Lipids II Flashcards
Generation of Energy through Ketogenesis
Ketone bodies provide ____ energy than glucose because they enter the TCA ____. In liver, much of energy generated as Acetyl CoA is used to synthesize ____.
less
later
ketone bodies
Useful Definitions
Ketogenesis-process by which ketone bodies are ____. ____ after meal
____-metabolic state where most of the body’s energy comes from ketone bodies in blood.
Ketoacidosis-decrease in blood ____ due to ketone body dissociation-most often in ____ or ____ because ketone not adequately used as fuel
Amino acids that produce ____ or ____ are
Ketogenic:
they are Isoleucine ____, Phenylalanine, Tyrosine , ____, Leucine and ____

produced
12hours
ketosis
pH
diabetics
alcoholics
acetyl CoA acetoacetate threonine tryptophan lysine
Ketone Body Formation in Liver Mitochondria
Thiolase. The final step of the β- oxidation pathway runs ____
The liver is able to ____ ketone bodies but does not contain the enzymes to ____ them down for fuel- formation of ketone bodies is a mechanism by which the liver gets rid of ____ it does not need
backward
synthesize
break
fuel
ketone bodies formed in liver ____
liver = ____; provides energy to the body at its own expense; doesn’t have any of the enzymes in order to break it down
ketone body formation; similar to ____
formation of acetyl coA; intermediate in ____ metabolism
mitochondria
altruistic
b-oxidation
cholesterol
Regulation of Ketogenesis (REWATCH)
1. Increase in supply of ____ as high glucagon/insulin
- Malonyl CoA inhibition of CPT1 ____ (inactivation of ____)
- β-oxidation ____, ____ NADH and FADH2 enough ATP to supply energy needs of liver
- ____ converted to ____- enters cytosol for gluconeogenesis. ____ citrate synthase activity
- Acetyl CoA from ____ into ketogenesis
FA lifted acetyl CoA carboxylase high high OAA malate low TCA
Utilization of ketone bodies as fuel
Ketone bodies are utilized by the ____ and to a much larger extent ____ and ____.
Can be used by ____.
Can cross placenta and be used by ____.
CANNOT be used by ____ and ____
heart brain intestinal mucosa fetus liver RBC
FA Synthesis
when we will synthesize FA > high ____, ____ > anabolic, synthesize
longer, more unsaturated, the more the ____
blood glucose
insulin
energy
Catabolic-process are ____, ____, ____ of energy
Anabolic- processes are ____, ____, ____ of energy
oxidative
LEO
production
reductive
GER
utilization
Fatty acid synthesis
Fatty acids used for fuel originate from
____ lipids
Fatty acids released from ____ in adipocytes
Synthesized in liver and delivered by ____
____ lipoprotein deliver FA for storage in adipocytes; dietary FA in ____
ingested
storage
lipoproteins
VLDL
chylomicrons
Role of Liver in Metabolism
• When blood glucose levels are ____ the liver synthesizes fatty acids which are delivered by ____ to other tissues. In times of excess caloric intake lipids can be synthesized from carbons obtained from ____ (mostly glucose and fructose) or ____.
• Fatty acids are the major ____ in the liver.
high lipoproteins carbohydrates proteins oxidative fuel
Fatty Acid Synthesis
Features
• Location: ____.
• Building blocks: ____ units (____)
derived mostly from carbohydrates, sometimes proteins.
• Reducing equivalent: ____ (electron donor)
• Energy Source: ____
• Fatty acids are highly reduced compounds therefore their synthesis requires enormous ____ input.
• The product, 16 C, palmitic acid, is the ____ for the synthesis of longer chain and monounsaturated fatty acids.
• Fatty acid synthesis is regulated ____ and through ____ modification and long term by ____
(FA beta oxidation is hardly regulated by ____)
cytosol acetate acetyl CoA NADPH ATP
energy precursor allosterically covalent gene expression gene expression
Challenges of Synthesis
• The building blocks for synthesis are made in the ____, synthesis occurs in ____.
• Building blocks are ____ units and product is large ____ compound.
• Energy requiring process- where do we obtain reducing equivalents (NADPH)?
• Since it requires so much energy how do we regulate the process?
• How do we add double bonds? What does this cost the system?
mitochondrial matrix
cytosol
small water soluble
hydrophobic
High Fructose-corn syrup
• Conversion of Fructose to DHAP + G3P in red.
– These two compounds are intermediates of ____ and are converted in the liver principally to glucose, glycogen, or fatty acids.
• In the liver, ____ cleaves both Fructose 1-phosphate in the pathway for ____ and Fructose 1,6- bisphosphate in the pathway for ____.
• FRUCTOSE METABOLISM BYPASSES ____- major regulatory point of glycolysis- therefore the generation of ____ and ____ not regulated if carbon source is fructose. The fructose serves as an ____ source of intermediates for hepatic lipogenesis
glycolysis
aldolase B
fructose metabolism
glycolysis
PFK
G3P
pyruvate
unregulated
High Fructose-corn syrup
glucose has a ____ form; fructose has no ____ (everything ingested will form intermediates for ____)
bc fructose bypasses phosphofructose step > fructose metabolism is completely ____ > generates ____ and ____ (which is then precursor for ____ in the mitochondria)
fructose is more ____ than glucose
storage
storage
FA
unregulated
G3P
pyruvate
acetyl CoA
detrimental
Reciprocal regulation of PC and PDH
Pathway followed by mitochondrial pyruvate is dictated by mitochondrial ____ concentrations
Increased mitochondrial Acetyl CoA will
• Feedback inhibit-____
• Activate-____
As OAA condenses with Acetyl CoA to form citrate
• PDH activity ____
• PC activity ____
- Pyruvate carboxylase (forms OAA from pyruvate)
- Pyruvate dehydrogenase (forms acety CoA from pyruvate)
acetyl CoA
pyruvate dehydrogenase
pyruvate carboxylate
increase
decrease
