Linkage point for glycogen
alpha (1-->6)
Role of non reducing end of glucose
Breakdowns quickly, useful for rapid release of energy
Chitin
Unbranched repeating GlcNac
Strong material
EX of Glycosaminoglycans
Hyaluronic acid
Role of hyaluronic acid
fluid of joints, viscous solution, major component of cartilage
Proteoglycans
brings together chains of hyaluronic acid and chains coming off of glycosaminoglycan
Used in cartilage
What are biological processes thermodynamically driven by
All reactions favored by lowest energy state, maximum randomness
What is enthalpy
heat change @ constant pressure
Units of enthalpy
J/mol
Exothermic reaction and enthalpy sign
negative
What is entropy
Degree of randomness
Units of entropy
cal/K mol
What does T(delta)S measure
charge in randomness
What does (delta)S mean
increase in randomness
What is the second law of thermodynamics
change in entropy ? 0 for the universe
Equation for ?H
?H = ?E + P?V
What does enthalpy quantify?
Tendency to form bonds
Conversion of calories to joule
1 cal = 4.18 J
What does a positive ?S mean
increase in randomness
Why do free AA become folded polypeptides even though decreased randomness?
The universe has an overall increase in randomness and release heat
?G equation
?G = ?H = T?S
Sign of ?G predicts spontaneity
positive = endergonic, reverse reaction favored
negative = exergonic, forward reaction favored
Relationship between spontaneity and rate
no relation
Exergonic
flow of energy from system to the surrounding
Endergonic
flow of energy from surrounding into system
?G� standard conditions
[reactants] and [products] = 1M
gases 1 atm
Temperature = 298K
Functions of biological membranes
Selective permeability barrier
Organize complex reactions
Intracellular compartmentalization
Sensory transduction/amplification
4 things that make up liquid composition of membranes
P-lipid, sterol, sphingolipid, glycolipid
What do wedge shaped fatty acids form
micelles
What do cylindrical membrane lipids form
vesicles (lipid bi-layer)
Be able to recognize ATP and why it is important | Know part where chemistry happens
Adenine base, nitrogenous base, know bond names too
What leads to spontaneous assembly
hydrophobic interactions
VdW interactions
H-bonds
Important properties of membranes
self-sealing
highly impermeable to polar or charged molecules
Function of membrane proteins
some enzymes, permeases, ion channels, cell surface recognition, receptors for hormones
Role of permeases
uptake of metabolites
Integral membrane protein
embedded in lipid bilayer
how do you remove integral membrane proteins
detergent
What hold integral membrane proteins inside membrane.
held in membrane by hydrophobic interactions
Where are peripheral membrane proteins found
loosely bound to external portion of membrane
How do you remove peripheral membrane protein
high salt, urea
How is liquid anchored
peripheral but covalently bound to a membrane liquid
Fluid Mosaic Model of Membranes
integral proteins --> icebergs floating in 2D lipid sea
Fluid structure (though some proteins are immobile or have restricted movement)
Evidence of fluid mosaic model of membranes
lipids diffuse rapidly
Integral membrane proteins diffuse rapidly
Why a high energy of hydrolysis of phosphoanhydride bonds
electrostatic repulsion between O
Resonance stabilization of products
Ionization stabilization
Greater solvation of products
~P
high energy P
Phosphate group transfer potential
high energy vs low energy
ATP is in the middle (must donate and receive ~P)
?G of ATP hydrolysis differs from ?G� in a cell
Maintenance of asymmetry of membranes
Transverse diffusion of lipids is very slow
Transmembrane proteins do not flip
Factors affecting membrane fluidity
Degree of saturation
Length of fatty acid tail
Sterol content
Saturation :: Fluidity
Increase saturation = decrease fluidity
Length of tail :: Fluidity
Increase length of tail = decrease fluidity
Sterols at high temperature
Decrease fluidity, rigid sterol molecule restricts movement of lipid tails --> decreased permeability
Sterols at low temperature
Increase fluidity
Sterol prevents crystallization of membrane by blocking interactions between tails
Why is PEP energetic?
