Term
| Physiological roles of fatty acids |
|
Definition
-Fuel molecules
-Building blocks
-Covalent modification of proteins
-Hormones and intracellular messengers |
|
|
Term
| How are fatty acids stored for fuel? |
|
Definition
|
|
Term
| Fatty acids serve as the building blocks for... |
|
Definition
| Phospholipids and glycolipids |
|
|
Term
| Fatty acids covalently modify proteins for... |
|
Definition
|
|
Term
| Fatty acid ______ serve as hormones and intracellular messengers. |
|
Definition
|
|
Term
| Order of reaction TYPES in fatty acid degradation |
|
Definition
| Oxidation->Hydration->Oxidation->Cleavage |
|
|
Term
| Order of reaction TYPES in fatty acid synthesis |
|
Definition
| Condensation->Reduction->Dehydration->Reduction |
|
|
Term
| Triacylglycerols are highly concentrated... |
|
Definition
|
|
Term
| Why do triacylglycerols have so much energy? |
|
Definition
| They are a REDUCED carbon source (good electron donor) |
|
|
Term
| Compare the energy output of fatty acids vs. proteins and carbohydrates |
|
Definition
38 kJ g-1 fatty acids
17 kJ g-1 proteins/carbs |
|
|
Term
| _____ character of triacylglycerols results in nearly _____ storage. |
|
Definition
|
|
Term
| Triacylglycerol increases the energy per dry weight to ____ times over carbohydrates. |
|
Definition
|
|
Term
| Glycogen stores sustain function for ~24 hours vs. triacylglycerol stores that sustain function for... |
|
Definition
|
|
Term
| Triacylglycerols are degraded to ____ for absorption |
|
Definition
|
|
Term
| How do lipases gain access to insoluble substrates? |
|
Definition
| Triacylglycerols are presented to lipases on the surface of micelles, i.e., ester head groups on surface with tails buried on micelle interior |
|
|
Term
| Micelles are formed by... |
|
Definition
|
|
Term
|
Definition
-are amphipathic
-are secreted from the gall bladder
-are synthesized from cholesterol
-aid in the formation of micelles, orienting ester head groups |
|
|
Term
| Deficient production of bile salts due to liver disease leads to... |
|
Definition
| large amounts of fats in the feces |
|
|
Term
| Three ways fatty acids are used as fuel... |
|
Definition
-Mobilization of triacylglycerols within adipocytes and conversion to free fatty acids and glycerol followed by transport to energy-requiring tissues
-Activation of fatty acids and transport into mitochondria
-Stepwise fatty acid degradation forming acetyl CoA, which feeds into the citric acid cycle |
|
|
Term
| In hormonal signaling leading to lypolysis, what are the activators? |
|
Definition
|
|
Term
| In hormonal signaling leading to lypolysis, what is the inhibitor? |
|
Definition
|
|
Term
| What is perilipin and what does it do? |
|
Definition
| It is a fat droplet associated protein which makes triacylglycerols more accessible and triggers release of ATGL coactivator |
|
|
Term
| Glycerol is taken up by the ____, phosphorylated, and brought into the glycolytic or gluconeogenic pathway (to form glucose or pyruvate) |
|
Definition
|
|
Term
| Is it possible to form glycerol from DHAP? |
|
Definition
|
|
Term
| When making acyl CoA, what is the first step and where does it occur? |
|
Definition
Reaction of fatty acid with ATP to give acyl adenylate intermediate
Occurs in outer mitochondrial membrane |
|
|
Term
| Essentially reversible reactions are made irreversible by ____ |
|
Definition
| the hydrolysis of pyrophosphate |
|
|
Term
| When making acyl CoA, what is the second step? |
|
Definition
| attack on the tightly bound acyl adenylate intermediate by the sulfhydryl of CoA--yields activated acyl CoA |
|
|
Term
| What is acyl carnitine ester formed from? |
|
Definition
|
|
Term
| Acyl carnitine translocase exchanges incoming ____ for outgoing ____ |
|
Definition
|
|
Term
| _____ character of carnitine gives rise to its high group-transfer potential |
|
Definition
|
|
Term
| Impairment of acyl carnitine translocase action can give rise to... |
|
Definition
pathological condition
-cramping, muscle weakness, death
-primarily in muscle, kidney, and heart
-medium chain can be processed normally |
|
|
Term
| What are the recurring four reactions in B-oxidation pathway? |
|
Definition
