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288 Cards in this Set
- Front
- Back
- 3rd side (hint)
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GLUT1
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Ubiquitous.
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Low Km. 1-2
High glucose affinity. Low capacity. |
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GLUT2
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Liver
Pancreas Intestine Kidney |
High Km
16-20 |
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GLUT4
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Heart
Muscle Adipose |
Km=5
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Metabolism
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The complete set of chemical reactions that occur in living cells.
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Catabolism
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Yields energy (in the form of ATP) by breaking down food in cellular respiration.
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Uses nutrients directly absorbed from the GI tract or stored nutrients.
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Anabolism
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Uses energy to synthesize cellular components such as proteins and nucleic acids.
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Used for structural maintenance, repairs, growth, production of secretions, and building of nutrient reserves, such as fat and glycogen.
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Glycolysis occurs in?
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The cytosol
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The TCA/citric aicd/Krebs cycle occurs in?
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The mitochondria.
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In Glycolysis the Glucose becomes?
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Pyruvate. Which then becomes?
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Acetyl-CoA
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In the TCA/Citric acid/Krebs cycle, Acetyl-CoA...?
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Is oxidized to CO2 and H2O and produces ATP in...
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The process of oxidative phosphorylation.
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How is GLUT4 different from GLUT1 and 2?
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It is stimulated by insulin, i.e. it needs insulin to activate.
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Exercise can also activate GLUT4.
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After glucose is taken into a cell,it goes through a trapping reaction that phosphorylates it into...
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Glucose-6-Phosphate. By?
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Glucokinase or hexokinase.
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Glucose trapping is used to...
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Keep glucose in the cell. It requires...
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ATP, K+, and Mg2+
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Hexokinase is present in...
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all tissues (and most mammalian cells in low concentration). Glucose-6-Phosphate...
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inhibits hexokinase.
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Glucokinase (a type of hexokinase) is present in...
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the liver and pancreatic beta cells, small intestine,and hypothalamus. It regulates...
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insulin secretion. And is NOT inhibited by Glucose-6-Phosphate.
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In the brain, glucose is...
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an absolute requirement except in prolonged starvation. Then the brain can utilize...
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ketone bodies.
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In Adipose tissue, glucose is used for...
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Generation of NADPH (via the HMS) and generation of glycerol (then turned into triglycerides(fat)).
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In muscle cells, white muscle fibers (fast twitch) use glucose for...
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anaerobic glycolysis. They work so rapidly that oxygenation can't keep up. The result is...
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lactate in the white muscle fibers.
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Glucose in the red muscle fibers (slow twitch) of muscle cells can carry more...
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oxygen-rich mitochondria.
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Red blood cells have a(n) ______ requirement for glucose.
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Absolute
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Lactation has a ______ glucose demand.
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Heavy. _____ also have a heavy glucose demand.
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Fetuses
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Glucose-6-Phosphate in the muscles goes through...
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Glycolysis. And becomes...
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Pyruvic Acid. Fast twitch muscles then create Lactic Acid from it.
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Glucose-6-Phosphate can go through glycogenesis and become...
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Glycogen. Which is stored in...
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liver and muscle cells.
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Glucose-6-Phosphate can have the phosphate removed by Phosphitase and turned into...
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Glucose. Which can then travel...
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to blood and brain.
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The central molecule of Metabolism is...
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Acetyl CoA.
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Glycogenesis turns...
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Glucose into glycogen
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Glycogenolysis turns
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Glycogen into glucose.
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Glycolysis turns
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Glucose to pyruvate.
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Anaerobic respiration of Glycolysis turns glucose into...
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pyruvate into...
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lactate
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Aerobic respiration of Glycolysis turns glucose into pyruvate into...
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acetyl CoA which goes through the...
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TCA/Citric acid/Krebs cycle.
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The hexose monophosphate shunt creates
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NADPH. which is used for ______ synthesis.
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lipid
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The uronic acid pathway creates...
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UDP glucuronate. Used for...
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drug detoxication, systhesis of glycoproteins, heparin and hearan, biosynthesis of vitamin C.
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Glucose + triose phosphates becomes
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glycerol 3-phosphate. which becomes...
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the glycerol backbone of triglyceride phospholipids (fats).
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Glycogen is the major storage form of ________ in animals
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Carbohydrates. And is present in...
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cytosol. Exists in vivo in highly hydrated granules. (65%)
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Liver glycogen serves as a glucose reserve for maintaining...
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blood glucose levels. These levels fluctuate with...
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food intake.
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Muscle glycogen used as fuel reserve for...
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ATP within the muscle. _____ triggers mobilization of glycogen to form ATP.
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Exercise.
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Cannot make free glucose from _____ glycogen.
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Muscle. Can only make free glucose from liver and kidney glycogen (mainly liver).
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Free glucose can travel through the blood to other tissues, like the brain.
