Biology: Energy for Living

Questions and Answers

What is the definition of energy in the biological context?

The capacity to perform work.

What are the primary biological fuels used by the human body to obtain energy?

Glucose and fatty acids.

What is the term for the minimum amount of energy required by the body to function at rest?

Basal metabolism.

What is the purpose of vitamins and minerals in energy metabolism?

To regulate energy metabolism. Signup and view all the answers

How does the body release energy from biological fuels?

By breaking bonds within the compounds' molecules. Signup and view all the answers

What is the 'rule of thumb' method used for in estimating daily basal metabolic energy needs?

To estimate a person's daily basal metabolic energy needs. Signup and view all the answers

What is the fate of energy in living systems?

Energy can be stored, released, moved, or transformed from one kind to another, but the total amount remains constant. Signup and view all the answers

What is the role of oxygen in human energy production?

Oxygen is used in the metabolism of biological fuels to release energy. Signup and view all the answers

What percentage of the energy from macronutrients is captured and stored in ATP?

40% Signup and view all the answers

What is the primary purpose of ATP?

To store energy until it is needed Signup and view all the answers

What is the term for the minimal number of calories the body uses for vital physiological activities after fasting and resting for 12 hours?

Basal metabolism Signup and view all the answers

What hormone regulates metabolism?

Thyroid hormone Signup and view all the answers

What is the term for the body’s rate of energy use a few hours after resting and eating?

Resting metabolic rate (RMR) Signup and view all the answers

What is the difference between BMR and RMR?

RMR is slightly higher than BMR Signup and view all the answers

What is the major factor that influences the metabolic rate?

Lean body mass Signup and view all the answers

Why do males generally have higher metabolic rates than women?

Because they tend to have more lean body mass Signup and view all the answers

What is the term for the energy cells use to carry out their activities?

Energy output or energy expenditure Signup and view all the answers

What is the term for all chemical changes, or reactions, that constantly occur in living cells?

Metabolism Signup and view all the answers

Why does a tall, slender person who weighs 150 pounds have a higher metabolic rate than a shorter person who also weighs 150 pounds?

Because the taller person's body has more surface area than the shorter person's body, resulting in more heat energy lost. Signup and view all the answers

What happens to the basal metabolic rate as one grows older?

It declines, primarily due to the loss of fat-free tissues such as muscle. Signup and view all the answers

Why do fat cells continue to develop throughout life?

When a person overeats consistently, fat cells can fill in spaces formerly occupied by muscle and organ tissues. Signup and view all the answers

What is the effect of very-low-calorie diets on the metabolic rate?

Very-low-calorie diets reduce the metabolic rate. Signup and view all the answers

What is the formula to estimate the daily metabolic rate for men?

1.0 kcal/kg/hr Signup and view all the answers

Why does a heavy person expend more kilocalories when performing the same physical activity?

The muscles of the heavier person must work harder to move the larger body. Signup and view all the answers

What is the effect of fever on the metabolic rate?

It increases the metabolic rate. Signup and view all the answers

Why does regular exercise help maintain a higher metabolic rate?

It helps build and preserve lean body mass. Signup and view all the answers

How does milk production in a female who has given birth affect the metabolic rate?

It increases the metabolic rate. Signup and view all the answers

Why does a person who is overfat need to reduce caloric intake to enhance the rate of weight loss?

To maintain a normal metabolic rate. Signup and view all the answers

According to Table 10.4, approximately how many kilocalories does a 150-pound person expend while walking at 3.5 mph for 30 minutes?

130 kcal Signup and view all the answers

What is nonexercise activity thermogenesis (NEAT), and what are some examples of NEAT activities?

NEAT is involuntary skeletal muscle activity, and examples include shivering, fidgeting, maintaining muscle tone, and maintaining body posture when not lying down. Signup and view all the answers

What is the thermic effect of food (TEF), and what percentage of total caloric intake does it typically represent?

TEF is the energy used to digest, absorb, and process macronutrients, and it typically represents 5-10% of total caloric intake. Signup and view all the answers

How can an individual manipulate their energy output to increase, decrease, or maintain their weight?

