Name: _____________________________________________________
Date: ______ Period: _____
Macromolecules: You are what you eat
Engage:
A group of students were discussing the elements found in the human body. Which student do you agree with and why?
Marco: Hydrogen is the most common element found in the body
because it bonds with carbon and oxygen.
Eli: Oxygen is the most common element found in the body because
our bodies are mostly water.
Jose: Calcium is the most common element found in the body
because our bones need calcium.
Benjamin: Carbon is the most common element found in the body
because all life on Earth is carbon-based.
Who do you agree with and why?
Introduction: All organisms are composed of compounds containing common elements. All organisms take in matter
and rearrange atoms through chemical reactions to form molecules essential for life and to obtain the energy they need
to carry out life processes. Animals, such as humans, consume food in order to obtain the energy they need to power
their bodies and the matter they need to produce more cells in their bodies. The atoms in the sugar molecules formed
by plants during photosynthesis and ingested by animals are used to create the macromolecules (e.g., carbohydrates,
lipids, proteins, and nucleic acids) found in all multicellular organisms. Macromolecules are large molecules found within
cells and may consist of thousands of atoms. Carbohydrates and proteins are polymers, formed by repeating subunits
called monomers. Lipids have various roles within a cell, including serving as energy storage molecules. In this lab, we
will focus on the three macromolecules that are important energy sources for biological organisms: carbohydrates,
proteins and lipids. In this assignment, you will examine the common elements found in organisms, explore the
nutritional content of your food, and determine which macromolecules you are ingesting.
Explore:
Watch the video: How to Read a Nutrition Facts Label (4:43): Link http://bcove.me/nq9hn96t
Purposeful Viewing: Answer the following.
1. What are calories?
2. Where do the calories in your food come from?
3. True or False (circle one): 2% milk has more nutrients than skim milk.
Task 1: Nutrition Facts Labels
1. Find at least 6 nutrition labels from food items you have eaten (or will eat).
2. For each label, transfer the information onto the data sheet.
Nutrition Facts Label Data Sheet
Food Item # 1: ____________________________
What are the main ingredients of this food item?
Identify the TOTAL GRAMS of…
a. Carbohydrates: _________
b. Fats: _________
c. Proteins: _________
d. Calcium: ________
e. Iron: _______
f. Sodium: _______
Food Item # 2: ____________________________
What are the main ingredients of this food item?
Identify the TOTAL GRAMS of…
a. Carbohydrates: _________
b. Fats: _________
c. Proteins: _________
d. Calcium: ________
e. Iron: _______
f. Sodium: _______
What surprised you as you read the nutrition facts for
this food item?
What surprised you as you read the nutrition facts for
this food item?
Food Item # 3: ____________________________
What are the main ingredients of this food item?
Identify the TOTAL GRAMS of…
a. Carbohydrates: _________
b. Fats: _________
c. Proteins: _________
d. Calcium: ________
e. Iron: _______
f. Sodium: _______
Food Item # 4: ____________________________
What are the main ingredients of this food item?
Identify the TOTAL GRAMS of…
a. Carbohydrates: _________
b. Fats: _________
c. Proteins: _________
d. Calcium: ________
e. Iron: _______
f. Sodium: _______
What surprised you as you read the nutrition facts for
this food item?
What surprised you as you read the nutrition facts for
this food item?
Food Item # 5: ____________________________
What are the main ingredients of this food item?
Identify the TOTAL GRAMS of…
a. Carbohydrates: _________
b. Fats: _________
c. Proteins: _________
d. Calcium: ________
e. Iron: _______
f. Sodium: _______
Food Item # 6: ____________________________
What are the main ingredients of this food item?
Identify the TOTAL GRAMS of…
a. Carbohydrates: _________
b. Fats: _________
c. Proteins: _________
d. Calcium: ________
e. Iron: _______
f. Sodium: _______
What surprised you as you read the nutrition facts for
this food item?
What surprised you as you read the nutrition facts for
this food item?
