Chapter 8 Pictures

Potential and Kinetic Energy

2nd Law of Thermodynamics

Potential Energy-Fuel Kinetic Energy 25% drives the pistons75% lost as heat

*In every chemical reaction, some energy is lost as heat.

Theoretical metabolic pathway

Enzyme 1 Enzyme 2 Enzyme 3

A B C DReaction 1 Reaction 2 Reaction 3

Startingmolecule

Product

Fig 5.2. Catabolic vs. Anabolic Reactions

• Condensation → reactions (anabolic)

• Hydrolysis → reactions (catabolic)

• Catabolic Rxns – • O-O O + O + Energy

• Anabolic Rxns-

O + O + Energy O-O

Figure 8.6

In exergonic rxns∆G is a negative

number

ALL rxns require some input of energy

Fig 8.14 Energy Profile for a Catabolic (Exergonic) Reaction

Question 8.1

Example 1: Baking soda + vinegar (fast reaction)

fructose + glucose

Example 2: Sucrose hydrolysis (very slow reaction)

+ H2O

Examples of an exergonic and endergonic reaction

Glutamine

+

Glutamic AcidAmmonia

ΔG = - 3.4 kcal/mol

Glutamine

+

Glutamic AcidAmmonia

ΔG = + 3.4 kcal/mol

Chemical Equilibrium

An organism in metabolic equilibrium

Equilibrium

ATP

ATP

Metabolic Disequilibrium

ATP

ATP

Food

Waste Products

Fig 8.3

Chapter 8-ATP

ATP = Currency of the Cell

Fig 8.11

Fig 8.9 ATP hydrolysis

Fig 8.8

Coupled Reactions

Fig 8.10ATP hydrolysis

ATP synthesis

Question 8.2

Chapter 8 - Enzymes

Fig 8.13. Enzyme-catalyzed reaction: hydrolysis by sucrase

Metabolic Map

Fig 8.13. Enzyme-catalyzed reaction: hydrolysis by Sucrase

Fig 8.14Energy Profile

Energy (heat)absorbed from the surroundings

Energy (heat)released by the reaction

Fig 8.15 Energy Profile +/- Enzyme

Progress of the reaction

Products

Course of reaction without enzyme

Reactants

Course of reaction with enzyme

EA

withoutenzyme

EA with enzymeis lower

∆G is unaffected by enzymeF

ree

ener

gy

Fig 8.17

Fig 8.16

Fig 8.18aOptimal temperature for enzyme of thermophilic

Rat

e o

f re

actio

n

0 20 40 80 100Temperature (Cº)

(a) Optimal temperature for two enzymes

Optimal temperature fortypical human enzyme

(heat-tolerant) bacteria

Fig 8.18bR

ate

of

reac

tion

(b) Optimal pH for two enzymes

Optimal pH for pepsin (stomach enzyme) Optimal pH

for trypsin(intestinalenzyme)

10 2 3 4 5 6 7 8 9

Question 8.3

Fig 8.19 a, b

Figure 8.19 (b) Competitive inhibition

A competitiveinhibitor mimics the

substrate, competingfor the active site.

Competitiveinhibitor

A substrate canbind normally to the

active site of anenzyme.

Substrate

Active site

Enzyme

(a) Normal binding

Fig 8.19c

Figure 8.19

A noncompetitiveinhibitor binds to the

enzyme away fromthe active site, altering

the conformation ofthe enzyme so that its

active site no longerfunctions.

Noncompetitive inhibitor

(c) Noncompetitive inhibition

Fig 8.21

Question 8.4