Lipid Metabolism PPT Flashcards
precursors in synthesis of other compounds
Fatty acids
fuels for energy production
Fatty acids
substrates for ketone body synthesis.
Fatty acids
_________ may be exported to other tissues: used for energy production.
Ketone bodies
It’s an enzyme in the mouth, it has no effect on digestion.
Saliva
It’s in the stomach, which produces small fat droplets (chyme).
Churning action
An enzyme in the stomach which hydrolyzes some (10%) TAGs
Gastric lipases
It solubilizes “droplets”
Bile
An enzyme in the small intestine which produces monoacylglycerols, which form fatty acid micelles.
Pancreatic lipases
“repackaged” into TAGs, which form chylomicrons.
Micelles
Digestion in the stomach: causes a large physical change and it will produce this substance.
Chyme
Chyme triggers _________ to release bile from gallbladder.
Cholecystokinin
It transports micelles into the lymphatic system of the body.
Chylomicrons
hydrolyze ester linkages between glycerol and FA units of TAGs
Pancreatic lipase
Oil droplets will form spherical ______ shapes. Bile salts aid this process clumping fatty acids and monacylglycerols.
micelle
Free fatty acids & monoacylglycerols are reformed into __________.
triacylglycerols
TAGs are combined with membrane & water soluble proteins to form a _________, a lipoprotein
chylomicron
carry TAGs from intestinal cells into bloodstream via the lymph system.
Chylomicrons
________ are specialized cells that contain TAGs
Adipocytes
________ contains large number of adipocyte cells
Adipose tissue
are found mostly in the abdominal cavity and subcutaneous tissue. st heat loss, Store energy, insulation again shock absorber for organs.
Adipocytes
are metabolically very active: triacylglycerol constantly hydrolyzed & re-synthesized.
Adipocytes
The breakdown of triglycerides by lipases is under __________
hormonal control of lipolysis
Hormones involved in the hormonal control:
Epinephrin, glucagon, and insulin
Enzymes that promote breakdown of fat (lipolysis)
Epinephrine & glucagon
Enzyme that inhibits lipolysis
Insulin
is the hydrolysis of TAGs stored in adipose tissue, followed by release into the bloodstream of the fatty acids and glycerol so produced.
Triacylglycerol mobilization
Overall process of tapping the body’s triacylglycerol energy reserves (adipose tissue) for energy is called
triacylglycerol mobilization
One glycerol formed for each TAG hydrolyzed. Enter bloodstream & go to ______ or ______ for processing
liver or kidneys
It is the first step in glycerol metabolism.
Primary hydroxyl group is phosphorylated.
Second step of glycerol metabolism
Oxidized to form a ketone
Oxidation of fatty acids:
- The fatty acid must be _____ by bonding to ______.
activated, coenzyme A
Oxidation of fatty acids:
- The fatty acid must be ______ into the mitochondrial matrix by a ________.
transported, shuttle mechanism
Oxidation of fatty acids:
- The fatty acid must be repeatedly _____, cycling through a series of four reactions, to produce ______, ______, and _____
oxidized, acetyl CoA, FADH2, and NADH
The site for fatty acid activation.
Mitochondria
It converts fatty acids to a high-energy derivative of coenzyme A.
Fatty Acid Activation
FATTY ACID TRANSPORT:
Fatty acids are transported across the inner mitochondrial membrane in the form of _________
acyl carnitine
A shuttle mechanism involving the molecule ________ effects the transport of acyl coA into the mitochondrial matrix
carnitine
Repetitive series of four biochemical reactions that degrades acyl CoA to acetyl CoA by removing two carbon atoms at a time
BETA OXIDATION PATHWAY
Produces FADH2 and NADH
BETA OXIDATION PATHWAY
Produces FADH2 and NADH
BETA OXIDATION PATHWAY
Steps in Beta Oxidation Pathway:
- Oxidation
- Hydration
- Oxidation
- Chain cleavage
Beta Oxidation Pathway:
Oxidation: Acyl CoA to ______.
trans-Enoyl CoA
Beta Oxidation Pathway:
Hydration: trans-Enoyl CoA to ________.
L-B-Hydroxyacyl CoA
Beta Oxidation Pathway:
Oxidation: L-B-Hydroxyacyl CoA to _______.
B-Ketoacyl CoA
Beta Oxidation Pathway:
Chain cleavage: B-Ketoacyl CoA to _______ and ______
Acyl CoA and Acetyl CoA
C18 fatty acid produces how many acetyl CoA and repetitive sequence?
9 acetyl CoA and 8 repetitive sequences
C14 fatty acid produces how many acetyl CoA and repetitive sequence?
7 acetyl CoA (6 repetitive sequences)
The acetyl CoA produced enters the _______
CITRIC ACID CYCLE or KREBS CYCLE
B-oxidation of 18:0 FA (stearic acid) produces a net of ___ ATP molecules
12
2 ATP molecules are needed for activation of FA so net ATP produced is _____ molecules
120
1 glucose molecule (6 carbon atoms) produces ______ ATP molecules
30
3 molecules of glucose (18 C) produce _____ ATP
90
______ produces 2.5 times more energy than glucose.
Stearic acid
Skeletal muscle uses glucose (from glycogen) when in an ________
active state
Skeletal muscle uses fatty acids when in a _______.
resting state
________ depends first on fatty acids and secondarily on ketone bodies glucose, and lactate
Cardiac muscle
The _______ uses fatty acids as the preferred fuel.
liver
________ is maintained by glucose and ketone. Fatty acids
cannot cross the blood–brain barrier and thus are unavailable.
Brain function
The first step of the Krebs cycle involves the reaction between _____ and _______.
Oxaloacetate and Acetyl CoA
Oxaloacetate concentration depends on _____ produced from glycolysis; pyruvate can be converted to oxaloacetate by pyruvate carboxylase.
Pyruvate
When oxaloacetate supplies are too low for all acetyl CoA to be processed through the TCA cycle, _____ takes place where excess acetyl CoA is converted to ketone bodies.
Ketogenesis