Explain:
Read: Handout A- Macromolecules in My Food
Purposeful Reading: Answer the following.
1. Describe the function of carbohydrates in your body.
2. How are simple sugars used for energy compared to more complex sugars like the starch in pasta?
3. The building blocks (smaller subunits) of proteins are __________________________________.
4. Provide examples of foods high in protein.
5. If your body is capable of making only certain amino acids, how do we get the essential amino acids we need?
6. What word should you always associate with “lipids”?
7. Describe the function of lipids.
8. Triglycerides which are…
a. Solid at room temperature are called “______________________”
b. Liquid at room temperature are called “______________________”
Elaborate:
Read the Handout: Handout B- Chemistry of the Human Body
Purposeful Reading: Answer the following.
1. What four elements make up the largest percentage of your body weight? ______________________________
2. How does the information in the handout compare to how you answered the Engage question? Do you need to
revise your answer? If so, what is your new response and why?
Evaluate:
1. What atoms are found in each of the following macromolecules?
Carbohydrates: __________________ Proteins: __________________ Lipids: __________________
2. What types of organisms are found at the base of the food chain? __________________________________
3. What atoms are rearranged by plants in during photosynthesis? ___________________________________
4. Many patterns exist in nature. Based upon what you learned about the common elements that make up
humans, which four elements are the most common in plants? ____________________________________
5. What atoms are found in each of the following macromolecules?
Carbohydrates: __________________ Proteins: __________________ Lipids: __________________
6. Make a connection: How does an organism obtain the atoms it needs to build macromolecules?
Handout A: Macromolecules in your Food
Reading Nutrition Labels: The Nutrition Facts Label tells you what nutrients (components of food your body needs to
grow and stay healthy) and how much of those nutrients are in found in one serving. The Nutrition Facts label can help
you make choices about the food you eat. The Nutrition Facts label is on the outside of most food packages, but is not
on most fresh foods (like fruits and vegetables). Below is an example of a Nutrition Facts label and explanations of the
information found on the label.
Background Information:
Carbohydrates: A carbohydrate is an organic compound that consists only of carbon, hydrogen, and oxygen. Your body
uses carbohydrates (carbs) to give you energy and helps keep everything going. Your body can use carbohydrates
immediately or store them in your liver and muscles for when they are needed. In general, the smaller carbohydrate
compounds are commonly referred to as simple sugars, which are found naturally in foods such as fruits, vegetables,
milk, and milk products. These simple sugars are broken down quickly and give you short term energy. Starch is a
complex carbohydrate. Starch must be broken down through digestion before your body can use it as an energy source.
Quite a few foods contain starch and dietary fiber such as breads, cereals, and vegetables.
Proteins: Proteins, made up of carbon, hydrogen, oxygen, and nitrogen, are part of every cell, tissue, and organ in our
bodies. These body proteins are constantly being broken down and replaced by the protein in the foods that we eat.
Protein is mainly found in the following foods: meats, poultry, fish, legumes (dry beans and peas), tofu, eggs, nuts and
seeds, milk and milk products, and grains. Most adults in the United States get more than enough protein to meet their
needs. It is rare for someone who is healthy and eating a varied diet to not get enough protein. There are 20 different
amino acids that join together to make all types of protein. Our bodies cannot make some of these amino acids so these
are known as essential amino acids – it is essential that our diet provide these. A complete protein source is one that
provides all of the essential amino acids, for example, meat, poultry, fish, milk, eggs, and cheese are considered
complete protein sources. An incomplete protein source is one that is low in one or more of the essential amino acids.
Incomplete proteins found in plant foods can be mixed together to make a complete protein. As a general rule, grains,
cereals, nuts, or seeds can be eaten together with dried beans, dried peas, lentils, peanuts or peanut butter. Examples of
these combinations include peanut butter on wheat bread, rice and beans, and split pea soup with cornbread.
