Name: _____________________________
Period: ______
Date: _________
Macromolecules: the building blocks of Life
Why is Carbon an Essential Element for Life?
All living things share the same chemical building blocks and depend on chemical processes for survival. Life
without carbon (C) would be as unlikely as life without water. Other than water, most molecules of a cell are
carbon-based. The “biomolecules” are composed of a backbone of carbon atoms bonded to one another.
Atoms of other elements such as hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), and sulfur (S) may
branch off of this carbon backbone. This basic structure is the foundation for the different groups of
biomolecules: carbohydrates, lipids, proteins and nucleic acids.
Model 1: Monosaccharides: Simple Sugars
Name:
Sugar 1
Ratio of
Elements
C __3__ H _6__ O __3_
Simplest
Whole
Number Ratio
1:2:1
Sugar 2
Sugar 3
Sugar 4
C ___4__ H __8__ O
C ___5__ H __10__ O
C _6____ H _12___ O
__4__
__5_
__6__
1:2:1
1:2:1
1:2:1
Critical Thinking Questions
1. Circle all of the C (carbon) atoms in Sugar 1. Count and record your answer in the blank to the left of
the C (carbon) in the row labeled ratio of elements.
2. Put a slash through all of the H (hydrogen) atoms in Sugar 1. Count and record your answer in the
blank to the left of the H (hydrogen) in the row labeled ratio of elements.
3. Put an X on top of all of the O (oxygen) atoms in Sugar 1. Count and record your answer in the blank to
the left of the O (oxygen) in the row labeled ratio of elements
4. Repeat questions 1, 2, and 3 above for Sugar 2, Sugar 3, and Sugar 4.
5. What are the only three elements that are found in monosaccharides (simple sugars)?
C, H, O
6. What
is the simplest whole number ratio for each of the above simple sugars?
1:2:1
7. Monosaccharides (simple sugars) are also called carbohydrates. Using what you have learned about
the elements and their ratios in monosacharides, explain why the term carbohydrate is an appropriate
term for this group of compounds.
Carbo stands for a carbon molecule. Hydrate represents a water molecule which is two hydrogens
and one oxygen. CH2O which represents the ratio
Read This!
Lipids or fats are made up of two kinds of units: glycerol and fatty acids.
Lipids are produced when glycerol binds to fatty acids. A maximum of
three fatty acids can bind to one glycerol molecule to form a lipid.
Glycerol
8. What elements are present in glycerol?
C HO
9. Are there any elements in glycerol that are not in carbohydrates?
No
10. A monoglyceride contains 1 glycerol molecule and _____1____ fatty acids. A diglyceride contains 1
glycerol and ___2______ fatty acids. A triglyceride contains 1 glycerol and _____3____ fatty acids
Model 2: Lipids: Fatty acids
Name:
Ratio of
Elements
Simplest whole
number Ratio
Fatty Acid 1
Fatty Acid 2
Fatty Acid 3
Fatty Acid 4
C __4___ H __8__ O
C __6___ H _12___ O
C __7___ H __14__ O
C __8___ H __16__ O
__2__
__2__
__2__
__2__
2:4:1
3:4:1
7:14:2
4:8:1
11. Circle all the C (carbon) atoms in Fatty Acid 1. Count and record your answer in the blank to the left of
the C (carbon) in the row labeled ratio of elements.
12. Put a slash through all of the H (hydrogen) atoms in Fatty Acid 1. Count and record your answer in the
blank to the left of the H (hydrogen) in the row labeled ratio of elements.
13. Put a X through all of the O (oxygen) atoms in Fatty Acid 1. Count and record your answer in the blank
to the left of the O (oxygen) in the row labeled ratio of elements.
