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Cellular Respiration
What, if anything, is the difference between
respiration and breathing? Do fish breathe?
Do plants respire? What about anaerobic
bacteria like those we find buried in swamps?
Energy comes in a lot of different forms: light, heat,
electricity, etc. Living things use chemical compounds
that are converted within cells to store and release
energy.
Life requires energy to survive and organisms can either
make it themselves (autotrophs) or acquire it from
someone else (heterotrophs). The majority of
autotrophs are photosythesizers and use energy from
the sun to make sugars.
Whether you are a photoautotroph or heterotroph, all life
must release the energy contained within sugars and
other compounds for survival. This process is called
respiration.
http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/energyflow/energyflow.html
https://eapbiofield.wikispaces.com/file/view/CellResp1.gif
Fig. 9-2
Light
energy
ECOSYSTEM
Photosynthesis
in chloroplasts
CO2 + H2O
Organic
+O
molecules 2
Cellular respiration
in mitochondria
ATP
ATP powers most cellular work
Heat
energy
Glucose
This chemical is called adenosine triphosphate or
ATP. ATP is made up of adenosine – a
nitrogenous base, ribose – a five-carbon sugar,
and three phosphate groups. The negatively
charged phosphate groups are the source of
energy within the ATP molecule.
When energy is available within a cell, a third
phosphate group is added to adenosine
diphosphate (ADP) making ATP. Phosphate
groups are negatively charged and “do not like
being” bonded to each other. When the bonds
between phosphates are broken, energy is
released.
Fig. 8-8
Adenine
Phosphate groups
Ribose
Fig. 8-9
P
P
P
Adenosine triphosphate (ATP)
H2O
Pi
+
Inorganic phosphate
P
P
+
Adenosine diphosphate (ADP)
Energy
Fig. 8-12
ATP + H2O
Energy from
catabolism (exergonic,
energy-releasing
processes)
ADP + P i
Energy for cellular
work (endergonic,
energy-consuming
processes)
That energy is enough to power many cellular
activities like active transport across cell
membranes, protein synthesis, and muscle
contraction; however, cells are not chock full of
ATP molecules, instead they only contain about
enough to last a few seconds of activity. A single
glucose molecule stores about 90 times more
energy than a molecule of ATP. Cells break
down glucose effectively “recharging” ATP from
ADP. For this process to be most efficient,
oxygen is required.
We get oxygen from breathing.
Fig. 7-UN2
Active transport:
ATP
Fig. 17-18-4
Amino end
of polypeptide
E
3′′
mRNA
Ribosome ready for
next aminoacyl tRNA
P A
site site
5′′
GTP
GDP
E
E
P A
P A
GDP
GTP
E
P A
Fig. 50-27-4
Thick filament
Thin
filaments
Thin filament
Myosin head (lowenergy configuration
ATP
ATP
Thick
filament
Thin filament moves
toward center of sarcomere.
Actin
ADP
Myosin head (lowenergy configuration
ADP
+ Pi
Pi
ADP
Pi
Cross-bridge
Myosin
binding sites
Myosin head (highenergy configuration
http://www.qcc.cuny.edu/BiologicalSciences/Faculty/DMeyer/respiration.html
Question of the Day!
1. Can the flame move?
2. Can the flame grow?
3. Can it reproduce?
4. Does the flame respire?
5. Is the flame alive?
Think About This !!
Do plants respire?
Design an experiment that will test your answer?
Hypothesis: Plants will give off CO2.
Methods: Isolate a plant. Put in the dark. Measure CO2.
Note: Made sure plants had carbohydrates (ie sugar)
CO2 in water creates carbonic acid (H2CO3). This is the same thing
as carbonated water or seltzer.
Listen to This !!
http://weblogs.ccsd.k12.co.us/cth/brios/?m=20070509
Write !!
Any word or concept that you are unaware of or confused about.
ANSWER THESE !!
1. How is fermentation different from respiration?
2. Put the three parts of aerobic respirations in order.
3. How many ATP are made during the entire process?
4. How are NADH and NAD+ involved in aerobic respiration?
5. Some organisms, like yeast, can survive in oxygen-rich and
oxygen-depleted environments. In which situation would
you expect yeast to grow the fastest? Explain.
Fig. 9-UN1
becomes oxidized
(loses electron)
becomes reduced
(gains electron)
Fig. 9-UN2
becomes oxidized
becomes reduced
Fig. 9-3
Reactants
Products
becomes oxidized
becomes reduced
Methane
(reducing
agent)
Oxygen
(oxidizing
agent)
Carbon dioxide
Water
Fig. 9-UN3
becomes oxidized
becomes reduced
Glucose
Glycolysis
2 ADP 2 ATP
4 ATP
2 NAD+
Glucose
2 Glyceraldehyde-3phosphate
4 ADP
2 NADH
2 Pyruvic Acid
Krebs cycle
1 NADH
Enzyme
1 NADH
1 NADH
1 ATP
1 NADH
1 FADH2
Citric Acid
Pyruvic Acid
Answer These, Too !!
1. What can you say about the relationship between the reactants and products
the photosynthesis and respiration equations?
2. How many molecules of carbon dioxide and how many molecules of water are
needed for green plants to synthesize one molecule of glucose and six
molecules of oxygen?
3. What does respiration produce and what does it use?
4. Why is the Krebs cycle also called the Citric acid cycle?
5. How much of the ATP produced during aerobic respiration comes from the
Krebs cycle and how much comes from glycolysis?
Fill This Out !!
Question of the Day!
