Exam 4 Study GuideChapters 7-10

Chapter 7- Carbohydrates

General Terminology Aldose sugar—an aldehyde group (C=O on the end) & carbon chain with alcohol groups Ketose sugar—a ketone group (C=O in the middle) & carbon chain with alcohol groups

o To classify something as a complete sugar: it must have a ketone or an aldehyde group. o The carbon with the aldehyde group attached to it is labeled number 1 or the carbon that is closest to

the ketone group is labeled number 1 (NOT the carbon that is part of the ketone group) Monosaccharide stereoisomers two molecules are described as stereoisomers of each other if they are made

of the same atoms connected in the same sequence, but the atoms are positioned differently in space o Diastereomers stereoisomers that are not enantiomers; they are not complete mirror images of each

other; the arrangement of ONE group is different but all the other groups are in the same positioning Epimers diastereomers that differ a SINGLE carbon

EX. D-glucose and D-galactose differ in position of OH at C #4 Ex. D-glucose and D- mannose differ in position of OH at C #2

Anomers two possible diastereomers that form because of cyclization (alpha or beta) Alpha-D-glucose OH of carbon 1 is downward Beta-D-glucose OH of carbon 1 is upward

Enantiomers nonsuperimposible mirror imageso Ex. The D and L configurations of ribose

Furanose—5 membered ring (5 points) Pyranose—6 membered ring (6 points)

Monosaccharides- In nature glucose exists in the ring form NOT in the open form

o Ring form can form higher order molecules like starch and maltoseo How do you go from open form to ring form? Oxygen of carbon atom 5 attacks carbon 1 and pulls the

oxygen out - Alpha vs Beta (refers to the positioning of the OH group attached to carbon 1)

o Alpha OH is right in straight form, down in ring form Signified by + Trans arrangement

o Beta OH is Left in straight form, up in ring form Signified by – Cis arrangement

- Reducing atom—carbon 1 because aldehyde changes to OH - Aldohexoses 6 carbon rings formed with an aldehyde

Important MonosaccharidesGlucose

- Original called dextrose- Found in large quantities throughout the world- Primary fuel for living cells- Preferred energy source for brain cells and cells without mitochondria (RBC)

Fructose - D-Fructose or fruit sugar- Highly content found in fruit and nature! (sperm and honey)- It is twice as sweet as sucrose- used as a sweetening agent in processed food- Sperm use fructose as an energy source - It is a 6 carbon sugar but forms a furan ring – processed differently because it has an aldehyde

Galactose- Necessary to synthesize a variety of important biomolecules including lactose, glycolipids, phospholipids.

Proteoglycan and glycoproteins - NOT AN ENERGY SOURCE- Found in our cell membrane- Galactosemia a genetic disorder resulting from a missing enzyme in galactose metabolism

Chemical Reactions of Monosaccharides1. Oxidation- lose of electrons (C=O COOH)

a. Monosaccharides may readily undergo several oxidation reactions in the presence of metal ions or certain enzymes

b. Products are formed in open chain NOT ringc. Aldonic acid—formed when aldehyde group on Carbon 1 of glucose is oxidized into Carboxylic acid d. Uronic acid—formed when OH group on Carbon 6 (CH2OH) of glucose is oxidized into COOHe. Aldaric acid—formed when both aldehyde group on C1 and CH2OH group on C6 are oxidized to two

groups of COOH f. Lactone can be produced if carbonyl groups of aldonic or uronic acids react with an OH group in the

same moleculei. EX. Vitamin C—powerful reducing agent that protects cells from reactive oxygen and nitrogen

species ii. If these oxidation reactions don’t occur then we will not be able to absorb vitamin C

2. Reduction- Gain of electrons (C=O OH)a. Products of the reduction of monosaccharides are Alditols sugar alcohols

i. Sugar alcohols are used in commercial food processing and in pharmaceuticals ii. Ex. Sorbitol—can be used to prevent moisture loss, found in gum and other commercial foods

b. When carbonyl group (either ketone or aldehyde) reduce into alcohol group

3. Glycosidic Bond Formation-disaccharide formation a. two monosaccharides can link together via glycosidic bonds and form disaccharidesb. linkages are named by alpha or beta configuration and by which carbons are connected

i. carbon atom 1 is reducing agent because it is easily reduced or oxidizedii. Always name by first sugar.

