Module 6 Flashcards
When you eat your lunch, the energy in the chemical bonds of the food can be broken down and used by the body to do work. However, some of the energy in the bonds is given off as excess heat which the body cannot use. This is an example of
The second law of thermodynamics
If inhibition is to be competitive, which of the following must be true?
The substrate and the inhibitor must be similar
Which of the following is an example of kinetic energy?
A contracting muscle
Increasing the temperature increases the rate of an enzyme-catalyzed reaction. Once a critical temperature is reached, the reaction stops. Why does this happen?
The polypeptide chains in the enzyme denature
A reaction has a very low Km (Michaelis constant): this means that
A. The enzyme has a high affinity for the substrate
B. It takes very little substrate to reach half of the maximum velocity
Sarin, a nerve gas, was released into the Tokyo subway system in 1995 injuring more than 5000 people. Sarin blocked the active sites of the enzyme acetylcholinesterase, which degrades acetylcholine, a compound that causes muscles to contract. Over-contraction of muscles can cause asphyxiation. What is the biological term for this nerve gas?
Competitive inhibitor
Study this metabolic pathway: A -E1 -> B -E2 -> C -E3 -> D. Which of the following statements is NOT correct? (E represents enzymes)
C is the substrate for enzyme 1 and D is the product
The breakdown of glucose into carbon dioxide and water has a negative delta G value. This reaction is
exergonic, catabolic
Which of these statements best describes how enzymes function?
They lower the amount of energy needed to get the reactant molecules into the transition state
The breakdown of glucose into its components (carbon dioxide and water) is an example of
A catabolic reaction
Enzymes work by lowering the ________________________ of a chemical reaction.
activation energy
A molecule that binds to the enzyme and interferes with its ability to form an enzyme-substrate complex is a(n)
inhibitor
Why do you think lactase works better in an acidic environment?
It has to function in the stomach, which is acidic
Based on what you know about lactase, what would you predict to be its optimal temperature?
Human body temperature (about 37degrees Celsius)
Why does lactase not catalyze the breakdown of sucrose?
The active site on lactase does not fit sucrose