Oxidation by FAD
Hydration
Oxidation by NAD+
Thiolysis by CoA |
|
|
Term
| What are the products of B-oxidation? |
|
Definition
NADH
FADH2
Acetyl CoA
Fatty acid shorter by two carbon atoms |
|
|
Term
| The oxidation of acyl CoA is catalyzed by _____ to give ______ with a ____ bond between C-2 and C-3 |
|
Definition
acyl CoA dehydrogenase
enoyl CoA
trans |
|
|
Term
| In first step of B oxidation, FADH2 electrons are transferred to _____ |
|
Definition
| ETF (electron-transferring flavoprotein) |
|
|
Term
| ETF donates electrons to ______ and then ___ is reduced to ____ |
|
Definition
ETF ubiquinone reductase
ubiquinone
upiquinol |
|
|
Term
| How many ATP are generated per FADH2 in B oxidation? |
|
Definition
|
|
Term
| The hydration of the trans double bond in B-oxidation is catalyzed by ______ |
|
Definition
|
|
Term
| Hydration in B-oxidation is _____ |
|
Definition
|
|
Term
| Hydration of the trans double bond in B oxidation results in _____ |
|
Definition
| L isomer of 3-hydroxyacyl CoA |
|
|
Term
| Hydration of the cis double bond in B oxidation results in _____ |
|
Definition
| D isomer of 3-hydroxyacyl CoA (rare) |
|
|
Term
| The oxidation of the alcohol to a ketone in B-oxidation is catalyzed by ____ |
|
Definition
| L-3-hydroxyacyl CoA dehydrogenase |
|
|
Term
| How many ATP result from each NADH (via electron transport chain)? |
|
Definition
|
|
Term
| The cleavage of 3-ketoacyl CoA by thiol group is catalyzed by ____ |
|
Definition
|
|
Term
| Acetyl CoA gives how many ATP? |
|
Definition
|
|
Term
| Define long-chain, medium-chain, and short-chain |
|
Definition
Long: 12-18 C
Medium: 4-14 C
Short: 4-6 C |
|
|
Term
| Acyl CoA dehydrogenase is unique because it is sensitive to ____ |
|
Definition
|
|
Term
| Which two enzymes are also required for the oxidation of unsaturated fatty acids? |
|
Definition
cis (delta)3-Enoyl CoA isomerase
2,4-Dienoyl CoA reductase |
|
|
Term
| Propionyl CoA carboxylase is a ___ requiring enzyme homologous to ____ |
|
Definition
biotin
pyruvate carboxylase |
|
|
Term
| Which enzyme uses vitamin B12 to catalyze an intramolecular rearrangement via group migration? |
|
Definition
|
|
Term
| Another name for Vitamin B12? |
|
Definition
|
|
Term
| Unique groups on vitamin B12? |
|
Definition
|
|
Term
| What is the purpose of vitamin B12? |
|
Definition
A biological source of free radicals
Coenzyme |
|
|
Term
| Which three reactions is B12 a coenzyme for? |
|
Definition
Intramolecular rearrangements
Methylations
Reduction of ribonucleotides to deoxyribonucleotides |
|
|
Term
| Methylmalonyl CoA catalyzes______ |
|
Definition
| an intramolecular rearrangement reaction |
|
|
Term
| In the intramolecular rearrangement reaction catalyzed by methylmalonyl CoA, what exchange happens? |
|
Definition
| Exchange of two groups on adjacent carbons, in this case a hydrogen for a thioester |
|
|
Term
| In the methylmalonyl CoA reaction, what happens first? |
|
Definition
| Homolytic cleavage of the carbon-cobalt bond to give Co2+ (cobalamin) and 5'-deoxyadenosyl radical |
|
|
Term
| Coenzyme B12 in intramolecular migration serves as a _____ to drive the ______ |
|
Definition
source of free radicals
abstraction of hydrogen atoms |
|
|
Term
| What does the CH2 radical do in the methylmalonyl CoA reaction? |
|
Definition
| Pulls hydrogen from the substrate yielding a substrate radical |
|
|
Term
| The yielding of a substrate radical in the methylmalonyl CoA reaction induces ___ |
|
Definition
| an intramolecular rearrangement (carbonyl CoA) |
|
|
Term
| The new substrate radical in the methylmalonyl CoA reaction does what? |
|
Definition
| abstracts hydrogen from 5'-deoxyadenosine methyl group |
|
|
Term
| ______ is an essential feature of coenzyme B12 |
|
Definition
|
|
Term
| Enzyme ___ residue displaces benzimidazole |
|
Definition
|
|
Term
| The displacement of benzimidazole facilitates.... |
|
Definition
| cobalt-carbon bond cleavage and hydrogen abstraction |
|
|
Term
| _____ contributes to bond weakness in cobalt-carbon bond |
|
Definition
|
|
Term
| Fatty acids can also be oxidized in ____ |
|
Definition
|
|
Term
| FA oxidation stops at _____ |
|
Definition
|
|
Term
