1st Year Biology Chapter 3 Enzymes MCQs Short Questions Notes

biology 11th notes Chapter 3

1. An uncatalysed reaction requires a:


2. Vitamins are essential for the survival of organisms because vitamins usually function as:


3. The function of competitive inhibitors is defined by their ability to interact or bind to:


4. When the final product of a metabolic pathway turn off the first step of metabolic pathway it is:


5. The active site of an enzyme is composed of binding site and:


6. Amino acids:


7. The reversible inhibitors usually constitute:


8. The enzyme minus its coenzyme is referred to as the:


9. Chemical nature of enzymes is:


10. What is a coenzyme?


11. An enzyme with its coenzyme or prosthetic group, removed is called as:


12. Consider this reaction. A + B C + D + energy.


13. At high temperature the rate of enzyme action decreases because the increased heat:


14. The enzymes are classified into:


15. Almost all enzymes are:


16. substrate interaction?


17. Emil Fischer:


18. Photosynthesis:


19. Every enzyme functions effectively at:


20. Activation energy:


21. Metal ions:


22. The binding of the substrate to the enzyme alters the structure of the enzyme:


23. Many enzymes function by the activation energy of reactions.


24. A certain enzyme will hydrolyze egg white but not starch. Which statement best explains this observation?


25. The optimum pH value for pancreatic lipase is:


26. The name enzyme was suggested in 1878 by the German physiologist:


27. Koshland in 1959 proposed the modified form of:


28. In human body the optimum temperature for enzymatic activities is:


29. What is a cofactor?


30. The enzymes are sensitive to:


31. protein organic molecules bound to enzymes near the active site:


32. Optimum pH value for pepsin is:


33. The enzymes involved in the cellular respiration in eukaryotes are found in:


34. Medium required for Enzymes vigorous activity:


35. When a molecule binds to an area of an enzyme that is not the active site, and changes the shape of the enzyme so that it no longer can work, this is called:


36. Even traces of enzymes can bring about change in large amount of:


37. The rate of reaction of enzyme directly depends upon:


38. Enzymes are highly specific for a given substrate which is due to the shape of their:


39. The reaction below occurs within the cells to prevent the accumulation of hydrogen peroxide. In this reaction, catalase functions as an:
2H₂O2 + Catatase à2H₂O+ O₂


40. If an enzyme solution is saturated with substrate, the most effective way to obtain an even faster yield of products would be:


41. At about 0°C, most enzymes are:


42. Which type of inhibitor is shown in this diagram?


43. Enzyme B requires Zn’ in order to catalyze the conversion of substrate X. The zinc is best identified as:


44. A student conducts an experiment to test the efficiency of a certain enzyme. Which would probably not result in a change in the enzyme’s efficiency?


45. An enzyme that hydrolyzes protein will not act upon starch. This fact is an indication that enzymes are:


46. Which one inactivates an enzyme by indirectly changing the shape of the active site of an enzyme?


47. Competitive:


48. Enzymes function as:


49. Proteinaceous part of holoenzyme is:


50. Enzymes:


51. An inhibitor that changes the overall shape and chemistry of an enzyme is known as:


52. The minimum amount of energy needed for a process to occur is called the:


53. The “lock and key” model of enzyme action illustrates that a particular enzyme molecule:


54. DDT and Parathion are inhibitors of key enzymes in:


55. Inhibitors:


56. protein components of enzymes are known as:


57. Which of the following enzymes would digest a fat?


58. In the lock and key model of enzyme action, the part of the enzyme that recognizes the substrate is known as the:


59. Salivary amylase:


60. factor of an enzyme (if it is an inorganic ion) is called as:


61. The “lock and key hypothesis” attempts to explain the mechanism of:


62. The first step in any reaction catalysed by an enzyme is the formation of a specific association between the molecules called:


63. Mg’ is an inorganic activator for the enzyme:


64. Which one is not attribute of enzyme?


65. A catalyst is a chemical involved in, but not by, a chemical reaction.


66. proteinaceous part of holoenzyme is:


67. The catalytic activity of an enzyme is restricted to its small portion called:


68. The catalytic activity of an enzyme is restricted to its small portion called:


69. The site where enzyme catalyzed reaction takes place is called:


70. protein part is covalently bonded to the protein part of an enzyme, it is called as:


71. An enzyme is generally named by adding to the end of the name of the


72. When the inhibitory chemical, which does not have to resemble the substrate, binds to the enzyme other than at the active site is called:


73. Competitive inhibitors stop an enzyme from working by:


74. Zn+2 is an inorganic activator for enzyme:


Short Questions

1. Define activator?
2. Define active site of enzyme.
3. Define enzyme inhibitors. Give its two types.
4. Define feedback mechanism of enzyme with diagram.
5. Define holoenzyme?
6. Define inhibitors and give an example.
7. Define oprimum pH of enzyme?
8. Define optimum temperature of enzyme?
9. Define prosthatic group and apoenzyme.
10. Define prosthetic group and give example.
11. Differentiate between irreversible and reversible inhibitors?
12. Differentite between apoenzyme and holoenzyme.
13. Diiferentiate between substate and active site of an enzyme.
14. Do mononucleotides work independently as heredity material? Why?
15. Give difference between prosthetic group and activator.
16. How conjugated molecules are formed?
17. How DNA is different from RNA in nucleotides?
18. How do irreversible inhibitors check the reaction rate of enzyme?
19. How does an enzyme and substrate react?
20. How does enzyme concentration affect the rate of enzyme action?
21. How extreme changes in pH affect enzyme?
22. How many essential amino acid are found in the body of living organisms?
23. How many regions are present in active site?
24. Many birds must store large amounts of energy to power flight during migration which type of organic molecules would be the most advantageous for energy storage why?
25. What do you know about lock and key model?
26. What is active site?
27. What is an optimal or optimum value of a factor during reaction?
28. What is Apoenzyme?
29. What is co-enzyme?
30. What is co-factor? Give its types.
31. What is effect of change in pH on working of enzymes?
32. What is induce fit model of enzyme reaction.
33. What is induced fit model?
34. What is inhibitor?
35. What is irreversible inhibitor?
36. What is meant by optimum temperature? Give an example.
37. What is optimum pH? Give one example.
38. What is substrate?
39. What is the optimum temperature for enzynes of human body?
40. What would happen if amount of enzhme is incressed by two fold?
41. Which factor can affect rate of catalysis of enzyme?
42. Who proposed lock and key model?
43. Why butter solidifies at room temperature but not mustered oil?
44. Why carbohydrates are called as hydrated carbons?
45. Why DNA is considered as heredity material?
46. Why enzymes are denatured at high temperature?
47. Why glycolipids are also called as cerebrosides?
48. Why lipids are used to store energy?
49. Why monosaccharide’s are also called as simple sugars?
50. Why phospholipids are most important class are most important class of lipids?
51. Why proteins are called nitrogenous compounds?
52. Why water molecules are considered as amphoteric molecules?
53. Why water requires higher amount of energy to change into vapours or ice?

Long Questions

1. What are enzymes? Give their characteristics.
2. Give the two ideas proposed about the formation of enzyme substrate complex.
3. Define Cofactor, poenzyme, Substrate, Competitive inhibitor.
4. What are inhibitors? How do they effect enzyme? Give their types.
5. What is co-factor? Write its importance
6. Differentiate between apoenzyme and holoenzymes?
7. Compare pepsin with pepsinogen.
8. Write distribution of enzyme in the cell?
9. Write characteristics of enzyme?
10. Differentiate between product and substrate?
11. What is feedback inhibition? Give an example.
12. What is the mechanism of enzyme action?
13. Differentiate between binding and catalytic sites?
14. What is lock and key model?
15. What is induced fit model? Who proposed it?
16. Differentiate between reversible and irreversible inhibitors?

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