Transcript Glencoe Biology

Ch 8 ~ Cellular Energy
Section 1:
How Organisms Obtain Energy
Section 2:
Photosynthesis
Section 3:
Cellular Respiration
Cellular EnergyObtain Energy
8.1 How Organisms
Transformation of Energy
 Energy - ability to do work.
 Thermodynamics - study of
flow & transformation of
energy in universe.
Cellular Energy
Laws of Thermodynamics
 First law —energy converted from one form
to another, but cannot be created nor
destroyed.
 Second law —energy
cannot be converted
without the loss of
energy
Cellular Energy
 Autotrophs -make their own food.
 Heterotrophs -need to ingest food to obtain
energy.
Cellular Energy
Metabolism - All chemical reactions in a cell
 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
Cellular Energy
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.
ATP
Cellular Energy
Vocabulary
Section 8.1
energy
thermodynamics
metabolism
Photosynthesis
cellular respiration
adenosine triphosphate (ATP)
Chapter 8
Cellular Energy
8.1 Formative
Questions
Why is adenosine triphosphate (ATP) such an
important biological molecule?
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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.
Chapter 8
Cellular Energy
8.1 Formative
Questions
Which law of thermodynamics explains why the
ladybug receives the least amount of usable energy?
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A. the first law of
thermodynamics
B. the second law of
thermodynamics
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Chapter 8
Cellular Energy
8.1 Formative
Questions
All of the energy from the
food you eat comes from
the sun.
A. true
B. false
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Chapter 8
Cellular Energy
8.1 Formative
Questions
Why is cellular respiration a catabolic pathway?
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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.
Cellular Energy
8.2 Photosynthesis
Overview of Photosynthesis
 Photosynthesis occurs in 2 phases:
Light-dependent reactions
Light-independent reactions
Cellular Energy
Phase One: Light Reactions
 Absorption of light is 1st step in photosynthesis.
 Chloroplasts capture light energy.
Cellular 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 pigments
chlorophylls a & b,
carotenoids
absorb violet-blue light and
reflect green (chlorophylls)
or red/yellow/orange
(carotenoids)
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.
Cellular Energy
 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.
Cellular Energy
Photosystem
I transfers the electrons to protein
called ferrodoxin.
 Ferrodoxin transfers the electrons to the electron
carrier NADP+, forming the energy-storing
molecule NADPH.
Cellular Energy
Phase Two: The Calvin Cycle
In 2nd phase of photosynthesis, called Calvin cycle, energy is stored in
organic molecules such as glucose.
Why?
Chapter 8
Cellular Energy
Cellular Energy
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 Cycle
 6 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 highenergy 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.
Chapter 8
Cellular Energy
Vocabulary
Section 2
thylakoid
granum
stroma
pigment
NADP+
Calvin cycle
rubisco
Chapter 8
Cellular Energy
8.2 Formative
Questions
Where in the plant cell does
photosynthesis take place?
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A. chloroplasts
B. Golgi apparatus
C. mitochondria
D. vacuoles
Chapter 8
Cellular Energy
8.2 Formative
Questions
Which range of
wavelengths is reflected
by chlorophylls a and b?
A. 400-500 nm
B. 500-600 nm
C. 600-700 nm
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Chapter 8
Cellular Energy
8.2 Formative
Questions
Which mechanism of photosynthesis uses
the movement of hydrogen ions (H+) across
a concentration gradient to synthesize ATP?
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A. absorption
B. chemiosmosis
C. electron transport
D. C2 pathway
Chapter 8
Cellular Energy
8.2 Formative
Questions
How are the C4 pathway and the CAM pathway
an adaptive strategy for some plants?
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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.
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Overview of Cellular Respiration
 Organisms obtain energy in a process called
cellular respiration.
 The equation for cellular respiration is the
opposite of the equation for photosynthesis.
Chapter 8
Cellular Energy
8.3 Cellular Respiration
 Cellular respiration occurs in two main parts.
 Glycolysis
 Aerobic respiration
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Glycolysis
 Glucose is broken down in the cytoplasm
through the process of glycolysis.
