The Chemistry of Life

Name:       Sec:      

Chapter 2: The Chemistry of Life

Module 2.6 The pH is a measure of the acidity of a solution.

1. A solution where the water is the solvent is called a(n)       solution.

2. Label the diagram with the following terms: hydroxide ion, hydrogen ion


3. What are two negative effects of too much acid in nature?


4. Complete the pH scale with the following terms/phrases: greater H+, lower H+, H+ = OH-


5. As the pH increases the [H+] ____, and as the pH decreases the [H+] ____.

a. |_| decreases; increases

b. |_| increases; decreases

c. |_| increases; stays the same

d. |_| decreases; stays the same

6. Complete the following table regarding acids and bases:



Effect on [H+] when dissolved in H2O



pH range






7. The pH in your cells is dropping. You have buffers to minimize this change in pH. Briefly explain what the buffer would do in this situation with respect to the H+ concentration in your cells.


Module 2.7 All life on earth is based on carbon.

8. The element       is essential to an organic compound.

9. What is meant by the term carbon skeleton, and how can carbon skeletons vary?


10. Is the following molecule an organic compound?


11. The oxygen atom in ethyl alcohol forms a polar covalent bond with the carbon atom. Does ethyl alcohol readily interact with water? (Hint: revisit module 2.5 if necessary)


12. Explain why the circled elements comprise functional groups.


13.       help to determine the overall properties of molecules.

14. Complete the table that describes the four classes of large biological molecules:












Module 2.8 Most biological macromolecules are polymers.

15. Much of your mass consists of large biological molecules called      .

16. What is the process by which polymers are broken into monomers?

a. |_| metabolism

b. |_| dehydration synthesis

c. |_| macromolecules

d. |_| hydrolysis

17. A common polymer is starch. We break starch down for use as an energy source. Is starch digestion hydrolysis or dehydration synthesis?


18. Complete the following diagram using the following terms: dehydration synthesis, hydrolysis



19. Which of the following best describes the following process:

Glucose + Glucose Maltose + H2O

a. |_| polarity

b. |_| hydrolysis

c. |_| metabolism

d. |_| dehydration synthesis

20. What term is missing from the arrow of the following diagram, which illustrates dehydration synthesis and hydrolysis:


21.       is the total of all reactions that take place in your cells.

22. How are dehydration synthesis and hydrolysis opposites of each other?


Module 2.9 Carbohydrates are composed of monosaccharides.

23. Which of the following is not a characteristic of carbohydrates?

a. |_| Energy source for animals

b. |_| Inclusion of monosaccharides

c. |_| Use as a structure in plants

d. |_| All of the above

24. The monomers of carbohydrates are      .

25. Glucose is a monosaccharide. Is glucose also a carbohydrate? Explain your answer.


26. Glucose and fructose both have the molecular formula C6H12O6, yet they are different molecules. Glucose and fructose are      .

27. Two monosaccharides joined by dehydration synthesis would form a(n)      . List two examples of a disaccharide:



28. Complete the following illustration regarding monosaccharides and polysaccharides. Mark those polysaccharides that glucose is used to construct with an “*”.




29. Complete the following table regarding monosaccharides and polysaccharides.





Monomer or Polymer?










Module 2.10 Lipids are a diverse group of hydrophobic molecules.

30. The one feature common to all lipids is that they are      .

31. A tanker is carrying crude oil from Alaska to a port in California. During the trip, the ship’s hull is ruptured and spills the crude oil into the Pacific Ocean. The oil sits on top of the water and does not mix with it. What characteristic must be true about the oil?


32. A cell’s membrane consists, in large part, of a molecule called a phospholipid. Does a phospholipid “love” or “fear” water? Briefly explain your answer.


33. Complete the following diagram of a phospholipid:





34. The two layers of phospholipid that make up a cell’s membrane are arranged so that they are facing tail to tail. What would be the effect of this interior core of phospholipid tails? Hint: Keep in mind what you already know about phospholipid tails.


35. True or False. If false, make a true statement: Cholesterol is used within the cell to help maintain the structure of the cell’s membrane.


36. Which of the following is a lipid?

a. |_| triglycerides

b. |_| cholesterol

c. |_| anabolic steroids

d. |_| all of the above

37. Are both steroids and triglycerides in your body? If so, give a function performed by each.


Module 2.11 Your diet contains several different kinds of fats.

38. There are two kinds of triglycerides. What are they?


39. Which fatty acid tail from the following diagram is saturated? Which one is unsaturated? Explain how you know.





40. Saturated means that an object can hold no more of something. Explain why the terms saturated and unsaturated are good descriptors for the molecules they describe.


41. You are a biochemist working for a food manufacturer. You are working to identify a new fat you discovered in a plant from a rainforest in Brazil. During your investigation, you determine that the fat tends to be a liquid at room temperature, and biochemical analysis reveals to few hydrogen atoms for the amount of carbon that is present. What kind of fat have you likely discovered?


42. An unsaturated fat can be turned into a solid or semi-solid state by:

a. |_| omega-3 fatty acidification

b. |_| hydrophilic

c. |_| hydrogenation

d. |_| unsaturation

43. Two students are discussing triglycerides. One student tells the other that all fats are bad for your health. The second student disagrees. Which student is correct and why?


Module 2.12 Proteins perform many of life’s functions.

44. A protein’s       determines its function.

45. Which are the monomers from which large proteins are constructed:

a. |_| polymers

b. |_| amino acids

c. |_| polypeptides

d. |_| peptide bonds

46. Amino acids are joined by what type of covalent bond:

a. |_| peptide

b. |_| protein

c. |_| carboxyl

d. |_| amino

47. You are a biochemist working for a pharmaceutical company. You are identifying a new molecule you have isolated for a species of bat. You determine that the molecule contains a carboxylic acid group and a group of atoms that would give the molecule unique hydrophilic properties. The power goes out before you finish your analysis. Based on what you know so far, what kind of molecule is it? What else might you have learned from it if the power had not gone out?


48. True for False, If false make a true statement: Amino acids are joined together through a dehydration synthesis reaction forming a peptide bond.


49. Complete the table on protein structure:


Folded chain

Multiple Chain


50. Proteins serve many functions within your body. List three functions served by proteins in your body. Additionally, list a specific protein that performs that function.




51. Protein shape is crucial to its proper function. Students have difficulty grasping this idea and how changing shape affects its function. Briefly explain how the words tasty and nasty can serve as a good analogy for a teacher trying to explain the concept to students.


Module 2.13 Enzymes speed chemical reactions.

52. A protein that accelerates a chemical reaction is a(n)      .

53. True or False, if false make a true statement: A chemical reaction changes the shape of the enzyme permanently.


54. Complete the following diagram regarding enzymes and substrates.