1. If the first sugar is alpha configuration than the bond will be named alpha2. Alpha(1,4)—the first sugar’s carbon 1 in the alpha configuration attack the second sugar

at carbon 4 alcohol group3. Alpha (1,1)—very rare because sugar doesn’t like to use reducing end; likes to keep last

sugar reducing open 4. Beta (1,4) – the first sugar’s carbon 1 atom in the beta configuration attacks the second

sugar at the 4th carbon alcohol group. Important DisaccharidesLactose

- Milk sugar- Galactose + glucose- Beta(1,4) linkage- It is common to have a deficiency in lactase (the enzyme that breaks down lactose)—causing you to be lactose

intolerant - REDUCING SUGAR

Maltose- Malt sugar Intermediate product of starch hydrolysis- Glucose + glucose- Alpha (1,4) linkage

Cellobiose- Degradation product of cellulose - Glucose + glucose - Beta (1,4) linkage- Does not exist freely in nature (beta bonds rarely forms within body)- Comes from cell wall from plants

Sucrose- Common table sugar produced in the leaves and stems of plants (ex. Cane or beet sugar)- Glucose + fructose- Alpha (1,2) linkage - NON-REDUCING SUGAR

o Cannot add other sugars because the second C in fructose was originally a ketone and it is not free anymore so it cannot grow in size – cannot be polymerized further

- Only five carbon ring disaccharide we need to know

Important PolysaccharidesStarch

- Amylose (unbranched helix) + amylopectin (branched helices)- A-glucose + A-glucose (alpha glucose repeats)- Alpha (1,4) linkage- Function: used for energy storage in plant cells

Glycogen- A-glucose repeats- Alpha (1,4) linkage- Function: used for energy storage in animal cells- Makes more branched than starch – makes it harder to digest

Cellulose- B-glucose repeats- Beta (1,4) linkage- Function: used for structural support in cell walls of plants and many algae- Cannot be digested because enzymes are not qualified to make break beta bonds- Hydrogen bonds form between rows of B-glucose repeats

Chitin- Modified glucose repeats with a special NHCOCH3 group off of the second carbon- Beta (1,4) linkage- Function: used for structural support in the cell walls of fungi and the external skeletons of insets and

crustaceans - Parallel strands joined by hydrogen bonds

Peptidoglycan- Modified glucose repeat with a special NHCOCH3 group off of the second carbon- Beta (1,4) linkage- Function: used for structural support in bacterial cell walls- Heteropolymer- Parallel strands joined by peptide bonds

Lectins—proteins which bind to carbohydrates on cell surfaces- Help in cell to cell communication- They are harmful to humans! May cause anemia, GI distress, allergic reactions, and a variety of other symptoms

- Common in lentils! A popular source of protein in some areas- To prevent lectin related damage…

o Cook seeds and grains in high heat or moist heato Soaking seeds and grains for at least 1 hour prior to cooking and discarding the soaked water

- EXAMPLE- Ricin o Aka RIP- ribosome inactivating protein

It inactivates eukaryotic translation (not making any proteins so it causes certain death if consumed)

o Found in Castor seedso Destroys the glycosidic bond between sugar and nitrogen bases in rRNA- preventing eukaryotic

translation and promoting certain death

Chapter 8 – Glycolysis

Glucose—the molecule that provides the energy, stored in the form of ATP- How much ATP we make= how rich in energy we are- Make ATP by breaking down and processing food - Does not interact with proteins (glycogen does that)

Cellular Respiration- How glucose is used to produce energy!- 3 STEPS

o Glycolysis in the cytosol Converts on molecule of glucose to 2 pyruvates Does not require oxygen (occurs in an anaerobic environment) End products: 2 NADH, 2 ATP

o Kreb’s Cycle in the mitochondrial matrix Acetyl CoA enters the cycle creating NADH and FADH2 (electron carriers) End products after 2 cycles: 6 NADH, 2 ATP, 2 FADH2, 4 CO2 Cycle occurs twice!! Because one glucose makes 2 pyruvates 2 Acetyl coA

o Electron Transport Chain in the mitochondrial cristae NADH and FADH2 from the Krebs Cycle transport electrons to the chain and ultimately to

oxygen --- facilitating oxidative phosphorylation End Products: 25 ATP Maximum yield of ATP per molecule of glucose: 29

