Ch 8 ~ Cellular Energy
Section 1: How Organisms Obtain Energy
Section 2: Photosynthesis
Section 3: Cellular Respiration
Transformation of Energy
Energy - ability to do work.
8.1 How Organisms Obtain EnergyCellular Energy
Thermodynamics - study of flow & transformation of energy in universe.
Laws of Thermodynamics
First law —energy converted from one form to another, but cannot be created nor destroyed.
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Second law —energy cannot be converted without the loss of energy
Autotrophs -make their own food.
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Heterotrophs -need to ingest food to obtain energy.
Metabolism - All chemical reactions in a cell
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Photosynthesis—light energy from Sun converts to chemical energy for use by cell
Cellular respiration—organic molecules (CHO, lipid, Pro) broken down to release energy for use by cell
“catabolism”, or catabolic pathway
ATP: The Unit of Cellular Energy
ATP releases energy when bond btwn 2nd & 3rd P group is broken, forming molecule called adenosine diphosphate (ADP) & 1 free P group.
Cellular Energy
ATP
energy
thermodynamics
metabolism
Photosynthesis
cellular respiration
adenosine triphosphate (ATP)
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Vocabulary
Section 8.1
FQ 4
1. A
2. B
3. C
4. D
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8.1 Formative Questions
A B C D
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A. It captures light energy from the sun.
B. It is produced in anabolic pathways.
C. It stores and releases chemical energy.
D. It converts mechanical energy to thermal energy.
Why is adenosine triphosphate (ATP) such an important biological molecule?
FQ 1
1. A2. B
Cellular EnergyChapter 8
Which law of thermodynamics explains why the ladybug receives the least amount of usable energy?
A. the first law of thermodynamics
B. the second law of thermodynamics A B
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8.1 Formative Questions
FQ 2
1. A2. B
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A B
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8.1 Formative Questions
All of the energy from the food you eat comes from the sun.
A. true
B. false
FQ 3
1. A
2. B
3. C
4. D
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8.1 Formative Questions
A B C D
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Why is cellular respiration a catabolic pathway?
A. Energy is used to form
glucose and oxygen.
B. Energy is converted from
water to carbon dioxide.
C. Energy that is lost is
converted to thermal energy.
D. Energy is released by the
breakdown of molecules.
Overview of Photosynthesis
Photosynthesis occurs in 2 phases:
Cellular Energy
Light-dependent reactions
Light-independent reactions
8.2 Photosynthesis
Phase One: Light Reactions
Absorption of light is 1st step in photosynthesis.
Cellular Energy
Chloroplasts capture light energy.
Chloroplasts
capture light energy; mainly in leaf cells
thylakoids – form flat, sac-like membranes in stacks, or grana- light-dependent chem rx take place in
thylakoids
Stroma – fluid-filled space outside grana- light-independent chem rx takes place in stroma
Cellular Energy
Pigments absorb light; found in thylakoid membranes
Diff pigments absorb diff wavelengths of light.
Major pigmentschlorophylls a & b, carotenoidsabsorb violet-blue light and reflect green (chlorophylls) or red/yellow/orange (carotenoids)
Cellular Energy
Electron Transport Chain
Light energy excites e- in photosystem II causing water molecule to split & 3 events to occur:
1. releasing e- into electron transport system (ETC)
2. releasing H+ into thylakoid space
3. produce O2 as waste product.
Excited e- move from photosystem II to an electron-acceptor molecule in thylakoid membrane.
Electron-acceptor molecule (NADH or FAD) transfers e- along a series of electron-carriers to photosystem I.
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Cellular EnergyPhotosystem I transfers the electrons to protein called ferrodoxin.
Ferrodoxin transfers the electrons to the electron carrier NADP+, forming the energy-storing molecule NADPH.
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Phase Two: The Calvin CycleIn 2nd phase of photosynthesis, called Calvin cycle, energy is stored in organic molecules such as glucose.Why?
Cellular EnergyChapter 8
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Calvin Cycle
WHY?
Because NADPH & ATP provide cells with LOTS of energy, but not for a long time. So, 2nd phase of photosynthesis stores energy in glucose.
