Lipid Metabolism and Biochemistry

These flashcards cover key vocabulary and definitions relevant to the lecture material regarding lipid metabolism and biochemistry.

Exogenous Lipid Assimilation

The absorption of dietary lipids from food.

Endogenous Lipid Assimilation

Synthesis of fatty acids from excess dietary carbohydrates and proteins.

Chyme

The semi-fluid mass of partially digested food that combines with bile in the small intestine.

Chylomicron

A lipoprotein that transports dietary lipids from the intestines to other locations in the body.

Triacylglycerol Resynthesis

The process of reforming triacylglycerols from fatty acids inside the intestinal epithelial cells.

Apolipoprotein

A protein that binds lipids to form lipoproteins, essential for the transport of lipids in blood.

Hydrolysis Reaction

A chemical reaction where water is used to break down compounds; in lipids, this is catalyzed by esterases.

Epinephrine

A hormone that stimulates the breakdown of fat in adipocytes when glucose levels are low.

Fatty Acid Oxidation

The metabolic pathway for the breakdown of fatty acids into acetyl-CoA for energy production.

Carnitine Shuttle

A transport mechanism that facilitates the transfer of fatty acyl-CoA into mitochondria for β-oxidation.

β-Oxidation

The metabolic process that breaks down fatty acids into acetyl-CoA units.

Acyl Coenzyme A

An activated form of fatty acids that is converted into acetyl-CoA in mitochondrial oxidation.

Isomerase

An enzyme that catalyzes the conversion of one isomer to another, such as converting cis double bonds to trans.

Excess Acetyl-CoA

A byproduct of fatty acid oxidation that leads to the formation of ketone bodies during excess energy production.

Acetoacetate

The first ketone body produced from acetyl-CoA; serves as an energy source during fasting.

NADH

A coenzyme that carries electrons in metabolic reactions, used in the conversion of acetoacetate to β-hydroxybutyrate.

Krebs Cycle

A series of enzymatic reactions in the mitochondria, oxidizing acetyl-CoA to produce energy.

Citrate Shuttle

A mechanism by which acetyl-CoA is transported from the mitochondria to the cytosol.

Palmitate

A saturated fatty acid and a primary product of fatty acid biosynthesis.

Elongases

Enzymes that add carbon atoms to fatty acid chains during biosynthesis.

Desaturases

Enzymes that introduce double bonds into fatty acid chains.

NADPH

A reducing agent that provides the necessary electrons for fatty acid biosynthesis.

Cholesterol

A sterol that is a critical component of cell membranes and a precursor for steroid hormones.

HMG-CoA Reductase

The rate-controlling enzyme in cholesterol biosynthesis that uses NADPH.

Isopentenyl-PP

A key intermediate in the cholesterol biosynthesis pathway.

Eicosanoids

Signaling molecules derived from arachidonic acid involved in inflammation and other physiological processes.

Sphingolipids

A class of lipids that form part of the cell membrane structure and play roles in cell signaling.

Neiman-Pick Disease

A genetic disorder relating to sphingolipid metabolism causing various health issues, including neurological impairments.

Fasted State

Condition in which the body relies on stored energy, including fatty acid breakdown, for fuel.

Ketone Body Synthesis

The production of ketone bodies from excess acetyl-CoA in the liver during starvation or low carbohydrate intake.

Fatty Acid Activation

The conversion of fatty acids into acyl-CoA prior to entering the mitochondria for oxidation.

Malonyl-CoA

A key regulatory compound in fatty acid biosynthesis that inhibits fatty acid oxidation.

AMP Kinase

An enzyme that regulates energy balance and plays a role in increasing glucose uptake during exercise.

Diabetes Type 1

A condition characterized by insufficient insulin production due to impaired pancreatic β cells.

Diabetes Type 2

A condition resulting from insulin resistance and often associated with obesity.

Eicosanoids Metabolism

The pathway through which fatty acids, particularly arachidonic acid, are converted into signaling molecules.

Acetone

A volatile ketone body produced from the non-enzymatic decarboxylation of acetoacetate.

Carbon Chain Length in Fatty Acids

Fatty acids generally have chains of 14, 16, or 18 carbons.

Cytosolic Acetyl-CoA

Acetyl-CoA produced in mitochondria and exported to the cytosol for fatty acid synthesis.

Ketone Body Utilization

The process by which tissues, such as heart and brain, utilize ketone bodies for energy.

Substrate-level phosphorylation

A type of metabolic reaction that generates ATP without the need for oxygen or electron transport chain.

Bile Emulsification

The process of breaking down large fat globules into smaller droplets, facilitating lipid digestion.

Protein modification by lipids

The attachment of lipid molecules to proteins, affecting their function and location.

VLDL (Very Low-Density Lipoprotein)

A type of lipoprotein that transports endogenous triglycerides synthesized in the liver.

Lipid Synthesis Regulatory Factors

Molecules that modulate the enzymes involved in lipid metabolic pathways.

Peroxisomes

Cell organelles responsible for the partial oxidation of very long chain fatty acids.

Fat Storage in Adipocytes

The process by which adipocytes synthesize and store triacylglycerols.

Plasma Membrane Structure

The lipid bilayer that forms the outer layer of cells, composed primarily of phospholipids and cholesterol.

Insulin's Role in Lipid Metabolism

A hormone that promotes lipid storage and inhibits fatty acid oxidation.

Triglyceride Breakdown

The hydrolysis of triglycerides into fatty acids and glycerol, stimulated in a fasted state.

Muscle Cell Energy Sources

Muscle cells utilize both fat and ketone bodies for energy, especially during exercise.

Mechanisms of Lipid Transition

The processes and regulations involved in switching between fed and fasted states for lipid metabolism.

Starvation Effects on Lipid Metabolism

The body's shifts to utilize fatty acids and ketone bodies as primary energy sources when food is scarce.

Skeletal Muscle and Lipids

Skeletal muscle can utilize fat and ketone bodies for energy, especially during prolonged exercise.