1. Cellular respiration is the process by which cells obtain energy from glucose to sustain life. 2. Nearly all energy for life on Earth comes from sunlight, which is captured through photosynthesis. Cells must break the carbon bonds in glucose to release energy stored in these bonds. 3. Cellular respiration requires oxygen, glucose as a starting material, and involves a series of redox reactions where the oxidation of carbon in glucose is tied to the reduction of other molecules like NAD+.

1. CELLULAR RESPIRATION
How Cells Obtain Energy To Sustain Life

2. ENERGETICS
Life Requires Energy!

3. ORIGIN OF ENERGY
• Nearly all energy for life on earth comes from
sunlight
• Energy in sunlight is captured by photosynthesis

4. THE BIG PICTURE

5. CELLULAR RESPIRATION
• The physical act of breathing
and the process of cellular
respiration share reactants and
products

6. REQUIREMENTS OF RESPIRATION
• Cellular Respiration Requires:

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

8. STARTING MATERIAL
Glucose:
• All cells must break C-bonds in glucose to
release energy
• Energy stored in bonds

9. MANY REACTIONS REQUIRE AN
INPUT OF ENERGY
• Many Reactions in Cells are Not Spontaneous

10. MANY REACTIONS REQUIRE AN
INPUT OF ENERGY

11. MANY REACTIONS REQUIRE
AN INPUT OF ENERGY
HYDROLYSIS OF ATP RELEASES ENERGY
P P P P P Pi
ATP Water ADP Energy
Inorganic
phosphate
+
H2O
+ +
7.3
kcal/molATP
Bonds in ATP hold significant amount of energy!

12. CATYLSTS INCREASE
RATES OF REACTION
• Even with enough energy, there is no
guarantee rxns will proceed at a suitable speed

13. CATYLSTS INCREASE RATES OF
REACTION
Lock & Key
Model:
• Substrate fits into
enzyme like a key
fits into a lock
• Enzyme then catalyzes the chemical reaction and
releases the products

14. CATYLSTS INCREASE RATES OF REACTION
Substrate
Enzyme
LOCK & KEY MODEL OF ENZYME AND SUBSTRATE
Substrate
(Key)
Enzyme
(Lock)
A B —C
A B C
A— B C
Shape
change

15. CATYLSTS INCREASE
RATES OF REACTION
Enzymes:

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

17. OXIDATION-REDUCTION REACTIONS
Oxidation =
Reduction =
OIL
RIG

18. CELLULAR RESPIRATION IS A SERIES
OF REDOX REACTIONS
In
Cellular
Respiration:
• Oxidation of C in glucose tied to reduction of other
molecules (ex:NAD+)