Take off ~P to form enol form which can tautomerize to keto form (more stable)
So direction always being driven to the right
1,3-bis-phosphoglycerate
Split ~P --> ionize new carboxyl group so resonance stabilization happens to stabilize products
What is the advantage of using
ATP over pyrophosphate as a major carrier of energy for a cell?
ATP is used over pyrophosphate because its more complex structure allows it to bind enzymes in multiple ways
What does phosphate group transfer potentials refer to>
Change in free energy that results in a reaction in which a phosphate bond is broken
What does comparing the values of phosphorylated compounds yield?
Information as to which ones may be useful to couple to spontaneous reactions
Why are metabolites phosphorylated?
The addition of this charged group retains the compound in the cell
The higher energy bond lowers the activation energy
Can be used to make ATP via substrate level phosphorylation
What does substrate level phosphorylation?
Transfer of a phosphate group from a metabolic intermediate to ADP directly through an enzymatic pathway
What is the non-catabolic function of glycolysis?
Production of substrates needed for anabolic reactions
If one function of glycolysis is to obtain energy in catabolism, why is ATP consumed in the first half of the pathway?
ATP is consumed in the first part of the pathway to prime the sugars so they can be broken down later into high energy compounds capable of producing more ATP than is initially used.
Given that many steps of glycolysis have an unfavorable (positive) ?G, why does glycolysis proceed in the cell when all enzymes are active?
Glycolysis proceeds because the products of the reactions are reactants in the next step in the pathway and are always kept at low levels. By the Law of Mass Action or Le Chatlier's principle, this drives reactions forward
What step in glycolysis commits metabolized glucose to the glycolytic pathway?
The non-catabolic function of glycolysis is the production of substrates needed for
anabolic reactions.
What is the key enzyme and how it is positively and negatively regulated? Normally a
regulated enzyme is inhibited by a downstream product; however, one of the allosteric
inhibitors of this enzyme is actually a substrate for the enzyme. Explain this appar
ATP is consumed in the first part of the pathway to prime the sugars so they can be
broken down later into high energy compounds capable of producing more ATP than is
initially used. Glycolysis proceeds because the products of the reactions are reactants
What is channeling and how does it increase the efficiency of glycolysis within a cell?
Metabolite channeling�some glycolytic enzymes associate with each other in a cell. It
increases the efficiency of glycolysis because the products of one enzymatic reaction are
very close to the next glycolytic enzyme. Chemically labile reactants are prote
What is the important functional difference between NADH and NADPH? Why do
these two different forms exist in cells?
NADPH is primarily used in anabolism. NADH is primarily used in catabolism. They
both exist in cells because even though they both act as electron acceptors and
donors,they serve different pathways, and because they are differentially recognized, this
all
Under what circumstances and why do some cells carry out fermentation?
Cells carry out fermentation under anaerobic conditions to regenerate NAD+. This
results in the rapid output of energy, because NAD+
quickly becomes available for
reduction to NADH
What needs of a cell can be provided by the pentose phosphate pathway? Which of
these cannot be provided by glycolysis?
The pentose phosphate pathway is primarily anabolic- it produces metabolic
precursors.
Some products that cannot be provided by glycolysis are NADPH, ribose-5-phosphate,
and erythrose-4-phosphate.
What do you suppose is the rationale that some athletes use in eating a high carbohydrate meal the evening before an event?
They hope to increase readily available energy stores by the breakdown of
carbohydrates through glycolysis and the TCA cycle.
Depending on the organism, sucrose can be cleaved to monosaccharides by either
hydrolysis (using the enzyme sucrase) or phosphorolysis (using sucrose phosphorylase).
(The latter is analogous to the reaction catalyzed by glycogen phosphorylase.) Calculate
First of all, since the conversion of pyruvate to ethanol does not yield any ATP, we
only need to be concerned with getting to pyruvate.