An individual can control the type, intensity, and duration of their physical activities to manipulate their energy output. Signup and view all the answers

What is the recommended limit for nonwork-related screen time, including activities involving computers and video games?

No more than 2 hours/day Signup and view all the answers

According to Table 10.4, which physical activity expends the most kilocalories per 30 minutes for a 150-pound person?

Cycling (15 mph) with approximately 408 kcal Signup and view all the answers

What is the estimated daily energy expenditure in kilocalories that can be attributed to NEAT for some individuals?

Up to 700 kcal Signup and view all the answers

How can an individual estimate their daily energy expenditure, according to the chapter?

By adding the kilocalories burned for basal metabolism, physical activity, and TEF in a day, or by using a formula published by the Food and Nutrition Board of the Institute of Medicine. Signup and view all the answers

What is the relationship between watching television and obesity, according to scientific studies?

Watching television is associated with obesity among children and adults. Signup and view all the answers

Why is it important to consider individual differences in energy expenditure when developing a weight management plan?

Because individual differences in energy expenditure can affect the success of a weight management plan, and tailoring the plan to an individual's needs can improve outcomes. Signup and view all the answers

Study Notes

Energy for Living

Energy is the capacity to perform work and is essential for the body's functions.
There are various forms of energy, including heat, mechanical, chemical, and electrical energy, which can be stored, released, moved, or transformed from one kind to another.

Energy Intake

The body uses a mixture of biological fuels (macronutrients) and oxygen to obtain energy.
Biological fuels are foods and beverages that contain macronutrients, such as glucose, fatty acids, and amino acids.
Cells release energy stored in biological fuels by breaking bonds within the molecules, capturing and storing it in compounds like ATP.

Energy Output

Energy output (energy expenditure) refers to the energy cells use to carry out their activities.
Energy output includes:
- Basal metabolism (energy used for vital physiological activities)
- Physical activity (voluntary skeletal muscle movement)
- Nonexercise activity thermogenesis (NEAT, involuntary skeletal muscle activity)
- Thermic effect of food (energy used for digestion, absorption, and processing of macronutrients)

Basal Metabolism

Basal metabolism is the minimal number of calories the body uses for vital physiological activities after fasting and resting for 12 hours.
Basal metabolic rate (BMR) is influenced by:
- Thyroid hormone
- Body composition (lean body mass)
- Sex
- Body surface area
- Age
BMR declines with age, primarily due to the loss of fat-free tissues like muscle.

Factors that Influence Metabolic Rate

Factors that increase metabolic rate:
- Fever
- Stimulant drugs (e.g., caffeine)
- Pregnancy
- Milk production in lactating females
- Recovery after exercise
- Emotional stress
Factors that decrease metabolic rate:
- Hypothyroidism (underactive thyroid gland)
- Low calorie intake

Calculating Metabolic Energy Needs

The "rule of thumb" formula for estimating daily metabolic rate:
- For men: 1.0 kcal/kg/hr
- For women: 0.9 kcal/kg/hr
Estimate daily basal metabolic rate by multiplying the hourly value by 24.

Physical Activity

Physical activity increases energy expenditure above basal energy needs.
Energy expenditure during physical activity depends on:
- Type and intensity of activity
- Duration of activity
- Weight of the person
A heavier person expends more kilocalories when performing the same activity.

Nonexercise Activity Thermogenesis (NEAT)

NEAT refers to involuntary skeletal muscle activity, such as shivering, fidgeting, and maintaining muscle tone.
NEAT can account for up to 700 kcal daily in some individuals.

Thermic Effect of Food (TEF)

TEF is the energy used for digestion, absorption, and processing of macronutrients.
TEF accounts for 5-10% of total caloric intake.

Putting It All Together

To estimate daily energy expenditure, add kilocalories burned for basal metabolism, physical activity, and TEF.
Use formulas published by the Food and Nutrition Board of the Institute of Medicine to estimate daily energy expenditure.

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Description

Test your knowledge on energy metabolism, basal metabolic rate, and factors that influence it. Learn how vitamins and minerals regulate energy levels.