Flashcards in 23 Ketone Bodies, Complex Lipids, Adipose tissue Hormones Deck (28):
In what tissue and organelle are ketone bodies made?
ketone bodies are made in the mitochondrial matrix of cells in the liver
What kind of conditions favor ketogenesis in liver cells?
ketone body synthesis is stimulated under these conditions: fasting, starving, high fat/low carb diet, heavy alcohol consumption, and diabetes
Which tissues use ketone bodies as fuel?
all tissues use it, except for 2
Which tissues do not use ketone bodies as fuel and why not?
Liver, it lacks enzyme, succinyl CoA: acetate transferase and Red blood cells, which do not have mitochondria, the site of ketone body synthesis
ketone body synthesis regulation
What are examples of the physiological functions of glycerophospholipids?
1. main components of cellular membranes along with sphingomyelin 2. make up lipoproteins, bile, lung surfactant 3. sources of polyunsaturated fatty acids, like Arachidonic Acid, leads to eicosanoid production
Phosphatidic acid is necessary for glycerophospholipid synthesis, so how is it produced?
it is made from glycerol-3-phosphate and 2 fatty acyl CoAs.
glycerophospholipids made from diacylglycerol
glycerophospholipids made from CDP-diacylglycerol intermediate
How is diacylglycerol formed from phosphatidic acid?
Phosphatidic acid loses a phosphate, by the enzyme phosphatase, to form diacylglycerol
examples of activated head groups
CDP-ethanolamine and CDP-choline
example of activated backbone (glycerophospholipid synthesis)
role of phosphatidylglycerol
it makes cardiolipin, which is found in the inner mitochondrial membrane, and makes the membrane impermeable to small molecules
what is phosphatidic acid?
a key intermediate and precursor of glycerophospholipids
purpose of ketone bodies
ketone bodies serve as a source of fuel during fasting, starvation or a high fat diet. they are synthesized mainly in the liver mitochondria whenever fatty acids are high in the blood.
physiological functions of sphingolipids
are involved in intercellular communication, are antigenic determinants of ABO blood groupd, used as virus receptors, and component of myelin sheaths
the three classes of glycolipids, and are all made by reacting with
cerebrosides, globosides and gangliosides are all made by reacting with ceramides
ceramide reacts with a UDP sugar, have only one sugar attached
forming globosides and gangliosides
ceramide reacts with additional sugars to form globosides, and ceramide reacts with additional sugars and a sialic acid (NANA) to form a ganglioside
the enzyme and the substrates of glycosphingolipids
use of glycosyltransferases to add activated sugars, UDP sugars
how are glycosphingolipids degraded?
sphingolipids are degraded by lysosomal enzymes, they are known as acid hydrolyses, until all that is left is the ceramide
causes of sphingolipidoses
these are lysosomal storage diseases caused by decreased activity of lysosomal enzymes, due to the mutational defects of enzymes specifically involved in the breakdown of sphingolipids
defective enzyme of Tay Sachs disease, what would it normally cleave
defective enzyme is called Hexosaminidase A, it normally cleaves ganglioside GM2, but causes buildup of vacuoles in cells since they're not cleaved, leading to a disruption of normal cell function
adipose tissue as an endocrine gland and what hormones does it release
adipose tissue not only stores TAGs, but also secretes the hormones leptin and adiponectin to regulate fat and glucose metabolism
what causes leptin release
an increase in TRIGYCERIDE levels, stimulates leptin release, it signals us to stop eating by binding to leptin receptors in the brain
what causes adiponectin release
its secretion is reduced as adipoctyes get larger
Adiponectin affect on muscle metabolism
adiponectin causes a signal cascade, by binding to receptors, it activates AMPK, and a nuclear transcription factor, PPAR.
Leads to enhanced fatty acid oxidation and enhanced glucose uptake by the muscle