Lecture 33 Flashcards
(23 cards)
______ reactions of triglycerides provide the breakdown products - fatty acids and glycerol.
HYDROLYSIS reactions
Both Brown and Beige fat are known to be ________, increase _______ sensitivity (decrease diabetes), decrease inflammation and decrease ________ disorders.
Known to be THERMOGENIC , increase INSULIN sensitivity, decrease inflammation and decrease METABOLIC disorders.
Pancreatic _____ breaks down triglycerides to _____ and _____/_____in the gut lumen so they may cross the cell membrane and enter into intestinal enterocytes.
Pancreatic LIPASE breaks down triglycerides to FATTY ACIDS and MONO/DIACYLGLYCEROL.
_____ is a drug that inhibits pancreatic lipase. This makes it so triglycerides are not metabolized or absorbed, and can thus be excreted.
Orlistat
____ is the enzyme that re-synthesizes triglycerides in the enterocytes. ____ is a drug that inhibits this enzyme.
DGAT re-synthesizes triglycerides in the hepatocytes. LOVAZA is a drug that inhibits DGAT.
____ chain fatty acids have < 6 Carbons, ____ chain have 6-12, and ____ chain have > 12.
Short chain have < 6, MEDIUM chain have 6-12, and LONG chain have > 12.
______ acid (an omega-6 fatty acid, because the first C=C double bond is 6 Cs awa from the Omega C) is an essential fatty acid that we must obtain from our diet. It is the precursor to all omega-6 fatty acids, including ______ acid, which is required for prostaglandin synthesis.
LINOLEIC acid is the precursor for all omega-6 fatty acids, including ARACHIDONIC acid, which is required for prostaglandin synthesis.
_____ acid is the precursor to all omega-3 fatty acids.
LINOLENIC acid
____ and ____ chain fatty acids (which can be produced from dietary fiber by bacteria in the colon) are directly absorbed into the blood where they must be bound to ____ for transport. _____ chain fatty acids on the other hand must be packaged into _____ protein particles for transport in the blood.
SHORT and MEDIUM chain fatty acids are directly absorbed into the blood and must be bound to ALBUMIN. LONG chain fatty acids on the other hand must be packaged into LIPOproteins.
Lipogenesis occurs primarily in the _____, and requires _____ and NADPH, as well as ______ as a carbon source. Keep in mind it takes place in the cytosol of the cells. Fatty acid synthase (FAS) is then enzyme that elongates long chain fatty acids by combining _____ CoA onto an acetyl group –> this is what requires energy and NADPH.
Occurs primarily in the LIVER, and requires ATP and NADPH, as well as ACETYL CoA as a carbon source.
Fatty acid synthesis requires Acetyl CoA and _____ CoA.
MALONYL
Acetyl CoA is produced in the _____ matrix, and is transported to the _____ via the _____ shuttle. This converts acetyl CoA to _____ (which can pass the mitochondrial membrane into the cytosol) via the enzyme _____. In the cytosol, ______ is converted back to Acetyl CoA via the enzyme ______ (ATP dependent.)
Produced in the MITOCHONDRIAL matrix, and is transported to the CYTOSOL via the CITRATE shuttle. This converts Acetyl CoA to CITRATE via the enzyme CITRATE SYNTHASE. In the cytosol, CITRATE is converted back to Acetyl CoA via the enzyme ATP-CITRATE LYASE.
Acetyl CoA is carboxylated to form ______ CoA by Acetyl CoA Carboxylase (ACC), which is the rate limiting step in fatty acid synthesis and is ATP dependent and requires _____ as a cofactor.
To form MALONYL CoA. Requires BIOTIN as a cofactor.
ACC is an inactive dimer or active polymer whose regulation can be allosteric, phosphorylation, hormonal, or dietary.
Allosteric: ______ stimulates; ____ chain fatty acids inhibit.
Phosphorylation/hormonal: _____ activates protein phosphatase which dephosphorylates ACC polymers to ACTIVATE them, whereas _____ activates AMP activated Kinase which phosphorylates ACC polymers to DEACTIVATE them.
Think about how ATP:AMP ration might affect ACC and how calorie intake might affect it.
Citrate
Long chain fatty acids
Insulin
Glucagon
_____ contractility depends almost exclusively on fatty acid oxidation for energy. Think about scenarios that might cause the body overall to shift its metabolism to fatty acid oxidation.
Cardiac contractility
For beta-ox of fatty acids, which occurs in the mito _____ of hepatocytes, PKA requires ______ to phosphorylate Hormone sensitive lipase (HSL) to its active form. Short and medium chain fatty acids enter the mito ____ via _____ _____, while long chain fatty acids use the _____ shuttle.
Matrix
ATP
Matrix
Passive Diffusion
Carnitine
____ is the first enzyme in the carnitine chuttle and catalyzes the rate limiting step (addition of carnitine to fatty acyl CoA) in fatty acid beta-ox, and is the one located in the mito outer membrane. ____ is the second enzyme in the carnitine shuttle, and it is located in the inner mito membrane.
CPT I
CPT II
In beta-ox, 1 ____, 1 ____, and 1 _____ are produced for every 2-carbon segment that’s oxidized off of the fatty acid. For Palmitic acid, this results in formation of _____ molecules of ATP.
FADH2
NADH
Acetyl CoA
131
For odd chain fatty acids, ____ is used as the building block, rather that malonyl CoA. Beta-ox of odd chain fatty acids produces ____ CoA instead of Acetyl CoA, but both enter the TCA cycle, just at different points. This means they can produce the same number of ATP.
Propionyl CoA
Succinyl CoA
Ketone bodies are made from _____ _____ and ____ CoA in the mito _____ of heparocytes. When ____ CoA exceeds the capacity of the TCA cycle, it is used to create ketone bodies. Ketone bodies are _____, so they do not need to be bound to albumin or packaged in lipoprotein to be transported in the blood.
Fatty Acids
Acetyl CoA
Matrix
Acetyl CoA
Soluble
Ketone body synth is as follows: Fatty acids and 2 acetyl CoAs form Acetoacetyl CoA which is converted to ____CoA by the enzyme _____CoA _____. This is converted to _______, which can become acetone or D-beta-hydroxybutyrate (all three of these last products are the ketone bodies.)
HMG-CoA
HMG-CoA Synthase
Acetoacetate
Ketone bodies can be converted back to acetyl CoA via the enzyme ____ which is present in all tissues EXCEPT the _____.
Thiophorase
Liver
Leptin binds receptors in the _____, where it signals satiety.
Hypothalamus
