Biology 160
Unit 01 – Flow of Matter: Am I Really What I Eat?
This is DUE ________________
Reading Guide 03: Biochemistry and Biological Macromolecules
Come prepared to share your findings with your group.
Review: OK, so now we have evidence that the food we eat comes from all sorts of different types of organisms, from plants and animals to
bacteria, fungi, and protists! But if you eat a plant, does that mean you are a plant? Hmmmm…. Then we looked closer at ourselves and some
unprocessed foods through a microscope and found evidence that both we and our food are made out of cells! Amazing! However, a closer
inspection (and some research in our textbooks) gave us more evidence that, while animal, plant, and bacterial cells do have some structures in
common, they also have some very different structures as well. So here’s how our evidence stacks up so far:
Evidence that REFUTES this claim:
Claim: We ARE what we eat. (From class discussion)
Evidence that SUPPORTS this claim:
Are we able to sufficiently support our claim that we are what we eat? Let’s look even a little closer at our cells and our food’s cells. What are all of
those cellular structures made out of? Let’s find out…
What you will learn in this reading guide: 1) All matter, including the stuff of cells, is made out of atoms. 2) Atoms are held together by different
types of chemical bonds to make molecules. 3) Chemical bonds are broken and formed during chemical reactions to rearrange atoms and form new
molecules. 4) Large biological molecules can be built by linking together smaller building block molecules! 5) The four major types of large
biological molecules that make up cellular structures are carbohydrates, lipids, proteins, and nucleic acids. 6) The structure and chemical properties
of these molecules give them different functions in those cellular structures. 7) Cells are made up of 70-95% water! What is so special about water?
And how do these large biological molecules interact with it?
Read: Chapters 2 and 3, Essential Biology, 4th or 5th Ed. (Simon, Reece, & Dickey)
1. Draw the structure of an atom. Make sure to label the
2. Define each of the following types of chemical bonds and give an example:
electrons, protons, neutrons, nucleus, and electron shells. 1) covalent bonds
2) ionic bonds
3) hydrogen bonds
3. Critical Thinking: In the following chemical reactions:
A) label the reactants and products
B) count the number of each type of atom on both sides of the chemical reaction – are any atoms gained or lost?
i.
ii.
iii.
2 H2 + O2  2 H2O
Reactants
number of H ____
Products
number of H ____
number of O ____
number of O ____
Reactants
number of C ____
Products
number of C ____
number of H ____
number of H ____
number of O ____
number of O ____
Reactants
number of C ____
Products
number of C ____
number of H ____
number of H ____
number of O ____
number of O ____
C6H12O6 + 6 O2  6 CO2 + 6 H20
C6H12O6 + 6 O2  6 CO2 + 6 H20
4.  Why is water so special?
Draw several water molecules (H2O). Label the covalent bonds
holding the atoms together and the hydrogen bonds holding the
molecules together.
Explain how the hydrogen bonds formed. Include in your explanation
why water is a polar molecule. See page 28.
Critical Thinking: How do you think water molecules interact with carbohydrates, proteins, lipids, and nucleic acids? Explain why. (See page 31 as
well as Ch 3).
5. From Checkpoint question 1. on page 39:
“Chemical reactions that build _______________ from ______________ are called ________________ reactions. _______________ reverses these
reactions.”
6. a. The textbook gives an example of how the enzyme lactase functions. What does this enzyme do? (pg 39)
b. According to Figure 3.21, what type of biological molecule is this enzyme?
7. Redraw the Figure on page 52 under the title “Giant Molecules from Smaller Building Blocks” to help you learn these important chemical
reactions.
8. If polymers are made out of monomers, fill out the following table with the names of these molecules:
Polymers
H
Carbohydrates
Give a specific example of the type of polymer
OH
What are the monomers called?
H
Polysaccharides:
_______________
Disaccharides:
_______________
_______________
_______________
_______________
Proteins
One example of a specific protein from the text:
Nucleic Acids
Two types of nucleic acids:
_______________
_______________
OH
9. Lipids are a special class of biological molecule. They are not macromolecules or polymers, but they are made from building blocks.
Name the two main types of lipids: _______________, _______________
True or False: Lipids hate to be around water! ________________; What is this property called? __________________
What are the names of the smaller building blocks that link together to make a fat? (See Figure 3.11)
_________________________, _________________________
10. Protein Structure
What are the four levels of protein structure? Draw and label a diagram of each (See Figure 3.20)
What type of chemical bond holds together the monomers to form the primary structure? ___________________________
What type of chemical bond “reinforces” the protein’s secondary structure? ______________________________
11. Protein Denaturation
According to the text, what happens during the “denaturation” of a protein and what causes it?
What do you think would happen to the function of a protein if it were denatured?
12. Critical Thinking: Protein Denaturation and acid
Look back to page 32. What is an “acid”?
Remember that a hydrogen bond is formed when a weak positive charge is attracted to a weak negative charge. How do you think an acid (with lots
of positively charged H+ ions floating around) can denature (or unravel) the secondary structure of a protein?
What would happen to a protein’s structure in the stomach, where the gastric juices are at pH 2? Why do you think this is necessary?
13. Cellular structures are made of large biological molecules!
Now that we’ve learned about the different types of large biological molecules and their properties, let’s use Chapters 3 and 4 to find out what their
functions are, where in the cell we can actually find them, and whether they can be found in all different kinds of cells found in our bodies and our
foods. Fill out the following table to help you piece this puzzle together.
Large biological
In what organelle(s) or cellular structure(s)
What are the molecules’ general
Can you find these
molecule
could you find these molecules? (Ch 4)
functions in the cell?
molecules in animal, plant,
(Ch 3)
and bacterial cells? Yes/No
Carbohydrates
Lipids
Proteins
Nucleic Acids
14. Critical Thinking: So are we what we eat? What new evidence do we have to support/refute this claim? Do you need any more information?