Bio200 POGIL Cell Biology Activity 1 – Polarity, hydrophobicity, and hydrogen bonds
MODEL 1: Polarity and hydrophobicity
Methanol (
) and ethane (
) are mixed with water (
):
= Oxygen
= Carbon
= Hydrogen
1. Which molecule(s) are polar? Methanol and water
2. Which molecule(s) are non-polar? Ethane
3. Which molecule is "water-fearing" or "hydrophobic"? Ethane
4. Which molecule is "water-loving" or "hydrophilic"? Methanol
5. What is the relationship between polarity and hydrophobicity (in general)?
In general, nonpolar molecules are hydrophobic.
6. By looking at the bonds in each of the following important biological molecules, indicate
whether the molecule is primarily hydrophobic or hydrophilic.
Hydrophilic
Hydrophilic
Hydrophilic
Hydrophobic
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Bio200 POGIL Cell Biology Activity 1 – Polarity, hydrophobicity, and hydrogen bonds
MODEL 2: Hydrogen bonds
δ+
Hydrogen Bond
δ-
δδ+
δ+
δ+
δ-
7. Draw in the shared electrons for bonds that are shown in bold (like for this bond).
8. Draw the partial charges on the atoms involved in the bonds that are bold.
9. Why is an attraction possible between the H and O involved in the Hydrogen Bond?
The hydrogen has a partial positive charge that is attracted to the partial negative charge of the oxygen.
10. Draw an alternative hydrogen bond between different atoms of these two molecules in the
space below:
There are multiple possible answers.
11. For the mixtures in Q1, draw in some of the possible hydrogen bonds.
12. For the following pairs of molecules, draw their structures and at least one hydrogen bond
connecting them. If no hydrogen bond is possible between these two molecules, indicate that.
a. Water and CH NH
3
b. Methanol and CH NH
2
3
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