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Red muscle fibers (slow twitch) are high in....
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myoglobin and mitochondria. Provides energy for _____ activities.
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long sustained.
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White muscle fibers (fast twitch) have more capacity for...
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glycogenolysis and glycolysis. Glycogen is converted to _____ primarily.
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lactate.
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Because ______ is in the liver, glucose-6-phosphate can become glucose and move into the blood.
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Glucose-6-phosphatase. It removes the phosphate from the Glc-6-P
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Glycogenesis is the ______ of glucose
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linkage. They are linked together by a [1-4] glucosidic linkages and branching occurs by ____ glucosidic linkage.
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a[1-6].
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Glycogen functions as ______ energy storage in animal cells.
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Short term. Is made primarily by...
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liver and muscles, but can also be made within the brain and stomach.
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Glycogen forms an energy reserve that can be _______ mobilized to meet a sudden need for glucose.
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Quickly. But glycogen has less energy than...
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fat.
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Although metabolism of fat provides more energy, muscle mobilize glycogen _____ than fat
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faster. And animals cannot convert _______ to glucose.
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fatty acid. (Glycerol can be converted to glucose.)
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In Glycogenolysis, Glycogen phosphorylase (regulatory enzyme) converts Glycogen to ________
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glucose-1-P. Which then becomes _______ by phosphoglucomutase.
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glucose-6-P
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When Glycogenolysis occurs in the liver (and the kidney to a small degree), _______ converts glucose-6-P to free glucose.
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Glucose-6-phosphatase. The free glucose then exits the cell and enters __________
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blood circulation
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Glycogenolysis in the liver (and kidney) requires _________ ATP(s).
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0.
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Glycogenolysis in the muscle cells results in glucose-6-P turning into _____ in white muscle fibers (fast twitch) or _______ in red muscle fibers (slow twitch).
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lactate.
CO and Water. This is because the muscle cells do not contain _______ |
Glucose 6-phosphatase.
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_______ occurs in the liver during both exercise and early in starvation.
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Glycogenolysis.
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The presence of Epinephrine and Glucagon results in the __________ of glycogen synthesis.
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Inhibition.
This occurs through the ________ of glycogen synthase (which is then called glycogen synthase b- this is a deactivation step). |
phosphorylation.
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Glycogen synthase b differs from glycogen synthase a, because b __________.
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Has a phosphate. This makes glycogen synthase b _______
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inactive.
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Epinephrine and Glucagon are _____ hormones.
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Stress. They stimulate _____, which activates _______.
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cAMP
Protein kinase A. |
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Protein kinase A when activated by cAMP, phosphorylates glycogen synthase a, which ______ glycogen synthesis.
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Inhibits.
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Protein kinase A activated by cAMP activates the phosphorylation of phosphorylase kinase, which phosphorylates glycogen phosphorylase b into a, which _______ glycogen degradation.
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Activates.
Glycogen degradation creates ______ |
glucose.
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_______ is an enzyme which converts glucose to glycogen.
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Glycogenin.
It polymerizes the first few molecules of glucose, then ________ takes over |
glycogen synthase.
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The 3 reactions of Glycogenesis are:
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1- Glucose-6-P to glucose-1-P
2- Glucose-1-P + UTP to UDP-glucose 3- Glycogen synthase (regulatory enzyme) - UDP-glucose + glycogen to (glucose)n+1+UDP. |
Overall equation for Glycogenesis (glycogen synthesis):
(Glucose)n+glucose+2 UTP to (Glucose)n+1+2 UDP |
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Insulin is a(n) _______ hormone
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anabolic. When we have a lot of insulin, we make glycogen. Basically, the reaction is the opposite of ________
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epinephrine and glucagon
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Insulin stimulates _________ of glycogen phosphorylase a, which turns it into b (a deactivation step)
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dephosphorylation.
This deactivates glycogen _______. |
Degradation
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Insulin ________ glycogen synthase b, which turns it into a (an activation step).
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dephosphorylates.
This ______ glycogen synthesis. |
activates.
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Insulin _________ glycogen production
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increases
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________ storage diseases exist in dogs (usually miniature breed puppies), cats, cattle, horses, and primates.
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Glycogen
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But they are rare.
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Hexose Monophosphate, or ____________ Pathway.
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Pentose Phosphate.
This pathway creates ______ and ______. |
NADPH
Ribose (nucleotides). |
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When glycogen reserves in the liver are filled, glucose enters the _________.
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Pentose phosphate pathway, which produces NADPH which is necessary for ______ biosynthesis.
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Fat.
Fat can be stored as energy for later use. |
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Hexose monophosphate shunt =
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Pentose phosphate pathway.
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The ________ is an alternate cytoplasmic route for the metabolism of Glucose-6-P. It produces 10-20% of glucose.
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hexose monophosphate shunt.
It does not generate ______. |
ATP.
