Chapter 2: Essentials of Bioenergetics and Anaerobic Metabolic Pathways

Flashcards covering key vocabulary from the lecture on Bioenergetics and Anaerobic Metabolic Pathways, including energy sources, ATP production, and the ATP-PC and Glycolysis systems.

Bioenergetics

The chemical process of converting food into energy, also referred to as Metabolism.

Forms of Energy

Chemical, Electrical, Heat, and Mechanical.

Carbohydrates

A rapid, readily available source of energy, existing as monosaccharides, disaccharides, and polysaccharides.

Monosaccharides

Simple sugars like glucose, fructose, and galactose.

Disaccharides

Sugars composed of two monosaccharides, such as maltose and sucrose.

Polysaccharides

Complex carbohydrates like starch, cellulose, and glycogen.

Glucose

A simple sugar (monosaccharide) also known as blood sugar, used for energy or stored as glycogen.

Glycogen

The storage form of glucose in animals, typically stored in muscle and liver.

Glycogenesis

The formation of glycogen from glucose.

Glycogenolysis

The breaking down of glycogen into glucose.

Fats

Metabolized for energy and found in both plant and animal tissues.

Fatty Acid

Composed of an even number of 4 to 24 carbon atoms bound in a chain; can be saturated or unsaturated.

Triglyceride

The storage form of fatty acids in fat cells, consisting of a glycerol molecule plus three fatty acids.

Saturated Fatty Acid

Contains the maximal number of hydrogen atoms and no double bonds.

Unsaturated Fatty Acid

Does not contain the maximal number of hydrogen atoms and has at least one double bond.

Monounsaturated Fatty Acid

A fatty acid with at least one double bond.

Polyunsaturated Fatty Acid

A fatty acid with more than one double bond.

Lipolysis

The process of breaking down triglycerides into three fatty acids and glycerol when needed for energy.

Glycerol

A component of triglycerides that cannot be metabolized by muscle but can be used to synthesize glucose at the liver.

Proteins

Composed of approximately 20 amino acids; only a small amount is metabolized to provide energy.

Essential Amino Acids

Amino acids that must be ingested in food because the body cannot synthesize them.

Nonessential Amino Acids

Amino acids that can be synthesized by the body.

Enzymes

Protein molecules that facilitate a chemical reaction by lowering the energy of activation, thereby speeding it up without initiating it.

Rate-Limiting Enzyme

In multistep reactions, the enzyme that typically controls the overall speed of the reaction.

Catabolic Reaction

The breaking down of a substrate into smaller molecules, releasing energy (often indicated by the suffix -ase).

Anabolic Reaction

The process of using energy to form a product from separate molecules.

Mass Action Effect

The principle that the concentration of substrates and products determines the direction a chemical reaction will proceed.

Coenzymes

Organic molecules, often B vitamins, required by certain enzymatic reactions to facilitate metabolic processes.

Adenosine Triphosphate (ATP)

The most important energy molecule in cells, composed of adenine, ribose, and three phosphate molecules, and a product of both aerobic and anaerobic metabolism.

ATP Breakdown

The hydrolysis of ATP (ATP + H2O) to ADP, inorganic phosphate (Pi), H+, and energy.

Adenosine Diphosphate (ADP)

A molecule formed when ATP loses one phosphate group and releases energy.

Inorganic Phosphate (Pi)

A phosphate ion released during the hydrolysis of ATP.

Anaerobic Metabolism

Energy production pathways that do not require oxygen, emphasized during short, high-intensity activities.

Aerobic Metabolism

Energy production pathways that require oxygen and occur in the mitochondria, emphasized during activities lasting longer than 3 minutes.

ATP-PC System

The primary anaerobic energy system providing energy for the first 30 seconds of short, high-intensity activities like sprints and weight lifting.

Glycolysis (Time Frame)

An energy system that produces ATP anaerobically, predominating during high-intensity activities lasting from 30 seconds to 3 minutes.

ATP-Phosphocreatine (ATP-PC) System

Also known as the phosphagen system, it quickly replenishes ATP using phosphocreatine during short, intense bursts of activity.

Phosphocreatine (PC)

A high-energy phosphate compound that rapidly donates Pi to ADP to replenish ATP in the ATP-PC system.

Creatine Kinase

The enzyme that breaks phosphocreatine (PC) into creatine and inorganic phosphate (Pi) to facilitate ATP replenishment.

ATP-PC System Adaptations to Training

Increases in the activity of enzymes like creatine kinase and, with anaerobic training, increased intramuscular concentrations of ATP and PC at rest.

Glycolysis

A series of 10 enzymatic reactions in the sarcoplasm that metabolize glucose to produce ATP, without directly using oxygen. Provides energy for the first 2.5 minutes of exercise.

Pyruvate (Aerobic Fate)

The end product of glycolysis that can be converted to acetyl-CoA and enter aerobic pathways.

Pyruvate (Anaerobic Fate)

The end product of glycolysis that can be converted to lactate when aerobic metabolism cannot accept hydrogens.

Cori Cycle

The metabolic pathway in which lactate produced by anaerobic glycolysis in muscles is transported to the liver and converted to glucose.

Nicotinamide Adenine Dinucleotide (NAD+)

A coenzyme that accepts hydrogens produced during glycolysis, becoming NADH.

NADH

The reduced form of NAD+ that transports hydrogens to mitochondria for use in aerobic metabolism.

Lactate Energy System

Another name for glycolysis, particularly when pyruvate accepts hydrogens to become lactate.

Glycogen Phosphorylase

A glycolytic enzyme responsible for breaking down intramuscular glycogen into glucose.

Phosphofructokinase (PFK)

A rate-limiting enzyme in glycolysis, crucial for controlling the speed of the pathway.

Lactate Dehydrogenase (LDH)

An enzyme that converts pyruvate to lactate.

Intramuscular (IM) Glycogen Adaptations

Increases in stored glycogen within muscles due to training, affecting both glycolytic and aerobic ATP production.

Buffering Capacity Adaptations

Improvements in skeletal muscle's ability to buffer hydrogen ion acidity produced during glycolysis can enhance performance and recovery.

Intracellular Buffers

Substances within skeletal muscle, such as proteins, phosphate groups, and bicarbonate, that help neutralize H+ ions.

Bicarbonate (NaHCO3)

A chemical buffer that combines with H+ ions to form carbonic acid (H2CO3), a weaker acid, reducing intramuscular acidity.

Energy Contribution During 3-Second Sprint

The ATP-PC system dominates (55%), followed by intramuscular ATP (32%), anaerobic glycolysis (10%), and minimal aerobic metabolism (3%).