Chapter 22 - Gross Metabolism-1

What are the two competing behavioral states involved in the control of food intake?

Appetite (or hunger) and satiety.

What is the function of the hypothalamus in appetite regulation?

The hypothalamus contains two control centers: the feeding center and the satiety center.

What theories explain the regulation of appetite?

Glucostatic theory and lipostatic theory.

What are the three categories of work done by our cells?

Transport work, mechanical work, and chemical work.

What is the difference between an anabolic pathway and a catabolic pathway?

Anabolic pathways synthesize larger molecules from smaller ones; catabolic pathways break down large molecules into smaller ones.

What is glycogenesis?

The synthesis of glycogen from glucose.

What is the role of glucagon in metabolism?

Glucagon raises plasma glucose levels by promoting glycogenolysis and gluconeogenesis, especially in the fasted state.

What is the dominant hormone in the fed state?

Insulin.

What impact does the balance of insulin and glucagon have on metabolism?

It regulates the metabolism: insulin dominates in the fed state while glucagon dominates in the fasting state.

What factors influence metabolic rate?

Age, sex, amount of lean muscle mass, activity level, diet and diet-induced thermogenesis, hormones, and genetics.

What are some key fates of ingested biomolecules?

Energy to do mechanical work, synthesis for growth and maintenance, and storage as glycogen or fat.

What stimulates the release of insulin?

Increased plasma glucose, increased plasma amino acids, feedforward effects of gastrointestinal hormones, and parasympathetic activity.

What is lipolysis?

The breakdown of triglycerides into free fatty acids and glycerol.

What is the function of leptin in appetite control?

Leptin decreases food intake and increases energy expenditure.

What is the primary energy source for brain metabolism during fasting?

Glucose and ketone bodies.

What is the end result of glycogenolysis?

The conversion of glycogen into glucose.

What mechanisms do insulin and glucagon use to exert their effects?

Insulin uses receptor tyrosine kinase signaling, while glucagon uses G protein-coupled receptors linked to cAMP signaling.

What is the role of the pancreas in metabolic control?

It secretes hormones like insulin and glucagon that regulate blood glucose levels.

What happens to free fatty acids during fasted-state metabolism?

They undergo beta-oxidation to produce acetyl CoA for energy production.

How does exercise impact energy balance?

Conscious increases in energy output through physical activity can help manage energy balance.

What is the relationship between low-density lipoprotein cholesterol (LDL-C) and heart disease risk?

High levels of LDL-C are associated with increased risk of atherosclerosis and coronary heart disease.

What role does insulin play in fat synthesis?

Insulin promotes the synthesis of fats from non-lipid precursors during fed-state metabolism.

What is deamination and what does it produce?

Deamination is the removal of the amino group from an amino acid, producing ammonia and an organic acid.