GLYCOLYSIS- Proceeds through a series of 10 reactions!- Step 1-5 are energy investment phase and steps 6-10 is energy generation phase- Reactants: 1 molecule of glucose- Products: 2 pyruvates

Step 1: Glucose + ATP glucose 6-phosphate - Enzyme: hexokinase

o Transferase enzyme- Purpose: traps glucose inside the cell (the big phosphate group attached to the glucose make it difficult for the

molecule to leave the cell)- Energy investing step because it uses ATP - Irreversible reaction (can be controlled by activators and inhibitors) - Inhibited by its product!! – Glucose 6-phosphate inhibits hexokinase- This is a commitment step for glucose to enter glycolysis

Glucose-6- phosphate - An important compound at the junction of several metabolic pathways- Too much blood sugar—glucose is sent to the liver- Liver can do glycolysis and glycogen synthesis

o Glycogen synthesis (the storage of glucose as glycogen) only occurs in liver

Step 2: Glucose 6- phosphate ↔ fructose 6- phosphate - Enzyme: phosphohexoseisomerase or phosphoglucoisomerase

o isomerase - Reversible reaction - no inhibitors or activators- Not ATP invested

Step 3: Fructose 6-phosphate + ATP fructose 1,6-biphosphate - Enzyme: phosphofructokinase 1

o The most regulated enzyme in glycolysis o Transferase enzyme

- Purpose: commits the cell to metabolizing glucose rather than converting to another sugar or storing it- Irreversible reaction - Activators: AMP, ADP, fructose 2,6-biphosphate, insulin

o Insulin: normal activator; triggers the activation of the transcriptional activator on the enhancer region - Inhibitors: ATP, citrate, glucagon (opposite of insulin, deactivates the transcriptional activator of enhancer

region)- ATP invested

Phosphofructokinase- Enzyme that catalyzes fructose 1,6-biphosphate from fructose 6- phosphate- Inhibited by ATP binding to the enzyme at the regulatory site (slows down the reaction)

o Allosteric regulation/inhibition- When ATP is part of substrate, it binds to the active site on the enzyme - Composed of alpha helices and beta sheaths

Step 4: fructose 1,6- biphosphate ↔ dihydroxyacetone + glyceraldehyde 3- phosphate - Enzyme: aldolase

o Lyase enzyme- Reversible reaction- NO ATP invested or activators or inhibitors - Step of splitting a 6C compound into two 3C compounds

Step 5: dihydroxyacetone phosphate ↔ glyceraldehyde 3-phosphate- Enzyme: triose phosphate isomerase

o Isomerase enzymeo Kinetically perfect enzyme

- A very fast reaction - The end of the ATP investment phase- Now we have two molecules of G3P so the next steps will occurs twice!!

Step 6: glyceraldehyde 3- phosphate + NAD + ↔ 1, 3- bisphosphoglycerate + NADH - Enzyme: glyceraldehyde 3-phosphate dehydrogenase

o Oxoreductase enzyme - Reversible reaction- no activators or inhibitors- Generation of the reducing agent NADH (2 molecules produced)

- An oxidation + phosphorylation reaction Step 7: 1,3-biphosphoglycerate ↔ 3- phosphoglycerate + ATP

- Enzyme: phosphoglycerate kinaseo Transferase enzyme

- Reversible reaction- no activator or inhibitors- First ATP generation in glycolysis via Substrate Level Phosphorylation (total of 2 ATP molecules are generated)- 1,3-bisphosphoglycerate is a very high energy molecule.

o The extra energy is given off as heat (why you feel warmer when you work out)

Step 8: 3-phosphoglycerate mutase ↔ 2-phosphoglycerate + H2O- Enzyme: phosphoglycerate mutase

o Isomerase enzyme - Reversible reaction- no activators or inhibitors- An intermediate is involved

Step 9: 2-phosphoglycerate ↔ phosphoenolopyruvate - Enzyme: enolase

o Lyase enzyme- Reversible reaction- no activators or inhibitors- Dehydration reaction: you are losing a molecule of water and forming a double bond

