The most important metabolic fuel in the human body is:

1

• The most important metabolic fuel in the human
  body is
• A. Sucrose
• B. Starch
• C. Protein
• D. Cellulose
• E. Glucose

2

• When two monosaccharides undergo a condensation
  reaction
• A. a new monosaccharide is formed
• B. a disaccharide is formed
• C. a polysaccharide is formed
• D. a starch is formed
• E. hydrolysis occurs

3
Metabolism Enzymes

• Constraints on Reactions
• Making Reactions Possible with ATP
• Making Reactions Probable with Enzymes
• Why does Grandma take St. Josephs

4
What is Metabolism

• All the chemical reactions of the body

5
What is Metabolism

• All the chemical reactions of the body
• Catabolism
• breaking large molecules into smaller molecules
  (hydrolysis)
• releases energy (an exergonic process)

6
What is Metabolism

• All the chemical reactions of the body
• Catabolism
• breaking large molecules into smaller molecules
  (hydrolysis)
• releases energy (an exergonic process)
• Anabolism
• builds a large molecule from smaller ones
  (dehydration synthesis/condensation)
• consumes energy (an endergonic process)

7
Metabolism Enzymes

• Constraints on Reactions
• Making Reactions Possible with ATP
• Making Reactions Probable with Enzymes
• Why does Grandma take St. Josephs

8
Constraints on Reactions

• First Law of Thermodynamics
• Energy can be converted from one form to another
  but it cannot be created or destroyed
• Chemical energy is stored in macromolecules we
  eat
• When bonds are broken energy is released
• We use this energy to power our bodies

9
Constraints on Reactions

• First Law of Thermodynamics
• Energy can be converted from one form to another
  but it cannot be created or destroyed
• Chemical energy is stored in macromolecules we
  eat
• When bonds are broken energy is released
• We use this energy to power our bodies
• Second Law of Thermodynamics
• In every energy transfer some energy is lost as
  heat
• Unless our bodies obtain energy from our
  surroundings we lose energy over time (entropy)

10
To counter the loss of energy (as heat) we add
energy to our bodies in the form of food
11
Using ATP to Build Macromolecules
12
Using ATP to Build Macromolecules
13
ATP is Recycled
(Breakdown of food)
14
Metabolism Enzymes

• Constraints on Reactions
• Making Reactions Possible with ATP
• Making Reactions Probable with Enzymes
• Why does Grandma take St. Josephs

15
Enzymes are Everywhere
16
Enzymes are Biological Catalysts

• Enzymes are proteins that function as biological
  catalysts
• Increase the speed of chemical reactions
• Increase likelihood of chemical reactions

17
Enzymes are Biological Catalysts

• Enzymes are proteins that function as biological
  catalysts
• Increase the speed of chemical reactions
• Increase likelihood of chemical reactions
• Can increase rate of chemical reactions by over
  1000000X

18
Enzymes Bind to Substrates

• Bind with one or more reactants termed
  substrates

19
Enzymes Bind to Substrates

• Bind with one or more reactants termed
  substrates
• Enzymes are named after the substrate with which
  they bind
• -ase forms the suffix (e.g. the enzyme amylase
  digests the starch amylose)

20
How do Enzymes Work

• Enzymes can affect reactions by
• 1) Placing reactants in proper orientation
• 2) Create environment that promotes the reaction
• 3) Chemically weakening the bonds within the
  reactants
• 4) Donating electrons or protons to the reactants

21
How do Enzymes Work

• Enzymes can affect reactions by
• 1) Placing reactants in proper orientation
• 2) Create environment that promotes the reaction
• 3) Chemically weakening the bonds within the
  reactants
• 4) Donating electrons or protons to the reactants
• Enzymes catalyze specific reactions

22
How do Enzymes Work

• Enzymes can affect reactions by
• 1) Placing reactants in proper orientation
• 2) Create environment that promotes the reaction
• 3) Chemically weakening the bonds within the
  reactants
• 4) Donating electrons or protons to the reactants
• Enzymes catalyze specific reactions
• Enzymes are reusable (i.e. recycled)

23
Enzymatic Reactions
24
Cofactors

• Cofactors bind to enzyme and change its shape
  creating an active site (e.g. iron copper
  zinc magnesium or calcium ions)

25
Cofactors

• Cofactors bind to enzyme and change its shape
  creating an active site (e.g. iron copper
  zinc magnesium or calcium ions)
• Vitamins are used to make organic cofactors
  called coenzymes.
• Many enzymes cannot function without cofactors.

26
Rate of Enzymatic Reactions

• The basis for chemical reactions is molecular and
  collision

Molecular Motion Animation
27
Rate of Enzymatic Reactions

• Rates of reactions are affected by various
  factors
• Substrate and enzyme concentration
• Temperature
• pH
• Why do these influence reaction rates

28
Enzyme/Substrate Concentration

• Slow at low concentration

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Enzyme/Substrate Concentration

• Slow at low concentration
• Increase until point of saturation
• Why does saturation occur

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Temperature

• Slow at low temperatures

Reaction Rate
Temperature (C)
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Temperature

• Slow at low temperatures
• Slow at high temperatures
• Explain rate at each arrow

Reaction Rate
Temperature (C)
32
pH

• Enzymes function best within a specific pH range
• Why does pH alter enzyme function

33
Competitive Inhibition

• Slow down enzyme function
• Effect is reversible

Substrate
Active Site
Inhibitor
Enzyme
Enzyme
34
Non-Competitive Inhibition

• Binds to enzyme away from active site

Substrate
Enzyme
Inhibitor
35
Non-Competitive Inhibition

• Binds to enzyme away from active site
• Substrate no longer binds to active site
• Irreversible damage to enzyme function
• - Mercury Cyanide

Substrate
Enzyme
Inhibitor
36
Metabolism Enzymes

• Constraints on Reactions
• Making Reactions Possible with ATP
• Making Reactions Probable with Enzymes
• Why does Grandma take St. Josephs

37
Aspirin is a Non-Competitive Inhibitor

• Inhibits COX enzyme which functions in blood
  platelet aggregation
• What do blood platelets do
• Hence Aspirin reduces risk of a heart attack

38
Patient Profile Laurie

• Ate a Cheese Omelet Blueberry yogurt and 2
  glasses of chocolate milk at IHOP
• Symptoms Diarrhea Nausea Stomach Ache
• What do you think Laurie suffers from

39
Summary

• Building macromolecules is an anabolic process
  that requires energy released from the catabolism
  of adenosine triphosphate (ATP)
• Enzymes bring together reactants and create an
  environment that favors a reaction
• Like any protein the structure of an enzyme is
  critical to its function. Environmental
  conditions cofactors and inhibitors alter the
  structures of enzymes and hence alter their
  functions