CELLULAR RESPIRATION

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CELLULAR RESPIRATION
How Cells Obtain Energy To Sustain Life
2
ENERGETICS

• Life Requires Energy!
• Muscle contraction
• Cellular transport
• Drive cellular reactions

3
ORIGIN OF ENERGY

• Nearly all energy for life on earth comes from
  sunlight
• Energy in sunlight is captured

4
THE BIG PICTURE
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CELLULAR RESPIRATION

• The physical act of breathing and the process of
  cellular respiration share reactants and products
• But cellular respiration refers to

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REQUIREMENTS OF RESPIRATION

• Cellular Respiration Requires

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STARTING MATERIAL FOR CELLULAR RESPIRATION
H
O
1
C
6
CH2OH
2
H
OH
C
5
H
H
C
O
3
C
H
HO
1
4
H
C
C
4
OH
OH
H
C
H
HO
OH
2
3
C
C
5
H
C
OH
H
OH
6
C
H
OH
H
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STARTING MATERIAL

• Glucose
• All cells must break C-bonds in glucose to
  release energy

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MANY REACTIONS REQUIRE AN INPUT OF ENERGY

• Many Reactions in Cells are Not Spontaneous

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MANY REACTIONS REQUIRE AN INPUT OF ENERGY
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MANY REACTIONS REQUIRE AN INPUT OF ENERGY
HYDROLYSIS OF ATP RELEASES ENERGY
Pi
P
P
P
P
P
H2O
Energy
Water
Inorganic phosphate
ADP



ATP
7.3 kcal/molATP
Bonds in ATP hold significant amount of energy!

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CATYLSTS INCREASE RATES OF REACTION

• Even with enough energy, there is no guarantee
  rxns will proceed at a suitable speed

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CATYLSTS INCREASE RATES OF REACTION

• Lock Key
• Model
• Substrate fits into
• enzyme
• Enzyme then catalyzes the chemical reaction and
  releases the products

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CATYLSTS INCREASE RATES OF REACTION
Substrate
Enzyme
LOCK KEY MODEL OF ENZYME AND SUBSTRATE
Substrate (Key)
A
B C
A B
C
A
B
C
Shape change
Enzyme (Lock)
3. Thereby speeding the rate of reaction
2. Enzyme lowers activation energy
1. Enzyme brings reactants together in
proper orientation
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CATYLSTS INCREASE RATES OF REACTION

• Enzymes

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MOLECULAR HELPERS

• Two Molecules Help Cell Respiration Proceed
• Carry (and store) high energy electrons
• Later transfer energy to other molecules

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OXIDATION-REDUCTION REACTIONS
Oxidation Reduction
OIL RIG
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CELLULAR RESPIRATION IS A SERIES OF REDOX
REACTIONS

• In
• Cellular
• Respiration

• Oxidation of C in glucose tied to reduction of
  other
• molecules (exNAD)