Download metabolism - Chavis Biology

UNIT 18: Enzymes and Metabolism
Essential Idea(s): Living Organisms control their composition by complex web of chemical reactions.
Metabolic reactions are regulated in response to the cell’s needs. Enzymes control the metabolism of the cell.
IB Syllabus Statements
Unit Objectives. Students will be able to:
2.1.U4
Metabolism is the web of all the
enzyme-catalyzed reactions in a cell
or organism.
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8.1.U1
Metabolic pathways consist of
chains and cycles of enzymecatalyzed reactions.
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2.5.U1
Enzymes have an active site to
which specific substrates bind.
2.5.U2
8.1.U2
Enzyme catalysis involves molecular
motion and the collision of
substrates with the active site.
Enzymes lower the activation energy
of the chemical reactions that they
catalyze.
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8.1.S2
Calculating and plotting rates of
reaction from raw experimental
results.
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2.5.U3
Temperature, pH, and substrate
concentration affect the rate of
activity of enzymes.
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2.4.A2
Denaturation of proteins by heat or
by deviation of pH from the optimum.
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2.5.U4
Enzymes are denatured.
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8.1.U3
Enzyme inhibitors can be
competitive or noncompetitive.
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8.1.U4
Metabolic pathways can be
controlled by end-product inhibition.
8.1.A1
8.1.S1
8.1.NOS
End-product inhibition of the
pathway that converts threonine is
isoleucine.
Distinguishing different types of
inhibition from graphs at specified
substrate concentrations.
Developments in scientific
research follow improvements
in computing-developments in
bioinformatics, such as
the interrogation of databases
have facilitated research
into metabolic pathways.
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Define metabolism and catalysis.
State the role of enzymes in metabolism.
Contrast metabolic chain reactions pathways with cyclical
reaction pathways.
State the relationship between enzyme substrate and enzyme
product.
Explain the relationship between enzyme structure and
enzyme specificity, including the role of the active site.
Outline the three stages of enzyme activity.
Explain the role of random collisions in the binding of the
substrate with the enzyme active site.
Describe the induced-fit model of enzyme action.
Define activation energy.
Explain the role of enzymes in lowering the activation energy of
a reaction.
State two methods for determining the rate of enzyme
controlled reactions.
State the unit for enzyme reaction rate.
Given data, calculate and graph the rate of an enzyme
catalyzed reaction.
Explain how temperature affects the rate of enzyme activity.
Draw a graph depicting the effect of temperature on the rate of
enzyme activity.
Explain how pH affects the rate of enzyme activity.
Draw a graph of depicting the effect of pH on the rate of
enzyme activity.
Identify the optimum temperature or pH for enzyme activity on
a graph.
Explain how substrate concentration affects the rate of enzyme
activity.
Draw a graph of depicting the effect of substrate concentration
on the rate of enzyme activity.
Define denaturation.
Outline the effect of heat and pH on protein structure and
function.
Define enzyme inhibitor.
Contrast competitive and noncompetitive enzyme inhibition.
Outline one example of a competitive enzyme inhibitor and one
example of a noncompetitive enzyme inhibitor.
Describe allosteric regulation of enzyme activity.
Outline the mechanism and benefit of end-product inhibition.
Illustrate end-product inhibition of the threonine to isoleucine
metabolic pathway.
State the consequences of an increase in isoleucine
concentration.
Explain why the rate of reaction with increasing substrate
concentration is lower with a non-competitive inhibitor
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8.1.A2
Use of databases to identify potential
new anti-malarial drugs.
2.5.S1
Design of experiments to test the
effect of temperature, pH, and
substrate concentration on the
activity of enzymes.
2.5.S2
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Experimental investigation of a factor
affecting enzyme activity.
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Experimental design - accurate,
quantitative measurements in
enzyme experiments require
replicates to ensure reliability.
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2.5.U5
Immobilized enzymes are widely
used in industry.
2.5.A1
Methods of production of lactosefree milk and its advantages.
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2.5.NOS
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compared to a competitive inhibitor.
Outline the use and benefits of the bioinformatics technique of
chemogenomics in development of new pharmaceutical drugs.
Outline the reasons for development of new anti-malarial
drugs.
Explain the use of databases in identification of potential new
anti-malarial drugs.
Identify the manipulated, responding, and controlled variables
in descriptions of experiments testing the activity of enzymes.
Describe three techniques for measuring the activity of an
example enzyme.
Define quantitative and qualitative.
Determine measurement uncertainty of a measurement tool.
