Exam 6: Energy Flow in the Life of a Cell

When certain molecules are pumped across biological membranes against a concentration gradient via active transport, ATP is used. In the cells of our bodies, for example, sugars are actively transported and metabolized within the membrane- enclosed mitochondria. Prokaryotes, in contrast, lack mitochondria but are nonetheless ab metabolize the same sugars. Based on the details provided in this scenario, which of the following statements is expected to be TRUE?

All of the following statements about catalysts are true EXCEPT

Imagine that you are conducting an experiment on a yeast enzyme known as sucrase. This enzyme is used by yeast cells to break down the disaccharide sucrose into the monosaccharides glucose and fructose. What type of reaction is this?

When a muscle cell demands energy to perform its work of contraction, ATP

Which of the enzymes shown in the figure is active in the stomach of the human digestive tract?

To say that an enzyme has been denatured means that

The burning of sugar is an example of an endergonic reaction, and photosynthesis is an example of an exergonic reaction.

The most common energy carrier molecule in living organisms is

The second law of thermodynamics states that the , or disorder, of the universe is constantly increasing.

Why is photosynthesis considered an endergonic reaction?

The enzyme phosphoglucoisomerase catalyzes the conversion of glucose- 6- phosphate to fructose- 6- phosphate. The region on phosphoglucoisomerase where glucose- 6- phosphate binds is called the .

In cells, endergonic reactions are often coupled with exergonic reactions that store energy.

A(n) chemical reaction releases energy, whereas a(n) reaction requires an input of energy.

What is the ultimate source of energy for almost all forms of life on Earth?

Which of the following lowers the activation energy of a biochemical reaction?

Sulfa antibiotics damage bacteria by affecting a certain bacterial enzyme. The sulfa antibiotic looks similar to a substrate normally required by the bacterial cells to live. The sulfa antibiotic occupies the active site of the required enzyme and blocks entry of its normal substrate. This prevents the bacteria from making nucleotides that are required for their reproduction and survival. Based on this information, the action of sulfa antibiotics is an example of

Kinetic energy is like sitting at the top of a hill, and potential energy is like coasting down that hill on your bike.

Special molecules such as NADH and FADH₂ transport in cells, which can then be used as energy in the cell.

Most reactions in the body occur too slowly to sustain life. This is because

When a high- energy bond in ATP is broken, what primarily happens to the released energy?