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UNIT 2 Lecture 6. Metabolism. Unit 2: Life’s Energy Sources and Conversions. Metabolism Cellular Respiration: Sugar ATP Photosynthesis: Light Sugar. Key Themes. • Energy acquisition & conversions in metabolism. The Molecules of Life Structure-Function Relationship - PowerPoint PPT Presentation
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UNIT 2Lecture 6
Metabolism
Unit 2:Life’s Energy Sources and Conversions
• Metabolism• Cellular Respiration: Sugar ATP• Photosynthesis: Light Sugar
Key Themes
• Energy acquisition & conversions in metabolism
The Molecules of Life
Structure-Function Relationship
Life’s Energy Conversions
An organism’s metabolism is the total of the organism’s chemical reactions
•Two types of reactions:
– Big molecule Several small molecules• Releases energy
– Small molecules Big molecule • Requires energy
Metabolism
An organism’s metabolism is total of the organism’s chemical reactions
•Two types of reactions:– Big molecule Several small molecules
• Releases energy
• This sounds like:a) Cellular respiration
b) Photosynthesis
c) Neither
Metabolism
Order and Chaos
Nature “wants” to be random/chaotic
Mydesigningsolutions.com; bedroomdisaster.blogspot.com; fritolay.com; slashfood.com
Energy
Energy
Order and Chaos
Nature “wants” to be random/chaotic
Mydesigningsolutions.com; bedroomdisaster.blogspot.com; fritolay.com; slashfood.com
Energy
Energy
A complex, ordered molecule
Several small, disordered molecules
A complex, ordered molecule
Several small, disordered molecules
Newenergyandfuel.com; ualberta.ca; all-water.org
Energy
Requires
Releases
GlucoseCO2 H2O
Fig. 8-6Reactants
Energy
En
erg
y
Products
Amount ofenergy
released
Progress of the reaction
(a) Energy-releasing reactions
Products
ReactantsEnergy
En
erg
y
Amount ofenergy
required
(b) Energy-requiring reactions
Progress of the reaction
Lightenergy
ECOSYSTEM
Photosynthesisin chloroplasts
CO2 + H2OCellular respiration
in mitochondria
Organicmolecules+ O2
ATP then powers cellular work
Heatenergy
ATP
Fig. 9.2Ecosystem energy flow 1. Be able to
link producers and consumers via cycles of energy and carbon flow
ATP
Lightenergy
ECOSYSTEM
Photosynthesisin chloroplasts
CO2 + H2OCellular respiration
in mitochondria
Organicmolecules+ O2
ATP then powers cellular work
Heatenergy
ATP
Fig. 9.2Energy flowin ecosystems
1. Be able to link producers and consumers via cycles of energy and carbon flow
ATP
Lightenergy
ECOSYSTEM
Photosynthesisin chloroplasts
CO2 + H2OCellular respiration
in mitochondria
Organicmolecules+ O2
ATP then powers cellular work
Heatenergy
ATP
Fig. 9.2Energy flowin ecosystems
ATP
Newenergyandfuel.com; ualberta.ca; all-water.org
Energy
Requires
Releases
GlucoseCO2 H2O
Chaos = Entropy
Low Entropy System(less random, more ordered) High Entropy System
(more random, less ordered)
Newenergyandfuel.com; ualberta.ca; all-water.org
Energy
Requires
Releases
GlucoseCO2 H2O
Potential energy is stored in chemical bonds (C-H especially)
Chemicalenergy
Heat CO2
H2O
+
Cells’ ability to store energy in chemical bonds is what makes organisms and ecosystems function
Chemicalenergy
Heat CO2
H2O
+
Cells’ ability to store energy in chemical bonds is what makes organisms and ecosystems function
Without photosynthesis…
There is no way to convert light
energy into chemical energy
What about cellular respiration?
Chemicalenergy
Heat CO2
H2O
+
Without cellular respiration:A. Nothing could liveB. No animals could liveC. Nothing non-
photosynthetic could liveD. Everything could live
Where does energy go?
Where does energy go in an ecosystem?
• Heat, growth, reproduction, etc.
Heat Heat Heat
Heat
Trophic levels: Energy Flow Through Ecosystem
http://www.britannica.com/EBchecked/media/15/Transfer-of-
energy-through-an-ecosystem
5 minute break
Energy for all cellular work is provided by the same energy-rich compound:
ATP (adenosine triphosphate)
A cell (in any organism) constantly performs work that requires energy:
ATP
Fig. 8.8
ATP consists of three phosphate groups, a sugar, and a nitrogenous base.
What does that sound like?A) a triglycerideB) a nucleotideC) a phospholipidD) a trisaccharide
A = adenineA + Ribose = adenosine
adenosine mono-phosphate (AMP)
adenosine di-phosphate (ADP)adenosine tri-phosphate (ATP)
Each nucleotide is composed of: a monosaccharide sugar, a phosphate group,
and a (N-containing) nitrogenous base
(b) Nucleotide
Nitrogenousbase
Phosphategroup Sugar
Fig. 5.27
Fig. 8.8
ATP takes the energy released from the breakdown of energy-rich food molecules
and does cellular work
P iADP+
Energy frombreakdown ofenergy-rich molecules
Energy for cellularwork
ATP + H2OEnergy loaded onto
ATPEnergy released from
ATP
Fig. 8.12
Fig. 8-9
Inorganic phosphate
Energy
Adenosine triphosphate (ATP)
Adenosine diphosphate (ADP)
P P
P P P
P ++
H2O
i
Fig. 8.8
ATP: Energy carrier
“Phosphorylated” (=energized!)
molecule+ Lower
Energy
Higher Energy
Fig. 8.11 (b)See Campbell Figures 50.27 & 50.29 for additional details on muscle contraction.
