BIOD 121 TEST 2025/2026 QUESTIONS WITH SOLUTIONS
GRADED A+
✔✔Thermogenesis - ✔✔is the ability to regulate body temperature and activities such
as fidgeting, maintaining body posture, and shivering. The amount of energy burned
through thermogenesis is very small. Recently scientists have begun to study the link
between brown adipose (fat) tissue and weight maintenance. Brown adipose tissue is
found in infants below the collar bone. The brown fat metabolizes the energy yielding
nutrients, which results in heat production to be used by the body. Most adults have little
brown fat, but lean adults have been found to have higher levels than their heavier
counterparts. Studies are underway to see how this knowledge could be used to benefit
those that struggle with being overweight.
✔✔Physical activity - ✔✔accounts for 15-40% of our energy expenditure. A number of
factors, such as body size, fitness level, and the actual activity, determine how many
calories are expended. Low physical activity and a "couch potato" mentality often lead
to weight gain. Previous generations expended many more calories than we do today
as jobs were physically demanding. In contrast, modern conveniences do much of the
work for us. As a result, we live a much more sedentary lifestyle and must intentionally
choose to be active.
✔✔The amount of energy used can be measured both directly and indirectly. - ✔✔
✔✔Direct calorimetry - ✔✔measures the amount of heat given off by the body. An
insulated chamber surrounded by a thin layer of water is used to measure the amount of
heat emitted by the subject in the chamber. This method is used infrequently due to the
expense and complexity of the procedure.
✔✔Indirect calorimetry - ✔✔uses oxygen intake and carbon dioxide output, along with
scientific formulas, to measure energy expended. It is convenient, fairly cheap, easy,
and very portable.
✔✔BMR Calculations: - ✔✔Male BMR = 66 + (6.23 x weight in pounds) + (12.7 x height
in inches) - (6.8 x age)
Female BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age)
Once the BMR is calculated, the activity level can then be added:
Physical Activity (PA) Estimates
1.2 = little to no exercise
1.375 = light exercise 1-3 days per week
1.55 = moderate exercise 3-5 days per week
1.725 = hard exercise 6-7 days per week
1.9 = hard daily exercise/job
To determine individual energy requirements, multiply the BMR x PA estimates (relative
to the appropriate activity level). The resulting value is the number of calories required
to expend daily in order to maintain their current weight.
, ✔✔Height-to-weight tables - ✔✔often published by insurance companies, were used in
an attempt to link longevity to a person's weight as based on their height (Figure 3.1).
However, these tables were used for the general population but did not take into
account individual differences. Today, the term "healthy weight" is used, rather than
ideal or desirable. Each person should consider their weight history, where fat is
distributed in the body, family health history, current weight, and activity status in order
to determine their own healthy weight. Remember, the number on the scale is just a
general guideline. The real goal is to be healthy and fit.
✔✔Body Mass Index (BMI) - ✔✔is an improved measure of body fat relative to one's
height and weight. As a more recent replacement to the height-to-weight tables, the BMI
can be used to categorize an individual as being underweight, at a healthy weight,
overweight, or obese. BMI is calculated by dividing one's weight (in kilograms) by the
square of one's height (in meters).
BMI = weight (kg) / height2 (meters)
Although the BMI is an improvement from the height-to-weight tables, in certain
populations the BMI is not as accurate. Such populations include children, teens,
pregnant or breast-feeding moms, short statute adults, very muscular individuals, and
the elderly. For this reason, separate BMI tables are available for children and pregnant
women, etc. As shown in Figure 3.2, a calculated BMI of < 18.5 would be considered
underweight (purple), while a BMI > 30 is considered obese (blue). In between these
two extremes falls the normal or healthy BMI with values between 18.6 and 25 (green)
and the overweight BMI with values between 25 and 30 (yellow). Taken together, a BMI
table is a quick tool to determine an individual's healthy weight for height.
✔✔Males should have between 8% to 24% body fat, while females should have
between 21% to 35% body fat. Females require higher levels of fat for reproduction.
Levels greater than 24% for males and 35% for females are considered an indicator of
obesity. There are several methods that can be used to determine a person's body fat
content. - ✔✔
✔✔Underwater weighing - ✔✔is a very accurate process where an individual is weighed
on a scale and then again while under water. The difference between the two
measurements (normal vs. underwater) is then used to estimate the total body volume.
From this the percentage of lean muscle and body fat can be calculated.
✔✔Bioelectrical impedance - ✔✔is based on the principle that water conducts electricity
and fat resists electricity. As muscle is primarily composed of water, an instrument with
electrodes is connected to the body and a painless low energy electric current is sent
through the body. Since fat resists electricity, higher levels of resistance indicate a
higher percentage of body fat.