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In ______ tissue, HMS activity is high during lactation for producing milk fats.
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mammary.
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HMS is a source of _______
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NADPH, which is used for reductive biosynthesis of ______
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lipids
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In RBC, HMS produces NADPH, which increases reduced ________
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glutathione, which protects RBC from _________
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oxidative damage
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HMS increases ribose residues for _________ and _________ biosynthesis
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nucleotide
nucleic acid (e.g. ATP, NAD, FAD, RNA, and DNA) |
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Glucuronic Acid Synthesis leads to the production of _________
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Glucuronate. Which then becomes L-Ascorbate, also known as ________
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Vitamin C.
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In the liver, glucuronate solubilizes bilirubin, which is the secreted into the _____.
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Bile.
This prevents __________ or ________ |
hepatic disease
jaundice |
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Basically, _________ keeps in the liver toxin free.
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Glucuronate
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_________ is the initial process of most carbohydrate catabolism
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Glycolysis
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Glycolysis serves three principal functions:
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1- Generation of ATP and NADH
2- Production of pyruvate for the TCA cycle 3- Production of a variety of 6- and 3- carbon intermediate compounds. |
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__________ is the foundation of both aerobic and anaerobic respiration.
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Glycolysis.
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In glycolysis, aerobic respiration creates ________
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pyruvate
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In glycolysis, anaerobic respiration creates __________
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lactate
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__________ is a metabolic pathway by which a 6-carbon glucose is oxidized to two molecule of pyruvate.
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Glycolysis
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In glycolysis, _________ converts PEP (Phosphoenolypyruvic acid) to pyruvate.
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Pyruvate kinase
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In glycolysis, you use ______ ATPs and create _____ ATPs.
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4
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Glycolysis has two separate phases, the ________ phase which requires ATP, and the _________ phase which yields ATP.
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preparatory
pay-off |
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In the preparatory phase of glycolysis, glucose is phosphorylated into glucose-6-phosphate by ________ or _________
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hexokinases
glucokinase (This step requires an ATP) |
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Hexokinase is present in most mammalian cells in low concentrations and is inhibited by ________-
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Glucose-6-phosphate
Hexokinase is the rate-limiting RBC enzyme whose activity declines with AGE. |
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Glucokinase is present in ______, ________, ________, and _____________
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liver cells
pancreatic beta cells hypothalamus small intestine |
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Glucokinase is stimulated by ________ and is inhibited by __________.
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insulin
diabetogenic hormones (stress hormones) |
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In the preparatory phase of glycolysis, glucose-6-phosphate is isomerized by phosphohexose (phosphoglucose) isomerase to form __________
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Fructose-6-phosphate
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In glycolysis, fructose-6-phosphate is phosphorylated by _____________ to form ___________
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PFK-1
Fructose-1,6-bisphosphate (This step requires an ATP). |
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PFK-1 is the _________ enzyme of glycolysis.
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Rate-limiting
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PFK-2 produces ________ which stimulates PFK-1 and glycolysis.
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Fructose-2,6-bisphosphate
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In glycolysis, _________ is cleaved to form dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.
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Fructose-1,6-bisphosphate
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The rate of glycolysis is regulated to meet two major cellular needs:
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1- Production of ATP
2- Provision of building blocks for biosynthetic reactions |
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The reverse process of glycolysis is...
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Gluconeogenesis
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The 4 inhibitors of PFK-1 are:
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1-ATP
2-phosphocreatine 3-citrate 4-glucagon (in liver) |
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The 4 stimulators of PFK-1 are:
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1-AMP
2-ADP 3-Fructose-6-phosphate 4-Pi (Inorganic phosphate) |
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The most important regulator of both glycolysis and gluconeogenesis is _______ which is not an intermediate in glycolysis or in gluconeogenesis
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Fructose-2,6-bisphosphate
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___________ is at a major crossroad of carbohydrate, protein, and lipid metabolism.
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Pyruvate
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In anaerobic lactic acid (lactate production in cytoplasm) there is _____ net gain of NADH.
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No
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Accumulation of lactic acid leads to muscle ____________.
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stiffness
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_________ measurement in blood is used to diagnose cell death- it is a "leakage" enzyme.
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LDH
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In alcohol fermentation, pyruvate is converted to __________.
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ethanol.
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Hepatocytes (liver cells) contain ____________ and AcDH (acetaldehyde dehydrogenase) in mitochondria
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alcohol dehydrogenase (ADH in cytosol)
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__________ leads to the hangover effects of alcohol.
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Acetaldehyde
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In anaerobic conditions, pyruvate becomes ___________ in plants, or ___________ in animals.
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ethanol
lactate |
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In the aerobic respiration of TCA cycle in the mitochondria, pyruvate becomes _______
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acetyl CoA
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Acetyl CoA production is catalyzed by _________
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pyruvate dehydrogenase
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The production of acetyl CoA is an important __________ step in animal cells, because acetyl-CoA cannot convert back to glucose.
