Metabolism Lecture Notes

Flashcards for metabolism, catabolism, anabolism, glycolysis, citric acid cycle, oxidative phosphorylation, nutrient metabolism pathways, vitamins, food energy content, and disorders.

What is metabolism?

The sum of catabolic and anabolic reactions; the sum of all chemical reactions that occur in an organism.

What is catabolism?

The breakdown of organic substrates in the body; an exergonic process that releases heat.

What is anabolism?

The synthesis of new organic molecules; a build-up process that is endergonic and requires energy.

What is Glycolysis?

The first step in glucose catabolism, an anaerobic process that breaks down a 6-carbon glucose into two 3-carbon pyruvates in the cytoplasm.

What are the end products of Glycolysis?

2 net ATP, 2 NADH, and 2 pyruvate molecules.

What is the Citric Acid Cycle (Krebs Cycle)?

A cycle which transfers hydrogen atoms to coenzymes and requires oxygen (aerobic metabolism); pyruvate is converted to Acetyl-CoA to enter the cycle.

What is the net energy gain in the Citric Acid Cycle per glucose molecule?

1 ATP (the cycle turns twice per glucose molecule)

What is Oxidative Phosphorylation?

An energy-making process in the cristae, where the electron transport chain establishes a proton gradient; it generates ATP within the mitochondria, requires coenzymes, and consumes oxygen.

What percentage of ATP is produced by Oxidative Phosphorylation?

More than 90% of ATP in the body.

What is Glycogenesis?

The anabolic formation of glycogen from glucose; an endergonic process that requires energy.

What is Glycogenolysis?

The catabolic breakdown of glycogen into glucose; an exergonic process.

What is Gluconeogenesis?

The formation of glucose from non-carbohydrates (proteins or fats).

What is the function of Salivary amylase?

Begins chemical digestion of complex carbs in the oral cavity.

What is the function of Lingual Lipase?

Begins chemical digestion of lipids in the oral cavity.

What is the function of Pepsin?

Begins protein digestion in the stomach; pepsinogen is converted to pepsin by stomach acid.

What is the importance of Peyer's patches?

They protect against infection in the Jejunum + Ileum.

What are the fat-soluble vitamins?

A, D, E, and K.

What are the water-soluble vitamins?

All vitamins except A, D, E, and K (B and C).

Why do most water-soluble vitamins need to be consumed daily?

Because they are not stored in the body (exceptions: B12 and C).

What is the energy yield per gram of Carbohydrates?

4.18 calories/gram

What is the energy yield per gram of Proteins?

4.32 calories/gram

What is the energy yield per gram of Lipids?

9.46 calories/gram

What is Anorexia Nervosa?

Self-induced starvation or lack/loss of appetite.

What is Bulimia?

A disorder characterized by eating binges followed by induced vomiting.

What is Phenylketonuria (PKU)?

A metabolic disorder where individuals lack the enzymes to convert phenylalanine to tyrosine, which is essential in the synthesis of norepinephrine, epinephrine, dopamine, and melanin.

What is Kwashiorkor?

Protein deficiency.

What is ketoacidosis?

A condition resulting from restricting carbohydrate intake or in Type 2 Diabetes when glucose supplies are limited (inside the cell), leading to acidic blood and ketosis.

What is Gout?

A disorder caused by overconsumption of purine-containing food.

List the four methods of Heat transfer.

Radiation, Evaporation, Convection, and Conduction