Untitled Quiz

Study Notes

ATP is the primary energy currency in the human body.
It is formed from the breakdown of carbohydrates, fatty acids, and proteins through various metabolic processes.
Carbohydrates are broken down through glycolysis, a process that produces ATP.
Fatty acids are broken down through oxidation, producing ATP.
Proteins are broken down through hydrolysis, also producing ATP.

Phosphocreatine is a high-energy phosphate molecule, serving as a storage reservoir of energy.
Excess ATP can be converted into phosphocreatine, allowing for reversible conversion back to ATP during periods of high energy demand.
Phosphocreatine plays a crucial role in recycling ATP during muscle activity, providing readily available energy for muscle contractions.

Anaerobic respiration occurs when oxygen supply becomes limited, such as during intense exercise or acute hypoxia.
The body uses anaerobic pathways to generate ATP, producing lactic acid as a byproduct.
Oxygen debt arises during anaerobic respiration, requiring additional oxygen to replenish ATP stores, convert lactic acid back to glucose, and restore normal oxygen levels in the body.

The rate of enzyme-catalyzed reactions, and thus energy release, is influenced by multiple factors:
- Enzyme concentration: higher enzyme concentrations generally lead to faster reaction rates.
- Substrate concentration: increasing substrate concentration usually enhances the rate of reaction.
- Rate limiting step: the slowest step in a metabolic pathway controls the overall rate of the pathway.
- ADP concentration: high ADP levels stimulate energy production, signaling the need for more ATP.

Metabolic rate refers to the rate of energy expenditure within the body, typically measured by heat production.
Not all energy from food is converted into ATP; a significant portion is released as heat.
Calorimetry is used to measure metabolic rate, using direct or indirect methods.
- Direct calorimetry: measures heat liberated from the body.
- Indirect calorimetry: measures oxygen consumption, using the energy equivalent of oxygen to estimate metabolic rate.

Energy output is influenced by various factors:
- Physical activities: increased physical activity raises energy expenditure.
- Essential metabolic functions: the body's basic metabolic processes require energy.
- Digestion, absorption, and processing of food: the energy demands of these processes contribute to overall energy output.
- Maintaining body temperature: the body expends energy to maintain a stable internal temperature.

BMR represents the minimum energy required to maintain essential body functions at rest.
It is measured after a period of rest and fasting, under comfortable environmental conditions.
Factors influencing BMR include:
- Thyroid hormone: elevated thyroid hormone levels increase BMR.
- Testosterone: high testosterone levels can increase BMR.
- Growth hormone: growth hormone increases BMR.
- Fever: fever increases metabolic rate.
- Sleep: BMR decreases during sleep.
- Malnutrition: malnutrition typically lowers BMR.

The thermogenic effect of food refers to the increase in metabolic rate following a meal due to the energy demands of digestion, absorption, and storage.
Different food types have varying thermogenic effects, with protein generally exhibiting a higher thermogenic effect than carbohydrates or fats.