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irreversible
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_______ and __________ cannot leave the mitochondria unless they bond to each other and form citrate, which can leave the mitochondria.
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acetyl CoA
Oxaloacetate |
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Other than glycolysis, pyruvate can be made by converting ________ to pyruvate by decarboxylation in cytoplasm.
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malate.
This is called the pyruvate/malate cycle and involves malic enzyme. |
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When citrate reaches the cytosol, it is cleaved back into ______ and _______.
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OAA (Oxolacetate)
Acetyl CoA |
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The pyruvate/malate cycle serves as an additional source of ______ for lipogenesis.
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NADPH
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Pyruvate that results from this reaction is able to go down 2 paths:
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1- Reenter mitochondria for conversion to OAA or acetyl-CoA
2- Be converted to alanine via ALT (alanine amino transferase) |
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________ if found mainly in serum, cytosol of hepatocytes and is commonly measured clinically as a liver test to screen hepatic necrosis.
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ALT
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ALT is also called _______.
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SGPT (serum glutamate-pyruvate trannsaminase)
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The other pathway for metabolism of glucose that is not glycolysis is __________
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the polyol pathway
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The polyol pathway is responsible for _______ and _______ formation.
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fructose
sorbitol |
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The polyol pathway is also called the _____________ pathway.
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sorbitol/aldose reductase
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__________ inhibitors are given in humans to prevent sorbitol buildup in eyes, which causes cataracts.
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Aldose reductase
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Sorbitol is a(n) ________. It draws in water, so when sorbitol accumulates in the eye, swelling and cloudiness occur and can develop into cataracts.
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alcohol.
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The glucose uptake in cells of retina, kidney, and nervous tissues are insulin-_________
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independent.
This means there is a free interchange of glucose from inside to outside of the cell. The cells will use glucose for energy as normal, and any glucose not used will enter the polyol pathway and be converted into sorbitol. |
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In the polyol pathway, glucose undergoes reduction by ________ to sorbitol, catalyzed by aldose reductase.
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NADPH
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In the polyol pathway, oxidation of sorbitol, in the presence of NAD+ and sorbitol deydrogenase, yields ________.
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fructose
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In the polyol pathway, ____________ is the rate-limiting step.
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sorbitol dehyodrogenase
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_________ develop when not all sorbitol is metabolized, causing an increased accumulation of sorbitol which increases the osmotic pressure and water retention, which leads to cell swelling and damage.
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Diabetic cataracts.
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_________ is the generation of glucose-6-phosphate from non-sugar carbon substrates, which is then converted to free glucose or glycogen.
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Gluconeogenesis
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Gluconeogenesis occurs mainly in the ______ and a little in __________
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liver
cortex of kidneys. This is because only the liver and cortex of kidneys contain the glucose-6-phosphatase needed. |
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_________ occurs mainly during periods of fasting, starvation, or intense exercise
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Gluconeogenesis
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Gluconeogenesis is often associated with _________.
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Ketosis (from fat metabolism)
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A decrease in gluconeogenesis leads to __________ which leads to brain dysfunction and comas
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hypoglycemia
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In humans, the main gluconeogenic precursors are these 4:
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1- lactate
2- glycerol (from triacylglycerol) 3- alanine 4- glutamine All togethery, the account for over 90% of the overall gluconeogenesis. |
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In ruminants, ________ is the principal gluconeogenic substrate.
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propionate
It can also go directly into the TCA cycle. |
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The 4 substrates of gluconeogenesis are:
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1- Glucogenic amino acids (alanine, glutamine)
2- Lactate 3- Glycerol 4- Propionate |
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In gluconeogenesis, lactate goes through the _________ cycle, which is when the lactate from anaerobic respiration in skeletal muscle is converted to pyruvate in liver cells.
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Cori
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The majority of amino acids form TCA intermediates and pyruvate and are therefore _________
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glucogenic
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The three ketogenic amino acids are_______, ________, and _________, because they form acetyl CoA.
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Leucine
tryptophan isoleucine |
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In gluconeogenesis, _______ is converted to glucose in the liver. It is a significant source of glucose in hibernating animals.
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glycerol
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In gluconeogenesis, __________ is produced from microbial carbohydrate digestion in herbivores and is a major hepatic gluconeogenic substrate.
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Propionate.
It contributes to 70% of glucose for ruminants |
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Gluconeogenesis bypasses 3 steps that are in glycolysis:
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1- pyruvate kinase
2- phosphofructokinase 3- hexokinase |
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When gluconeogenesis bypasses pyruvate kinase, it requires __________
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oxaloacetate.