Processes in Calvin Cycle6 CO2 molecules combine w/ 6 x 5-C
compounds to form 12 x 3-C molecules called 3-PGA.
The chemical energy stored in ATP & NADPH is transferred to the 3-PGA molecules to form high-energy molecules called G3P.
Cellular Energy 2 G3P molecules leave the cycle to be used for production of
glucose and other organic compounds.
Enzyme called rubisco converts remaining 10 G3P molecules into 5-C molecules called RuBP.
These molecules combine with new CO2 molecules to continue the Calvin cycle.
thylakoid
granum
stroma
pigment
NADP+
Calvin cycle
rubisco
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Vocabulary
Section 2
FQ 5
1. A
2. B
3. C
4. D
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A B C D
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A. chloroplasts
B. Golgi apparatus
C. mitochondria
D. vacuoles
Where in the plant cell does photosynthesis take place?
8.2 Formative Questions
FQ 6
1. A
2. B
3. C
Cellular EnergyChapter 8
8.2 Formative Questions
A. 400-500 nm
B. 500-600 nm
C. 600-700 nm
Which range of wavelengths is reflected by chlorophylls a and b?
A B C
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FQ 7
1. A
2. B
3. C
4. D
Cellular EnergyChapter 8
8.2 Formative Questions
A. absorption
B. chemiosmosis
C. electron transport
D. C2 pathway
Which mechanism of photosynthesis uses the movement of hydrogen ions (H+) across a concentration gradient to synthesize ATP?
A B C D
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FQ 8
1. A
2. B
3. C
4. D
Cellular EnergyChapter 8
8.2 Formative Questions
A B C D
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A. They accelerate photosynthesis.
B. They release more oxygen.
C. They help the plant conserve water.
D. They reduce the requirement for ATP.
How are the C4 pathway and the CAM pathway
an adaptive strategy for some plants?
Overview of Cellular Respiration
Organisms obtain energy in a process called cellular respiration.
8.3 Cellular Respiration
Cellular Energy
The equation for cellular respiration is the opposite of the equation for photosynthesis.
Chapter 8
8.3 Cellular Respiration
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Cellular respiration occurs in two main parts.
Glycolysis
Aerobic respiration
Chapter 8
Glycolysis
Glucose is broken down in the cytoplasm through the process of glycolysis.
8.3 Cellular Respiration
Cellular Energy
Two molecules of ATP and two molecules of NADH are formed for each molecule of glucose that is broken down.
Chapter 8
Krebs Cycle
Glycolysis has a net result of two ATP and two pyruvate.
8.3 Cellular Respiration
Cellular Energy
Most of the energy from
the glucose is still contained in
the pyruvate.
The series of reactions
in which pyruvate is broken
down into carbon dioxide is called
the Krebs cycle.
Chapter 8
8.3 Cellular Respiration
Cellular Energy
The net yield from the Krebs cycle is six CO2 molecules, two ATP, eight NADH, and two FADH2.
Chapter 8
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8.3 Cellular Respiration
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Electron Transport
Final step in the breakdown of glucose
Point at which ATP is produced
Produces 24 ATP
Chapter 8
8.3 Cellular Respiration
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Anaerobic Respiration
The anaerobic pathway that follows glycolysis
Two main types
Lactic acid fermentation
Alcohol fermentation
Cellular Respiration
Chapter 8
anaerobic process
aerobic respiration
aerobic process
glycolysis
Krebs cycle
fermentation
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Vocabulary
Section 3
FQ 9
1. A
2. B
3. C
4. D
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A B C D
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A. to make ATP
B. to process H2O
C. to store glucose
D. to deliver oxygen
What is the overall purpose of cellular respiration?
8.3 Formative Questions
FQ 10
1. A
2. B
3. C
4. D
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A B C D
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Which represents the general sequence of cellular respiration?
