Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

3. Energy & Cell Processes

Enzyme Activation Energy

Anatomy & Physiology

3. Energy & Cell Processes

Enzyme Activation Energy

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2:14 minutes

Problem 15

Textbook Question

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. (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?.

Verified step by step guidance

Step 1: Plot the data from Table A on a graph with enzyme concentration on the x-axis and reaction rate on the y-axis.

Step 2: Plot the data from Table B on a separate graph with lactose concentration on the x-axis and reaction rate on the y-axis.

Step 3: Analyze the graph from Table A to observe the relationship between enzyme concentration and reaction rate. Note how the reaction rate increases as enzyme concentration increases.

Step 4: Analyze the graph from Table B to observe the relationship between lactose concentration and reaction rate. Note how the reaction rate increases with lactose concentration up to a certain point and then levels off.

Step 5: Compare the results of the two experiments. Explain that in Table A, the reaction rate increases with enzyme concentration because more enzyme molecules are available to catalyze the reaction. In Table B, the reaction rate increases with lactose concentration until the enzyme becomes saturated, after which the rate levels off because the enzyme is working at its maximum capacity.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Enzyme Kinetics

Enzyme kinetics is the study of the rates of enzyme-catalyzed reactions. It involves understanding how various factors, such as substrate concentration and enzyme concentration, affect the speed of the reaction. The Michaelis-Menten model is often used to describe the relationship between substrate concentration and reaction rate, highlighting the concept of saturation where increasing substrate concentration no longer increases the reaction rate.

Substrate Concentration

Substrate concentration refers to the amount of substrate available for an enzyme to act upon. In enzyme-catalyzed reactions, as substrate concentration increases, the reaction rate typically increases until a maximum rate is reached, known as Vmax. This relationship is crucial for understanding how enzymes function under different conditions, as seen in the experiments where varying lactose concentrations affected galactose production.

Enzyme Concentration

Enzyme concentration is the amount of enzyme present in a reaction mixture. Higher enzyme concentrations generally lead to increased reaction rates, provided there is sufficient substrate available. In the experiments, varying enzyme concentrations in Table A showed a direct correlation with the rate of galactose production, illustrating how enzyme availability can limit or enhance reaction rates depending on substrate levels.