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Gluconeogenesis acquires oxaloacetate from 4 sources:
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1- Aspartic acid (ammonia can be removed to yield oxaloacetate in cytosol)
2- Addition of CO2 to pyruvate in mitochondria by pyruvate carboxylase 3- Malate 4- Pyruvate carboxylase and PEP carboxykinase |
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Gluconeogenesis bypasses the PFK step by ____________
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Fructose-1,6-bisphosphatase
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Gluconeogenesis bypasses the hexokinase step by _____________
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glucose-6-phosphatase
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The major enzymes involved in gluconeogenesis are ________, __________, and ____________
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PEP carboxykinase,
fructose-1,6-bisphosphatase Glucose-6-phosphatase |
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The major enzymes in gluconeogenesis are stimulated by 4 things:
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1- Stress hormones epinephrine and glucagon
2- Glucocorticoids 3- Growth hormone 4- T3 |
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The major enzymes of gluconeogenesis are inhibited by ________
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insulin
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When insulin is present, instead of gluconeogenesis, __________ will begin.
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glycolysis
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TCA Cycle stands for...
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Tricarboxylic acid cycle
Also called citric acid cycle or Krebs cycle |
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TCA cycle occurs in the __________
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mitochondrial matrix
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The main function of the TCA Cycle is:
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the oxidation of acetyl CoA
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In the TCA cycle, oxaloacetate and acetyl CoA combine to form _______ which can leave the mitochondria and enter the cytosol.
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citrate
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_______ and _______ are made in the TCA cycle and enter into oxidative phosphorylation.
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NADH
FADH2 |
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CO2 is made in the _________
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TCA Cycle
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In the TCA cycle, acetyl CoA and OAA (oxaloacetate) combine using the enzyme __________
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citrate synthase
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The formation of citrate in the TCA cycle is inhibited by 3 things:
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1- high mitochondrial concentrations of ATP
2- citrate 3- acyl-CoA |
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Acetyl-CoA and OAA are __________ to mitochondrial membranes.
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impermeable
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Citrate is __________ to mitochondrial membranes
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permeable
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After citrate leaves the mitochondria and goes into the cytosol, it is cleaved into ______ and _______
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acetyl CoA
oxaloacetate |
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In the cytosol, acetyl CoA is used for __________ via combination with _________.
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fat (lipid) biosynthesis
malonyl CoA |
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In the cytosol, oxaloacetate is used for _______.
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pyruvate production
(OAA-malate-pyruvate: production of NADPH) |
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Bottomline: TCA Cycle creates ______ and ______ which are needed for oxidative phosphorylation.
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NADH
FADH2 (Some ATP generated, but most in oxidative phosphorylation). |
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This is the overall reaction of?
Acetyl CoA + 3NAD+ + FAD + GDP + Pi + 2H2O ---> 2CO2 + 3NADH + FADH2 + GTP + CoA-SH |
TCA Cycle
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The TCA cycle is a(n) ________ pathway, having both oxidative (breakdown) and biosynthetic functions.
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amphibolic
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Citrate can be used for _______ and/or ______ biosynthesis in the cytoplasm.
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fatty acid
steroid |
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OAA can also be used for ________ biosynthesis.
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Glucose
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________ can be used for porphyrin metabolism (for example heme synthesis).
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Succinyl CoA
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__________ is a highly efficient metabolic pathway that uses energy released by the oxidation of nutrients to produce ATP.
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Oxidative phosphorylation
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During oxidative phosphorylation, e- is transferred from electron ______ to electron _______.
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donors
acceptors |
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e- is transferred by the ____________
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electron transport chain (ETC, also called respiratory chain)
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ETC is a series of protein complexes within the _______
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mitochondria
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When e- is transferred, considerable energy is ________
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released.
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______ is the final e- acceptor in the ETC.
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O2. It combines with H to form water.
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______ is when e- is removed.
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Oxidation
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________ is when e- is gained.
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Reduction
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The ETC functions by passing electrons from more _____________ compounds, such as NADH and FADH2, to more ___________ ones, such as coenzyme Q (CoQ), and cytochrome c (Cyt c).
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electronegative
electropositive |
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In the ETC, Complex I accepts electrons from ______ and passes them to ________
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NADH
coenzyme Q |
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In the ETC, Complex II accepts electrons from _______ and passes them to _______
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Succinate
Coenzyme Q |
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Coenzyme Q passes the electrons to ______ which then passes them to _______.
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Complex III
Cytochrome c |
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Cytochrome c passes the electrons to ______, which uses the electrons and hydrogen ions to reduce oxygen to water.
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Complex IV
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The energy obtained through the transfer of electrons down the ETC is used to pump _____ from the mitochondrial matrix into the intermembrane space, creating an electrochemical ______ gradient across the mitochondrial inner membrane.
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proton
proton |
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The electrochemical proton gradient in the ETC allows ________ to use the flow of prtons through the enzyme back into the matrix to generate _______.
