Lipid Metabolism

What is the main energy currency of the cell?

ATP (adenosine triphosphate)

What percentage of energy produced in the human body is used to accomplish work?

~20%

What are the main sources of fuel in humans?

Liver glycogen, muscle glycogen, blood glucose, fat, and protein

Which metabolic process occurs in the absence of oxygen?

Anaerobic metabolism (glycolysis and glycogenolysis)

Which metabolic process uses oxygen?

Aerobic metabolism (oxidation of glucose, fat, and amino acids)

What is glycogenesis?

The synthesis of glycogen

What is glycolysis?

The oxidation of glucose

What is the function of the Krebs cycle?

Oxidation of pyruvate and acetyl CoA to generate ATP

Which hormone predominates in the fed state?

Insulin

Which hormone predominates in the fasting state?

Glucagon

What is the role of peroxisomes in lipid metabolism?

They break down very long-chain fatty acids

Which enzyme is responsible for activating fatty acids for beta-oxidation?

Acyl-CoA synthetase

What are the three primary ketone bodies?

Acetoacetate, beta-hydroxybutyrate, and acetone

Which tissue primarily uses ketone bodies during prolonged fasting?

The brain

What is fatty liver disease and what causes it?

Excess fat accumulation in the liver, often due to alcoholism or obesity

What is the function of phospholipids in the body?

They are essential components of cell membranes

Which hormone inhibits lipolysis in adipose tissue?

Insulin

What happens to excess cholesterol in the body?

It is excreted in bile or converted to bile acids

What is the significance of omega-3 fatty acids?

They reduce inflammation and support cardiovascular health

Which organ regulates lipid homeostasis?

The liver

What are eicosanoids?

Lipid-derived signaling molecules involved in inflammation and immunity

Which enzyme converts acetyl-CoA into malonyl-CoA?

Acetyl-CoA carboxylase

What is the role of bile in lipid digestion?

It emulsifies fats for better enzyme action

Which fatty acid transport protein facilitates uptake into cells?

Fatty acid translocase (CD36)

How does fasting impact lipid metabolism?

It increases lipolysis and ketogenesis

What is the function of sphingolipids?

They are involved in cell signaling and membrane structure

Which enzyme is responsible for breaking down stored triglycerides?

Hormone-sensitive lipase

What is the main regulatory factor of fatty acid oxidation?

Carnitine shuttle availability

What is the primary storage form of fatty acids in adipose tissue?

Triglycerides

Which enzyme catalyzes the final step of cholesterol synthesis?

Squalene monooxygenase