Question

is meant by a "pacemaker" enzyme is an enume that catalyzes the fastest reaction in a pathway A It is an nuryme the catalyzes the slowest reaction in a pathway c) It is in en ryme that requires a significant energy source to function D) It is an enzyme that requires a co-factor to function E) It is an enzyme that is covalently modified during the reaction process 24. What is the difference bet between the lock-and-key and the induced-fit models of enzyme-substrate complex formation A) In the lock-and-key model the active site is a relatively reid sincture that accommodates only those substrates with the correct corresponding share the induced-fit model the cryme changes its shape when binds to the whole that these siteurends and precisely fits the substrate. B) In the lock-and-key model the enzyme changes is share when it binds to the substrate so that the active site surrounds and precisely fits the substrate in the induced fit model the active site is a relatively rigid structure that accommodates only those substrates with the correct corresponding shape. C) In the lock-and-key model the substrate causes the enuryme to change shape thereby becoming unlocked. In the induced-fit model the substrate causes a chemical reaction whereby the active site of the enzyme becomes permanently induced and can no longer function. D) Both models refer to an enryme that functions only in the presence of a co m e E) None of the above are correct 25. What is an enzyme's active site? A) Specific region on the surface of an enzyme where allosteric inhibitors bind non-covalently B) Specific regions on the surface of an entryme where allosterie inhibitors bind covalently C) Amount of collision energy required for a chemical reaction D) Specific region on the surface of an enzyme that interacts with a substrate E) Specific region on the surface of an enzyme where noncompetitive inhibitors bind covalently 26. Where does glycolysis (es. Embden-Meyerhof pathway occur in Bacteria? Where does it occur in Eukaryotes? A) cytoplasm, mitochondrial matrix B) mitochondrial matrix; nucleus C) cytoplasm, cytoplasm O plasma membranes mitochondrial inner membrane E) nucleus, nucleus 27. Where does the TCA cycle occur in Bacteria? Where does it occur in Eukaryotes? A) cytoplasm, mitochondrial matrix B) mitochondrial matrix; nucleus C) cytoplasm; cytoplasm O plasma membrane; mitochondrial inner membrane E) nucleus, nucleus 28. Which products of Glycolysis (Embden-Meyerhof pathway) transfer electrons to the electron transport system (ETS)? A) ATP B) NADH C) FADH D) Carbon dioxide and oxygen All of the above can transfer electrons to the ETS 29. What are amphibolic pathways? A) Pathways with enzymes that involve the use of light energy to fix atmospheric carbon dioxide B) Pathways with enzymes that function only catabolically C) Pathways with enzymes that function only anabolically D) Pathways with enzymes that function both catabolically and anabolically E) Pathways with enzymes that function neither catabolically nor anabolically

Answer 1

23. B. It is an enzyme that catalyses the slowest reaction in a pathway - it is the trend setting enzyme that determines the rate of the entire pathway

24. A. In the lock and key model the enzyme is relatively rigid structure that accommodates only those substrate with corresponding shape. In induced fit model the enzyme changes its shape when it binds to substrate so that the active site surrounds and precisely fits the substrate.

25. D. Specific region on the surface of the enzyme that interacts with a substrate.

29. D. Pathways with enzymes that function both catabolicaly and anabolically