Using Sucrase:
1. Enzyme produces: glucose + fructose
2. To get to Fructose-1,6-bP takes: 4 ATP
3. Yield from rest of
If it were possible to label glucose with the radioisotope 14C at any position or combination of positions, which form or forms of labeled glucose would give the most radioactivity in CO2 and the least in ethanol when anaerobically catabolized? Which
labe
The carbon in the CO2 that is liberated in fermentation comes from the carboxylic
acid on pyruvate, which is either C3 or C4 from glucose. Labeling either of these carbons
would give the most radioactivity in CO2, and labeling any of the other carbons wou
had a final alcohol concentration of only1 0% (10 g / 100 ml). A good chardonnay usually has about 12-13% ethanol. What was the molar concentration of glucose or its equivalent in the initial grape juice before yeast was added? How many moles of sucrose p
The molecular weight of ethanol is 46. So a solution that is 10g/100ml of ethanol has
a concentration of (10/46)/0.1 L = 2.17 M. Because 1 glucose yields 2 ethanol, the starting concentration of glucose is half the final concentration of ethanol, or 1.085
. Given:
glucose ? 2 ethanol + 2 CO2
?Go' = -229 kJ / mol
glucose + 6 O2 ?6 CO2 + 2 H2O ?Go' = -2870 kJ / mol
ATP ? ADP + Pi
?Go' = -30.5 kJ / mol
Calculate the number of moles of ATP that could in principle be synthesized by the conversion of one mole of
The energy from one mole of ethanol is -2641/2 = -1320.5 kJ/mol. At 44% efficiency,
that energy value is reduced to 0.44 x (-1320.5) = -581 kJ/mol.
The number of ATP that would make is 581/30.5 = 19 ATP per ethanol, which is more
than the 15 ATP one gets
a) If the C-1 carbon of glucose were labeled with a 14C radioisotope and the
labeled glucose allowed to undergo glycolysis, which carbon atom on pyruvate would be
labeled? Why? b) Answer the same questions if the C-4 carbon were labeled.
a. C-3, the methyl carbon, on pyruvate would be labeled.
b. C-1, the carboxylic carbon, on pyruvate would be labeled.
The six carbons of glucose can be followed through glycolysis to see which carbons end
up where in the products. When fructose-1,6-bP get
Substrate level phosphorylation
Direct transfer of Pi from compound to ADP
Catabolism
Breakdown, energy yielding
Anabolism
Synthesis, energy requiring
Pathway
sequence of enzymatically catalyzed reactions
How many enzymes are in glycolysis?
10
What is the net reaction of glycolysis
Glucose + 2ADP + NAD+ + 2Pi ==> 2Pyruvate + 2ATP + 2NADH
What happens at the first stage of glycolysis
Priming and Splitting Reactions
1st Priming: Glucose + ATP --> Glucose-6-Phosphate + ADP
2nd Priming: Fructose-6-phosphate + ATP --> Fructose-1,6-bisphosphate
Splitting: Fructose-1,6-bisphosphate --> Glyceraldehyde-3-phsophate + Dihydroxyacetone phosphate
Reaction 1: Hexokinase what is the feedback inhibitor
Glucose-6-Phosphate
Regulated steps are highly
Exergonic
Why P'd Intermediates for glycolysis?
Retains in cell (charged)
Specificity of reaction: lower activation energy
Used to make ATP
Reaction 2 of glycolysis
Phosphoglucoisomerase
What is the role of phosphoglucoisomerase?
Keto-enol isomerization
Glucose --> fructose
What is the major control point of glycolysis?
Reaction 3: Phosphofructokinase
Conversion of Fructose 6-phosphate + ATP --> Fructose 1,6-bisphosphate
What is the rate limiting state of glycolysis?
PFK
What type of enzyme is PFK
Allosteric enzyme
What inhibits PFK
ATP (high energy status)
Citrate (downstream product)
What inhibit hexokinase?
The immediate down-stream product
What activates PFK
AMP and ADP (low energy status)
F2,6 bP (unusual compound)
Reaction 4 enzyme
Aldolase
What does aldolase do
Aldol cleavage
F-1,6-bP --> dihydroxyacetone phosphate + glyceraldehyde 3 phosphate
What is the enzyme for reaction 5?
Triosephosphate isomerase
What is the purpose of triosephosphate isomerase?
Simplifies pathway: 2 products are now one
What does a perfect enzyme means
Reaction is faster than it takes to uptake a substrate
Can never make it better
What is the second stage of glycolysis?
