Chapter 6 Flashcards
(14 cards)
Distinguish between the nature and purpose of catabolic and anabolic chemical reactions.
Some metabolic pathways release energy by breaking down complex molecules to simpler compounds. These processes are called catabolic pathways, or breakdown pathways. A major catabolic pathway is cellular respiration, which breaks down glucose and other organic fuels in the presence of oxygen to carbon dioxide and water. Energy stored in the organic molecules becomes available to do cellular work, such as ciliary beating or membrane transport. Anabolic pathways, in contrast, consume energy to build complicated molecules from simpler ones; they are called biosynthetic pathways. Examples of anabolism are synthesis of an amino acid from simpler molecules and synthesis of a protein from amino acids. Catabolic and anabolic pathways are the “downhill” and “uphill” avenues of the metabolic landscape. Energy released from downhill reactions of catabolic pathways can be stored and then used to drive uphill reactions of anabolic pathways.
Distinguish between different types of energy (potential energy, chemical energy, kinetic energy, thermal energy, heat) and describe how each of those types of energy is present and changes within a system.
Energy can be associated with the relative motion of objects; this energy is called kinetic energy. Moving objects can perform work by imparting motion to other matter: Water gushing through a dam turns turbines, and the contraction of leg muscles pushes bicycle pedals. Thermal energy is kinetic energy associated with the random movement of atoms or molecules; thermal energy in transfer from one object to another is called heat. Light is also a type of energy that can be harnessed to perform work, such as powering photosynthesis in green plants.
n object not presently moving may still possess energy. Energy that is not kinetic is called potential energy; it is energy that matter possesses because of its location or structure. Water behind a dam, for instance, possesses energy because of its altitude above sea level. Molecules possess energy because of the arrangement of electrons in the bonds between their atoms. Chemical energy is a term used by biologists to refer to the potential energy available for release in a chemical reaction. Recall that catabolic pathways release energy by breaking down complex molecules. Biologists say that these complex molecules, such as glucose, are high in chemical energy
Define entropy and apply the concept of how entropy changes within an example system.
Define free energy and describe how the free energy levels of reactants and products can be used to predict the direction in which a chemical reaction will proceed.
Apply knowledge of exergonic vs. endergonic and spontaneous vs. non-spontaneous reactions to specific examples.
Explain how reaction coupling allows cells to function and where the energy comes from to drive unfavorable reactions.
Describe the role of ATP in the cell.
Explain how enzymes enable a chemical reaction to proceed more rapidly, including where/how the substrate binds and how an enzyme can be re-used for multiple reactions.
Predict how the rate of a chemical reaction will change based on changes in the energy level of the transition state or changes in enzymes (e.g., addition, removal, change in enzyme shape, addition of different types of inhibitors). Explain why the chemical reaction would be affected by each change.
How does free energy change when comparing the reactants and products of exergonic and endergonic reactions?
Is the overall reaction for cellular respiration spontaneous or nonspontaneous?
How does adenosine triphosphate (ATP) transform into adenosive diphosphate (ADP)?
What type of molecule is an enzyme and how does it impact the activation energy of metabolic reactions?
How does temperature and pH affect the function and regulation of enzymes?
