Module 8 - Metabolism Flashcards
Nutrient Types
Nutrient Types
Chemicals in food from which energy is extracted
Classes
Carbohydrates
Lipids
Proteins
Water
Minerals
Vitamins
Carb composition
Carb molecules composed of carbon, hydrogen, and oxygen
Simple carbs
Simple carbs – monosaccharides – glucose & fructose
Complex carbs
Complex carbs – polysaccharides – multiple monos – starch, glycogen, and cellulose – energy storage
Glycolysis
Glycolysis – process where glucose is oxidized, releasing energy store in bonds – produces ATP – immediate energy for cells
Glycogenesis
Glycogenesis – storage of glucose as glycogen in liver and skeletal muscles – glucose can form amino acids – used for proteins
Lipogenesis
Lipogenesis – excess glucose – glycogen storage is full – liver and fat cells convert glucose to glycerol and fatty acid – later synthesize triglycerides
Glycogenolysis
Glycogenolysis – splitting up stored glycerol in liver
Phosphorylated
Phosphorylated – glucose trapped in a cell
Metabolism
Metabolism – sum of all chemical reactions – catabolism and anabolism – needs to be balanced
Catabolism
Catabolism – breakdown of food to obtain energy – produce energy
Energy is released from chemical bonds being broken down
Release ATP – adenosine triphosphate – to power molecular machines – support cells, tissues, and organs
Hormones stim breakdown molecules and production of energy
Cortisol, glucagon, epinephrine, and cytokines
Anabolism
Anabolism – use energy to synthesize larger molecules
Biosynthesis reactions – create new molecule – form new cells and tissues
Need ATP for power
Hormones needed for synthesis of molecules
HGH, insulin-like growth factor, insulin, testosterone, and estrogen
Glucose Catabolism
Glucose Catabolism
Glucose oxidation – cellular respiration – cell mitochondria – chief source of cells energy
Liver
“ogen” – stored – inactive
“lysis” splitting
Start: Glucose
End: CO2, H20 & Energy
Produces large amounts of energy in 4 stages
Glycolysis
Formation of aetyl coenzyme A
Krebs cycle
Electron transport chain
Glycolysis
Glycolysis – breaking up glucose
Glycolysis – glucose to pyruvate
Occurs in cytosol
Anaerobic respiration – no Oxygen needed
When Oxygen in low supply – pyruvic acid will reduce to lactic acid
Aerobic respiration – with oxygen
Pyruvic acid is converted to Acetyl coenzyme A
Glucose – 6-carbon ring into 2 3-carbon molecules w/ phosphate – pyruvate acids – drop phosphate
2 phosphates leave – spend 2 ATP
Pyruvate – enter mitochondria & combines with coenzyme A – turns into Acetyl CoA
Lactate produces – absorbs and buffers H+ from pyruvate – turns back into pyruvate
Start: Glucose +2NAD+ 2 ATP + 4 ADP + 2P
End: 2 pyruvates + 2NADH +2 ADP + 4 ATP
NAD picks up H+ (reduction)
Net: 2ATPS + 2NADH + 2 Pyruvates
Acetyl CoA
Acetyl CoA
Pyruvate wants to enter the membrane needs conformational change
Pyruvate Dehydrogenase – brings H into molecule
NADH+ brings H & H electron – NADH + H+
Product – Acetyl CoA – loses a carbon and add CoA
CoA -co enzyme – helps transport carbon molecule
1 Pyruvate gets oxidized – combined with oxygen
1 carbon leaves – forms CO2
Gains CoA
NAD+ addes H+ = NADH+ – Steals 2H+ from pyruvate molecule –
1 full H+
Takes electron from other H+
Positive proton is in the solution
Leaves 2 carbons – acetyl coenzyme A
Enters Mitochondria matrix – double membranes structure
Best friend – 4 carbon molecule – Oxaloacetic acid – OAA – binds making 6-carbon molecule – citrate – lose CoA
Citrate rearranges its self – gains and loses H20 – loses a carbon
Citric acid – by-product Oxidized over and over in Krebs cycle to become OAA
Krebs Cycle – Citric acid – Tricarboxylic acid (TCA)
Krebs Cycle – Citric acid – Tricarboxylic acid (TCA)
Cycle of dropping carbon, making NADH & FADH & ATP – by losing carbons and bring in H20
Aerobic – needs oxygen
Matrix of mitochondria
Molecule rearranges itself over and over – creating more NADH+ and FADH2+
Brings together phosphate for each pyruvate with ADP = ATP
Drops off carbons – making CO2 – loses 2 carbons = 2CO2 molecules leave the cell
Produces NADH & FADH2 – hold on to H+ ions and electrons – they release electrons and H+ ions – like batteries picking up H+ from pyruvate
NAD+ comes and picks up hydrogen – NADH – drive electron transport chain
FADH2
2 acetyl CoA into Krebs – 6 NADH, 6H+, and 2 FADH2 + 2 ATP
Energy from glucose turned pyruvic acid is now in the reduced coenzymes NADH + H+ & FADH2
