Human Physiology
15th Edition
ISBN: 9781259864629
Author: Fox, Stuart Ira
Publisher: Mcgraw-hill Education,
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Chapter 4, Problem 25RA
Summary Introduction
To review:
The pH (potential of hydrogen) values of half maximal activity of pepsin.
Introduction:
Enzymes catalyse the biochemical reactions to speed up the product formations. Most of the enzymes are protein in nature. The enzymes require optimum temperature and pH to perform efficiently. The rise in temperature results the in degradation of the enzyme and the low temperature inactivates the enzymes.
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The activity of pepsin was measured at various pH values. The temperature and the concentrations of pepsin and substrate were held constant. The following activities were obtained:
pH activity
1.0 0.5
1.5 2.6
2.0 4.8
3.0 2.0
4.0 0.4
5.0 0.0
Plot a graph of the pH dependence of pepsin activity.
Based on the graph what is the optimum pH?
Predict the activity of pepsin in the blood at pH 7.4.
Answer the following using the picture attached:
A. How does pepsin differ from chymotrypsin in terms of its active site residues and mechanism?
B. How do these changes permit pepsin to operate at such a low pH?
Below is a list of steps that occur after an exercising muscle cell begins degrading amino acids for ATP production. For each step, choose (A) if the process occurs in the muscle cell and (B) if the process occurs in the liver.
It will be easiest to answer this question if you first put the steps in order, then decide in which organ they occur.
______ Alanine is transaminated with a-ketoglutarate.______ Branched chain amino acids are transaminated with a-ketoglutarate.______ Glutamate is deaminated.______ Glutamate is transaminated with pyruvate.______ Ketoacid skeletons resulting from branch chain amino acids enter the CAC.______ Pyruvate enters gluconeogenesis.______ Urea is formed from the nitrogen removed from the original branched chain amino acid.
Chapter 4 Solutions
Human Physiology
Ch. 4 - Use the lock-and-key model to explain how enzymes...Ch. 4 - Explain how enzymes are named, and the nature of...Ch. 4 - Draw graphs to represent the effects of changes in...Ch. 4 - Prob. 4CPCh. 4 - Prob. 5aCPCh. 4 - Prob. 5bCPCh. 4 - Prob. 5cCPCh. 4 - Prob. 6aCPCh. 4 - Define the terms exergonic reaction and endergonic...Ch. 4 - Prob. 7aCP
Ch. 4 - Prob. 7bCPCh. 4 - Which of these statements about enzymes is...Ch. 4 - Which of these statements about enzyme-catalyzed...Ch. 4 - Which of these statements about lactate...Ch. 4 - In a metabolic pathway, a. the product of one...Ch. 4 - In an inborn error of metabolism,
a. a genetic...Ch. 4 - Which of these represents an endergonic...Ch. 4 - Which of these statements about ATP is true? a....Ch. 4 - When oxygen is combined with 2 hydrogens to make...Ch. 4 - Enzymes increase the rate of chemical reactions...Ch. 4 - According to the law of mass action, which of...Ch. 4 - Explain the relationship between an enzyme's...Ch. 4 - Explain how the rate of enzymatic reactions may be...Ch. 4 - Explain how end-product inhibition represents a...Ch. 4 - Prob. 14RACh. 4 - The coenzymes NAD and FAD can "shuttle" hydrogens...Ch. 4 - Prob. 16RACh. 4 - Why do we need to eat food containing niacin and...Ch. 4 - Metabolic pathways can be likened to intersecting...Ch. 4 - Prob. 19RACh. 4 - Suppose you come across a bottle of enzyme tablets...Ch. 4 - Describe the energy transformations that occur...Ch. 4 - Use the reversible reactions involving the...Ch. 4 - Use the graph here and in figure 4.4 to answer the...Ch. 4 - Use the graph here and in figure 4.4 to answer the...Ch. 4 - Prob. 25RACh. 4 - Prob. 26RACh. 4 - Prob. 27RA
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