Harvesting energy
How is the energy of glucose oxidation stored?
ATP
NADH (aerobic only)
What is the enzyme of reaction 6 of glycolysis?
Glyceraldehyde-3-Phosphate Dehydrogenase
What is the only redox reaction in glycolysis?
Glyceraldehyde-3-phsophate to 1,3-bisphosphoglycerate
Oxidation = reduce or increase C
Reduce C
Is NAD+/NADP+ oxidized or reduced?
Oxidized
What is the enzyme for reaction 7 of glycolysis?
phosphoglycerate kinase
What happens at reaction 7?
Substrate-level phosphorylation
What is the enzyme for reaction 8?
Phosphoglyceromutase
What does phosphoglyceromutase do?
3-phosphoglycerate --> 2-phosphoglycerate
What is a mutase?
Type of isomerase that moves a functional group to another position
What is the enzyme of reaction 9 of glycolysis?
Enolase
What does enolase do
2-phosphoglycerate to phosphoenolpyruvate
What is the enzyme for reaction 10
Pyruvate Kinase
What is the role of pyruvate kinase
Rapid tautomerization to more stable keto
KNOW WHICH ARE THE HIGH ENERGY PHOSPHATE
...
Regulation of pyruvate kinase
Inhibitor: ATP (feedback inhibition)
Activator: F-1, 6bisP (feedforward activation)
Overall Free Energy change of Glycolysis
?G0 = -29.8
?G = -76.6 (in the cell)
Energy yield of glycolysis
Input = 2ATP
Output = 4ATP + 2NADH
Net Yield: 2ATP + 2NADH
Compartmentation of glycolysis
Occurs in cytosol
What is channeling
localized compartmentalization of enzymes
What does glycolysis produce?
Substrates for anabolic reactions
What is the alternative mode of glucose oxidation?
Pentose phosphate pathway
Why is pentose phosphate pathway primarily anabolic?
Produces precursos
NADPH: reductive biosynthesis
Ribose-5-P: nucleotides
Erythrose-4-P
Net reaction of Pentose Phosphate pathway
3 Glucose-6-P + 6NADP + 3H2O --> 6NADPH + 6H+ + 3Co2 + 2Fructose-6-P + Glyceraldehyde-3-P
Two phase of Pentose Phosphate Pathway
Oxidative: 2NADPH and ribulose-5-P
Non-oxidative rearrangements: ribose-5-P and fructose-6-P and glyceraldehyde-3-P
Is it possible to achieve net synthesis of oxaloacetate by adding acetyl CoA to a
mixture containing the enzymes and cofactors of the TCA cycle? Explain
No, because oxaloacetate is recycled during TCA and any oxaloacetate produced
would be used to consume more acetyl-CoA. The two carbons brought into the cycle by acetyl-CoA are eliminated as CO2. Addition of acetyl-CoA cannot produce any net TCA
intermedi
What is the function of the glyoxylate cycle and how does it differ from the TCA cycle?
The glyoxylate cycle nets oxaloacetate, and ultimately glucose, from precursors like
acetyl-CoA. This cycle stops the TCA cycle at isocitrate and goes through an alternate
pathway that doesn't lose the two carbons introduced by acetyl-CoA.
Succinate dehydrogenase activity is affected by oxaloacetate. Would you expect the enzyme activity to be enhanced or inhibited by oxaloacetate? Explain
Succinate dehydrogenase would be enhanced by oxaloacetate because a large amount of oxaloacetate would indicate that the cell can go through the TCA cycle and succinate dehydrogenase is an enzyme in the pathway.
Oxygen must be present in cells for the TCA cycle to progress; however, it is not an
intermediate or reactant in the cycle. Why is oxygen necessary for continued operation of
the TCA cycle?
O2 is needed because it is required for oxidative phosphorylation, the pathway to recycle NADH to NAD+
and FADH2 to FAD in aerobic environments. These recycling
events are where 2.5 ATPs are netted per 1 NADH and 1.5 per FADH2.
What are some of the problems of glycolysis?