Electron Transport Chain
Electron Transport Chain
Aerobic reaction
Channels on the mitochondria’s membrane
NADH + H+ - stole 1 full H and the electron from another
FADH2 – steals 2 hydrogen
Chemiosmosis – must hand off electrons and hydrogens to integral protein channels
Goes back to NAD+ - reduction and oxidation
LEO – loss of electrons = oxidation
Excites protein channel – allows H+ to follow into membrane space
Electron bounces to enzyme to hold onto it
FADH2 – gives electrons to next protein down the chain – excites – allows H to pass
Electrons bounces to excite other proteins to allow more Hydrogen to pass
H+ - builds up into membrane space – concentration gradient
Hydrogen wants to pump thru ATP synthase – Hydrogen flows down synthase back into matrix – proteins spin to synthesise ATP —– ADP + P
Electrons are passed off to oxygen – binds with hydrogen – H20
Protons flow back into matrix through synthase of ADP+P = ATP – 38 ATP is created
Glycogenesis
Glycogenesis – conversion of glucose to glycogen
– storage in liver and skeletal muscle
Occurs in liver
Stimed by insulin
Glucose enters liver – after meal
Insulin helps glucose enter muscle cells
Gets converted to glucose-6-phosphate – takes a phosphate from ATP
Enzyme moves phosphate to another spot
Amino acids are added – UDP – facilitates spanning glucose together
Added to glycogen chains – over and over – branched glucose molecule = glycogen
Glycogenolysis
Glycogenolysis – conversion of glycogen to glucose – b/w meals
Glycogen is reserve fuel for muscle contraction
Stimed by glucagon and epinephrine – triggered when blood sugar levels drop
Enzyme – phosphorylase aids breakdown of glycogen
Phosphorolysis – process of reducing glycogen – chops ends off of molecule
Gets glucose-6-phosphate
Pops phosphate off – can synthesized to ATP b/c of free phosphates
Balance blood sugar
Energy for muscle cells
Short-term energy for brain
Gluconeogenesis
Gluconeogenesis – breakdown of protein or fat molecules to glucose – beginning of new glucose from non-carb sources
Stimed by cortisol, thyroid hormone, epinephrine, glucagon, and HGH
Glycerol (from fats) converted to glyceraldehyde-3-phosphate
Sent to Krebs cycle
Pops in Smooth ER – packs and turns to glucose
Amino acids converted to pyruvic acid
Sent to Krebs cycle
Lipid capabilities
Lipids can
be oxidized for ATP
stored in adipose tissue in subcutaneous layer
used a structural molecule
synthesize essential molecules
Fat digestion and Absorption
Fat digestion and Absorption
Begins in intestines – triglycerides broken down into smaller fatty acid – monoglycerides
Pancreatic lipase
Emulsify with bile salts
Free fatty acids can travel across the intestinal membrane
Repacked to triglycerides – bind with cholesterol in chylomicrons (phospholipid vesicles)
Chylomicrons containing triglycerides, cholesterol, and protein molecules
Move into lymph circulation via lacteals
Transported to circulatory system
Sent to liver to be stored as fat cells – adipose cells
Lipolysis
Lipolysis – fat break down to glucose – for energy
Low levels of glucose
Adipose cells contain lipases – Adipose Triglyceride Lipase – catalyze the deposition of fats from chylomicrons – hydrolyze neutral fats into fatty acids and glycerol
Triglycerides converted to fatty acids & glycerol – by hydrolysis
Stimed by epinephrine, norepinephrine, & glucocorticoids
In cytoplasm of mitochondria in liver
Fatty acids are oxidized into acetyl CoA – thru beta-oxidation
Carbons are removed off fatty acid chain
Combines with carnitine – aids transport across mitochondrial membranes
Converted back into acetyl CoA
Goes into Krebs cycle and converted to ATP to make energy for cells
Ketone Bodies
Glycerol – converted to DHAP – goes into glycolysis pathway
Ketone Bodies
Ketone Bodies
Acetone, Acetoacetic acid & beta-hydroxybutyrate
Produced in liver when fatty acids are broken down and used as energy
Result of two acetyl CoA molecules converted to acetoacetyl-CoA by enzyme
Excess – acidosis or very low blood pH
Lipogenesis
Lipogenesis – conversion of glucose or amino acids into lipids –
Stimed by insulin
Glucose is converted to pyruvate through glycolysis
Pyruvate dehydrogenase – converts to acetyl-CoA
Acetyl-CoA synthesize into fatty acids
Fatty acids converted into triglycerides in liver and adipose tissue
Lipid Transport
Lipid Transport
