Question

1. What are the different sources of energy available to living organisms? 2. How do the acquisition and the use of energy by living organisms work according to the laws of thermodynamics? 3. Explain the energy use in the following reactions: endergonic/exergonic. 4. What is metabolism? How are chemical reactions related to metabolism? Why is energy needed to run a metabolism? What are coupled reactions? 5. Draw a picture of ATP. Why is this molecule so important for cells? How can a cell regenerate ATP? What types of activities within a cell are run by using ATP? 6. What are enzymes? What nomenclature is used to denote a molecule is an enzyme? How does a ribozyme compare with an enzyme? What is the relationship between an enzyme and the gene 7. Define the following: a substrate, active site, enzyme, activation energy, reactants, products, intermediate steps. Now, using the example of ADP + P → ATP, label all of the defined terms in the reaction as possible. 8. Ultimately, what does the enzyme do to lower the activation energy? 9. What are the three biggest factors that can limit the enzyme's function or speed? 10. Some enzymes use cofactors or coenzymes. What are these molecules and how do they enhance an enzyme's function? 11. Why would a cell want to control its enzymes? What are two ways a cell will control an enzyme? Explain each of these types of inhibition. 12. List and describe the following enzyme inhibitors: cyanide, MPTP, Sarin, Warfarin, Coumadin. How effective are these methods of enzyme control? What does enzyme control suggest about the impact enzymes have on living organisms? 13. Explain what a "REDOX" reaction is inside a cell. Where and when would these reactions be used in a cell? Why not use the reactions endergonic/exergonic instead of redox? 14. What role does NADP+ or NAD+ play in the specific reactions of cellular respiration and photosynthesis?

Answer 1

Ans 1: For living organisms sun is the major source of energy. Plants, which are designated as producers of the ecosystem have special mechanism called photosynthesis by which they can produce food in the form of carbohydrates from CO₂ and water utilizing energy from sun. They trap solar energy in their specialized pigment called cholorophyll and synthesize glucose using CO₂ and water. Herbivores which are called as the primary consumers, consume plants. Herbivores are further consumed by carnivores which are further consumed by omnivores. Thus, the solar energy ultimately enters the food chain from plants to different animals. Some microorganisms belonging to chemolithotrophs and chemoorganotrophs obtain energy by oxidizing inorganic and organic chemicals respectively. Thus, Light and inorganic/organic chemicals are the two main sources of energy for living organisms.