10/1 Metabolism Flashcards
What makes ketones?
Kidney
where are ketones used?
just about everywhere except the liver (not in the red blood cells)
How is most of our energy stored?
It is stored as fat in most cases.
in what ways does fatty acid oxidation support blood glucose during fasting?
It provides the ATP to perform gluconeogenisis. It provides energy directly to most cells to prevent them from having to use glucose – see this building up after a few hours of fasting and then peaking around 2 days.
how to we make use of triacylglycerols?
hydrolyzed by lipases, releasing fatty acids and glycerol
how do we get fatty acids to the mitochondria?
they are activated to acyl-CoAs and transfereed to carnitine for transport to the mitochondria matrix
how do we get fatty acids into the blood from the white adipocytes?
triglyceride lipases release fatty acids and glycerol into the blood
Adds carnitine to acyl-Coa and takes off the Coa
Carnitine palmitoyl Transferase I (CPTI)
why do we transfer a Carnitine onto Acyl-CoA and take the CoA off?
In order to move the acyl molecule across the mitochondrial matrix (the membrane) and into the mitochondria
What happens to the Acyl Carnitine once it is moved accross the mitochondrial matrix and it is now in the mitochondria
It interacts with carnitine palmitoyl transferase II (CPTII) and gets the carnitine group removed and a CoA added back on.
What is inside the mitochondria that will remove a carnitine from Acyl carnitine and add a CoA?
carnitine palmitoyl Transferase II (CPTII)
one of the adipose triacylglycerol lipases that is sensetive to the catecholamines and insulin/glucagon
Hormone-sensitive lipase
Attached to the luminal surface of endothelial cells that line the capillaries in tissues that can oxidize or store fatty acids (muslce, adipose etc.), and aids in taking up these molecules
Lipoprotein lipase
very large molecules of fatty acids
Chylomicron
triglyceride-rich lipoprotein particle sectreted by the liver – fasting serum triglycerides
VLDL
what is the key intermediate in making de novo fat from Acetyl CoA when blood glucose is high and insulin is high
Malonyl Coa
Inhibits CTPI and prevents the transfer of Acetyl CoA accross the mitochondria for use in TCA
Malonyl CoA
when is Malonyl CoA in high levels
when there is lots of ATP insulin and Glucose
how does high levels of ATP, glucose, and Insulin inhibit the use of fatty acids in mitochondria
by making Mallonyl CoA from acetyl CoA and then making fatty Acyl CoA from the Malonyl CoA and Malonyl CoA inhibits transport into the mitochondria.
when would CPT1 be activated? and inhibited?
it would be inhibited when glucose and insulin is low i.e. after a carbo meal; and it would be activated when fasting or exercising!
what is Malonyl CoA in in the metabolic map (what is its big functional role)
It acts as an intermediate in fatty acid synthesis (also acts to inhibit the use of fatty acids in the mitochondria by blocking CPT1)
Consumption of a carbohydrate-rich meal simultaneously activates fat synthesis and inhibits fat oxidation in the liver. One known
mechanism for both outcomes is:
Activating the synthesis of malonyl CoA
what hydrolyzes and releases fatty acids and glycerol from adopocytes?
Lipases (this is a key reg. step)
what happens to fatty acids once they make it into a cell with the intent of using that fatty acid for energy?
they are activated to acyl-CoAs and transferred to carnitine for transport into the mitochondrial matrix
what is the major, but not the only pathway of fatty acid oxidation?
beta-oxidation of fatty acids
What is an important fuel sorce during starvation or low carb diet that come mainly from the acetyl CoA of fatty acid oxidation?
Ketone bodies