✔✔Dual Energy X-ray Absorptiometry (DEXA) - ✔✔is the most accurate measure of
body fat composition as well as bone mass. An instrument that emits small doses of
GRADED A+
✔✔Thermogenesis - ✔✔is the ability to regulate body temperature and activities such
as fidgeting, maintaining body posture, and shivering. The amount of energy burned
through thermogenesis is very small. Recently scientists have begun to study the link
between brown adipose (fat) tissue and weight maintenance. Brown adipose tissue is
found in infants below the collar bone. The brown fat metabolizes the energy yielding
nutrients, which results in heat production to be used by the body. Most adults have little
brown fat, but lean adults have been found to have higher levels than their heavier
counterparts. Studies are underway to see how this knowledge could be used to benefit
those that struggle with being overweight.
✔✔Physical activity - ✔✔accounts for 15-40% of our energy expenditure. A number of
factors, such as body size, fitness level, and the actual activity, determine how many
calories are expended. Low physical activity and a "couch potato" mentality often lead
to weight gain. Previous generations expended many more calories than we do today
as jobs were physically demanding. In contrast, modern conveniences do much of the
work for us. As a result, we live a much more sedentary lifestyle and must intentionally
choose to be active.
✔✔The amount of energy used can be measured both directly and indirectly. - ✔✔
✔✔Direct calorimetry - ✔✔measures the amount of heat given off by the body. An
insulated chamber surrounded by a thin layer of water is used to measure the amount of
heat emitted by the subject in the chamber. This method is used infrequently due to the
expense and complexity of the procedure.
✔✔Indirect calorimetry - ✔✔uses oxygen intake and carbon dioxide output, along with
scientific formulas, to measure energy expended. It is convenient, fairly cheap, easy,
and very portable.
✔✔BMR Calculations: - ✔✔Male BMR = 66 + (6.23 x weight in pounds) + (12.7 x height
in inches) - (6.8 x age)
Female BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age)
Once the BMR is calculated, the activity level can then be added:
Physical Activity (PA) Estimates
1.2 = little to no exercise
1.375 = light exercise 1-3 days per week
1.55 = moderate exercise 3-5 days per week
1.725 = hard exercise 6-7 days per week
1.9 = hard daily exercise/job
To determine individual energy requirements, multiply the BMR x PA estimates (relative
to the appropriate activity level). The resulting value is the number of calories required
to expend daily in order to maintain their current weight.
, ✔✔Height-to-weight tables - ✔✔often published by insurance companies, were used in
an attempt to link longevity to a person's weight as based on their height (Figure 3.1).
However, these tables were used for the general population but did not take into
account individual differences. Today, the term "healthy weight" is used, rather than
ideal or desirable. Each person should consider their weight history, where fat is
distributed in the body, family health history, current weight, and activity status in order
to determine their own healthy weight. Remember, the number on the scale is just a
general guideline. The real goal is to be healthy and fit.
✔✔Body Mass Index (BMI) - ✔✔is an improved measure of body fat relative to one's
height and weight. As a more recent replacement to the height-to-weight tables, the BMI
can be used to categorize an individual as being underweight, at a healthy weight,
overweight, or obese. BMI is calculated by dividing one's weight (in kilograms) by the
square of one's height (in meters).
BMI = weight (kg) / height2 (meters)
Although the BMI is an improvement from the height-to-weight tables, in certain
populations the BMI is not as accurate. Such populations include children, teens,
pregnant or breast-feeding moms, short statute adults, very muscular individuals, and
the elderly. For this reason, separate BMI tables are available for children and pregnant
women, etc. As shown in Figure 3.2, a calculated BMI of < 18.5 would be considered
underweight (purple), while a BMI > 30 is considered obese (blue). In between these
two extremes falls the normal or healthy BMI with values between 18.6 and 25 (green)
and the overweight BMI with values between 25 and 30 (yellow). Taken together, a BMI
table is a quick tool to determine an individual's healthy weight for height.
✔✔Males should have between 8% to 24% body fat, while females should have
between 21% to 35% body fat. Females require higher levels of fat for reproduction.
Levels greater than 24% for males and 35% for females are considered an indicator of
obesity. There are several methods that can be used to determine a person's body fat
content. - ✔✔
✔✔Underwater weighing - ✔✔is a very accurate process where an individual is weighed
on a scale and then again while under water. The difference between the two
measurements (normal vs. underwater) is then used to estimate the total body volume.
From this the percentage of lean muscle and body fat can be calculated.
✔✔Bioelectrical impedance - ✔✔is based on the principle that water conducts electricity
and fat resists electricity. As muscle is primarily composed of water, an instrument with
electrodes is connected to the body and a painless low energy electric current is sent
through the body. Since fat resists electricity, higher levels of resistance indicate a
higher percentage of body fat.
✔✔Dual Energy X-ray Absorptiometry (DEXA) - ✔✔is the most accurate measure of
body fat composition as well as bone mass. An instrument that emits small doses of