Step 10: phosphoenolopyruvate + ADP pyruvate + ATP - Enzyme: pyruvate kinase

o Transferase enzyme - Irreversible reaction- Activators: fructose 1,6 bisphosphate, ADP, AMP- Inhibitors: ATP, acetyl CoA, alanine- Substrate level phosphorylation generation of ATP ( total of 2 ATP molecules are generated)

Pyruvate Kinase- Regulated by direct covalent modification - When pyruvate kinase is phosphorylated it is less active and will eventually stop - Glucagon—influences during very low levels of blood glucose; add a phosphate group on pyruvate to slow down

glycolysis so you don’t expend too much energy when low levels of glucose in blood.o Doesn’t go away until you eat something

- Insulin- influenced by the dephosphorylated state (allow another enzyme to remove phosphate group and make It more active)

o High blood glucose levelo Increases the levels of glucokinase in the liver by sensing sugar levelso Glucokinase can lead to glycogen and lipogenesis in the presence of insulin during high blood glucose

levels In liver

Glycolysis Summary- Net gain of ATP is 2 molecules

o We invested 2 ATPo We made 4 ATP

- Net gain of 2 NADH- Net gain of 2 pyruvate molecules (3 C compounds)- Occurs in the absence of oxygen - A crossroads of other catabolic and anabolic process- Irreversible reactions in glycolysis are regulated

- Pyruvate can either participate in aerobic respiration or fermentation afterwards

PRODUCTS:Glucose glucose 6- phosphate fructose 6-phosphate fructose 1, 6- bisphosphate dihydroxyacetone G3P 1,3-bisphosphate glycerate 3-phosphohlycerate 2-phosphogylcerate phosphoenolopyruvatepyruvate

ENZYMES:HexokinasePhosphoglucoisomerase phosphofructokinasealdolase triase phosphate isomerase G3P dehydrogenase phospohogylcerate kinase phosphoglycerate mutase enolase pyruvate kinase

Three Possible Fates for glycolytic pyruvate1. TCA CYCLE—oxidized to produce more NADH & ATP- best for aerobic organisms to completely oxidize it 2. Lactic Acid Fermentation—reduced to form lactic acid and NAD+

- we carry this out when we exercise 3. Alcoholic fermentation – reduced to form ethanol and NAD+

- By microbes -applied in breweries

Lactic Acid Fermentation - Allows regeneration of NAD+ so that glycolysis can continue producing some ATP- Especially important in “over-exercised” muscles when oxygen actually becomes limiting - Other acids can be produced- NADH is recycled in this process

Alcohol Fermentation - Ethanol consumption stimulates NADH synthesis in the liver by the ADH reaction- Excess NADH will inhibit glycolysis and fatty acid oxidation- Acetaldehyde acetic acid fatty acid synthesis- Result is accumulation of fat in the liver (cirrhosis) and loss of function - Pyruvate carboxylase : pyruvate acetaldehyde releasing CO2

NADH Recycling

Glyceraldehyde-P Dehydrogenase

Lactate Dehydrogenase

- Alcohol dehydrogenase: Acetaldehyde ethanol and NAD+

Chapter 9 – Aerobic Respiration

Citric Acid Cycle- A series of reactions associated with mitochondria where partly oxidized carbohydrate and lipids are completely

oxidized to CO2 to produce some ATP and a lot of reduced nucleotides- Also known as the TCA or Krebs Cycle - Occur in the mitochondrial matrix- Complete oxidation of pyruvate to carbon dioxide - Reduction of nucleotide electron carrier- Production of some ATP

o ATP is never a substrate!- Regeneration of oxaloacetate (OXAL)- The cycle continues as long as there is pyruvate present; lack of pyruvate causes the cycle to stop - One cycle generates 4 NADH, 1 FADH2, 1 ATP- The cycle occurs twice per every molecule of glucose because glucose forms 2 pyruvates!

