Urea
• Liver enzyme reactions occur in the urea cycle
• As a Result, it produces the substance called urea

###Amino acids and ATP production

• When glucose and lipid reserves are inadequate, liver cells break down internal proteins and absorb additional amino acids from blood
• Because Amino Acids are Deaminated, this Converts to Chains for the Mitochondria
• Not All Amino Acids Enter Cycle at Same Point
• ATP Benefits will therefore vary

###Protein Catabolism

• Three Factors Make the Use of Proteins for Catabolism Impractical:
• Proteins are more difficult to break down than complex carbohydrates or lipids
• Ammonium Ions Yielded are Toxic
• Proteins Provide Too Many Important Structural/Functional Components

###Protein synthesis

• Body Synthesizes Half Of The Required Amino Acids for Building Proteins
• Therefore, Ten Essential Amino Acids Are Required
• Eight are not synthesized at all
• Two a insufficiently synthesized
• The Body Can Build Nonessential Amino Acids on demand, a Process Requiring Amination

###Nutrient Requirements

• Types+ quantities of enzymes need vary with each tissue. The five metabolic tissue are: liver, adipose tissue, skeletal muscle, nervous tissue and other peripheral tissues

###The Liver

• Key Regulatory Centre. It contains a great enzymatic variety for the breakdown/synthesis cycle relating to every macromolecule
• Liver has Significant Energy Reserves from Glycogen Deposits
• Hepatocytes (Liver Cells)
• It has significant supplies of blood
• Blood is routinely monitored and has nutrient data tracked

###Adipose Tissue

• Stores Lipids, Primarily As Triglycerides
• Adipocytes Are Located in Many Areas
• Areolar Tissue, Mesenteries
• Red and Yellow Bone Marrows
• Epicardium
• Location around the Eyes and Kidneys

###Skeletal Muscle

• Maintains a substantial glycogen reserves.
• If Other Nutrients Are Unavailable, the contractile proteins can be broken down the Amino Acids can also be used as an Energy Source

###Nervous Tissue. It,

• Does not maintain a carbohydrate, protein or fat storage
• Has Need for a Steady Supply of Glucose Has an inability to Metabolize Other molecules
• The result of Lack of Adequate Supply of Glucose is Loss of Consciousness
• The result of Lack of Adequate Supply of Glucose is Cellular Dysfunction

###Peripheral tissues exhibit three main properties:

• No Large Metabolic Reserves
• Ready to metabolize fats, carbs and substrates
• Has Preferred Energy Source. The type varies with instructions from the endocrine system

###Metabolic Activity

• Two types of metabolic activity occur daily: an absorptive period of 4hrs after a meal and normal blood conditions, and normal reliance on energy supplies

###Lipid and Amino Acid Catabolism

• Generate acetyl-CoA
• High-Concentration of Acetyl-CoA - Creates Ketone Bodies
• Ketone Body Organic compound that is a byproduct of Fatty Acid Metabolism Dissociates in Solution to Release Hydrogen Ions

###Ketone Bodies

• Three Main Varied Types: Acetoacetate Acetone Betahydroxybutyrate
• Not Catabolized by Liver Cells
• Peripheral Cells Extract Them from the Blood then convert them. Reconvert them to acetyl-CoA so, for use in the Citric Acid Cycle
• Fasting Produces Ketosis Thus causing, a Large/High Amounts of Ketone Bodies in Body, and Body Tissue/Fluids

###Ketonemia

• An influx/Appearance of Ketone Bodies in Body Circulation and Systemwide
• The reduction in blood pH can be addressed with Buffers The final result of Starvation is then Ketoacidosis and a potentially lethal acidification of internal fluids and tissue. Possible effects = Coma, Cardiac Problems or Death

###Nutrition

• To Maintain Perfect Function, Digestion Requires Fluid, Nutrition, Nutrients, etc.

###Nutrition

• Body needs Nutrient absorption From foods
• Body’s requirement for each nutrient usually varies

###Balanced Diet

• Balanced Diets includes all needed ingredients and materials for optimal/regular System homeostatis

###Malnutrition

• Malnutrition is a direct Result from Nutrient problems/Imbalance

###Complete Proteins

• Provide all essential amino acids in adequate proportions
• The foods which Provide it is: -Beef, Fish, & Poultry -Eggs -Milk

###Incomplete Proteins

• Incomplete Proteins tend To be Deficient in Essential Amino Acids
• Therefore you can Find these in Plants

###Minerals

• Minerals Are Inorganic Ions and Dissociate Electrolytes are essential due too:
• Cation such (sodium, chloride) levels determine osmotic flow throughout
• Help assist with Physiological Functions in the body
• Play Many Important Catalytic roles in enzyme actions

###Mineral Types Bulk minerals include sodium, potassium, chloride, calcium, phosphorus, and magnesium. Trace minerals include iron, zinc, copper, manganese, cobalt, selenium, and chromium.

• Several important mineral reserves are stored throughout the body

###Vitamins Vitamins are vital organic nutrients used as coenzymes in vital enzymatic reactions Both are: Fat- or Water-Soluble

###Fat-Soluble Vitamins:A, D, E, and K

• Absorbed along the digestive tract with the food lipid materials
• The skin has vitamin D, the intestines have bacteria to synthesize vitamin K

###Vitamin Types Overview

• The Epithelia is mainly Maintained By Vitamin A intake
• Required For Synthesis of Visual Pigments
• Normal bone Growth is aided by and is Required for Normal Bone Growth
• Vitamin E Functions in this: "It" reduces the vitamin A
• Essential for Clotting Factors is Vitamin K

###Vitamin Reserves Vitamins are Fat-Soluble in Significant reserves Long Periods of Homeostasis can occur without them

• Hypovitaminosis in the human Body (vitamin Deficiency) (RARELY seen in these)
• Hyperitaminosis (Occurs from A higher intake that can can be used) (This can overload the Storage Capabilities

###Water-Soluble Vitamins Components of important coenzymes. These:

• Transfer Between The body tissue, Fluid, and Circulating blood areas very fast
• Excess in Bloodstream = Excreted Quickly in Urine. Therefore, HyperVitaminosis for This Class is Rare

###Intestinal Bacterial

• In the Intestines Bacteria Produce this and more -Five of the Nine water-soluble, vitamin types -The Body can create Vitamin K from this.

The All body types easily absorb water-soluble materials. However, B12s, with their larger molecular structure must bind To assist in absorption , to properly bind to the Intrinsic Factot

###Metabolic rate

• Average caloric expenditure
• Daily activities and levels affect what is seen, as those daily energy Expenditures "change very much often with the body"

###Energy Gains and Losses

• Chemical bonds in the human cells and tissues transfer energy during and after breakage and synthesis
• Some energy usually lost as heat

###Measuring Energy

• Calorie = water 1g -Temp rises 1'C
• Kilocalorie (Calorie) = water 1kg -Temp rises 1'C

###Energy content of food (kcal/g) Lipids = 9.46 Carbohydrates = 4.18 Proteins = 4.32 Total energy can be determined via calorimetry by measuring the energy release by organic bonds broken in oxygen environment

###Metabolic Rate

• The Clinical Evaluation includes assessing The Body's "Calories Used"
  • What are the current metrics ? (Hours, Days, W etc