Question

11. How do cells transform energy? Consider the first and second law of thermodynamics.

12. Describe the chemical reactions that either release or stores energy. Remembering that energy must be conserved. what do you think happens to the energy we obtain from food during cellular respiration? photosynthesis?

13. What is this energy that drive ALL cellular work? Is it a renewable source?

14. Explain how ATP transfers energy from exergonic to endergonic processes in the cell.

15. How do enzymes function?

16. Are enzymes specific? Why?

17. What is a cofactor? Provide 3 inorganic ions that are cofactors.

18. What is a co-enzyme? Provide an example. Is it organic or inorganic?

19. Enzyme inhibition can regulate enzyme activity in a cell. Explain the benefits of feedback inhibition to a cell.

Answer 1

11. Cells do not use energy as it is released. they are converted into energy rich molecules ATP , NADH which can be used throughout the cell to form new cellular components.

12. Energy is released when new bonds are formed .ie. Exothermic reaction and energy is used when bonds are broken down i.e. Endothermic reaction.

during cellular respiration, glucose and oxygen are converted into carbon dioxide and water and the energy is transferred to ATP. during Photosynthesis , light energy is captured and used to convert carbon dioxide and water into oxygen and energy rich organic compounds.

13. ATP( Adenosine Triphosphate) known as energy carrying molecule. Yes, it is a renewable source as it can be regenerated.

14. ATP transfers energy from exergonic to endergonic by phosphorylation. i.e adding phosphate groups.

Exergonic processes phosphorylate ADP to ATP.

15. Enzymes contains active site which are specific for specific substrate. when that specific substrate enters the active site, enzyme changes its shape slightly for better binding with substrate, forms enzyme substrate complex, reaction occurs forms enzyme-product complex. Products are released and once again enzyme is ready for the new substrate attachment.

16. Yes, enzymes are specific. One kind of enzymes can catalyse only one type of reaction.There is a lock and Key hypothesis. Like a lock can only be opened by a specific key and not any other key. In the same manner , substrate can only react with specific enzymes to carry out specific reactions.

17. Organic or inorganic molecules that are required for the activity of a certain conjugated enzymes. Inorganic ions- Cu2+, Fe2+, Mg2+

18. Coenzymes are substances which enhances the action of an enzyme. They are small, non protein molecule. example: Vitamin B1, B2 and B6. It is organic.

19. a) preventing excess prodcution of products.

b) Conserves energy

c) Maintains balance within the cell