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Cellular Respiration
& Fermentation
4.4, & 4.6
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4.4 & 4.6 – Overview of Cellular
Respiration & Fermentation
 Key
Concept:
 The overall process of cellular respiration
converts sugar into ATP using oxygen.
 Cellular respiration is an aerobic process
with two main stages.
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Purpose of Cellular Respiration
 To
make ATP from the energy stored in
glucose
 Glucose comes from an organism doing
photosynthesis themselves or from eating
foods containing glucose
 Remember: the purpose of
photosynthesis was just to get glucose
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Cellular Respiration has 2 parts
 Anaerobic
(does not require oxygen)
 Glycolysis
 Aerobic
(requires oxygen)
 Kreb’s Cycle (Citric acid Cycle)
 Electron Transport Chain (ETC)
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STOP & REVIEW

1. What is the main reason that an organism needs to go through cellular respiration (to make
what)?

1. ATP

2. What word means does not require oxygen?

2. Anaerobic

3. What word means requires oxygen?

3. Aerobic

4. What step of cellular respiration happens first and is anaerobic?

4. Glycolysis

5. What 2 steps happen next in cellular respiration and are aerobic?

5. Krebs Cycle & ETC
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Glycolysis
 Takes
place in cytoplasm (eukaryotes and prokaryotes
do this step since all cells have cytoplasm)
 Splits
one glucose molecule into two pyruvate
molecules
 Costs the cell 2 ATP molecules to do this
4
ATP molecules are produced (only gain 2 ATP)
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STOP & REVIEW

1. Glycolysis (the first step in C.R.) takes place where?

1. Cytoplasm

2. One glucose is split into 2?

2. Pyruvates

3. How many ATP does the cell actually gain from this part?

3. 2 ATP

4.Can prokaryotes and eukaryotes go through glycolysis? Why or why
not?

4.Yes, they both have cytoplasm, so both types of cells can go through
glycolysis.
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Kreb’s Cycle (Citric Acid Cycle)
 Takes
place in matrix of mitochondria (only
in eukaryotes)
2
pyruvate (made during glycolysis) enter the
mitochondrion
 Each
 Total
pyruvate is broken down to create 1 ATP
products of Kreb’s cycle (because of 2 pyruvates):
 2 ATP
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STOP & REVIEW

1. The Kreb’s Cycle (second step) takes place where?

1.Matrix of mitochondria

2. The 2 pyruvates from glycolysis are broken down here to
make how many total ATP’s?

2.2 ATP

3. So, with the last step (glycolysis) and this step (Kreb’s) how
many total ATP have been made so far?

3. 4ATP
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Electron Transport Chain (ETC)
 Takes
place in inner membrane of mitochondria (cristae)
 Folded to create more surface area for reactions to
produce more ATP in a small space
 Oxygen
and hydrogen ions combine to form water
(released as a waste product)
 32
ATP are made
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STOP & REVIEW

1. The third step (ETC) takes place where?

1. Inner membrane of mitochondria

2. Why is the inner membrane folded?

2. To create more surface area to make more ATP.

3. What combines here and gets released as waste?

3. H and O combine to make/release water.

4. How many ATP are made by just this step?

4. 32 ATP

5. How many total ATP have been made by all three steps together?

5. 36 ATP
Anaerobic
+Glycolysis:
1 cytoplasm
process in
1. mitochondrion
3. Kreb’s Cycle
Takes place in: matrix of
mitochondria; produces 2 ATP
that splits glucose
matrix (area enclosed
into two 3C molecules by inner membrane)
Makes 2 ATP
ATP
2. 2 Pyruvates
ATP
and
4. 6CO2
5. Energy transferred to
2nd stage (aerobic stage)
inner membrane
6. ETC: energy from
glycolysis and 6O2 enter
ATP
7. 4
6 H2O produced
and a large amount
of ATP (32)
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ATP from Cellular Respiration
4
from Glycolysis (uses up 2, so really only gain 2 ATP)
2
ATP from Kreb’s cycle
 32
ATP from ETC
 GAIN
36 ATP from one glucose molecule
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Equation for Cellular Respiration
C6H12O6 + 6O2
6CO2 + 6H2O + 36ATP
 Like the reverse of photosynthesis
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What happens when there’s no/not
enough oxygen or there are no
mitochondria?
 Answer: Fermentation
 Two
Kinds:
 Lactic Acid Fermentation
 Alcoholic Fermentation
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Allows glycolysis to continue
making ATP without oxygen
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Lactic Acid Fermentation
 Anaerobic
 Occurs
in muscle cells
 Produces burning feeling in muscles
 Occurs
when body is worked to the point that
more oxygen is being used than what is being
taken in
 This is why you breathe harder when
you’re exercising is to get more oxygen to
keep making ATP
 Produces
Lactic Acid and 2 (net) ATP
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Alcoholic Fermentation
 Anaerobic
 Occurs
in some bacteria and yeast
 Produces
 Used
CO2, ethyl alcohol, and 2 (net) ATP
in food production (bake bread and
make wine)
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STOP & REVIEW

1. Why does fermentation occur?

1. Because too little or no oxygen is available.

2.Out of all 3 steps of cellular respiration, which one does fermentation only use? Why?

2. Glycolysis (only one that is anaerobic)

3. Which form of fermentation occurs in animals when not enough oxygen is consumed?

3. Lactic Acid Fermentation (produces lactic acid)

4. How many ATP are made by this form of fermentation?

4. 2ATP (glycolysis only makes 2)

5. Which form of fermentation do bacteria and yeast use?

5. Alcoholic Fermentation

6.What are the byproducts of this form of fermentation (produced)?

6. Alcohol, 2 ATP, CO2
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Overall Energy Transfer in Cellular
Respiration
 CPE

(Glucose) -----------------> CPE (ATP)
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