Reviewing Concepts
Multiple Choice
Choose the letter of the best answer.
1. Which of the following is not an organic molecule?
a. cellulose
b. sucrose
c. water
d. testosterone
2. Which of the following terms includes all the other terms on this list?
a. polysaccharide
b. carbohydrate
c. monosaccharide
d. glycogen
3. Which term is most appropriate to describe a molecule that dissolves easily in water?
a. hydrocarbon
b. hydrophobic
c. hydrophilic
d. organic
4. Cholesterol is an example of what kind of molecule?
a. protein
b. lipid
c. amino acid
d. carbohydrate
5. The 20 amino acids vary only in their
a. carboxyl goups.
b. side groups.
c. amino groups.
d. lipid groups.
6. A specific reactant an enzyme acts upon is called the
a. catalyst.
b. sucrase.
c. active site.
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
Short Answer
8. Besides satisfying your hunger, why else might you consume a big bowl of pasta the night before a race?
One might eat pasta before a race to consume starch, long chains of glucose. Out of the many forms of carbohydrates, monosaccharides are the shortest, allowing them to take the least time to digest. Eating pasta before a race will enable you to consume the energy from glucose broken down fairly quickly - not running out of energy during the race.
9. How are glucose, sucrose, and starch related?
All three contain glucose monomers. Glucose is glucose, sucrose is glucose and fructose, and starch is many glucose in a chain.
10. What are steroids? Describe two functions they have in cells.
Steroids can circulate in one's body as chemical signals and is used in creating cell membranes.
11. How are polypeptides related to proteins?
Polypeptides are chains of many many amino acids linked, what makes up proteins, too.Proteins are composed of one or more polypeptide chains.
12. How does denaturation affect the ability of a protein to function?
Denaturation being the distortment in shape of a protein by heat or other factors, the protein cannot work to its original purpose or function. Function of proteins are determined by shape.
Applying Concepts
Analyzing Information
14. Analyzing Diagrams The reaction below shows two amino acids joining together.
a. One product of this reaction is represented by a question mark. Which molecule is it?
The product be H2O, or water.
b. What is this kind of reaction called? Explain.
It is called a dehydration reaction because a water molecule is formed during the reaction and falls separate with the lump of combined molecules, making the combined molecules minus one potential water molecule.
c. If an amino acid were added to this chain, at what two places could it attach?
15. Analyzing Graphs Use the graph to answer the ques
tions below.
a. At which temperature does enzyme A perform best? Enzyme B?
The rates of reactions are highest for enzyme A just before 40'C and just before 80'C for enzyme B.
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.
Knowing enzymes are used to allow chemical reactions to happen at average temperatures to their host, enzyme A is probably in humans, and enzyme B, in thermophilic bateria.
c. Propose a hypothesis that explains why the rate of the reaction catalyzed by enzyme A slows down at temperatures above 40°C.
If the cell of enzyme A exceeds 40'C, then its cell wall we deteoriate.