metabolism (chapter 8) - valenciafd.valenciacollege.edu/file/sclark/metabolism (8).pdf · 2007. 1....

metabolism(chapter 8)

The laws of ThermodynamicsThe laws of Thermodynamicsas dictated by the Universeas dictated by the Universe

1) Energy can neitherbe created nor destroyed,

but only converted.

2) Entropy is alwaysincreasing in any

spontaneous process.

potential

potential

potential

kinetic

potential

kinetic

kinetic

kinetic

Did I pack my hair

gel?

-7.3 kcal/moleof ATP

transfer of

phosphate group

catabolism anabolism

enzyme function . . .

organic catalysts

factors affecting enzyme activity

a) enzyme activity as a function ofsubstrate concentration

b) enzyme activity as a function oftemperature

c) enzyme activity as a function of pH

substrate concentration

0

10

20

30

40

50

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95100

Substrate Concentration

Rea

ctio

n ra

te (s

ubst

rate

to p

rodu

ct /

min

)

temperature

0

10

20

30

40

50

60

0 5 10 15 20 25 30 35 40 45 50 55 60

Temperature (C)

Rea

ctio

n ra

te (s

ubst

rate

to p

rodu

ct /

min

)

pH

0

10

20

30

40

50

60

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Rea

ctio

n ra

te (s

ubst

rate

to p

rodu

ct /

min

)

regulation of metabolism throughenzyme inhibition

a) competitive inhibition

b) noncompetitive (allosteric) inhibition

c) feedback inhibition

competitive inhibition . . .

noncompetitive inhibition . . .

typical metabolic pathway . . .

feedback inhibition . . .

enzyme helpers

a) cofactorsinorganic; metal atoms

(e.g. zinc, iron, copper)

b) coenzymesorganic; vitamins