A. TCA cycle chemiosmosis glycolysis
B. glycolysis Krebs cycle electron transport
C. electron absorption catalysis phosphorylation
D. aerobic pathway anaerobic pathway fermentation
8.3 Formative Questions
FQ 11
1. A
2. B
3. C
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A B C
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A. glycolysis
B. Krebs cycle
C. electron transport
Which stage of cellular respiration is the anaerobic process?
8.3 Formative Questions
FQ 12
1. A
2. B
3. C
4. D
Cellular EnergyChapter 8
A. CoA
B. CO2
C. FADH2
D. NADH
Which molecule generated by the Krebs cycle is a waste product?
A B C D
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8.3 Formative Questions
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CDQ 1
1. A2. B3. C4. D
A B C D
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A. Energy cannot be converted or destroyed.
B. Energy can be converted and destroyed.
C. Energy can be converted but not destroyed.
D. Energy can be destroyed but not converted.
Which statement describes the law of conservation of energy?
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Chapter Diagnostic Questions
Chapter 8
CDQ 2
1. A2. B3. C4. D
A B C D
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Chapter Diagnostic Questions
Chapter 8
A. photosynthesis
B. cellular respiration
C. homeostasis
D. fermentation
In which metabolic process are molecules broken down to produce carbon dioxide and water?
CDQ 3
1. A2. B3. C4. D
A B C D
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Chapter Diagnostic Questions
Chapter 8
A. NADPH
B. ATP
C. chloroplast
D. glucose
At the end of the Calvin cycle, where is energy stored?
CAQ 1
1. A
2. B
3. C
4. D
Cellular EnergyChapter 8
A B C D
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Look at the following figure. Which part of the chloroplast is a sac-like membrane arranged in stacks?
A. grana
B. stroma
C. thylakoids
D. Golgi apparatus
Chapter Assessment Questions
CAQ 2
1. A
2. B
3. C
4. D
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A B C D
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Chapter Assessment Questions
During the Krebs cycle, pyruvate is broken down into what compound?
A. H2O
B. O2
C. CO
D. CO2
CAQ 3
1. A
2. B
3. C
4. D
Cellular EnergyChapter 8
A B C D
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Chapter Assessment Questions
Look at the following figure. Which molecule is released when ATP becomes ADP?
A. phosphate group
B. water molecule
C. ribose sugar
D. energy cells
STP 1
1. A
2. B
Cellular EnergyChapter 8
A B
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Which metabolic process is photosynthesis?
A
B
Standardized Test Practice
STP 2
1. A
2. B
3. C
4. D
Cellular EnergyChapter 8
A B C D
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Standardized Test Practice
At the beginning of photosynthesis, which molecule is split to produce oxygen (O2) as
a waste product?
A. CO2
B. H2O
C. C6H12O6
D. 3-PGA
STP 3
1. A
2. B
3. C
4. D
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A B C D
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Standardized Test Practice
Which molecule helps provide the energy that drives this cycle?
A. 3-PGA
B. CO2
C. NADPH
D. rubisco
STP 4
1. A
2. B
3. C
4. D
Cellular EnergyChapter 8
A B C D
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Standardized Test Practice
Which product of the Calvin cycle is used for the production of glucose and other organic compounds?
A. ADP
B. CO2
C. G3P
D. NADP+
STP 5
1. A
2. B
3. C
4. D
Cellular EnergyChapter 8
A B C D
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Standardized Test Practice
What is the final step of cellular respiration?
A. O2 and H+ form H2O.
B. Electrons and H2O generate ATP.
C. C6H12O6 is broken down into CO2.
D. NADH and FADH2 gain electrons.
STP 6
1. A
2. B
3. C
4. D
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A B C D
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Standardized Test Practice
What prevents pyruvate from entering the Krebs cycle and instead results in this pathway?
A. a buildup of CO2
B. a lack of oxygen
C. an excess of glucose
D. an increased demand for ATP
STP 7
1. A
2. B
3. C
4. D
Cellular EnergyChapter 8
A B C D
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Standardized Test Practice
Which is not a process that occurs in both cellular respiration and glycolysis?
A. chemiosmosis
B. electron transport
C. glycolysis
D. production of G3P
Cellular Energy
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Cellular Energy
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