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ATP synthase
ATP |
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Inhibitors can block ETC at any of 4 sites:
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Complex I, II, III, and IV
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Inhibitors for complex I are _____ and ______
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Barbiturates (insecticide)
rotenone (fish poison) |
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Inhibitors for complex II are ______, ______, and ______
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malonate
TTFA carboxin |
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Inhibitors of complex III are ______ and _______
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antimycin
British anti-Lewisite (BAL) |
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Inhibitors for complex IV are ________, ______, ________, and __________
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H2S (hydrogen sulfide)
CO CN oligomycin |
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Inhibiting oxidative phosphorylation causes ________
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cell death
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________ dissociate oxidation from phosphorylation.
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Uncouplers
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_______ uncouplers allow the protons to pass into the mitochondria, which drops the proton gradient, which causes a rapid consumption of energy without generation of ATP. This causes a non-shivering heat.
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Exogenous
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2 exogenous uncouplers are _________ and _________
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2,4-Dinitrophenol (DNP)
CCCP |
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__________ uncoupler is an uncoupling protein, also called thermogenin (as a transmembrane proton transporter).
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Endogenous
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_________ make a scant ring of cytoplasm surrounding a single large lipid droplet. The cell nuclei are flattened and eccentric within the cell.
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White adipocytes
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__________ is seen mainly in newborn babies, hibernating animals, and migrating birds (but also occurs in adults) and is specialized for heat generation.
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Brown Adipose Tissue
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The brown color in brown adipose tissue is caused by abundant _______
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mitochondria
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Large blood vessels are surrounded by __________ which causes oxidation of fatty acids in adipose tissue which releases heat that dissipate to the blood and helps maintain the temperature of circulating blood.
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brown adipose tissue
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_________ are soluble in nonpolar solvents such as ether, cholroform, and benzene but are insoluble in water (hydrophobic).
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lipids
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Simple lipids are __________, which are an ester of glycerol (alcohol) with fatty acid. It is a neutral fat.
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Acylglycerols
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The main acylglycerol are ________.
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Fatty acids
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Linoleic acid (w6), linolenic acid (w3) and arachindonic acid (w6; in cats) are all ___________.
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Essential fatty acids
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________ and _________ are complex lipids.
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Phospholipids;
Glycolipids |
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_________ contain phosphoric acid, esterified FA, and alcohol.
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Phospholipids
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_________ contain nonphosphate containing combination of carbohydrate and FA.
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Glycolipids
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________ are lipids that were modified from regular lipids and now have a different structure. Examples are steroids and sterols, eicosanoids, ketone bodies, and fat soluble vitamins.
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Derived lipids
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Storage of triglycerides occur primarily in the cytoplasm of __________. In obesity, they are also stored in muscle cells.
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adipocytes
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The caloric value of triglycerides is _____ Kcal/g. They are more anhydrous than carbohydrates and protein.
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9
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__________ acids are a single carboxyl group at the end of a hydrocarbon chain. Weak acids such as acetic acid and propionic acid.
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Monocarboxylic
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Most fatty acids in mammals are of the ______ variety.
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Straight-chained
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___________ fatty acids contain no double bonds.
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Saturated
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The saturated acids end in _____
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-anoic.
Unsaturated end in -enoic. |
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Based on the ______ of carbons and ______ of double bonds, fatty acids can be different and have different names.
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number;
position |
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In saturated fatty acids, the longer the chain length, the _______ the melting point.
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Higher.
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In saturated fatty acids, the longer the chain, the ______ the stability.
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greater
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Palmitic acid and stearic acid are the most _________ saturated fatty acids.
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abundant
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In unsaturated fatty acids, the melting point _____ with chain length.
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increases
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In unsaturated fatty acids, the more double bonds, the _______ the melting point.
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lower
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Monounsaturated fatty acids have ____ unsaturated bond(s). They are liquid at room temperature but start to solidify at refrigerator temperatures.
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One
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The 4 functions of essential fatty acids are:
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1- As structural components of cell and mitochondria membranes
2- As precursors for eicosanoid synthesis 3- w3 is importnat for normal brain functions and as a blood thinner 4- w6 is important to the texture and appearance of the skin and blood vessel structure. |
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_____________ are also called neutral fats.
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Acylglycerols
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The general structure of a fatty acid is:
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H3C-(CH2)-C=O
\ OH |
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________ structural backbone is glycerol-3-phosphate.
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Phosphoglycerides (phospholipids)
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____________ is a phosphoglyceride that acts as a pulmonary surfactant (reduces surface tension). It is the major storage form for choline inside the brain (important neurotransmitter).
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Phosphatidylcholine.
Lack of pulmonary surfactants in newborns causes respiratory distress syndrome. |
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__________ is a phosphoglyceride that is an important constituent of cell membrane. Upon stimulation by a first messenger, it is cleaved into diacylglycerol (DAG) and inositol tripohsphate (IP3), both of which act as second messenger.
