1. Recognizing Biological Molecules
ANSWERS
Be sure to attempt these by first using the slides that do not have the answers. Otherwise, you will only recognize this limited set of illustrations rather than understanding how to recognize the molecules in general.

2. Question #1
From which of the four main groups of biological molecules does the the following molecule belong? Explain your choice.

3. Answer #1 Nucleic acids;
Nucleic acids are composed of nucleotide monomers that are each made up of a 5 C sugar, phosphate and nitrogenous base

4. Question #2
What type of lipid is the following? Be as specific as possible.
-O - C - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH3 O
H2C
H C O
-O - C - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH3 O
-O - C - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH3

5. Answer #2
A triglyceride, or triacylglycerol. These lipids are composed of 3 fatty acid chains attached to a glycerol backbone.

6. Question #3
Would you expect the following molecule to be soluble in water or nonpolar organic solvents? Explain your response.
CH3 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH3

7. Answer #3
Soluble in organic solvents. The molecule is a hydrocarbon. Hydrocarbons are nonpolar (each of the C-H bonds shares electrons evenly) and therefore are not soluble in polar solvents like water, but are soluble in nonpolar solvents.

8. Question #4
What type of molecule is shown below? The molecule is the building block/monomer for which of the four main groups of biological molecules?

9. Answer #4
Monosaccharide; the building block for carbohydrates

10. Question #5
Highlight the portion of the molecule below that is polar and the portion that is nonpolar.
CH3 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - C - OH O

11. Answer #5 Nonpolar Polar O
CH3 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - C - OH O

12. Question #6
What level of protein structure is shown below and what bonds are holding it in place?
Which building block shown below is used to make proteins and what is it called? A B C D E

13. Answer #6 Secondary structure held in place by hydrogen bonds
B is an amino acid and the building blocks for proteins