SUBSTRATES & PRODUCTS:Pyruvateacetyl Co-A citrateisocitrate alpha-ketoglutarate succinyl-CoAsuccinate fumarate malateOXAL

Enzymes:Pyruvate dehydrogenase Citrate synthase aconitase isocitrate dehydrogenase alpha-ketoglutarate dehydrogenase succinyl-CoA synthetase succinate dehydrogenae fumarase Malate dehydrogenase

Pyruvate dehydrogenase- pyruvate acetyl CoA- A complex of three separate enzyme

o One part of enzyme is oxidizing; moving carbon dioxide, and the third adds CoA to acetyl group- Promotes entry of pyruvate into cycle via formation of acetyl-CoA- Subjected to complex regulation - Allosteric Regulation

o Activators: ADP, AMP, NAD+, CoASHo Inhibitors: ATP, NADH

- Covalent Modificationo Phosphorylation of Enzyme 1 inactivationo Modulate PDH protein kinase

Citrate Synthase- acetyl CoA citrate - Claisen Condensation- Activators: ADP, NAD+, Acetyl-CoA

- Inhibitors: ATP, NADH, Citrate, Succinyl-CoA

Aconitase- Citrate isocitrate

Isocitrate dehydrogenase- Isocitrate alpha-ketoglutarate- Activators: ADP, NAD+, Ca 2+- Inhibitors: ATP and NADH

Alpha-ketoglutatarate dehydrogenase - Alpha-ketooglutarate succinyl coA- Activators: Ca 2+- Inhibitors: ATP and succinyl-CoA

Succinyl-CoA synthetase- Succinyl CoA succinate- A ligase enzyme- High energy CoA thioester is cleaved to form succinate- Energy is conserved in substrate level phosphorylation of GDP- ATP is synthesized via diphosphate kinase

Succinate Dehydrogenase - Succinate fumarate- Oxoreductase enzyme- Part of complex II in respiratory electron transport- Enzyme is bound with FAD which is then reduced to FADH2 which feed electrons directly to electron transport- Activators: succinate, ATP, Pi- Inhibitors: OXAL

Fumerase- Fumarate+ H2O malate- Ligase enzyme

Malate Dehydrogenase- Malate OXAL- The final reaction of the TCA cycle- Malate is oxidized to regenerate OXAL, NAD+ iis reduced to NADH- Reversible reaction

Amphibolic Nature of TCA Cycle- Acetyl-CoA fatty acids and sterols- Glutamate proteins & purines- Succinyl-CoA hemes, and chlorophylls- Citrate cholesterol- Alpha-ketoglutarate nucleotides- Malate pyruvate- OXAL glucose

Anaplerotic Reaction replenish intermediates in a metabolic pathway- Malate dehydrogenase

o Malate OXAL- Pyruvate carboxylase

o Pyruvate OXAL

BY the end of Krebs Cycle one molecule of glucose forms- 10 NADH- 2 FADH2- 4 ATP (although 2 more was produced during glycolysis it is cancelled because we invested 2 molecules of ATP)- 6 CO2

Summary of Glycolysis and TCA- Involved multiple ox/red reactions- Glucose is completely oxidized to Co2- A lot of nucleotides (NADH & FADH2) and some ATP are produced- Won’t stop unless oxidized nucleotides are regenerated

Chapter 10- Aerobic Respiration

Redox Reaction- LEO says GER

o Loss of electrons= oxidation Gain of oxygen

o Gain of electrons= reduction Loss of oxygen

- Redox between Cu and Fe are common - Oxidation (loss of electrons) of Malate to form OXAL (oxaloacetate)

o Releases NADH in the process

Reduction Potential - A measure of the affinity a substance has for electrons- A High reduction potential (E0) means that a substance has a high affinity for electrons

o Not likely to be oxidized (don’t want to loss electrons but gain them!)o Is likely to be reduced by other substanceso Is likely to be a good oxidizing agent

- When redox substances are mixed, electrons spontaneously flow from low to high reduction potential

Respiratory Electron Transport- A series of redox reaction associated with mitochondria where the electrons of reduced nucleotides produced in

glycolysis and the TCA cycle are transferred through a series of electron carries ultimately to oxygen to form H2O

- An electrochemical gradient is formed which is used to drive ATP synthesis- Occurs in the cristae membranes of mitochondria - Aka Electron Transport Chain- 10NADH+10H+¿+2 FADH 2+6O2−→10NAD

+¿+2FAD+12H 2O ¿ ¿

- FUNCTIONS:o Much ATP produced, little heat losso Regeneration of oxidized nucleotideso Aerobic respiration continues

Mitochondria Structure- Matrix—where TCA cycle occurs/ pyruvate procssesing- Cristae – the folds; where succinate deHAse and electron transport chain occurs- Inner Membrane—where the PDH complex is found