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Phosphatidylinositol
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The 3 examples of phosphoglycerides are:
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1- (phospholipids) glycerol-3-phosphate
2- Phosphatidylcholine 3- Phosphatidylinositol |
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The 3 phospholipases are:
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1- Phosphlipase A1
2- Phospholipase A2 3- Phospholpiase C |
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__________ cleaves on position 1; present in many mammalian tissues. Can cleave phosphatidylcholine and with a hydrolase leads to choline and glycerol-3-P.
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Phospholipase A1
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_________ is present in pancreatic juice, snake, and bee venoms. It acts on phosphatidylinositol to release arachidonic acid, the precursor of the prostaglandins.
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Phospholipase A2. It is a very important enzyme.
It is inhibitied by glucocorticoids. |
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_________ is found in liver lysosomes and the a-toxin of Clostridia. When it is membrane-bound it leads to production of second messengers: DAG and IP3.
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Phospholipase C
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Lipds are ingested in diet in the form of __________, _________, and ________ or they can be made de novo.
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Triglycerides.
Cholesterol Phospholipids |
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Lipids must be broken down and absorbed in the __________ in order for the body to use them.
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small intestine
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Triglycerides are broken down by _________ into 2-monoglyceride and 2 fatty acids.
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pancreatic lipase
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Phospholipids are broken down by ________ into lysophospholipids and fatty acids.
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Phospholipase A2
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Cholesterol ester is broken down by ____________ into free cholesterol and fatty acids.
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Cholesterol esterase
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In lipid metabolism, fatty acids and monoglyceride is absorbed by __________ and travel to smooth endoplasmic reticulum where triglycerides are formed.
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enterocyte
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Lipid and protein combine inside the ER of the enterocyte to form _________ particles.
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lipoprotein
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Lipoproteins have ______ core and _________ surface.
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Hydrophobic
Hydrophilic |
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Lipoproteins are responsible for the transport of lipids through the blood to tissues for either ______, ______, or _______
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metabolism
storage excretion |
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Lipids must bind to _______ to make them water-soluble for transport in the blood.
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proteins
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The ___________ are heterogeneous, named with letter and numbers to differentiate.
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apolipoproteins
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Lipoproteins can be separated by _______, based on difference in densities, or _________, based on difference in net charges.
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Ultracentrifugation
Electrophoresis |
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To form ________, fat is digested into fatty acids and monoglycerides, then in the enterocyte, cholesterol is esterified into cholesteryl esters. The reesterification of triglycerides plus the addition of proteins yields these.
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Chylomicrons
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_______ are large. To transport them, exocytosis occurs to send them out of the enterocyte. Then they go through central lacteal, then the thoracic duct, where they enter blood circulation and travel to the liver.
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Chylomicrons
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There are 6 lipid forms based on densities in the blood:
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1- Chylomicrons (CM)
2- Very low density lipoproteins (VLDL) 3- Low density lipoproteins (LDL) 4- Intermediate density lipoproteins (IDL) 5- High density lipoproteins (HDL) 6- Albumin-free fatty acids (FFA) - highest in density |
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_______ contains the largest amount of triacylglycerol.
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Chylomicrons
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______ refract light, have cloudy appearance in plasma. They are assembled in intestinal mucosal cells and are used to mobilize dietary (exogenous) lipids. They cannot pass through capillary endothelial layer.
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Chylomicrons
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Chylomicrons deliver exogenous products to: 80% to ______, ______, _____, and ______.
20% to _______ |
1- Adipose tissue
2- Heart 3- Muscle 4- Peripheral tissues 5- Liver |
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________ resides on the capillary walls of most tissues, especially the adipose tissue and cardiac and skeletal muscles. It is activated by apoC-II on circulating lipoprotein particles.
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LPL.
It hydrolyzes the triacylglycerol to yield fatty acids (which go to peripheral cells) and glycerol (which goes to liver) |
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The presence of ________ results in increased synthesis and translocation of LPL.
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Insulin
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After being degraded by lipoprotein lipase, the chylomicron decreases in size and increases in density. The remaining particle is called a _________, which is removed from the circulation by the liver.
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remnant
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________ main function: transport dietary TG to tissues after meal containing fat is consumed.
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Chylomicron
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_______ main purpose is to transport endogenous TG to tissues.
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VLDL
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In __________ metabolism, IDL can either be metabolized by hepatic lipase and become LDL, or go through reuptake and return to the liver.
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Endogenous
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In _________ metabolism, chylomicrons go through lipoprotein lipase and become fatty acids and go to adipose and muscle tissue. While the remnant goes to the liver.
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Exogenous
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In _______ metabolism, VLDL is broken down by lipoprotein lipase into fatty acids, where it goes to muscle and adipose tissue, and then becomes IDL.
