Concept explainers
A biologist performed two series of experiments on lactase, the enzyme that hydrolyzes lactose to glucose and galactose. First, she made up 10% lactose solutions containing different concentrations of enzyme and measured the rate at which galactose was produced (grams of galactose per minute). Results of these experiments are shown in Table A below. In the second series of experiments (Table B), she prepared 2% enzyme solutions containing different concentrations of lactose and again measured the rate of galactose production.
Table A Reaction Rate and Enzyme Concentration
Table B Reaction Rate and Substrate Concentration
a. Graph and explain the relationship between the reaction rate and the enzyme concentration.
b. Graph and explain the relationship between the reaction rate and the substrate concentration. How and why did the results of the two experiments differ?
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Chapter 5 Solutions
Campbell Biology: Concepts & Connections (8th Edition)
- A multi-enzyme complex Is made up of three polypeptide chains, A, B and C. A is associated with decarboxylase activity; B is a transacetylase, while C is a dehydrogenase. When the protein was placed in a nonpolar solvent, then run in PAGE, two protein bands were observed. Enzyme assays showed that one protein band exhibited decarboxylase activity while the other has both transacetylase and dehydrogenase activities. When the protein was also placed in an aqueous solvent at pH 5.0, then run in electrophoresis, two protein bands were also detected. Further enzyme assays also showed that one protein band exhibits transacetytase activity while the other has both decarboxylase and dehydrogenase activities. a. What types of non-covalent interactions are possible between A, B and C? b. Addition of urea, a reducing agent gave 4 bands in the PAGE profile with a subsequent loss of decarboxylase activity. What could be the reason for the observed result? Explain briefly in terms of the structure…arrow_forwardcreate a single illustration that will interrelate or link the two opposing pathways, the Glycogenesis and Glycogenolysis. I want you to include the enzyme in each step and include some important by-products as well. From the illustration, I want you to encircle the intermediate molecule to highlight the link between the two processes. Aside from the illustration, I want you to compare and contrast the two pathways in terms of function, number of reaction steps, and usage of UTP. You can tabulate this part to make it simpler.arrow_forwardLeia wants to determine the effect of enzyme concentration on enzyme activity using potato samples and hydrogen peroxide. However, her results do not follow the theoretical trend and thus she can't draw any conclusions from the data obtained. What might have caused errors in the experiment? I. Placing potato samples under room temperature II. Different treatments, with potato being proportional to the volume of hydrogen peroxide III. Placed the same amount of hydrogen peroxide for a different amount of potatoes IV. Placed the same amount of potatoes for a different volume of hydrogen peroxidearrow_forward
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- What are the correct names of the items, I, II and III in the reaction given below? a. Fructose-6P / Phosphofructokinase / Ribose-1,6P b. Glucose-6P / Hexokinase / Glucose-1,6 P c. Fructose-6P / Glucokinase / Glucose-1,6 P d. Fructose-6P/ Phosphofructokinase / Fructose-1,6 P e. Fructose-6P / Phosphoglucose isomerase / Fructose-1,6 Parrow_forwardIdris has successfully extracted enzymatic proteins from the fish viscera (intestines and stomach). After homogenization and centrifugation, he managed to pool the crude enzyme extract. He is characterizing the enzymes. Please help Idris by answering the followingquestions: (a) How do I run the experiment to find the kinetic properties of the enzyme, KMand Vmax? (b) The enzyme decreased in activity in the presence of NaCl. How do I find out if NaCl is a competitive or non-competitive inhibitor? Explain.arrow_forwardCompounds I, II, and III are in the following biochemical pathway: precursor compound I enzyme A enzyme B compound II ► compound III enzyme Mutation a inactivates enzyme A, mutation b inactivates enzyme B, and mutation c inactivates enzyme C. Mutants, each having one of these defects, were tested on minimal medium to which compound I, II, or III was added. Fill in the results expected of these tests by placing a plus sign (+) for growth or a minus sign (-) for no growth in the table below. Minimal medium to which is added Strain with mutation Compound I Compound II Compound IIIarrow_forward
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