Chp 7: Metabolism: From Food to Life

Stored triglycerides are an important source of energy during fasting. As fasting is prolonged, the body adapts to use this form of energy in different ways. Which of the following statements correctly describes lipid metabolism during the fasting state?

Fatty acids are rapidly broken down from adipose tissues and converted to ketone bodies during the later stages of the fasting state.

____ is the process in which excess glucose or amino acids are converted into fatty acids to be stored as a triglyceride in the adipose cells.

Lipogenesis

Fatty acids are cleaved from the glycerol backbone to yield free fatty acids in a process called

Lipolysis

Anabolic Processes during Fed State:

-Excess glucose is stored as glycogen in the liver and muscle. -Excess amino acids are converted to fatty acids and stored as triglycerides in the adipose tissue. -Amino acids from the amino acid pool are used to replace old proteins. -Excess fatty acids combine with glycerol to form triglycerides, which are stored in adipose tissue.

Processes in Long-Term Fasting:

-Fatty acids are converted to ketone bodies that can be utilized for fuel by all cells and tissues except red blood cells. -The liver utilizes single amino acids from the catabolism of muscle for gluconeogenesis.

Catabolic Processes during the Fed State:

-Glucose is used as the primary fuel for energy. -Dietary carbohydrate from a meal is digested and absorbed as monosaccharides, mainly glucose. -Dietary protein from a meal is digested and absorbed as single amino acids. -Dietary fat from a meal is digested and absorbed as monoglycerides, free fatty acids, and glycerol.

Processes in Short-Term Fasting:

-Glycogen degradation in the liver helps maintain blood glucose levels. -Glucose from glycogen degradation in muscle is used for energy by the muscle cells.

Processes in Long-Term and Short-Term Fasting:

-Triglycerides in adipose tissue are broken down during lipolysis to provide fatty acids for energy. -Glucose is used as a fuel source for red blood cells, brain cells, and other tissues.

The process of converting excess glucose to glycogen in the liver and muscle is a(n) ______ reaction

Anabolic

Anabolic reactions are those that combine smaller compounds to build larger compounds. Anabolic reactions are favored over catabolic reactions during the fed state. Which of the following statements is correct regarding the anabolic reactions that occur during the fed state?

During the fed state, glycogen synthesis is favored to store excess glucose as glycogen in the liver and the muscle.

Part complete Short-term fasting states occur for most people every day. However, if fasting is prolonged, the body must make more drastic adaptations to make up for the lack of glucose and energy. Which of the following statements correctly describes protein metabolism during the fasting state?

Glucogenic amino acids are used to produce glucose through gluconeogenesis during the fasting state.

The formation of glucose from noncarbohydrate sources such as glucogenic amino acids is called

Gluconeogenesis

The process in which glucose is broken down to yield pyruvate and energy is called

Glycolysis

Part complete Both catabolic and anabolic reactions are regulated by hormones. When the endocrine system detects a change in the concentration of nutrients, such as glucose levels dropping below normal, hormones are released to activate or deactivate the enzymes in the metabolic pathways. Which of the following statements is correct regarding the hormonal control of metabolism during the fed state?

Insulin released from the pancreas stimulates glycogen synthesis, lipogenesis, and protein synthesis.

Part complete The brain adapts during periods of fasting when energy and carbohydrate intake are low, but it still needs some glucose for fuel. Which of the following statements correctly describes carbohydrate metabolism during the fasting state?

Muscle glycogen stores are depleted early in the fasting state.