Make a flow chart using as many of the following terms as possible:
Sun
Cytoplasm
lactic acid
Glucose
Yeast
Mitocondria
Glycolysis
CO2
1st order consumers
Oxygen
ethyl alcohol
Water
Autotrophs
Krebs cycle
Photosynthesis
Some prokaryotes
pyruvic acid
FAD/FADH2
2nd order consumers NAD+/NADH
ATP
Student
study
School
Mr
Schmalz
Good
grade
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Happy
Test
No
study
Bad Grade
No College
Sad
Cellular respiration is the process that releases energy
by breaking down glucose and other food molecules.
When oxygen is present, it’s aerobic; when oxygen is
absent, it’s anaerobic. There are four pathways in
cellular respiration (not all function at the same place or
at the same time): glycolysis, fermentation (2 types –
alcoholic and lactic acid), Krebs cycle, and electron
transport chain.
Respiration is a process of breaking down glucose in
such a way that energy capture is maximized. When
sugars are burned, all the energy is released at one
time; however, if cells truly “burned” sugars, much of the
energy contained within each glucose molecule would
be lost as heat and light and cells might even catch fire.
Fig. 9-6-1
Electrons
carried
via NADH
Glycolysis
Pyruvate
Glucose
Cytosol
ATP
Substrate-level
phosphorylation
Fig. 9-6-2
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Citric
acid
cycle
Glycolysis
Pyruvate
Glucose
Mitochondrion
Cytosol
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Fig. 9-6-3
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Citric
acid
cycle
Glycolysis
Pyruvate
Glucose
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
Mitochondrion
Cytosol
ATP
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Oxidative
phosphorylation
http://www.qcc.cuny.edu/BiologicalSciences/Faculty/DMeyer/respiration.html
Glycolysis is the process in which one molecule of
glucose is broken into 2 glyceraldehyde 3-phosphates
(a 3-carbon compound) “investing” 2 ATP. These are
converted into two molecules of pyruvic acid and the
‘investment’ pays out a total of 4 ATP and 2 NADH.
The process of glycolysis produces and then captures
two pairs of high-energy electrons using the carrier
NAD+. NADH carries some of glucose’s energy to a
place where it can be converted to ATP.
Glycolysis is fast and does not require oxygen; however,
when it occurs anaerobically, it hits a roadblock when all
the NAD+ get tied up carrying electrons.
Fig. 9-8
Energy investment phase
Glucose
2 ADP + 2 P
2 ATP
used
4 ATP
formed
Energy payoff phase
4 ADP + 4 P
2 NAD+ + 4 e– + 4 H+
2 NADH + 2 H+
2 Pyruvate + 2 H2O
Net
Glucose
4 ATP formed – 2 ATP used
2 NAD+ + 4 e– + 4 H+
2 Pyruvate + 2 H2O
2 ATP
2 NADH + 2 H+
Fig. 9-UN5
Outputs
Inputs
2
ATP
Glycolysis
+
2 NADH
Glucose
2
Pyruvate
http://www.science.smith.edu/departments/B
iology/Bio231/
When oxygen is absent, glycolysis is followed by
fermentation. The two main types of fermentation are
alcoholic fermentation and lactic acid fermentation.
Both types of fermentation function by passing the high
energy electrons back to pyruvic acid, freeing up NAD+
again so glycolysis can continue.
In the absence of oxygen, yeast and a few other
microorganisms use alcoholic fermentation, forming
ethyl alcohol and carbon dioxide as wastes.
Animals cannot perform alcoholic fermentation, but
some cells, such as human muscle cells, can convert
glucose into lactic acid. This is called lactic acid
fermentation.
Fig. 9-19
Glucose
CYTOSOL
Glycolysis
Pyruvate
No O2 present:
Fermentation
O2 present:
Aerobic cellular
respiration
MITOCHONDRION
Ethanol
or
lactate
Acetyl CoA
Citric
acid
cycle
Fig. 9-18
2 ADP + 2 Pi
Glucose
2 ATP
Glycolysis
2 Pyruvate
2 NAD+
2 NADH
+ 2 H+
2 CO2
2 Acetaldehyde
2 Ethanol
(a) Alcohol fermentation
2 ADP + 2 Pi
Glucose
2 ATP
Glycolysis
2 NAD+
2 NADH
+ 2 H+
2 Pyruvate
2 Lactate
(b) Lactic acid fermentation
Fig. 9-18a
2 ADP + 2 P i
Glucose
2 ATP
Glycolysis
2 Pyruvate
2 NAD+
2 Ethanol
(a) Alcohol fermentation
2 NADH
+ 2 H+
2 CO2
2 Acetaldehyde
Fig. 9-18b
2 ADP + 2 P i
Glucose
2 ATP
Glycolysis
2 NAD+
2 NADH
+ 2 H+
2 Pyruvate
2 Lactate
(b) Lactic acid fermentation
Sun
Autotroph
1st Order
consumer
2nd Order
Alcohol
fermentation
Cytoplasm
H2O
Photosynthesis
Yeast
Glucose
O2
Glycolysis
Some
CO2
Prokaryotes
Pyruvic acid
Lactic acid
fermentation
Krebs cycle
NAD+/NADH
ATP
FADH2
Mitocondria
Electron transport chain
Fig. 9-10
CYTOSOL
MITOCHONDRION
NAD+
NADH + H+
2
1
Pyruvate
Transport protein
3
CO2
Coenzyme A
Acetyl CoA
Fig. 9-11
Pyruvate
CO2
NAD+
CoA
NADH
+ H+
Acetyl CoA
CoA
CoA
Citric
acid
cycle
2 CO2
3 NAD+
FADH2
3 NADH
FAD
+ 3 H+
ADP + P i
ATP
Fig. 9-UN6
Inputs
Outputs
S—CoA
C
2
ATP
O
CH3
2
Acetyl CoA
6 NADH
O
C
COO
CH2
COO
2
Oxaloacetate
Citric acid
cycle
2 FADH2