ATP transfers phosphate group to motor protein(phosphorylated motor protein = energized)
Pi
ADP
+
Vesicle Cytoskeletal track
Motor protein Protein moved
ATP
ATP
High-energy P transferred to motor proteins for mechanical work
High-energy P transferred to transport proteins for transport work
Membrane protein (Na+/K+ pump)
Pi
ADP
+
P
Na+ Na+ moved uphill
Pi
ATP Fig. 8.11 (a); see also Fig. 7.16 for more detail
Na+/K+ Pump
• Cells want to pump Na+ out
• Cells want to pump K+ in
K+
Na+
ATP
Active transport and the sodium-potassium pump
Both Na+ and K+ are moved AGAINST their concentration gradient
http://www.colorado.edu/ebio/genbio/07_16ActiveTransport_A.html
See Fig. 7.16 for a six panel, blow-by-blowdescription of the sodium-potassium pump.
8. Be able to apply the principal features and functions of an ATP-fueled ion pump to the Na+/K+ pump
http://onlinephys.com/circuit1.html
Fig.8.7
http://onlinephys.com/circuit1.html
ATP fuels the Na+/K+ pumpNa+ accumulates “on top of the hill” (against its concentration gradient)
Na+ flows downhill again
Releasing useful energy
Cotransport: Using potential energy
ATP
Na+
ATP fuels the Na+/K+ pumpNa+ accumulates “on top of the hill” (against its concentration gradient)
Na+ flows downhill again
Releasing useful energy
Cotransport: Using potential energy
ATP
Na+
POTENTIAL ENERGY
35
Cotransport: Using potential energy
This potential energy can be used… To transport other molecules
AGAINST their concentration gradient
The Na+ gradient built up by the Na+/K+ pump also fuels the secondary active transport
of glucose (& other substances) AGAINST their concentration gradient
In Na+/glucose co-transport, Na+ flows back downhill & drags glucose
uphill AGAINST its concentration gradient
What provides the energy for the uphill transport of Na+ against its concentration gradient?A)No energy is needed.B)the Na+/K+ transport protein itselfC)ADP and PiD)ATP
What provides the energy for the Na+/glucose cotransporter?A)No energy is needed.B)the Na+ gradientC)ATP as a direct energy sourceD)ATP as an indirect energy sourceE)B and D
High-energy P transferred to transport proteins for transport work
Membrane protein (Na+/K+ pump)
Pi
ADP
+
P
Na+ Na+ moved uphill
Pi
ATP Fig. 8.11 (a); see also Fig. 7.16 for more detail41
High-energy P transferred to reactant molecules for chemical work
Fig. 8.10 (b)
(Ammonia displacesphosphate group,forming the amino acidglutamine.)
PP
GluNH3
NH2
Glu i
GluADP+
P
ATP+
+
Glu
(ATP adds phosphategroup to glutamic acid,making it less stable.)
+
1. Mechanical work
2. Transport work
3. Chemical work
Energy for all 3 types of work provided by:
ATP (adenosine triphosphate)
Summary: To stay alive, living cell performs 3 kinds of work that require energy:
• ATP is too unstable to serve as an actual
storage form of energy.
• Therefore, C-H bonds in macromolecules (e.g. sugars) are instead used for energy storage.
Photosynthesis:
Respiration:
ATP
Since ATP is too unstable,
C-H bonds in sugars are used for energy storage.
Converts solar energy
to ATP and uses ATP to make sugars
Converts the energy of sugars back to ATP as needed.
Sugar [CH2O]x + O2CO2 + H20
ATPLight (energy)
http://www.youtube.com/watch?v=00jbG_cfGuQ&feature=relmfu
Hank’s crash course in ATP0-3:30
Key Themes
(2) “Think Like a Biologist”: Understand What Life Is.“Unity” of life: What are common features of eukaryotes?
Energy conversions: Sugar breakdown & mitochondrial ATP formation
Food-to-Energy
Fig. 9.1
Fig. 8.3
Respiration
Cellular respiration breaks down energy-rich molecules to CO2 & water, extracting their energy.
Fig. 9.2
Lightenergy
ECOSYSTEM
Photosynthesisin chloroplasts
CO2 + H2OCellular respiration
in mitochondria
Organicmolecules+ O2
ATP powers most cellular work
Heatenergy
ATP
High energy
Low energy
C-H bond!
“burned” with O2 to formH2O + CO2
Photosynthesis:
Respiration:
ATP
Since ATP is too unstable,
C-H bonds in sugars are used for energy storage.
Converts solar energy
to ATP and uses ATP to make sugars
Converts the energy of sugars back to ATP as needed.
Sugar [CH2O]x + O2CO2 + H20
ATPLight (energy)
Today’s Exit Ticket
• In a few sentences:– Describe energy-releasing and energy-
requiring reactions. – Use the creation and use of ATP for cellular
work as examples of these reactions.– Be sure to use the word “entropy.”