Ch 6 Flashcards
Q: What is the first law of thermodynamics?
A: Energy cannot be created or destroyed; it can only change form. The total amount of energy in the universe is constant.
Q: What is entropy, and how does it relate to systems?
A: Entropy is the measure of disorder. As systems lose energy, they become more disorganized, and they naturally move toward maximum entropy.
Q: What is the second law of thermodynamics?
A: Energy spontaneously flows from high- to low-quality forms, increasing disorder (entropy).
Q: How does life maintain organization despite entropy?
A: Life uses energy from the sun to maintain a high degree of organization.
Q: What are reactants and products in a chemical reaction?
A: Reactants are the starting substances in a reaction, while products are the substances formed as a result of the reaction.
Q: What is the difference between endergonic and exergonic reactions?
A: Endergonic reactions require energy input (e.g., photosynthesis), while exergonic reactions release energy (e.g., aerobic respiration).
Q: What is activation energy?
A: Minimum amount of energy required to start a reaction.
Q: How does ATP act as the cell’s energy currency?
A: ATP stores energy by linking a phosphate to ADP (phosphorylation) and releases it by donating a phosphate group to other molecules.
Q: What are cofactors, and what do they do?
A: Cofactors, including metal ions and coenzymes, help enzymes by transferring electrons, atoms, or functional groups.
Q: How do transport proteins influence reactions?
A: Transport proteins move solutes across membranes, altering their concentration and affecting reaction rates.
Q: How do enzymes speed up reactions?
A: Enzymes act as catalysts, lowering the activation energy required for reactions to proceed.
Q: What is the transition state in a reaction?
A: The transition state occurs when reactants have absorbed enough energy to overcome activation energy and proceed spontaneously.
Q: What is the induced-fit model of enzyme activity?
A: The induced-fit model describes how enzymes adjust their shape slightly to better bind the substrate and catalyze the reaction.
Q: How do temperature, pH, and salinity affect enzymes?
A: Extreme conditions can denature enzymes by disrupting their shape, and reduces their function.
Q: What are antioxidants, and how do they assist enzymes?
A: Antioxidants like Vitamin E and catalase neutralize free radicals, protecting enzymes and other molecules from damage.
