FATTY ACUD, KETONE BODY, AND TRIACYGLYCEROL METABOLISM Flashcards
are long-chain carboxylic acids. They are the main component of triglycerides, which are stored in fat cells and used for energy.
(Examples: palmitic, oleic, linoleic, stearic acids)
Fatty acids (FAs)
FAs are highly ____in water
insoluble
are also structural components of membrane lipids, such as phospholipids and glycolipids.
Fatty acids
They are ___ in nature (both hydrophilic and hydrophobic
amphipathic
are a type of lipid that are the building blocks of fats, oils, and waxes. They are carboxylic acids with a long, unbranched hydrocarbon chain
Fatty acids
Long-chain polyunsaturated FAs with first double bond starting with 3rd carbon from the methyl end.
Omega-3 fatty acids:
They reduce serum triglycerides, blood pressure and risk for heart disease
Omega-3 fatty acids:
Major source: Omega-3 fatty acids:
Fish (or in fatty fish, such as salmon, tuna, and mackerel.)
Long-chain polyunsaturated FAs with first double bond starting with 6th carbon from the methyl end .
They reduce serum cholesterol
Omega-6 fatty acids
Omega-6 fatty acids Major source:
Vegetable oils, nuts, and seeds.
are fatty acids that the body cannot produce on its own and must obtain from the diet.
Essential fatty acids (EFAs)
Symptoms of ___: dry, scaly skin, hair loss, and brittle nails
essential fatty acid deficiency
: is an omega-6 fatty acid.
Linoleic acid (precursor of arachidonic acid)
are essential for the production of prostaglandins
Omega-6 fatty acids
which are hormone-like substances that regulate a variety of cellular processes, including inflammation, blood pressure, and blood clotting.)
prostaglandins
is an omega-3 fatty acid.
Alpha-linolenic acid
are important for brain development,heart health, and inflammation
(Omega-3 fatty acids
Essential fatty acids are components of the ___, which is the outermost layer of the skin.
stratum corneum
Essential fatty acids are also involved in the production of ___ (lipids that are essential for maintaining the skin’s water barrier.)
ceramides
is the process by which the body makes fatty acids from scratch.
It occurs primarily in the liver, lactating mammary glands, and adipose tissue.
De Novo Synthesis of Fatty Acids
De Novo Synthesis of Fatty Acids Steps
Step 1: Production of Cytosolic Acetyl Coenzyme A
Step 2: Carboxylation of Acetyl Coenzyme A to Malonyl Coenzyme A
Step 3: Elongation of the Fatty Acid Chain
Step 4: Termination of the Fatty Acid Chain
where acetyl CoA is condensed with oxaloacetate to form citrate
citrate shuttle
Acetyl CoA can also be synthesized from pyruvate in the cytosol. This occurs through a series of reactions known as ___
glycolysis
Once cytosolic acetyl CoA is available, it is carboxylated to malonyl CoA by ___
acetyl CoA carboxylase (ACC
The fatty acid chain is elongated by the addition of two-carbon units from malonyl CoA. This process is catalyzed by ___
fatty acid synthase (FAS).
When dietary fat intake is ____, the rate of de novo fatty acid synthesis decreases.
high
insulin -__ the rate of de novo fatty acid synthesis,
stimulates
epinephrine and glucagon __it.
inhibit
is allosterically activated by citrate
acetyl CoA carboxylase (ACC)
acetyl CoA carboxylase (ACC) is allosterically activated by citrate and ___by long-chain fatty acyl CoA
inactivated
the primary form of energy storage in the body.
Constitutes majority of dietary lipids
synthesized in the liver and adipose tissue.
Stored in adipocytes (fat cells) as energy reservoir.
Triacylglycerols or Triglycerides (TAGs)
TAGs are synthesized from ___
glycerol 3-phosphate and fatty acyl
is the process of breaking down TAGs into fatty acids and glycerol.
Lipolysis
Lipolysis is initiated by ___, which generates a diacylglycerol.
adipose triglyceride lipase (ATGL)
__ then converts the diacylglycerol to a monoacylglycerol.
Hormone-sensitive lipase (HSL)
___ converts the monoacylglycerol to glycerol and a free fatty acid.
monoacylglycerol lipase
is the key enzyme in lipolysis.
HSL
Insulin inhibits lipolysis by:
dephosphorylating HSL and,
by suppressing the expression of ATGL
Red blood cells and the brain cannot use fatty acids for energy because they lack ___
mitochondria
Over 50% of the fatty acids released from adipose TAGs are reesterified to ___
glycerol 3-phosphate
are three water-soluble compounds (acetoacetate, β-hydroxybutyrate, and acetone) that are produced by the liver from fatty acids. They act as an alternative fuel source when glucose levels are low.
Ketone bodies
produced in the liver through a process called ___. is activated when glucose levels are low, such as during fasting or prolonged exercise.
ketogenesis. Ketogenesis
Ketone bodies are __in water.
soluble
most abundant ketone body
3-hydroxybutyrate
___ converts 3-hydroxybutyrate to acetoacetate.
3-hydroxybutyrate dehydrogenase (3-HBDH)
___converts acetoacetate to acetoacetyl CoA.
acetoacetate CoA transferase (thiophorase)
If the rate of ketone body production exceeds the rate of ketone body utilization, ketone bodies will begin to accumulate in the blood (ketonemia) and urine (ketonuria). This is known as
diabetic ketoacidosis (DKA).
symptoms:
Fruity odor on the breath
Nausea and vomiting
Abdominal pain
Shortness of breath
Confusion
Drowsiness
diabetic ketoacidosis (DKA).