Lipids: The term lipid is sometimes used as a synonym for fats, but this is technically incorrect. True fats are composed
of triglycerides. Moreover, triglycerides that are solid at room temperature are called “fats” while those that remain
liquid at room temperature are called “oils.” Triglycerides are also composed of carbon, hydrogen and oxygen atoms,
but in different ratios than in carbohydrates. Triglycerides have long chains of carbon and hydrogen bonds, which
creates the hydrophobic (“water fearing”) tail. This property prevents triglycerides from mixing readily with water and
causes them to separate relatively easily in solution.
Unsaturated Fats, Saturated Fats and Trans-Fats: Most of the fat that you eat should come from unsaturated sources:
polyunsaturated fats and monounsaturated fats. A fat is unsaturated if it contains at least one double bond. In general,
nuts, vegetable oils, and fish are sources of unsaturated fats. Saturated fats are oftentimes the "solid" fats, but other
saturated fats can be more difficult to see in the foods we consume. A fat is saturated if it consists of only single bonds.
In general, saturated fat can be found in the following foods: high-fat cheeses, high-fat cuts of meat, whole-fat milk and
cream, butter, ice cream and palm and coconut oils.
Food Calories: When speaking of the energy content of a macromolecule we often refer to calories or Calories. There is
a big difference between discussing "calories" and "Calories." A calorie is defined as the amount of heat needed to raise
the temperature of 1g of water by 1°C. Notice that the word "calorie” is spelled with a lower case letter "c." This is how a
physicist would describe a calorie. Nutritionists measure the amount of energy in food in Calories (with a capital letter
"C'), which is equivalent to 1 kcal or 1000 calories (lower case "c"). The amount of Calories per gram of each
macromolecule is listed below. You can see from the values above that one gram of fat contains more than double the
amount of energy as a gram of carbohydrate or protein. By analyzing nutrition labels, it is possible to calculate the
amount of Calories that each macromolecule contributes by multiplying the number of grams by the Caloric value.
1 gram of carbohydrate = 4 Calories
1 gram of protein = 4 Calories
1 gram of fat = 9 Calories
Handout B: The Chemistry of the Human Body
You are what you eat. But do you recall munching some molybdenum or snacking on selenium? Some 60 chemical
elements are found in the body, but what all of them are doing there is still unknown. Of the elements found in the
human body, four of them make up the largest percentage of our body weight (96%). The four elements are
oxygen, hydrogen, carbon, nitrogen. Before you start thinking we should float away with all the oxygen, hydrogen,
and nitrogen atoms, remember that the oxygen
molecules are mainly part of the water in our body
(H2O). In fact, over half of the human body is made up
of water (50-70%). The remaining 4 percent of body
weight is a sparse sampling of the periodic table of
elements. Figure 1 shows the eleven common
elements found in the human body and their
percentage of total body weight. The other trace
elements (less than 0.01%) are: boron (B), chromium
(Cr), cobalt (Co), copper (Cu), fluorine (F), iodine (I),
iron (Fe), manganese (Mn), molybdenum (Mo),
selenium (Se), silicon (Si), tin (Sn), vanadium (V), and
Figure 1: Elements of the Human Body
zinc (Zn).
Some of the more prominent representatives are called macronutrients, whereas those appearing only at the level
of parts per million or less are referred to as micronutrients. These nutrients perform various functions, including
the building of bones and cell structures, regulating the body's pH, carrying charge, and driving chemical reactions.
The FDA has set a reference daily intake for 12 minerals (calcium, iron, phosphorous, iodine, magnesium, zinc,
selenium, copper, manganese, chromium, molybdenum and chloride). Sodium and potassium also have
recommended levels, but they are treated separately. However, this does not exhaust the list of elements that you
need. Sulfur is not usually mentioned as a dietary supplement because the body gets plenty of it in proteins.