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Endogenous
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________ is produced in the liver and its function is to carry lipid from liver to peripheral tissues (mainly muscle and adipose)
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VLDL
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The dietary intake of both fat and carbohydrate, in excess of the needs of the body, leads to the conversion into _________ in liver.
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trigllycerides
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After degradation of triacylglycerol by lipoprotein lipase, VLDL is converted in the plasma to _________.
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LDL
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The ______ is present during the transition from VLDL to LDL in the plasma.
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IDL.
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_______ can also be taken up by cells through receptor-mediated endocytosis.
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IDLs
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_________ occurs in conditions where there is an imbalance between hepatic triacylglycerol synthesis and the secretion of VLDL.
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Fatty liver
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There are 5 causes of fatty livers:
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1- Diabetes mellitus
2- Hepatic lipidosis (cats) 3- Hepatitis 4- Chronic ethanol ingestion 5- Starvation |
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______ is the only apolipoprotein on LDL.
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ApoB100
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_______ delivers cholesterol and CE to tissues through its receptor. OR ______ is returned to the liver and HDL is released.
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LDL
LDL |
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________ is about 80% lipid, and have a high concentration of cholesterol and cholesteryl esters. Its function is as the primary plasma carriers of cholesterol for delivery to all tissues.
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LDL
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______ and _____ increase the binding of LDL to liver cells.
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Insulin and T3
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_______ decrease the binding of LDL to liver cells
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Glucocorticoids
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_______ is the precursor for steroid hormones and bile acids.
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Cholesterol
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_______ is assembled mainly in the liver and does not come from catabolism of any other LP. Its main role is to return cholesterol from periphery to liver or steroidogenic organs.
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HDL.
Dogs and cats are HDL animals. |
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In the fed state, there is excess _____ which diffuses out of mitochondria and is cleaved into OAA and acetyl-CoA.
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citrate
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Acetyl CoA is converted to ________ by acetylCoA-carboxylase.
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malonyl-CoA
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The conversion of acetyl CoA to malonyl CoA is ________ and is the rate limiting step in fatty acid biosynthesis.
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irreversible
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The __________ complex is when once malonyl CoA is synthesized, long carbon fatty acid chains can be assembled in a step-wise fasion; 2 carbons are added at each step.
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Fatty Acid synthase
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_________ is the process by which fatty acids, in the form of acyl-CoA are broken down in mitochondria to generate acetyl-CoA, the entry molecule for the Krebs cycle.
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Beta oxidation
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The _______ shuttle brings the fatty acid into the mitochondria for beta oxidation to occur.
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Carnitine
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______ regulates the carnitine shuttle. If it is high, the entry of fatty acids into the mitochondria is inhibited. Things are going well if this is high.
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Malonyl CoA
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The breakdown of fatty acids with an odd number of carbons, instead of producing acetyl CoA, the last round of beta oxidation produces 1 acetyl CoA and 1 ________.
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Propionyl CoA
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In the fed state, in the liver, glycolysis synthesizes _________
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fatty acids
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In the fed state, in the adipose, there is an uptake of fatty acids from ________ or ________, which synthesizes triacylglycerides
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chylomicrons
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In the fed state, the regulating hormone is ________
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insulin
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In the fasting state, in the liver, the breakdown of ________ released by adipose tissue synthesizes ________
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fatty acids;
ketone bodies |
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In the fasting state, in the adipose, fatty acids are produced from breaking down _____________
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triacylglycerides
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In the fasting state, the regulating hormone is _______-
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glucagon
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During fasting, the adipose tissues release FAs. These are taken up and oxidized by muscle and liver. The liver also increases gluconeogenesis during fasting (to produce glucose for the brain). OAA is consumed in gluconeogenesis. This lowers OAA in cells in the liver, so there is not enough OAA to be an acceptor in the TCA cycle for all the acetyl CoA produced by beta oxidation. These acetyl CoAs build up and combine with themselves, creating ________
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ketone bodies
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Ketone bodies are a sign of ________ deficiency
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insulin
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When insulin is high, ______ cannot enter the mitochondria. This is because when insulin is high, citrate is produced, which creates malonyl CoA. Malonyl CoA controls the carnitine shuttle which allows this to enter the mitochondria.
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Fatty acids
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When insulin is high, fatty acids are turned into _______
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triglycerides
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Acetone, acetoacetic acid, and beta-hydrozybutyric acid are all ___________
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ketone bodies
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Under normal condition, _________ are utilized as energy source in peripheral tissues, especially cardiac muscle and renal cortex.
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Ketone bodies
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Under starvation conditions, ketone bodies are used as energy for ________. This spares muscle protein from being used for gluconeogenesis.
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the brain.
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Ketone bodies in the tissues can be used to produce ________.
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acetyl CoA
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Because __________ is absent in the liver, the liver cannot utilize ketone bodies.
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CoA transferase
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