Exam 6: Making Life Work: Capturing and Using Energy

Phosphofructokinase is an allosteric enzyme in the pathway that breaks down glucose to produce ATP. Regulation of glycolysis is directly related to the level of ATP and citrate. If ATP or citrate levels are high, phosphofructokinase is inhibited. What will happen to this enzyme when ATP levels drop?

Which of the following type(s) of inhibitor can bind to the active site of an enzyme?

Plants power most of their cellular processes by breaking down the sugar they make.

A given enzyme in a pathway can be activated by one molecule and inhibited by a different molecule.

ATP is a nucleotide composed of adenine, _____, and three phosphate groups.

The figure below shows a three-dimensional model of the enzyme lysozyme (A) and a map of the location of the important binding and catalytic amino acids that participate at the active site (B). Why are the amino acids of an enzyme that participate in substrate binding and in catalytic activity widely separated on the polypeptide chain, rather than being close together in the primary sequence?

Imagine that a researcher tries to reduce the size of an enzyme by removing all the amino acids from the protein except those flankingand constitutingthe active site. Why would this NOT work?

Which of the following is TRUE about exergonic reactions?

Lactose is composed of _____ joined by a _____ linkage.

Which of these equations is/are endergonic? Equation 1: ATP + H₂O  ADP + P_i G₁ = -7 kcal/mol Equation 2: phosphoenolpyruvate + H₂O  pyruvate + P_i G₂ = -14.8 kcal/mol Equation 3: glucose + P_i  glucose-6-phosphate + H₂O G₃ = +3.3 kcal/mol Equation 4: ADP + P_i  ATP + H₂O G₃ = +7 kcal/mol

Which of the following statements is a consequence of the first law of thermodynamics?

Imagine that a farmer has applied a pesticide to his crops. This pesticide contains an inhibitor that targets an enzyme in beetles. What types of beetles will he find on his farm after three years of pesticide use?

Which of the following examples is considered catabolism?

It is often stated that the phosphate bonds in ATP are "high energy," but in fact, they are not notably high in energy. Rather, they are easy to break, and the G of hydrolysis is a "useful" quantity of energy. What makes the phosphate bonds easy to break?

As atmospheric carbon dioxide levels increase, the oceans become more:

A biologist working in a lab adds a compound to a solution that contains an enzyme and substrate. This compound binds to the enzyme and decreases the rate at which the enzyme converts substrate to product. This decrease in enzyme activity persists even if the concentration of substrate in the reaction mix is increased. Therefore, which of the following is TRUE of the compound?

You have entered a 5K race. As you finish the last 50 yards, you are breathing harder than at the start of the race and sweating profusely. This is an example of the _____ law of thermodynamics because _____ is increasing.

Autotrophs typically obtain their carbon from:

Entropy is often increased by:

A cellular reaction with a G of 8.5 kcal/mol could be effectively coupled to the hydrolysis of a single molecule of ATP.