MACROMOLECULES
Standard H.B.-2A: The student will demonstrate an understanding that the essential functions of life take place within cells or systems of cells.
What You Need To Know:
You need to be able to: construct explanations of how the structures of carbohydrates, lipids, proteins, and nucleic acids (DNA/RNA) are related to their functions in organisms.
Plan and conduct investigations to determine how various environmental factors affect enzyme activity and the rate of biochemical reactions.
You need to know the role of enzymes as catalysts that lower the activation energy of biochemical reactions.
You need to know how factors such as pH and temperature affect enzyme activity.
Example One
As food travels through the digestive system, it is exposed to a variety of pH levels. The stomach has a pH of 2 due to the presence of hydrochloride acid (HCl), and the small intestine has a pH ranging from 7 to 9. HCl converts pepsinogen into pepsin, an enzyme that digests proteins in the stomach. Which of the following most likely happens to pepsin as it enters the small intestine?
A. It becomes inactive.
B. It begins to replicate.
C. It's shape changes to engulf large proteins.
D. It's activity increases to digest more proteins.
Example Two
In living cells, enzymes act as catalysts, which may reduce the amount of activation energy required for a chemical reaction to occur. In the graphs below, pathway x is a solid line representing the uncatalyzed reaction. The dotted line shows the catalyzed reaction. Which graph best illustrates the changes in a reaction when the catalyst reduces the amount of energy required?
Example Three
The diagram below shows the general structure of an amino acid. Which type of molecule is formed from amino acids?
A. lipids
B. proteins
C. carbohydrates
D. nucleic acids
Example Four
You are analyzing a compound in the laboratory. You find that it is made up of carbon, hydrogen, and oxygen in a ratio of two hydrogen atoms for each carbon atom. How will you classify the compound?
A. lipid
B. protein
C. carbohydrate
D. nucleic acid
Example Five
Fats, oils and cholesterol are all types of what?
A. cell membranes
B. hormones
C. lipids
D. fatty acids
Example Six
RNA and DNA are which type of macromolecules?
A. carbohydrate
B. lipid
C. nucleic acid
D. protein
Example Seven
What will most likely happen if an appropriate enzyme is added to a chemical reaction?
A. The reaction rate will increase.
B. The equilibrium of the reaction will be maintained.
C. The reaction rate will decrease.
D. The reaction will stop.
Example Eight
A sugar, a phosphate group, and a nitrogen base form the building blocks of which organic compound?
A. carbohydrates
B. lipids
C. nucleic acids
D. proteins
Example Nine
The human body maintains a temperature of around 98.6 degrees at all times. Enzymes are involved in almost every chemical reaction in the body. Which of the following describes the connection between these two statements?
A. Enzymes function best at a specific temperature.
B. The body needs to be warm to prevent hypothermia.
C. The body is kept relatively warm to prevent too much enzyme action.
D. There is no connection between the two statements.
Example Ten
The enzyme lactase will break down the sugar lactose into which of the following components?
A. monosaccharides
B. nucleic acids
C. amino acids
D. phospholipids