And there are several other elements—such as silicon, boron, nickel, vanadium and lead—that may play a
biological role but are not classified as essential. "This may be due to the fact that a biochemical function has not
been defined by experimental evidence," said Victoria Drake from the Linus Pauling Institute at Oregon State
University. Sometimes all that is known is that lab animals performed poorly when their diets lacked a particular
non-essential element. However, identifying the exact benefit an element confers can be difficult as they rarely
enter the body in a pure form. "We don't look at them as single elements but as elements wrapped up in a
compound," said Christine Gerbstadt, national spokesperson for the American Dietetic Association.
A normal diet consists of thousands of compounds (some containing trace elements) whose effects are the study of
ongoing research. For now, we can only say for certain what 20 or so elements are doing. Here is a quick rundown,
with the percentage of body weight in parentheses.
Oxygen (65%) and hydrogen (10%) are predominantly found in water, which makes up about 60 percent of the
body by weight. It's practically impossible to imagine life without water.
Carbon (18%) is synonymous with life. Its central role is due to the fact that it has four bonding sites that allow for
the building of long, complex chains of molecules. Moreover, carbon bonds can be formed and broken with a
modest amount of energy, allowing for the dynamic organic chemistry that goes on in our cells.
Nitrogen (3%) is found in many organic molecules, including the amino acids that make up proteins, and the nucleic
acids that make up DNA.
Calcium (1.5%) is the most common mineral in the human body — nearly all of it found in bones and teeth.
Ironically, calcium's most important role is in bodily functions, such as muscle contraction and protein regulation. In
fact, the body will actually pull calcium from bones (causing problems like osteoporosis) if there's not enough of
the element in a person's diet.
Phosphorus (1%) is found predominantly in bone but also in the molecule ATP, which provides energy in cells for
driving chemical reactions.
Potassium (0.25%) is an important electrolyte (meaning it carries a charge in solution). It helps regulate the
heartbeat and is vital for electrical signaling in nerves.
Sulfur (0.25%) is found in two amino acids that are important for giving proteins their shape.
Sodium (0.15%) is another electrolyte that is vital for electrical signaling in nerves. It also regulates the amount of
water in the body.
Chlorine (0.15%) is usually found in the body as a negative ion, called chloride. This electrolyte is important for
maintaining a normal balance of fluids.
Magnesium (0.05%) plays an important role in the structure of the skeleton and muscles. It also is necessary in
more than 300 essential metabolic reactions.
Iron (0.006%) is a key element in the metabolism of almost all living organisms. It is also found in hemoglobin,
which is the oxygen carrier in red blood cells. Half of women don't get enough iron in their diet.
Fluorine (0.0037%) is found in teeth and bones. Outside of preventing tooth decay, it does not appear to have any
importance to bodily health.
Zinc (0.0032%) is an essential trace element for all forms of life. Several proteins contain structures called "zinc
fingers" help to regulate genes. Zinc deficiency has been known to lead to dwarfism in developing countries.
Copper (0.0001%) is important as an electron donor in various biological reactions. Without enough copper, iron
won't work properly in the body.
Iodine (0.000016%) is required for making of thyroid hormones, which regulate metabolic rate and other cellular
functions. Iodine deficiency, which can lead to goiter and brain damage, is an important health problem
throughout much of the world.
Selenium (0.000019%) is essential for certain enzymes, including several anti-oxidants. Unlike animals, plants do
not appear to require selenium for survival, but they do absorb it, so there are several cases of selenium poisoning
from eating plants grown in selenium-rich soils.
Chromium (0.0000024%) helps regulate sugar levels by interacting with insulin, but the exact mechanism is still not
completely understood.
Manganese (0.000017%) is essential for certain enzymes, in particular those that protect mitochondria — the place
where usable energy is generated inside cells — from dangerous oxidants.
Molybdenum (0.000013%) is essential to virtually all life forms. In humans, it is important for transforming sulfur
into a usable form. In nitrogen-fixing bacteria, it is important for transforming nitrogen into a usable form.
Cobalt (0.0000021%) is contained in vitamin B12, which is important in protein formation and DNA regulation.