Ch 6 Energy & Enzyme Quiz

The explanation for the given correct answer is that sunlight is the ultimate source of energy for almost all living organisms on Earth. Through the process of photosynthesis, plants and some other organisms convert sunlight into chemical energy, which is then passed on to other organisms through the food chain. This energy is crucial for the survival and functioning of all living things, making sunlight the primary source of energy in most ecosystems.

The explanation for the given correct answer is that the energy of activation is indeed the energy required for molecules to interact in a chemical reaction. This energy is needed to overcome the energy barrier between reactants and products and initiate the reaction. Without the energy of activation, the molecules would not have enough energy to overcome this barrier and the reaction would not occur. Therefore, it is true that the energy of activation is necessary for molecules to interact in a chemical reaction.

Enzymes are known to lower the energy of activation of a reaction by binding the substrate. This means that enzymes facilitate the reaction by reducing the amount of energy required for it to occur. By binding to the substrate, enzymes create a favorable environment for the reaction to take place, allowing it to proceed at a faster rate. This characteristic of enzymes is essential for their role in catalyzing biochemical reactions in living organisms.

All organisms produce heat as a byproduct of their metabolic processes. This heat is generated through various biochemical reactions that occur within cells. These reactions involve the breakdown of nutrients to release energy, which is then used by the organism for various functions such as growth, movement, and reproduction. The production of heat is a fundamental characteristic of living organisms and is essential for maintaining their internal body temperature. Therefore, the statement that all organisms produce heat during their metabolic processes is true.

Mitochondria and chloroplasts are the correct answer because both organelles contain functioning ATP synthetase complexes in their membranes. ATP synthetase is an enzyme that plays a crucial role in the production of ATP, the main energy currency of cells. In mitochondria, ATP synthetase is located in the inner mitochondrial membrane, while in chloroplasts, it is found in the thylakoid membrane. These organelles are known as the powerhouses of the cell because they are responsible for generating energy through cellular respiration and photosynthesis, respectively.

Coupling occurs when the energy released by an exergonic reaction is used to drive an endergonic reaction. This means that the energy produced from the exergonic reaction is harnessed and utilized to power the endergonic reaction, which would not occur spontaneously on its own. This coupling of reactions allows for the overall energy balance to be maintained and for the endergonic reaction to proceed. The other options are incorrect because they do not accurately describe the concept of coupling.

Endergonic reactions require an input of energy in order to occur. This is because these reactions involve the formation of products with higher free energy than the reactants. Therefore, the correct answer is that endergonic reactions can only occur if there is an input of energy.

Enzymes are generally named by adding "-ase" to the end of the name of the substrate. This naming convention helps to identify the specific reaction that the enzyme catalyzes. The substrate is the molecule that the enzyme acts upon, so including it in the enzyme's name helps to indicate its function. The other options, "-ose" and "-ase" followed by the cell in which the enzyme is found or a coenzyme, are not commonly used naming conventions for enzymes.

The currently accepted theory of how an enzyme and its substrate fit together is that as the substrate binds to the enzyme, the shape of the active site changes to accommodate the reaction. This means that the enzyme and substrate have a complementary shape, similar to a lock and key, and the active site adjusts to create an optimal environment for the reaction to occur. This theory explains how enzymes are able to catalyze specific reactions and increase the rate of chemical reactions in living organisms.

A coenzyme is a nonprotein organic cofactor that interacts with an enzyme to allow it to work. Unlike protein cofactors, which are usually proteins themselves, coenzymes are small, nonprotein molecules that bind to enzymes and assist in catalyzing reactions. Coenzymes often act as carriers of specific functional groups or electrons, enabling enzymes to perform their functions effectively. Examples of coenzymes include NAD+, FAD, and coenzyme A.

The statement is false because cells do not completely use up energy. Instead, they convert energy from one form to another through metabolic processes. Cells obtain energy from food molecules and convert it into a usable form called ATP. This ATP is then used to fuel various cellular activities. Therefore, cells do not require more energy to enter in the form of food, but rather they require a constant supply of energy to sustain their functions.