AN INTRODUCTION TO METABOLISM
Metabolism, Energy, and Life
1. Explain the role of catabolic and anabolic pathways in cellular metabolism.
Catabolic means the molecule is broken down into smaller parts. Anabolic means molecules are used to build bigger compounds. 2. Distinguish between kinetic and potential energy.
Kinetic energy is the energy of object in motion. Potential energy is the energy a object has due to its position or traits. 3. Distinguish between an isolated and an open system. Explain why an organism is considered an open system.
Isolated systems do not receive or give energy to its surroundings while open systems do. An organism is considered an open system because it gives and takes energy from its environment. 4. Explain the first and second laws of thermodynamics in your own words.
The total amount of energy in the universe is constant, never being created or destroyed.
Energy is transformed in different forms.
5. Explain why highly ordered living organisms do not violate the second law of thermodynamics.
Because we receive energy in the form of food and water and expend energy in the form of motion and body regulation, never creating or destroying pure energy. 6. Distinguish between exergonic and endergonic reactions in terms of free energy change.
An exergonic reaction releases free energy in the process while an endergonic reaction uses energy in the process of the reaction. 7. Explain why metabolic disequilibrium is one of the defining features of life.
The constant exchange of molecules keeps the cells and its environment from reaching equilibrium. This lack of equilibrium is the driving force for gradient diffusion, allowing flow of materials. 8. Describe the structure of ATP (include a sketch) and identify the major class of macromolecules to which ATP belongs.
ATP is made up of ribose, adenine, and a chain of three phosphate groups.