Cellular Respiration
Chapter 9
Ag Biology
Ms. Prescott
9-1
Overview
Lactic Acid
Electron Trans.
9-2
Glycolysis
Krebs Cycle
Flowchart
9-1
Chemical Pathways
9-1
Overview
Lactic Acid
Electron Trans.
9-2
Glycolysis
Krebs Cycle
Flowchart
Feel The Burn
Do you like to run, bike, or swim? These all are
good ways to exercise. When you exercise, your
body uses oxygen to get energy from glucose,
a six-carbon sugar.
1. How does your body feel at the start of exercise, such as a long,
slow
run? How do you feel 1 minute into the run; 10 minutes into the
run?
2. What do you think is happening in your cells to cause the changes
in how you feel?
3. Think about running as fast as you can for 100 meters. Could you
keep up this pace for a much longer distance? Explain your
answer.
9-1 Chemical Pathways
Vocabulary

Calorie

Glycolysis

term used by scientists to measure the energy
stored in food
first step in releasing the energy of glucose, in
Glucose
which a molecule of glucose is broken into two
molecules of pyruvic acid.
PA
PA
Cellular respiration
process that releases energy by breaking down
food molecules in the presence of oxygen; made
up of glycolysis, the Krebs cycle, and the electron
transport chain.
Cellular Respiration
Glycolysis
Krebs Cycle
ETC
9-1 Chemical Pathways
Vocabulary
 NAD+
(nicotinamide adenine
dinucleotide) –

electron carrier involved in glycolysis
 Fermentation
Energy
O2
process by which cells release energy in the
absence of oxygen
 Anaerobic
Electron
process that does not require oxygen.
O2
9-1 Chemical Pathways
1. Cellular respiration is the process that releases
energy by breaking down food molecules
(protein, fat, carbohydrates: glucose) in the
presence of oxygen within the mitochondria of
the cell
2. The equation is the opposite of photosynthesis:
a.
6O2
+ C6H12O6
 6CO2
+ 6H2O+ Energy
b. oxygen+ glucose  carbon dioxide+ water+ Energy
9-1 Chemical Pathways
3. If energy was released quickly in one stage, the
energy would be lost as heat and light
4. Most of the energy is converted into ATP, that powers
the cell’s activities
5. The cellular respiration cycle includes three
processes:
a. Glycolysis
b.
Kreb’s Cycle
c.
Electron Transport
Section 9-1
Chemical Pathways
Glucose
Glycolysis
Krebs
cycle
Fermentation
(without oxygen)
Go to
Section:
Electron
transport
Alcohol or
lactic acid
9-1 Chemical Pathways
6. Glycolysis
a. During glycolysis, one
molecule of glucose is
broken in half, making
two carbon compound
molecules
b. Glycolysis requires a
small amount of energy
to get it going
Figure 9–3 Glycolysis
Section 9-1
Glucose
2 Pyruvic acid
To the electron
transport chain
Go to
Section:
Figure 9–3 Glycolysis
Section 9-1
Glucose
2 Pyruvic acid
To the electron
transport chain
Go to
Section:
Figure 9–3 Glycolysis
Section 9-1
Glucose
2 Pyruvic acid
To the electron
transport chain
Go to
Section:
9-1 Chemical Pathways
c. After glycolysis there are two
possible paths:
i. Fermentation- ends cellular
respiration
1.Releases energy from food molecules in
the ABSENCE of oxygen so it is called
anaerobic
2.Alcoholic Fermentation: Alcohols and
carbon dioxide are produced (Example
= Rootbeer)
3.Lactic Acid Fermentation: Lactic acid is
produced (Example = yogurt & muscle
cramps)
ii. Kreb’s Cycle- continues cellular
respiration
Section 9-1
Glucose
Go to
Section:
Figure 9–4 Lactic
Acid Fermentation
Pyruvic acid
Lactic acid
Section 9-1
Glucose
Go to
Section:
Figure 9–4 Lactic
Acid Fermentation
Pyruvic acid
Lactic acid
Section 9-1
Glucose
Go to
Section:
Figure 9–4 Lactic
Acid Fermentation
Pyruvic acid
Lactic acid
9-2
The Krebs Cycle and
Electron Transport
9-1
Overview
Lactic Acid
Electron Trans.
9-2
Glycolysis
Krebs Cycle
Flowchart
Rolling and Folding
Some of the steps in cellular respiration take place in the
membrane inside the cell structure called the
mitochondrion, which has a folded inner membrane.
What purpose do these folds serve?
To find out the answer to this question, perform this activity.
1. Obtain two sheets of paper and a metric ruler. What is the
surface area of the paper?
2. Roll one sheet of paper into a tube lengthwise. What is the
surface area of the rolled paper?
3. Fold the second sheet of paper into a fan. Then, roll the first
sheet of paper around the folded paper so it is inside the rolled
paper.
What has happened to the surface area of the inside of the rolled
paper?
4. What would be the value of increasing the surface area of the
membrane inside a mitochondrion?
9-2 Vocabulary
Warning
O2
AerobicRequired
process that requires oxygen
Krebs CycleEnerg
second stage of cellular respiration, in which
y
pyruvic acid is broken down into carbon
dioxide in a series of energy-extracting
Pyruvic Acid
reactions.
CO2
Electron transport chainCO2
a series of proteins in which the high-energy
electrons from the Krebs Cycle are used to
convert ADP into ATP.
ADP
Before
ATP
After
9-2 Krebs Cycle
1. Krebs Cycle
a.
Krebs Cycle happens in the
mitochondrial matrix
b.
It occurs in the PRESENCE
of oxygen and is aerobic
c.
Carbon compounds from
glycolysis break down and
release CO2
Figure 9–6 The Krebs Cycle
Section 9-2
Citric Acid
Production
Go to
Section:
Mitochondrion
Figure 9–6 The Krebs Cycle
Section 9-2
Citric Acid
Production
Mitochondrion
Go to
Section:
9-2 Electron Transport
2. Electron Transport
a. The electron transport chain is located in the
cristae (membrane of the mitochondria)
b. There are 4 main steps
i.
Electrons are passed through the electron transport
chain
ii. Energy is built up
iii. The energy is used to transport hydrogen ions
across the membrane
iv. As this happens, ATP is produced
Section 9-2
Figure 9–
7 Electron
Transport Chain
Electron Transport
Hydrogen Ion Movement
Channel
Mitochondrion
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
ATP Production
Go to
Section:
9-2 Krebs Cycle & Electron
Transport
3. Energy Totals
a.Glycolysis  Fermentation =
2 ATP
(without oxygen)
b.Glycolysis  Krebs Cycle  Electron Transport =
(with oxygen)
-------------------
+ 34 ATP
36 ATP Total!!
 Which process is better at providing energy for the
cell? 
Is this process anaerobic or aerobic?
Section 9-1
Figure 9–
2 Respiration: An
Overview
Mitochondrion
Electrons carried in NADH
Pyruvic
acid
Glucose
Glycolysis
Krebs
Cycle
Electrons
carried in
NADH and
FADH2
Electron
Transport
Chain
Mitochondrion
Cytoplasm
Go to
Section:
Section 9-2
Flowchart
Cellular Respiration
Glucose
(C6H1206)
+
Oxygen
(02)
Go to
Section:
Glycolysis
Krebs
Cycle
Electron
Transport
Chain
Carbon
Dioxide
(CO2)
+
Water
(H2O)