Source of glucose
Fate of pyruvate
Necessity to regenerate NAD+
What does hydrolyzing sucrose form?
glucose and fructose
What does hydrolyzing lactose form?
glucose and galactose
What does hydrolyzing trehalose form?
2 glucose
What does hydrolyzing maltose form?
2 glucose
What is the role of alpha amylase
digest amylose or glycogen
What is the role of cellulase
digest cellulose
What is phosphorolysis
Conserves energy of glycosidic bond
Which enzymes debranch glycogen?
transferase and hydrolase
What is the phsophoglucomutase reaction of glycolysis
Enz-P G-1-P --> Enz::G-1,6-bis-P --> Enz-P + G-6-P
3 overall reactions for glycogen breakdown
RxN 1: glycogen phosphorylase
RxN 2: glycogen-debranching enzyme
RxN 3: phosphoglucomutase
Why is glycogen breakdown only 97% effective
Some glucose is also produced along with glucose-6-P
What is the net reaction of glycolysis?
[Glucose (alpha 1-->4)]n + Pi --> n[Glucose-6-P + some glucose]
What does pyruvate become in anaerobic conditions
2 Ethanol + 2CO2 OR 2 Lactate
What does pyruvate become in aerobic conditions?
2 Acetyl-CoA
What cycle does Acetyl Co-A enter?
Citric Acid Cycle
What does the citric acid cycle produce?
4CO2 + 4H2O
For the generation of ethanol what are the main reactions
RxN 1: pyruvate decarboxylase [pyruvate --> acetaldehyde + CO2]
RxN 2: alcohol dehydrogenase
[acetaldehyde --> ethanol]
Reduction so NAD+ is regenerated
What is the enzyme that converts pyruvate to lactate?
Lactate dehydrogenase
What does fermentation recycle
NAD+
What allows glycolysis to continue in absence of O2
Converting pyruvate to ethanol or lactate using NAD+
Where does glucose become pyruvate in a cell
cytosol
Where does pyruvate become CO2 in a cell
mitochondria
Is ATP produced under anaerobic or aerobic conditions?
Aerobic
What step is oxidative decarboxylation
conversion of pyruvate to acetyl-CoA
What is required to convert pyruvate to acetyl CoA
CoA-SH + NAD+
TPP, lipoic acid, FAD
How many coenzymes are there in the pyruvate dehydrogenase complex?
5
Which enzymes are freely diffusible in the pyruvate dehydrogenase complex
Coenzyme A
NAD+
Which enzymes are tightly non-covalently bound in the pyruvate dehydrogenase complex
Thiamine pyrophosphate (TPP)
FAD
What enzymes are covalently linked to enzyme in the pyruvate dehydrogenase complex
Lipoic acid
How many enzymes are there in the pyruvate dehydrogenase complex
3
What remains from glucose in acetyl-coenzyme A
Acetyl group bound to S
Why is there a high energy bond in Acetyl-CoA
Ionization and resonance
For FADH2 which enzymes are reduced
N1 and N5
Do you need or produce ATP when converting carbohydrates to pyruvate
need ATP
Do you need or produce ATP when converting fats to acetyl CoA
Need ATP
What is the central energy-yielding pathway?
TCA cycle = citric acid
What produces the source of precursors for anabolic pathways
TCA cycle
What does it mean when intermediates are catalytic
Recycled
What is the net reaction of the TCA cycle
Acetyl CoA + 2H2O + 3NAD+ + FAD + GDO + Pi --> CoA + 3NADH + FADH2 + 3H+ + GTP
What steps produce NADH in TCA
Step 3 and 4: oxidative decarboxylation
Step 8: dehydrogenation
What steps produce ATP in TCA
Step 5: substrate level phosphorylation
What steps produce FADH2 in TCA
Step 6: dehydrogenation
What is the purpose of lipoproteins?
Lipoproteins allow easy transport of fat through the blood stream.
What is the basic structure of lipoproteins?
Inner core = non polar cholesterol and lipid
Outer core = phospholipids and proteins with hydrophilic heads facing water
Where is TAG carried in lipoproteins?
In inner core
Why do animals store most energy as fat instead of glycogen or protein?
