Dietary Energy and Cellular Respiration

These flashcards cover key concepts relating to dietary energy, cellular respiration, and the impact of macronutrients on energy balance and health.

What is obesity?

Having an unhealthy amount of body fat; often referred to as America’s #1 health crisis.

What is Body Mass Index (BMI)?

A measure that estimates body fat based on height and weight.

What causes obesity?

Obesity occurs due to long-term energy imbalance, where energy intake exceeds energy expenditure.

How is food energy measured?

Food energy is measured in calories (lowercase c) and Calories (capital C, where 1 Calorie = 1,000 calories).

How much energy do fat, protein, and carbohydrates contain?

Fat: 9 C/g; Protein and carbohydrate: 4 C/g; Nucleic acids are not a significant source of stored energy.

What is Nonexercise Activity Thermogenesis (NEAT)?

NEAT involves daily activities like yard work and walking that contribute to calorie burning distinct from formal exercise.

What happens during aerobic respiration?

Aerobic respiration is a series of reactions that converts stored food energy into ATP in the presence of oxygen.

What are the three stages of aerobic respiration?

Glycolysis, citric acid cycle, and electron transport chain.

What occurs during glycolysis?

Glycolysis breaks down sugar into smaller units (pyruvate) and occurs in the cytoplasm.

What is the role of NAD+ in the citric acid cycle?

NAD+ picks up and transfers high-energy electrons during the reactions that extract energy from food.

What is the electron transport chain?

A series of reactions in the inner mitochondrial membrane where electrons flow down a chain of molecules, leading to ATP production.

What is fermentation?

An anaerobic process that occurs when oxygen is scarce, enabling glycolysis to continue and producing lactic acid or alcohol, along with a small amount of ATP.

How do humans store excess energy?

As glycogen in muscle and liver cells for short-term energy, and as triglycerides in fat cells for long-term storage.

How do photosynthesis and respiration relate to energy conversion?

They form a continuous cycle, with the outputs of one process serving as the inputs of the other, conserving energy.

What happens to excess calories not utilized in energy?

Excess calories are stored as glycogen and triglycerides.