1. Cellular Energy

2. Potential vs. Kinetic Energy
Potential = stored
Kinetic = motion

3. What kind of energy do cells use?
ATP (adenosine triphosphate)
The high energy is stored in the last P bond
3 Phosphates
Ribose Sugar
Adenine Base

4. Where do we get ATP? Our bodies have less than a gram of ATP!
Our cells must recycle ATP

5. Recycling ATP Occurs in the cytoplasm and mitochondria
We use the energy in glucose to reattach phosphates to ADP.
This process is called Cellular Respiration
Occurs in the cytoplasm and mitochondria

6. Cellular Respiration
1 Glucose = 38 ATP

7. Overview of Cellular Respiration
Four stages:
Glycolysis
Transition Reaction
Citric Acid Cycle
Electron Transport Chain

8. Cellular Respiration Electron Transport Chain NADH
FADH2
GLYCOLYSIS
Glucose
Pyruvate
CITRIC ACID CYCLE
Electron Transport Chain
Substrate-level phosphorylation
Oxidative phosphorylation
Mitochondrion
and
High-energy electrons carried by NADH
ATP
CO2
Cytoplasm

9. 1. Glycolysis (cytoplasm)
Glucose (6-carbon chain) is broken down to two Pyruvates (3-carbon chains)
This cost 2 ATPs, but produced 4 ATPs
Net gain = 2 ATPs
In the process, 2 H+ ions combine with NAD+ to form NADH molecules – electron carriers
Net gain = 2 NADH

11. 2. Transition Reaction
2 Pyruvates (3-carbon chains) react with coenzyme A (CoA) to form 2 acetyl CoA’s (2- carbon chains)
CoA is like a trailer loading up carbon to get into the Mitochondria
Output = 2 CO2
Net gain = 2 NADH

12. Acetyl CoA (acetyl coenzyme A)
Pyruvate
NAD+
NADH
+ H+
CoA
Acetyl CoA (acetyl coenzyme A)
Coenzyme A
Figure 6.8

13. 3. Citric Acid Cycle (Krebs)
In Mitochondria
CoA drops off 2-C chain which combines with a 4-C compound to form a 6-C chain
Through the cycle Carbons are snapped off and released as CO2
For 2 trips around the cycle:
4 CO2 released
6 NADH made
2 FADH2 made
2 ATP made

15. 4. Electron Transport Chain (ETC)
Located on inner membrane of Mitochondria
Electrons from NADH and FADH2
Travel down the electron transport chain to oxygen, which picks up H+ to form water (H2O)
Electron movement causes an H+ gradient
H ions rush through ATP enzyme producing:
NADH  3 ATP 10 NADH = 30 ATP
FADH2  2 ATP 2 FADH2 = 4 ATP

16. Intermembrane space
Inner mitochondrial membrane
Mitochondrial matrix
Protein complex
Electron flow
Electron carrier
NADH
NAD+
FADH2
FAD
H2O
ATP
ADP
ATP synthase H+ + P O2
Electron Transport Chain
Chemiosmosis .
OXIDATIVE PHOSPHORYLATION
+ 2 1 2
Figure 6.10

17. Electron Transport Chain Animation

18. Cellular Respiration Electron Transport Chain NADH
FADH2
GLYCOLYSIS
Glucose
Pyruvate
CITRIC ACID CYCLE
Electron Transport Chain
Substrate-level phosphorylation
Oxidative phosphorylation
Mitochondrion
and
High-energy electrons carried by NADH
ATP
CO2
Cytoplasm

19. Photosynthesis

20. Can you account for everything?
Cellular Respiration!
Photosynthesis!
Light
energy 6
CO2 +
H2O
Carbon dioxide
Water
C6H12O6 O2
Glucose
Oxygen gas

21. Potential vs. Kinetic Energy
Through the process of photosynthesis, plants can store energy by making glucose.

22. They are so good at it that they make enough for us too!
Plants are autotrophs
They make their own food (sugars)
They are so good at it that they make enough for us too!
Plant cells full of chloroplasts!

24. Light Reactions
Thylakoids – stacks of chlorophyll inside the chloroplast
Wavelengths of visible light are absorbed by plant pigments
This drives the light reactions of photosynthesis
Increasing energy
10–5 nm
10–3 nm
1 nm
103 nm
106 nm
1 m
103 m
Gamma
rays
X-rays UV
Infrared
Micro-
waves
Radio
Visible light
400
500
600
700
750
650 nm
Wavelength (nm)
Transmitted
light
Absorbed
Reflected
Light
Chloroplast
380

25. Light Reaction 18 ATPs will help make 1 glucose Photo system 1 & 2
Photons from sun split water into O2 (released) and H+
Photons absorbed by chlorophyll excite H+ ions
H+ ions are passed between photosystems until they reach final electron carriers = NADPH
The final H+ ion cycles six times to make a total of 18 ATPs
Net gain = 12 NADPH and 18 ATP
18 ATPs will help make 1 glucose

27. Calvin Cycle
ATP and NADPH from light reaction powers sugar production in the Calvin cycle
Plant is taking in CO2
3 (5-Carbon) chains cycle around picking up CO2
Each cycle makes half a sugar, so two cycles will make a full sugar

30. TA-DA!!! Light energy 6 CO2 + H2O Carbon dioxide Water C6H12O6 O2
Glucose
Oxygen gas