Fig. 5-2, p. 74

Table 5-1, p. 80

Fig. 5-3, p. 74

Exergonic reactions, such asaerobic respiration, end with a netoutput of energy. Such reactionshelp cells access energy storedin chemical bonds of reactants.

glucose (C6H12O6) + 6 O2

6 CO2 + 6 H2O

energy in energy out

Endergonic reactions, suchas photosynthesis, proceedonly with a net input of energy.Cells can store energy in theproducts of such reactions.

Fig. 5-4, p. 75

ENERGY OUTWith each conversion,there is a one-way flow ofa bit of energy back to theenvironment. Nutrientscycle between producersand consumers.

NUTRIENTCYCLING

producers

consumers

ENERGY OUTEnergy continuallyflows from the sun.

ENERGY INSunlight energy reachesenvironments on Earth.Producers of nearly allecosystems secure someand convert it to storedforms of energy. Theyand all other organismsconvert stored energyto forms that can drivecellular work.

Fig. 5-5, p. 76

ADP + Pi

base(adenine)

ribose

three phosphategroups

reactionsthatrequireenergy

reactionsthatreleaseenergy

ATP

Fig. 5-6, p. 76

activation energywith enzyme

Time

En

erg

y

starting substances:glucose and phosphate

activation energywithout enzyme

product:glucose-6-phosphate

Fig. 5-27, p. 89

Fig. 5-8, p. 78

active site altered,substrate can bind

allosteric activator

allosteric binding site vacant

enzyme active site

substrate cannot bind

X

X

active sitealtered, can’tbind substrate

allostericbindingsite vacant;active sitecan bindsubstrate

allosteric inhibitor

Fig. 5-10, p. 79

Fig. 5-11, p. 79

Fig. 5-12, p. 80

Fig. 5-16, p. 82

waterdye

dye

Fig. 5-17, p. 83

Glucose and other large,polar, water-soluble molecules,and ions (e.g., H+, Na+, K+, Cl–,

Ca++) cannot cross on their own.

lipidbilayer

Oxygen, carbon dioxide,small nonpolar molecules, andsome molecules of water crossa lipid bilayer freely.

Fig. 5-18, p. 84

Fig. 5-18, p. 84

Fig. 5-19, p. 85

Fig. 5-20, p. 86

An ATP molecule bindsto a calcium pump.

higher concentrationof calcium ions outsidecell compared to inside

calcium pump

The shape of the pumpreturns to its resting position.

Fig. 5-20, p. 86

The ATP transfers aphosphate group to pump.The energy input causes thepump’s shape to change.

ADP + Pi

The shape change permitscalcium to be released to oppositeside of membrane. A phosphategroup and ADP are released.

Calcium enters a tunnelthrough the pump, binds tofunctional groups inside.

Fig. 5-21, p. 86

The fluid volume rises in thesecond compartment as waterfollows its concentration gradientand diffuses into it.

hypotonicsolution in firstcompartment

hypertonic solutionin secondcompartment

Initially, the volumes of the twocompartments are equal, but thesolute concentration across themembrane differs.

Fig. 5-22, p. 87

1 liter of 10%sucrose solution

2% sucrosesolution

1 liter ofdistilled water

1 liter of 2%sucrose solution

Fig. 5-23, p. 87