Enzymes, Water, and Membranes (SOL Review

Which line on the graph represents a catalyzed reaction?

• Blue
• Purple

• Both
• Neither

The equation below summarizes the process that produces the flashing light of a firefly. The molecule luciferin is broken down, and energy is released in the form of heat and light. In this process, luciferase functions as a(n) ______ .

• reactant
• product
• starch
• enzyme

A process that occurs in the human body is shown in the diagram. What would happen if a temperature change caused the shape of the active site to be altered?

• dipeptide would digest faster
• The dipeptide would digest slower or not at all.
• The amino acids would combine faster.
• The amino acids would combine slower or not at all.

Water is essential for life. Its special properties make water the single most important molecule in plant life. Which of the following properties of water enable it to move from the roots to the leaves of plants?

• Water expands as it freezes.
• Water is an excellent solvent.
• Water exhibits cohesive behavior.
• Water is able to moderate temperatures.

A competitive baseball player runs the same distance every day as part of his conditioning training. He notices that even on cold days, he perspires a great deal as his body temperature increases. Perspiration is the body’s way of releasing heat in the form of water from the body. Why does the body use water for this process?

• Water is a good solvent.
• Water is a good solute.
• Water has a low heat of vaporization.
• Water has a high heat of vaporization.

An osmosis investigation was conducted using chicken eggs to represent cells with semipermeable membranes. The mass of each egg was measured to determine how much water diffused into or out of the eggs. The eggs were first soaked in vinegar to dissolve the shell. Each egg was then placed in one of three different solutions for 24 hours. The table below shows the results of the investigation. Based on this experiment, which of the following should be inferred about cells with semipermeable membranes?

• Substances other than water may also cross the cell membrane.
• Substances other than water may block pores in the cell membrane.
• Water enters the cell when placed in environments of high water concentration.
• Water leaves the cell when placed in environments with a low concentration of solutes.

When a particle has to go against its concentration gradient through one of these gates, energy is supplied by the cell to the correct protein to move the particle through the membrane. A sodium-potassium ion pump is an example of a type of carrier protein that uses a large portion of the cell’s energy to move sodium ions through the cell membrane. The sodium-potassium ion pump found in some cell membranes is made of which of the following basic structural components?

• Amino acids
• Fatty acids
• Monosaccharides
• Nucleotides

What is a primary function of the cell membrane?

• Determining genetic traits
• Defending against foreign particles
• Breaking down proteins for energy
• Generating energy from mineral nutrients