Review- 1 glucose 2 pyruvate 2 acteylCoA 2x TCA- Pyruate processing occurs in the matrix of the mitochondria- 1 glucose 2 pyruvate

- 2 NADH, 2 ATP- 2 pyruvate 2 AcetylCoA

- 2 NADH- 20 H+,

- 2 ActeylCoA 2 x TCA- 6 NADH, 2 FADH2, 2 ATP- 60 H+ from then 6 NADH; 12 H+ from the 2 FADH2

Complexes in Cristae Membrane to Add in Electron Transport- Membrane consists of bound proteins that do not move- Complex 1 NADH dehydrogenase complex

o All electrons in mitochondria goes to the first complexo Iron and sulfur containing proteinso Reduces NADH to form NAD+

- Complex 2 succinate dehydrogenase complexo Builds FADH2 o Similar in structure to complex 1 (include iron sulfur containing proteinso Succinate fumarate

- Complex 1 and 2 lead to CoQo CoQ= ubiquinoneo A small lipophilic molecule

- CoQ leads to complex III cytochrome complexo cytochrome c is reduced

- Cytc C moves electrons from complex III to complex IV- Complex 4 cytochrome C oxidase- Oxygen is releases from Complex IV

o Oxygen has the highest reduction potentialo The molecule that receives the electrons last has the highest reduction potential

- Electrons flow from low electron reduction potential to high (each complex has their own characteristic reduction potential)

Inhibitors of electron Transport- Rotenone insecticide produced by some leguminous plants; toxic to fish

o Kills by inhibiting respiratory transport before complex I (inhibits NADH)- Amytal a barbiturate drug; sometimes uses as a sedative or sleep-inducing agent for animals

o blocks electron transport from NADH to coenzyme Q at the same point as insecticide rotenone- Antimycin antibiotic for fungi; approves as a fishicide to kill fish for management purposes

o Stops electron transport between cyt band C of complex III- Carbon monoxide, cyanide and azide inhibits the last step of complex IV

o Preventing oxygen to be released

Cyanide Insensitive Respiration- The alternate oxidase in plants!- Produce a lot of pheromones to attract insects to pollinate on them - Found in the Voodoo Lily, Skunk Cabbage

- Maintains a warm temperature which allow it to grow under extreme conditions- Basically bypass the end of the ETC (bypass complex III and IV)- Don’t make as much ATP but its potential energy is given off as heat or smell.

- FUNCTIONS:o Little ATP producedo Much heat losso Fragrances are volatized, insect pollinators are attractedo Regeneration of oxidized nucleotideso Aerobic respiration continues

Stoichiometry of Respiratory Electron Transport- Higher H+ proton concentration in intermembrane space—lower pH

o Extremely acidic- Lower proton concentration in matrix – higher pH

o basic- 1 NADH (Krebs) 10 H+- 1 FADH2 6 H+- 1 ATP 4 H+

Electron Transport Results- The creation of a transmembrane proton gradient

o High proton concentration in intermembrane space and low in matrix want to push protons in - Three instances where reduction potential are sufficient to drive ATP synthesis

Brain/ Muscle 30 ATP- 2 NADH made from glycolysis complex 1 releases 12 H+- 8 NADH made from Krebs complex 1 releases 80 H+ (10 H+ = 1 NADH)- 2 FADH2 made from Krebs complex 2 releases 12 H+ ( 1 FADH2 = 6 H+)- TOTAL: 104 H+

Liver 32 ATP- 2 NADH made from glycolysis complex 1 releases 20 H+- 8 NADH made from Krebs complex 1 releases 80 H+- 2 FADH2 made from Krebs complex 2 releases 12 H+- TOTAL: 112 H+

Electro-Chemical Potential- Proton gradient represents electrical and chemical free energy- Electrical potential—refers to the charge differential across the membrane - Chemical potential—refers to the concentration differential across the membrane- Chemiosmotic coupling theory

o Chemical reactions (ATP synthesis) could be coupled to osmotic gradientso Electrochemical potential across the membrane provided the energy for ATP synthesis

The force that pushes the protons is called proton motive force

Chemiosomotic Theory- Energy derived from electron transport is temporarily stores as a transmembrane difference in charge (electrical

potential) and pH (chemical potential) - Protons can pass back through the inner membrane to the matrix only through specialized channels, ie the ATP

synthase protein- Return of protons back to matrix is coupled to ATP synthesis - Functions like a windmill– has channels for protons to move across

