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
CAMPBEL BIOLOGY:CONCEPTS & CONNECTIONS
- Idris 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 determine the enzyme activity? Please give the unit. (b) How do I get the specific activity of this enzyme? Please give the unit.arrow_forwardPenicillin is hydrolyzed and thereby rendered inactive by penicillinase, an enzyme present in some resistant bacteria. The mass of this enzyme in Staphylococcus aureus is 29.6 kd. The amount of penicillin hydrolyzed in 1 minute in 10 ml solution containing 10–9 g of purified penicillinase was measured as a function of the concentration of penicillin. Assume that the concentration of penicillin does not change during the assay. [Penicillin] µM Amount hydrolyzed (nanomoles) 1 0.11 3 0.25 5 0.34 10 0.45 30 0.58 50 0.61 a) Plot V0 versus [S] and 1/V0 1/[S]. Does penicillinase appear to obey Michaelis-Menten kinetics? b) What is the value of KM? c) What is the value of Vmax? d) What is the turnover number of penicillinase under these conditions?arrow_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 following questions:(a) How do I determine the protein/enzyme concentration? Please give the unit.arrow_forward
- a. Which unknown sample is the negative control? And Which unknown sample is the positive control? b. The experiment she conducted aimed to determine the action of what enzyme?arrow_forwardFor each of the four possibilities listed below (a through d), only one answer is correct and the others are false. Identify the correct statement and explain why the others are false. In your answer, write CORRECT next to the statement that you think is true, and ONLY for the ones that you think are false, explain what is wrong with the statement . When glucose reacts with ATP to form glucose-6-phosphate (as shown on the figure below): 1. The synthesis of glucose-6-phosphate is exergonic 2. ADP is at a higher energy level than ATP 3. Glucose-6-phosphate is at a higher energy level than glucose 4. Because ATP donates a phosphate to glucose, this is not a coupled reactionarrow_forwardTyrosinase enzyme activity is assayed by monitoring the oxidation of 3, 4-dihydroxyphenylalanine (dopa) to the red-colored dopachrome. Calculate the tyrosinase activity (U/mL) by using the experimental data given belowarrow_forward
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