14. Repeat questions 10, 11, and 12 above for Fatty Acid 1, Fatty Acid 2, and Fatty Acid 3.
15. What are the only three elements that are found in fatty acids?
H,O,C
16. What is the simplest whole number ratio for each of the above fatty acids?
Carbon and Hydrogen have a 1:2 ratio but there is no overall ratio because the number of oxygen
molecules in a fatty acid is always two and does not increase, which does not allow for a uniform ratio1
17. Compare the molecules in Model 1 to the molecules in Model 2. In what ways are the molecules
similar? In what ways are the molecules different?
Similar
They are made up of the same elements
Those elements form the same number of bonds
Different
They are different structures
The amount and ratio of the elements differs
18. Using what you know about the properties of water, which Model (1 or 2) contains molecules that are
more likely to be polar and attracted to water (hydrophilic)?
Explain your answer.
The Monosaccharides are more likely to be polar and hydrophilic because they contain many O-H
hydrogen bonds just like water
19. Using what you know about the properties of water, which Model (1 or 2) contains molecules that are
more likely to be nonpolar and repel water (hydropbobic)?
Explain your answer.
The Lipids are likely to be nonpolar because they are long chains of hydrogen and carbon.
Read This!
Amino acid
General Structure
Amino acids are the basic building blocks or subunits of proteins. There
are twenty amino acids, and each one of them is a little different. Each
amino acid is composed of a “common group” and a “variable group“
designated as R. The “common group consists of all of the atoms except
for those designated as “R.” All organisms need some proteins, whether
they are used in muscles or as simple structures in the cell membrane.
Model 3: Amino acids: the subunits of proteins
Amino Acid 1
Name:
Ratio of
Elements
Amino Acid 2
Amino Acid 3
C __2__ H __5__ O _2___ N
C __3___ H __7__ O __2__ N
C __6___ H __13__ O __2__ N
__1__
__1__
__1__
20. Use a pen or a pencil and draw a box around the “common group” of, Amino Acid 1, Amino Acid 2
and Amino Acid 3.
21. What elements are present in the “common group” of an amino acid?
Carbon Hydrogen Oxygen Nitrogen
22. Circle the “R” group in each amino acid above.
23. Are there any elements in an amino acid that are not in carbohydrates or lipids? If so, what is / are
they? Nitrogen
24. Circle all the C (carbon) atoms in Amino Acid 1 (common group and variable group). Count and
record your answer in the blank to the left of the C (carbon) in the row labeled ratio of elements.
25. Put a slash through all of the H (hydrogen) atoms in Amino Acid 1 (common group and variable group).
Count and record your answer in the blank to the left of the H (hydrogen) in the row labeled ratio of
elements.
26. Put a X through all of the O (oxygen) atoms in Amino Acid 1 (common group and variable group).
Count and record your answer in the blank to the left of the O (oxygen) in the row labeled ratio of
elements.
27. Repeat questions 24, 25, and 26 above for Amino Acid 2 and Amino Acid 3.
28. Of the three amino acids given in Model 3, which one is the least complex in structure and which one is
the most complex in structure. Explain your answer.
Read This!
Nucleotides are the basic building blocks or
subunits of nucleic acids (DNA and RNA).
There are 2 types of nitrogen bases that form
nucleotides; they can either have 1 ring in their
nitrogen base or 2 rings in their nitrogen base.
Nitrogen base
Phosphate group
sugar
29. What are the 3 parts of a nucleotide? Phosphate Group, Sugar, Nitrogen base
30. What is the NEW element (one that has not been used in the three previous biomolecules) that we find
in a nucleotide?
Phosphorous
Extension Question
1. Study the diagrams below. Indicate whether the diagram is an example of a carbohydrate, fatty acid,
nucleotide or an amino acid.
Elements and ratio of elements:
Elements and ratio of elements:
__________C5:H10:O1_____________
_________ C3:H7:O3N1_
a. ______Lipid
b. _________Amino Acid
Elements and ratio of elements:
Elements and ratio of elements:
________ C1:H2:O1___________
___C9:H12:O6:N5;P1
c. ____carbohydrate_________
d. Nucleotide