L.5.1 Food Energy
Summarize how food provides the energy and the molecules required for building materials, growth and survival of all organisms (to include plants).
Student Know That:
Food provides molecules that serve as fuel and building material for all organisms.
- Plants use the energy in light to make sugars out of carbon dioxide and water.
- This food can be used immediately for fuel or materials or it may be stored for later use.
- Organisms that eat plants break down the plant structures to produce the materials and energy they
Cells carry on the many functions needed to sustain life.
- They grow and divide (mitosis or meiosis), thereby producing more cells. This requires that they take in
- The way in which all cells function is similar in all living organisms.
- Within cells many of the basic functions of organisms, such as releasing energy from food and getting rid
Matter is transferred among organisms in an ecosystem when organisms eat, or are eaten by others for food.
- Matter is transferred from organisms to the physical environment when molecules from food react with
- Through the process of cellular respiration, cells convert energy (glucose) to a usable form of energy
- The energy stored in ATP provides the means by which cells are able to carry out their functions such as need to survive. Then they are consumed by other organisms. nutrients, which they use to provide energy for the work that cells do and to make the materials that a cell or an organism needs. of waste, are carried out by different cell elements. oxygen to produce carbon dioxide and water in a process called cellular respiration. (ATP). growth, development, and repair of organisms, locomotion and transportation of molecules across cell membranes.
In plants and animals, molecules from food:
- react with oxygen to provide energy that is needed to carry out life functions
- build and become incorporated into the body structure, or
- are stored for later use (Also in Matter & Energy)
Matter moves within individual organisms through a series of chemical reactions in which food is broken down and rearranged to form new molecules.
Plants use the energy from light to make sugars (food) from carbon dioxide and water.
- This process transforms light energy from the sun into stored chemical energy.
Minerals and other nutrients from the soil are not food (they don’t provide energy), but they are needed for plants to make complex molecules from the sugar they make.
Chemical energy is transferred from one organism in an ecosystem to another as the organisms interact with each other for food.
The atoms that make up the organisms in an ecosystem are cycled repeatedly between the living and nonliving parts of the ecosystem.
- Over a long time, matter is transferred from one organism to another repeatedly and between
- As in all material systems, the total amount of matter remains constant, even though its form and
- Energy can change from one form to another in living things. organisms and their physical environment. location change.
Animals get energy from oxidizing their food, releasing some of its energy as heat.
Almost all food energy comes originally from sunlight.
Explain the relationship among a healthy diet, exercise, and the general health of the body (emphasis on the relationship between respiration and digestion).
Students will know that:
• A balanced diet combined with regular exercise aid in the overall general health of the body.
o Humans require energy to function.
o The total energy used by an individual depends on the type and intensity of the activity and the energy
o The amount of energy required to maintain minimum essential life functions is called basal metabolic
o Humans obtain the energy required to carry out basic life processes from the food they consume.
o Food energy is measured in calories.
o The amount of food energy (calories) a person requires varies with body weight, age, sex, activity level,
• For the body to use food (proteins, lipids, carbohydrates) for energy and building materials, the food must
first be digested into molecules that are absorbed and transported to cells.
• Metabolism is the set of chemical reactions involved in storing fuel (food) molecules and converting fuel
(food) molecules into energy.
o In order for the body to use the fuel energy stored in food, the food must first be digested and
o Three factors contribute to the overall metabolic rate of the body:
required for basic life processes.
rate, or BMR.
and natural body efficiency.
combined with oxygen (oxidized).
The Basal Metabolic Rate (BMR) accounts for about 60% of all energy used by the body.
Daily physical activities such as walking and moving around account for another 30% of the
energy used by the body.
Finally, 10% of the energy used by the body is used to digest and process (oxidize) food.
• If one consumes more calories than the body uses, the excess is stored and weight is gained.
o Weight loss occurs when fewer calories are taken in than the body needs.
• To burn food for the release of energy stored in it, oxygen must be supplied to cells, and carbon dioxide
o The heart /lung system work together to deliver oxygen rich blood to all of the organs, tissues and cells
o Lungs take in oxygen for the combustion of food and they eliminate the carbon dioxide produced.
o The circulatory system moves all these substances to or from cells where they are needed or produced,
• In order for systems to work properly, energy from the cells must be transformed into a useable form for cells
and ultimately, organs, to perform work.
o These systems work together in order for the body to function properly and maintain a balance.
o Regular exercise is important to maintain a healthy heart/lung system, good muscle tone, and bone
o Regular exercise and physical activity increases the heart rate providing more oxygen for the body to use
o A healthy body requires a delicate balance between a healthy diet and physical activity.
• In order for energy balance to occur, Energy In = Energy Out.
o This means that caloric intake equals caloric output.
o Food components (protein, fat, and carbohydrate) taken into the body have the following fates: they
of the body.
responding to changing demands.
for processing food.
can be used to fuel metabolic activities and physical activities, they can be incorporated into growing
body tissues, and they can be stored as fat.
o There are two important concepts of energy balance for adolescents.
First, to allow for normal body growth, more food energy must be consumed than can be
accounted for solely on the basis of energy required for metabolic and physical activities.
Second, insufficient energy intake may affect cellular metabolic activities, body weight, growth,
tissue formation, and health.
It is not essential for students to know how to calculate calories and BMI or to know the USDA food pyramid/plate