Fat has more energy per gram than protein or carbs
Highly reduced so stored without water
How does the beta-oxidation of fatty acids lead to an increase in the amount of ATP available in the body?
By production of acetyl-CoA which enters TCA
What is the purpose of lipase?
releases fatty acids from triglycerides
How are fatty acid breakdown and synthesis compartmenatilized in a cell?
fatty acid synthesis happens in the cytosol while breakdown takes place in mitochondria
How is the double bond in an unsaturated fatty acid dealt with during the beta-oxidation cycle?
The double bond is rearranged and then hydrated into a single bond
What conditions are necessary for the coupled processes of electron transport and oxidative phosphorylation to occur?
Aerobic conditions
Where does oxidative phosphorylation take place within the mitochondrion?
inner membrane of mitchondria
Why does TCA require aerobic conditions?
O2 acts as electron acceptor from electron transport chian
How does electron transport transfer electrons from NADH to O2?
Through a chain of carriers that ends in the production of water
Why is the transfer of electrons from NADH to O2 useful in a cell?
each time the electrons are transferred to another intermediate in the pathway, free energy is produced the can be used to synthesize ATP
What compounds make up the mobile carriers in the electron transport chain?
NADH, Coenzyme Q, cytochrome C
O2 is the ultimate acceptor
Which complex in the electron transport system leads to the consumption of O2 to water?
Complex IV leads to the conversion
Describe a method used to experimentally determine the sequence of electron carriers in the electron transport system.
1) Determine redox potentials of the intermediates and order them by strength
2) Measure the production of reduced forms of the intermediates over time using the different absorption spectra of reduced and oxidized forms
3) use stage specific inhibitors a
How many ATPs does palmitic acid yield?
106 ATP
What are the reactants to form acetoacetyl-CoA
ketone body acetoacetate and succinyl-CoA which also forms succinate
What does thiolase do?
Cleaves acetoacetyl-CpA into two acetyl-CoAs
How much ATP is produced from acetoacetyl-CoA
20 ATP
How much energy does it cost to convert ADP to ATP
30.5kJ/mol
What is the primary way hydrogen is lost from fatty acids?
Form of NADH, FADH2, H+ ions
Why is the oxidation of succinate to fumarate associated with the production of only 1.5 ATPs during oxidative phosphorylation while the oxidation of malate to oxaloacetate is associated with the production of 2.5 ATPs?
Succinate to fumarate yields FADH2, while the oxidation of malate to oxaoloacetate yields NADH.
All intermediates of TCA are ____
catalytic
What is the enzyme for reaction 2 of TCA
aconitase
What is reaction 2 of TCA
citrate --> cis-aconitate --> d-isocitrate
What is the enzyme for reaction 3 of TCA
Isocitrate dehydrogenase
Where is the first oxidative decarboxylation of TCA
Reaction 3
What is reaction 3 of TCA
isocitrate --> oxalosuccinate --> alpha-ketoglutarate
What is reaction 4 of TCA
Alpha-ketoglutarate --> succinyl-CoA
Where is the second oxidative decarboxylation of TCA
reaction 4
Why is the alpha-ketoglutarate dehydrogenase complex analgous to pyruvate dehydrogenase reaction
uses same 5 coenzymes
What is reaction 5 of TCA
succinyl-Coa --> succinate
What is the enzyme for reaction 5 of TCA
succinyl CoA synthetase
What does substrate level phosphorylation produce in reaction 5 of TCA
GTP
What is reaction 6 of TCA
succinate --> fumarate
What is the enzyme for reaction 6 of TCA
succinate dehydrogenase
Is flavoenzyme an electron donor or acceptor
acceptor
What is reaction 7 of TCA
fumarate --> L-malate
What is the enzyme of reaction 7 of TCA
fumarase
What is reaction 8 of TCA
L-malate to oxaloacetate
What is the enzyme of reaction 8 of TCA
malate dehydrogenase
What is the important regulation of TCA
NAD+ ratio to NADH
If low ratio of NAD+/NADH
cell is starving, do not inhibit
Lots of electron rich
Substrate availability
Regulation based on amount of substrate level
Why low levels of substrates in TCA
amphibolic
What is amphibolic
...