| The initial dehydrogenation reaction in peroxisomes is catalyzed by ____ to give ____ |
|
Definition
|
|
Term
| High _____ concentration within peroxisomes |
|
Definition
|
|
Term
| ____ is caused by dysfunctional peroxisomes due to enzyme importing defect |
|
Definition
|
|
Term
| Acetyl CoA can only enter TCA cycle if ____ is available |
|
Definition
|
|
Term
| In fasting or diabetes, ______ consumes oxaloacetate |
|
Definition
|
|
Term
| ______ can be diverted to form ketone bodies |
|
Definition
|
|
Term
| Three examples of ketone bodies |
|
Definition
-Acetoacetate
-D-3-hydroxybutyrate
-Acetone |
|
|
Term
| ______ combines two acetyl CoA to form _______ |
|
Definition
3-ketothiolase
acetoacetyl CoA |
|
|
Term
| _______________ formed from acetyl CoA and acetoacetyl CoA to give _________ and _ |
|
Definition
Hydroxymethylglutaryl CoA synthase
3-hydroxy-3-methylglutaryl CoA (HMG-CoA)
CoA |
|
|
Term
| Which enzyme in ketone body formation is similar to citrate synthase? |
|
Definition
| hydroxymethylglutaryl CoA synthase |
|
|
Term
| Which reaction in ketone body formation is the reverse of thiolysis in FA oxidation? |
|
Definition
| 3-ketothiolase combining two acetyl CoA to form acetoacetyl CoA |
|
|
Term
| What is the net reaction for ketone body formation? |
|
Definition
| 2 acetyl CoA + H2O -> acetoacetate + 2 CoA + H+ |
|
|
Term
| D-3-hydroxybutyrate is formed from... |
|
Definition
| reduction of acetoacetate in mitochondrial matrix by D-3-hydroxybutyrate dehydrogenase (subject to NADH availability) |
|
|
Term
| _____ is the major site of ketone body production (3-hydroxybutyrate and acetoacetate) |
|
Definition
|
|
Term
| What is the preferred energy source for heart muscle and renal cortex? |
|
Definition
|
|
Term
| Brain prefers ____ as a fuel source, but can use ____ when starved |
|
Definition
|
|
Term
| What is the first step in utilization of ketone bodies? |
|
Definition
| Activation by CoA transfer from succinyl CoA |
|
|
Term
| Succinyl CoA is ____ in the liver |
|
Definition
|
|
Term
| Acetoacetyl CoA is cleaved by a ____ to yield 2 acetyl CoA |
|
Definition
|
|
Term
| _______ is oxidized to acetoacetate |
|
Definition
|
|
Term
| High acetoacetate ____ lipolysis by adipose tissue |
|
Definition
|
|
Term
| What happens to the blood if there are excess ketone bodies present? |
|
Definition
| pH drops, coma and death can result |
|
|
Term
| Insulin-dependent diabetes mellitus can lead to... |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Steps leading to acidosis in diabetic ketosis: |
|
Definition
-Insulin signals glucose uptake (deficit means liver cannot uptake glucose to provide oxaloacetate to process fatty-acid derived acetyl CoA)
-Decreases fatty acid mobilization by adipose tissue (FA continue to be released, taken up by liver, and converted to ketone bodies)
-Leads to acidosis, affecting tissue function |
|
|
Term
| Ketogenic diets are rich in ____ and low in ___ with some protein, forcing ketone bodies as main fuel source |
|
Definition
|
|
Term
| Fatty acid synthesis takes place in the ____ |
|
Definition
|
|
Term
| Fatty acid intermediates are covalently linked to... |
|
Definition
| sulfhydryl group of an acyl carrier protein (ACP) |
|
|
Term
| The association of synthetic enzymes in FA synthesis is catalyzed by... |
|
Definition
|
|
Term
| FA chain is elongated by _ carbons at a time in synthesis, driven by _____ |
|
Definition
2
malonyl CoA decarboxylation |
|
|
Term
| _____ serves as the reductant in FA synthesis |
|
Definition
|
|
Term
| The defaul production of FA synthesis is of ______ |
|
Definition
|
|
Term
| What is the committed step in FA synthesis? |
|
Definition
|
|
Term
| The carboxylation of acetyl CoA in the formation of malonyl CoA is catalyzed by... |
|
Definition
|
|
Term
| Biotin prosthetic group attached to ____ |
|
Definition
|
|
Term
| Carboxybiotin intermediate formed through ____ |
|
Definition
|
|
Term
| In the ACP, ______ group attached to a serine residue contains a terminal ___ |
|
Definition
|
|
Term
| Fatty acid synthase in bacteria can be ___ |
|
Definition
| dissociated into individual components |
|
|
Term
| Malonyl transacylase is _____ |
|
