Chapter 5 Review

1. Which of the following is not an organic molecule?
a. cellulose
b. sucrose
c. water
d. testosterone
c.Water

2. Which of the following terms includes all the other terms on this list?
a. polysaccharide
b. carbohydrate
c. monosaccharide
d. glycogen
a. Polysaccharide

3. Which term is most appropriate to describe a molecule that dissolves easily in water?
a. hydrocarbon
b. hydrophobic
c. hydrophilic
d. organic
c. Hydrophilic

4. Cholesterol is an example of what kind of molecule?
a. protein
b. lipid
c. amino acid
d. carbohydrate
b. Lipid

5. The 20 amino acids vary only in their
a. carboxyl groups
b. side groups
c. amino groups
d. lipid groups
b. Side groups

6. A specific reactant an enzyme acts upon is called the
a. catalyst
b. sucrase
c. active site
d. substrate
d. Substrate

7. An enzyme does which of the following?
a. adds heat to a reaction, speeding it up
b. lowers the activation energy of a reaction
c. cools a reaction, slowing it down
d. raises the activation energy of a reaction
b. Lowers the activation energy of a reaction

8. Besides satisfying your hunger, why else might you consume a big bowl of pasta the night before a race?
Since pasta has plenty of carbohydrates in it, it is useful to an athlete as it contains lots of sugar.

9. How are glucose, sucrose, and starch related?
Glucose, sucrose, and starch are all related as they are all sugars. They all have the same ratio of carbon to hydrogen to oxygen (1:2:1, respectively)

10. What are steroids? Describe two functions they have in cells
Steroids are lipids with fused rings of carbon. Two functions they have in cells are being in the cell membranes and protecting the cell (cholesterol), and making sex cells (testosterone and estrogen).

11. How are polypeptides related to proteins?
Polypeptides are the long chains formed by amino acids that make up proteins.

12. How does denautration affect the ability of a protein to function?
When a protein denaturates, it unravels and breaks down, rendering it useless.

14. The reaction below (top of page 107) shows two amino acids joining together.
a. One product of this reaction is represented by a question mark. Which molecule is it?
H2O, or water.
b. What is this kind of reaction called? Explain.
This was a dehydration reaction as it lost a water molecule in the joining of the two amino acids.
c. If an amino acid were added to this chain, at what two places could it attach?
Another amino acid could be added at either of the two OHs on the bottom right.

15. Use the graph (middle of page 107) to answer the questions below.
a. At which temperature does enzyme A perform best? Enzyme B?
Enzyme A would perform best at about 38 degrees Celsius, while Enzyme B would perform best at about 78 degrees Celsius.
b. Knowing that one of these enzymes is found in humans and the other in thermophilic (heat-loving) bacteria, hypothesize which enzyme came from which organism?
I think that Enzyme A is from a human body, and Enzyme B is from the thermophilic bacteria because if the bacteria is thermophilic, it must be able to function in higher heats than human enzymes most likely would.
c. Propose a hypothesis that explains why the rate of the reaction catalyzed by enzyme A slows down at temperatures above 40 degrees Celsius.
I think that Enzyme A slows down at temperatures about 40 degrees Celsius because it is simply not designed to function under temperatures that humans could not survive in anyways.