Biol 122 – Fall 2021 Exam 4 Study Guide Chapter 25 – Metabolism (Vocabulary Flashcards)

Vocabulary flashcards covering key metabolism concepts from Chapter 25, including digestion, absorption, energy pathways, hormones, lipoproteins, and energy balance.

Monoglycerides

Digestion products of triglycerides; absorbed by intestinal cells and reassembled into triglycerides for transport in chylomicrons.

Fatty acids

Free fatty acids produced by lipase digestion; absorbed into enterocytes for energy or re-esterification into triglycerides.

Glycerol

Glycerol absorbed from fat digestion; can enter glycolysis or be converted to glucose in the liver.

Monosaccharides

Absorbed simple sugars (glucose, galactose, fructose) derived from carbohydrate digestion.

Amino acids

Digestion products of proteins; absorbed into the bloodstream for protein synthesis or energy.

Glycogenesis

Storage of glucose as glycogen in liver and skeletal muscle during the absorptive state.

Lipogenesis

Synthesis of fatty acids and triglycerides from excess carbohydrates or proteins for storage.

Glycolysis

Glucose-to-pyruvate pathway in the cytosol; yields net 2 ATP and 2 NADH per glucose.

Beta-oxidation

Breakdown of fatty acids in mitochondria to acetyl-CoA, generating NADH and FADH2.

Acetyl-CoA

Central metabolic intermediate produced by beta-oxidation (and glycolysis); enters the citric acid cycle.

NADH

Electron carrier produced in glycolysis, the Krebs cycle, and beta-oxidation; powers ATP production via the ETC.

FADH2

Electron carrier produced in beta-oxidation and the Krebs cycle; donates electrons to the ETC.

Mitochondrion

Organelle where most ATP is produced via aerobic respiration.

Cytosol

Cellular compartment where glycolysis occurs.

Krebs cycle (Citric acid cycle)

TCA cycle in the mitochondrial matrix; oxidizes acetyl-CoA to CO2, yielding NADH, FADH2, and GTP/ATP.

Electron transport chain

Set of protein complexes in the inner mitochondrial membrane that transfer electrons and drive ATP synthesis.

Glycolysis ATP yield

Net production of 2 ATP per glucose during glycolysis.

Krebs cycle ATP yield

Approximately 2 ATP (as GTP) per glucose via two turns of the cycle.

Electron transport chain ATP yield

About 26–28 ATP per glucose from oxidative phosphorylation (varies by conditions).

Lipoproteins

Particle complexes that transport lipids (triglycerides, cholesterol) in the blood.

HDL (high-density lipoprotein)

Transports cholesterol from tissues to liver for disposal; often termed 'good' cholesterol.

LDL (low-density lipoprotein)

Transports cholesterol to tissues; high levels can contribute to atherosclerosis; termed 'bad' cholesterol.

Lipoprotein lipase

Endothelial enzyme that hydrolyzes triglycerides in chylomicrons and VLDL to release fatty acids for tissue uptake.

Cholesterol transport (HDL vs LDL)

HDL returns cholesterol to liver; LDL delivers cholesterol to tissues; balance affects cardiovascular risk.

Hunger center

Hypothalamic region that drives the sensation of hunger.

Lateral hypothalamus

Part of the hypothalamus that promotes feeding (hunger) when activated.

Ventromedial hypothalamus

Hypothalamic center that promotes satiety and reduces feeding when activated.

Ghrelin

Stomach-derived hormone that stimulates hunger; rises before meals and falls after eating.

Leptin

Hormone from adipose tissue signaling energy stores; reduces appetite and increases energy expenditure.

Insulin

Pancreatic hormone promoting glucose uptake and storage; suppresses hunger in the fed state.

Glucagon

Pancreatic hormone raising blood glucose during fasting; promotes energy mobilization and can increase hunger.

CCK (cholecystokinin)

Digestive hormone that promotes satiety after meals and slows gastric emptying.

Neuropeptide Y (NPY)

Hypothalamic peptide that strongly stimulates appetite.

Peptide YY (PPY)

Intestinal hormone released after meals that reduces appetite.

BMR (basal metabolic rate)

Minimum energy expended at rest to maintain vital functions; influenced by age, hormones, and body composition.

TMR (total metabolic rate)

Total energy expenditure including basal metabolism and physical activity.

Absorptive state

Post-meal period when nutrients enter the bloodstream and insulin dominates; energy is used and stored.

Postabsorptive state

Between meals when nutrients are not absorbed; energy is supplied by stores and glucagon/other hormones dominate.

Vitamins, fat-soluble

A, D, E, K; stored in fat tissues; operate as coenzymes and in antioxidant roles.

Vitamins, water-soluble

C and B-complex vitamins; not stored extensively and must be consumed regularly; serve as coenzymes in metabolism.

Minerals

Inorganic nutrients acting as cofactors, electrolytes, or structural components (e.g., Ca, P, K, Fe, Mg).