- This enzyme takes in 3 protons at a time through the channel and a fourth proton comes in through different method to form 1 ATP Called oxidative phosphorylation

o The only enzyme that does this!- Substrate level phosphorylation during glycolysis and krebs

Inhibitors of ATP synthesis- Dinitrophenol—uncoupler

o Toxic phenol, used as an insecticideo Human toxicity sympotoms including marked fatigue, elevated body temperature, cyaniso Dieting aid—burn carbs without ATP productiono Overheating

- Gramicidin—ionophoreo Antibiotic produced by Bacillus brevao Used to treat local topical infections

- They are proteins that are able to from channels and behave like ATP synthase- Compete with ATP synthase for protons—don’t make ATP but cause slowing down of ATP synthase- Lower ATP synthesis- fatigue and anemic

Uncoupled Mitochondria- Important in hibernating and cold adapted animals, new born infants- Thermogenin decreases the proton gradient by enabling protons to reenter the mitochondrial matrix without

taking part in ATP synthesis.- Norepinephrine stimulates the hydrolysis of fatty acids, which activate the uncoupler protein.- In non-shivering thermogenesis, heat is dispersed from the energy produced in electron transport.- ATP synthase can be bypassed in brown adipocytes.- Babies don’t need as much ATP but need heat- Protons accumulate but some shunt to uncoupler protein--- converting to heat- Found specifically in fat deposits - Thermogenin -uncoupler in babies, competes with ATP synthase by taking some of its protons and producing

heat

ATP synthase - 22 different subunits- F0 – stalk; embedded in the membrane- F1— sphere; easily dislodged/separated during isolation mobile, rotates like a turbine- For every 3 H+ that enter the ATP synthase machinery and get released into matrix, 1 ATP is synthesized and

released into the mitochondrial matrixo Where does the fourth protein come from?? Inorganic phosphate

- In total: 4 H+ needs to enter the matrix to make 1 ATP

Mitochondria require ADP and Pi- Phosphate translocator in membrane; uses proton gradient to drive Pi uptake

o H+ brings in inorganic phosphate molecule (Pi or H2PO4-)o Helps to drive ATP uptake

- ADP/ATP translocator uses antiport to drive ADP uptake and exchange for ATPo Antiport- minus and plus charge comes in together by neutralizing the chargeo Once formed ATP must leave

- Every day the mass of ATP that crosses the mitochondrial membrane is roughly equal to your body mass- 26 ATP in oxidative phosphorylation in brain/muscle plus 4 from glycolysis in substrate level phosphorylation =

30 ATP- 28 ATP in oxidative phosphorylation in liver plus 4 from glycolysis in substrate level phosphorylation= 32 ATP

External NADH is NOT directly Accessible to Electron Transport- Mitochondrial membranes are not permeable to NADH

- Two “shuttles” can transport NADH equivalentso Glycerol-3-phosphate shuttle in brain and skeletal muscleso Malate/Aspartate shuttle in liver

Glycerol-3-phophate Shuttle- In brain and skeletal muscle- How NADH tries to enter mitochondria in brain and muscle- DHAP reductase converted to glycerol-3-phosphate dehase- Alcohol made because easier to push G3P across membrane when it is converted to DHAP- Gives electrons to FADH2 in complex 2 (complex 2 will give to coenzyme)

Aspartate-Malate Shuttle- In liver tissue- Electrons from NADH goes to complex 1 when enters mitochoncris - Liver is more complex—but it is more efficient with ATP- NADH donates electron to OXAL- OXAL MALATE (reverse reaction )- Because it goes to OXAL it is complex 1 ****

And then to complex I

How much ATP Is produced by the complete oxidation of a hexose? Glycolysis produces 2 NADH / hexose + 2 ATP (net). Pyruvate deHase produces 2 NADH / hexose. TCA cycle produces 6 NADH + 2 FADH2 / hexose + 2 ATP. Yield of ATP is related to the site where electrons feed into the transport chain.

- One hexose… 30 ATP TOTAL

o 8 NADH—20 ATPo 2 FADH2—3 ATPo 2 NADH (glycolysis)—3 ATPo SLP—4 ATP