Explain the need for repeated measurements (multiple trials) in
experimental design.
Explain the need to control variables in experimental design.
List industries that use commercially useful enzymes.
Explain how and why industrial enzymes are often
immobilized.
State the source of the lactase enzyme used in food
processing.
State the reaction catalyzed by lactase. Outline the reasons for
using lactase in food processing.
METABOLISM
_______________ is the chemical reactions of life; all the various processes by which you obtain energy, grow,
heal, think, feel and dispose of wastes. These reactions are controlled by ________________.
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Anabolism
Catabolism
Anabolism is …
Catabolism is …
Energy is added 
Energy is released 
Examples:
Examples:
Enzymes are Proteins
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Metabolic Pathways
A series of ‘steps’ from a starter molecule or ___________ towards a final end product.
Each step is __________ by a different enzyme. (Catalyze means to __________________________________.)
Cyclical Pathways
Some metabolic pathways operate in a ____________ way. Often named after the scientists who discover
them.
Metabolism of Phenylalanine
The metabolism of Phenylalanine is an example of a CHAIN ________________ ______________. Failure of
the enzymes controlling this metabolic pathway leads to a range of ________________ _________________.
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Protein in Diet
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Why Enzymes?
All chemical reactions require an initial energy input to get started.
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The initial energy input in the reaction is called the
______________ ____________.
__________ are employed to __________ (speed up) chemical
reactions in cells.
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Enzyme Structure
 Enzymes have a pocket called an ___________ ___________.
 Reactants (____________) bind to the active site.
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 Distinctive shape of active site is complementary and _____________ to the substrate.
 Active site amino acids bind to the substrate and distort the bonds to facilitate a reaction.
Not all Enzymes are the Same
 Some enzymes contain only _____________.
 Others, called __________ ____________, require additional components to complete their catalytic
properties.
 Enzymes will slightly shift in shape to better fit the substrate. This is called _____________ _______.
Three Steps on Enzyme Catalysis
How are Enzymes Named?
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How are enzyme-catalyzed reactions calculated?
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Environmental Control of Enzyme Activity
As proteins, the tertiary structure of an enzyme is sensitive to
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Each enzyme has specific environmental conditions in which its efficiency is optimized.
Enzymes will __________ if the pH, temperature or [salt] is not correct.
SUBSTRATE Concentration Effects Enzyme Activity
Assuming the amount of enzyme is constant,
an increase in substrate concentration causes a
diminishing increase in the reaction rate. A
maximum rate is obtained at a certain substrate
concentration where all enzymes are occupied
by substrate. The reaction rate cannot increase
further. Draw this:
ENZYME Concentration Effects Enzyme Activity
An increase in enzyme concentration causes an
increase in the reaction rate. Reaction rate will
eventually level off as all available substrates
are used up. Draw this:
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CONTROL OF METABOLISM
Remember that a given enzyme usually catalyzes a single step in a chain of metabolic reactions.
The overall activity of enzymes, and therefore, metabolism, is controlled by a number of factors:
1. The rate of enzyme production and breakdown.
Sometimes genes are _________ only when an enzyme product is required to catalyze reactions that
may occur infrequently. Other _________ are being transcribed all the time because their enzyme
products are in constants demand.
2. Enzyme interaction with the substrate or products of reaction.
Substrate
(starting chemical)
End Product
(finishing chemical)
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3. The influence of inhibitors.
Enzyme Inhibitor:
Types of Inhibitors:
Competitive Inhibitor
Non-Competitive Inhibitor
End-Production (Feedback)
Inhibition
Reading Enzyme
Inhibition Graphs
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We care about this because….
Enzyme inhibitors created or discovered in order to treat disease.
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Pesticides and herbicides are enzyme inhibitors.
Chemogenomics and Anit-Malarial Drugs
INDUSTRIAL APPLICATIONS OF ENZYMES
Enzymes aren’t just used in scientific investigations or metabolism. Many enzymes have been used in industry
to improve our lives in one way or another.
Sector
Role of Enzymes
Example of Enzymes
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Detergents
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Textiles
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Food Processing
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Pulp and Paper
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Immobilized Enzymes
Enzymes that have been physically ____________ to a _______________.
Benefits in industrial applications:
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Used in the Production of Lactose Free Milk
Reasons for using lactase in food processing:
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CHEMOGENOMICS AND COMPUTER AIDED DRUG DESIGN
WHO?
WHAT?
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WHY?
Example: The use of databases to discover anti-malarial drugs.
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