Transported in blood by combo of proteins as lipoproteins – life boat for lipid molecules – cannot travel thru the H2O of the blood
Carrier proteins – see lipid soluble
4 classes – different address tags
Chylomicrons
Very low-density lipoproteins (VDLs)
Low-density lipoproteins (LDLs)
High-density lipoproteins (HDLs)
Chylomicrons
Chylomicrons – large – produced after eating – ApoB48
Triglycerides and cholesterol packages
Form in mucosal cells in small intest. – packed in golgi
Enter villi lacteals – carried by lymph system into R or L subclavian
In bloodstream towards liver – binds to receptor in adipose tissue – lipoprotein lipases – allows chylomicrons to bind – break down – used for energy or storage
Two locations functions
Triglyceride fatty acids are released and stored in adipocytes
Skeletal muscle used by muscle cells for ATP production
Left over – converted to VDLs
Very low-density lipoproteins (VDLs)
Very low-density lipoproteins (VDLs) – deliver triglycerides to body cells
Produced in liver
Contain endogenous triglycerides
Carry triglycerides synthesized in hepatocytes in liver to adipocytes for storage
Converted to LDLs once triglycerides are extracted – cholesterol remains
Low-density lipoproteins (LDLs)
Low-density lipoproteins (LDLs) – liver to other tissues
Carry 75% of cholesterol to cells
Excess is deposited around smooth muscle fibres in arteries
plaque build up
High-density lipoproteins
High-density lipoproteins (HDLs)
High-density lipoproteins (HDLs) – produced in liver + Gi tract
Pick up cholesterol around body to liver for disposal
Cholesterol
Cholesterol – from food and liver synthesis – support plasma membranes of all cells
Protein Metabolism - Digestion
Digestion – proteins are broken down
into amino acids by digestive enzymes
Hydrolyzed – breaking down proteins
by adding water – digestive
liquids carrying enzymes are mostly water
Pepsin and hydrochloric acid
– stomach – acidic solution
will denature proteins – pepsin
cuts into smaller polypeptides
Secretin and CCK – small intestine
– stim process of breakdown protein to amino acids
Secretin stims pancreas to release more enzymes
Absorbed into blood stream and transported to liver
Protein Metabolism - Active Transport
Active Transport – amino acids are now small enough to be transported
across the mucosa membrane in the small intestine to liver
Liver dictates what happens
Sends free amino acids to body cells
Synthesize
Storage
HGH or insulin – stim uptake of amino acids by cells
Protein Metabolism - Anabolism
Anabolism – Synthesize – amino acids are built into proteins again that carry out body functions – based on DNA and RNA of proteins – Transcription & Translation
20 amino acids
10 essential – cannot be synthesized from present molecules – needs to be consumed
Protein Metabolism - Catabolism
Catabolism – Storage – if excess – Converted into fats or acetyl CoA and sent to Krebs cycle
Deamination/transamination – removal of an amino group from an amino acid
Changing to pyruvate of acetyl-CoA – for energy production
Decarboxylation – Co2 release – excess carbon is released
Krebs cycle entry – after deamination – remaining carbon skeleton of amino acid can be converted into molecules that can directly enter Krebs cycle
Hydrogenation – adds hydrogen to molecules – converted amino to fatty acids
Glucose, fatty acids, and ketone bodies
Protein Metabolism - Waste
Waste – breakdown of amino acids results in ammonium ions building up – primarily in liver – sent thru Urea cycle to be expelled by kidneys
Ammonium is combined with CO2 = urea and water
Glucose-6-phosphate
Glucose-6-phosphate
Synthesize glycogen or glucose to make ribose-5-phosphate for synthesis of RNA and DNA
Can be converted to pyruvate – glycolysis
Pyruvic acid
Pyruvic acid – protein and carb metabolism
Low ATP & high oxygen – pyruvic acids converted to acetyl CoA
Low oxygen – pyruvic acids converted to lactic acids
Acetyl CoA
Acetyl CoA
Gateway for Krebs cycle
Synthesize fatty acids, ketone bodies, and cholesterol
Basal Metabolism Rate
Basal Metabolism Rate
BMR – amount of daily energy expended at rest, quiet, fasting – body breaking down nutrients to liberate energy – measured by thyroxine from thyroid gland
70% basic function of organs
20% physical activity
10% thermoregulation
Normal body temp (37C or 98.6F) – maintained by a balance b/w heat-producing and heat-losing mechanisms