Definition
|
|
Term
| Acetyl transacylase can transfer ____ |
|
Definition
| acyl groups other than acetyl |
|
|
Term
| What two compartments make up mammalian fatty acid synthase? |
|
Definition
| Modification, selecting and condensing |
|
|
Term
| Carnitine only carries ____ |
|
Definition
|
|
Term
| ____ acts as a carrier of acetyl groups across the inner mitochondrial membrane |
|
Definition
|
|
Term
| What drives transport from mitochondria to cytoplasm? |
|
Definition
| High citrate concentration |
|
|
Term
| What is the default fatty acid? |
|
Definition
|
|
Term
| Where does elongation occur? |
|
Definition
| Cytoplasmic face of the ER membrane |
|
|
Term
|
Definition
| Adds two carbon units to carboxyl end of saturated and unsaturated FAs |
|
|
Term
| What drives elongation of FAs? |
|
Definition
| decarboxylation of malonyl CoA |
|
|
Term
| What catalyzes unsaturation of FAs? |
|
Definition
|
|
Term
| What substrates are needed for FA unsaturation? |
|
Definition
molecular oxygen
NADH or NADPH |
|
|
Term
| Unsaturation is catalyzed by three membrane-bound proteins. What are they? |
|
Definition
NADH-cytochrome b5 reductase
Cytochrome b5
Desaturase |
|
|
Term
| What does NADH-cytochrome b5 reductase do? |
|
Definition
| NADH reduces bound FAD coenzyme |
|
|
Term
| ____ of cytochrome b5 is reduced to ____ to form desaturase |
|
Definition
|
|
Term
| In desaturase, the ____ is reduced to Fe2+. It interacts with ___ and ____, and a double bond is formed with the production of____ |
|
Definition
non-heme iron
O2
fatty acyl CoA
two H2O molecules |
|
|
Term
| Unsaturated FAs are derived from... (4 answers) |
|
Definition
palmitoleate (16:1)
oleate (18:1)
linoleate (18:2)
linolenate (18:3) |
|
|
Term
| Other unsaturated FAs formed by... |
|
Definition
| various combinations of elongation and desaturation reactions |
|
|
Term
| Mammals cannot incorporate double bonds at carbons beyond... |
|
Definition
| C-9 (linoleate and linolenate) |
|
|
Term
| Essential FAs must be obtained from... |
|
Definition
|
|
Term
| Arachidonate (20:4) is derived from... |
|
Definition
|
|
Term
| _____ are derived from arachidonate |
|
Definition
|
|
Term
| What are eicosanoid hormones? |
|
Definition
Short range or local hormones
Act on producing cell or neighboring cells
Effects vary from one cell to another |
|
|
Term
| Examples of eicosanoid hormones? |
|
Definition
| Prostaglandins, Thromboxanes, Prostacyclin |
|
|
Term
| Aspirin blocks _____, blocking downstream eicosanoid production and their effects (ie: inflammation, fever, pain, blood clotting) |
|
Definition
| prostaglandin H2 synthase |
|
|
Term
|
Definition
20-carbon FA containing 5-membered ring
Modified by reductases and isomerases
9 classes (A-I), subscript denotes # of double bonds |
|
|
Term
|
Definition
| derived from prostaglandins by prostacyclin synthases |
|
|
Term
|
Definition
| derived from prostaglandins by thromboxane synthases |
|
|
Term
|
Definition
| catalyzed by lipoxygenase |
|
|
Term
| ____ is the key enzyme in the regulation of FA metabolism |
|
Definition
|
|
Term
| Acetyl CoA carboxylase is inactivated by |
|
Definition
|
|
Term
| AMP-dependent protein kinase (AMPK) modifies... |
|
Definition
|
|
Term
| AMPK is activated by ___ and inhibited by ___ |
|
Definition
|
|
Term
| Acetyl CoA carboxylase is activated by _____ |
|
Definition
|
|
Term
| Acetyl CoA carboxylase is allosterically stimulated by... |
|
Definition
|
|
Term
| Citrate induces _____, overcoming inhibition by phosphorylation |
|
Definition
| polymerization into filaments |
|
|
Term
| Palmitoyl CoA inhibits... |
|
Definition
by inducing filament dissociation
Citrate translocase
Glucose 6-phosphate dehydrogenase |
|
|
Term
|
Definition
| carnitine acyltransferase I, especially in heart and muscle |
|
|
Term
| Glucagon and epinephrine... |
|
Definition
-Stimulate release of FAs from triacylglycerols in adipocytes
-Inhibit FA synthesis by inhibiting acetyl CoA carboxylase (augment inhibition by AMPK) |
|
|
Term
|
Definition
-Inhibits FA mobilization
-Stimulates deposition as triacylglycerols in muscle and adipocytes
-Activates acetyl CoA carboxylase by stimulating phosphatase |
|
|