Go learn the regulation of TCA Cycle
...
What is citrate used for
starting substrate of tca cycle but also can produce fatty acids, sterols
What can alpha-ketoglutarate be used for not in TCA
become glutamate which can produce other amino acids and purines
What can succinyl-CoA be used for
Heme, chlorophyll, TCA intermediate
What can malate be used for
pyruvate, TCA intermediate
What can oxaloacetate be used for
convert to aspartate to produced other maino acids, purines, pyrimidines
Can become phosphoenol pyruvate
What can pyruvate of phosphoenol pyruvate be used to make
carbohydrates
Which reactions can replenish TCA
pyruvate carboxylase, PEP carboxykinase, PEP carboxylase, Malic enzyme
Reaction using pyruvate carboxylase
Pyruvate + HCO3- + ATP <-> oxaloacetate + ADP + Pi
Reaction using PEP carboxykinase
PEP + CO2 + GDP <-> oxaloacetate + GTP
Reaction using PEP carboxylase
PEP + HCO3- <-> oxaloacetate + Pi
Reaction using malic enzyme
pyruvate + HCO3- + NAD(P)H <-> malate + NAD(P)+
What is the glyoxylate cycle
Ac-S-CoA to oxaloacetate
Can mammals do glyoxylate cycle?
No
Where does glyxoylate cycle occur
glyoxysomes
What happens in glyoxylate cycle?
By pass steps where CO2 is lost
Net reaction of glyoxylate
2Ac-CoA + NAD+ --> succinate + NADH + H+ + 2CoA
Role of isocitrate lyase
Part of glyoxylate cycle
Isocitrate to succinate + glyoxylate
Role of malate synthase
glyoxylate + acetyl-CoA --> malate
Why does fat store so well
it is not hydrated
What carries TAG through blood stream
Lipoproteins
Example of LDL
chylomicron
Structure of transporting TAG
Tag inside and polar lipids/proteins on surface
Micelle like
What frees FA from TAG
lipases
Where does lipase lyse triacylglycerol
C-O bond of ester
Where are FA activated
inside cell
What activates FA
AMP
RCOO- + ATP + CoA -->
RCO-CoA + AMP + PPi
What does pyrophosphatase do?
Hydrolysis of PPi
What prevents build up of PPi in cell
Pyrophosphatase
What drives FA activation to the right?
Pyrophosphatase splitting PPi
What prevents FA from leaving cell
Activation
How does fatty acids enter into inner mitochondria
antiport where carnitine is exchanged for acyl carnitine
Where does FA degradation occur
mitochondrial matrix
Where does FA synthesis occur
cytosol
AcylCoA in mitochondira is converted into what to enter?B
acylcarnitine
What is the knoop experiment
beta-oxidation occurs at beta carbon
Stepwise breakdown by 2-carbon units
What is the tracer for knoop experiment
phenol group
What proved that it is 2 carbon breakdown in Knoop experiment
There was odd and even number carbons
What is reaction 1 of beta oxidation
acetyl-CoA --> trans-?2-enoyl-CoA + FADH2
What is FAD --> FADH2 known as
oxidative phosphorylation
What type of reaction is R1 of Beta oxidation
dehydrogenation (oxidation)
What is reaction 2 of beta-oxidation
trans-?2-enoyl-CoA --> L-3 hydroxy acyl coA
What type of reaction is R2 of beta-oxidation
hydration
What type of reaction is R3 of beta-oxidation
dehydrogenation
What type of reaction is R4 of beta-oxidation
thiolytic cleavage
What is reaction 3 of beta oxidation
...
What is reaction 4 of beta oxidation
...
How much ATP does it take to activate FA
2 ATP
What is most of energy from in the cell
glyxolysis, TCA and fatty acid oxidation
What is ATP initially harvested as
NADH and FADH2
How does NADH and FADH2 become ATP
electron transport and oxidative phosphorylation
Evidence of Chemiosmotic Theory
IM impermeability to H+'s and other ions
ET causes H+'s to be transported
Elimination of pH gradient by uncouplers blocks ATP synthesis
Artificial electrochemical gradient-> Atp synthesis