 Two molecules of ATP and two molecules
of NADH are formed for each molecule of
glucose that is broken down.
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Krebs Cycle
 Glycolysis has a net result of
two ATP and two pyruvate.
 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
Cellular Energy
8.3 Cellular Respiration
 The net yield from the
Krebs cycle is six CO2
molecules, two ATP,
eight NADH, and two
FADH2.
Chapter 8
Cellular Energy
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Electron Transport
 Final step in the breakdown of glucose
 Point at which ATP is produced
 Produces 24 ATP
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Anaerobic Respiration
 The anaerobic pathway that follows glycolysis
 Two main types
 Lactic acid fermentation
 Alcohol fermentation
Cellular
Respiration
Chapter 8
Cellular Energy
Vocabulary
Section 3
anaerobic process
aerobic respiration
aerobic process
glycolysis
Krebs cycle
fermentation
Chapter 8
Cellular Energy
8.3 Formative
Questions
What is the overall purpose of cellular
respiration?
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A. to make ATP
B. to process H2O
C. to store glucose
D. to deliver oxygen
Chapter 8
Cellular Energy
8.3 Formative
Questions
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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 
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fermentation
Chapter 8
Cellular Energy
8.3 Formative
Questions
Which stage of cellular respiration is the
anaerobic process?
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A. glycolysis
B. Krebs cycle
C. electron transport
Chapter 8
Cellular Energy
8.3 Formative
Questions
Which molecule
generated by the Krebs
cycle is a waste product?
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A. CoA
B. CO2
C. FADH2
D. NADH
Chapter 8
Cellular Energy
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Formative Test Questions
Chapter Assessment Questions
Standardized Test Practice
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Chapter 8
Cellular Energy
Chapter Diagnostic
Questions
Which statement describes the law of
conservation of energy?
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.
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Chapter 8
Cellular Energy
Chapter Diagnostic
Questions
In which metabolic process are molecules
broken down to produce carbon dioxide and
water?
A. photosynthesis
B. cellular respiration
C. homeostasis
D. fermentation
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Chapter 8
Cellular Energy
Chapter Diagnostic
Questions
At the end of the Calvin cycle, where is energy
stored?
A. NADPH
B. ATP
C. chloroplast
D. glucose
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Chapter 8
Cellular Energy
Chapter Assessment
Questions
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
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Chapter 8
Cellular Energy
Chapter Assessment
Questions
During the Krebs cycle,
pyruvate is broken down
into what compound?
A. H2O
B. O2
C. CO
D. CO2
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Chapter 8
Cellular Energy
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
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Chapter 8
Cellular Energy
Standardized Test
Practice
Which metabolic process is photosynthesis?
A
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Chapter 8
Cellular Energy
Standardized Test
Practice
At the beginning of photosynthesis, which
molecule is split to produce oxygen (O2) as
a waste product?
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A. CO2
B. H2O
C. C6H12O6
D. 3-PGA
Chapter 8
Cellular Energy
Standardized Test
Practice
Which molecule helps
provide the energy
that drives this cycle?
A. 3-PGA
B. CO2
C. NADPH
D. rubisco
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Chapter 8
Cellular Energy
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+
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Chapter 8
Cellular Energy
Standardized Test
Practice
What is the final step of cellular respiration?
A. O2 and H+ form H2O.
B. Electrons and H2O
generate ATP.
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D. NADH and FADH2
gain electrons.
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C. C6H12O6 is broken
down into CO2.
Chapter 8
Cellular Energy
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
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D. an increased
demand for ATP
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Chapter 8
Cellular Energy
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
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Chapter 8
Cellular Energy
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Chapter 8
Cellular Energy
Image Bank
Chapter 8
Cellular Energy
Animation
 ATP
 The Calvin Cycle
 Visualizing Electron Transport
 The Krebs Cycle (Citric Acid Cycle)
Chapter 8
Cellular Energy
Chapter 8
Cellular Energy
Chapter 8
Cellular Energy