Download Cellular Energy

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
Potential = stored
Kinetic = motion
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ATP (adenosine triphosphate)
The high energy is stored in the last P bond
Adenine Base
3 Phosphates
Ribose Sugar
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Our bodies have less than a gram of ATP!
Our cells must recycle ATP

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We use the energy in glucose to reattach
phosphates to ADP.
This process is called Cellular Respiration
• Occurs in the cytoplasm and mitochondria
1
Glucose = 38 ATP
Four stages:
1. Glycolysis
2. Transition Reaction
3. Citric Acid Cycle
4. Electron Transport Chain

NADH
High-energy
electrons
carried by NADH
NADH
FADH2
and
GLYCOLYSIS
CITRIC ACID
CYCLE
Pyruvate
Glucose
Electron
Transport
Chain
Mitochondrion
Cytoplasm
ATP
Substrate-level
phosphorylation
CO2
ATP
CO2
Substrate-level
phosphorylation
ATP
Oxidative
phosphorylation
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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
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2 Pyruvates (3-carbon chains) react with
coenzyme A (CoA) to form 2 acetyl CoA’s (2carbon chains)
CoA is like a trailer loading up carbon to get
into the Mitochondria
Output = 2 CO2
Net gain = 2 NADH
NAD+
NADH
+ H+
CoA
Pyruvate
Acetyl CoA
(acetyl coenzyme
A)
CO2
Figure 6.8
Coenzyme A

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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
6
2
2
CO2 released
NADH made
FADH2 made
ATP made
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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)

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Electron movement causes an H+ gradient
H ions rush through ATP enzyme producing:
◦ NADH  3 ATP
◦ FADH2  2 ATP
10 NADH = 30 ATP
2 FADH2 = 4 ATP
H+
Intermembrane
space
Inner
mitochondria
l membrane
Mitochondrial
matrix
.
Protein
complex
H+
FADH2
Electron
flow
NADH
H+
H+
H
H+
Electron
carrier
H+
H+
ATP
synthase
FAD
NAD+
H
1O + 2H+
2 2
+
H+
H+
H2O
Electron Transport Chain
OXIDATIVE PHOSPHORYLATION
Figure 6.10
H+
+
ADP
+
P
H+
ATP
Chemiosmosis
NADH
High-energy
electrons
carried by NADH
NADH
FADH2
and
GLYCOLYSIS
CITRIC ACID
CYCLE
Pyruvate
Glucose
Electron
Transport
Chain
Mitochondrion
Cytoplasm
ATP
Substrate-level
phosphorylation
CO2
ATP
CO2
Substrate-level
phosphorylation
ATP
Oxidative
phosphorylation
Light
energy
6 CO2
+ 6
Carbon dioxide
H2O
Water
C6H12O6 + 6
Glucose
O2
Oxygen gas

Through the process of photosynthesis,
plants can store energy by making glucose.

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!
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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
Gamma
rays
X-rays
1 nm
103 nm
UV
1m
106 nm
Microwaves
Infrared
103 m
Radio
waves
Light
Reflected
light
Visible light
380 400
500
600
700
750
Wavelength (nm)
650
nm
Chloroplast
Absorbed
light
Transmitted
light

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
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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
Light
energy
6 CO2
+ 6
Carbon dioxide
H2O
Water
C6H12O6 + 6
Glucose
O2
Oxygen gas