Warm Up
1. What is the chemical equation for
PHOTOSYNTHESIS?
2. What is the chemical equation for
CELLULAR RESPIRATION?
8.3 Pages 228 - 237
CELLULAR RESPIRATION
CELLULAR
RESPIRATION
Converts the food we
eat (glucose) into a
form of energy that
can be used by cells
- ATP.
How do we get energy out of
the foods we eat???
• By breaking down
sugars/carbohydrates/glucose to release
the stored energy.
What is Energy?
The ability to do work!!
• Who needs energy?
• All organism! Both plants and animals!
Plants and animals use glucose, the
product of photosynthesis, for metabolic
fuel.
• True or False:
Animals are the only
organisms that
perform cellular
respiration?
So both heterotrophs and
autotrophs get their energy from
glucose?
• Glucose is a LONG-TERM, energy storing
molecule.
Glucose
CELLULAR
RESPIRATION
Overview of
Respiration
1. All organisms respire!
2. Cellular respiration is like the reverse
reaction of photosynthesis
– Products of photosynthesis become the reactants
of cellular respiration
– Respiration breaks down glucose (Catabolic Rxn.)
3. ATP energy is released
– ATP is used for cellular processes like movement
of materials, cellular reproduction, protein
synthesis, etc.
CELLULAR
RESPIRATION
Overview of
Respiration
4. What Organelle is involved in
cellular respiration?
MITOCHONDRIA
CELLULAR
Overview RESPIRATION
of Respiration
Two Types of Cellular Respiration:
1. Aerobic (occurs in the presence of
Oxygen)
2. Anaerobic (occurs when oxygen
isn’t available)
Overview
of
Respiration
CELLULAR RESPIRATION
(Aerobic)
C6H12O6 + 6O2  6CO2 + 6H2O + Energy
Ok! Lets look at our Reactants!
1) Glucose
2) Oxygen
Where do the reactants come
from?
Glucose - made during Photosynthesis.
Oxygen - is in the air.
CELLULAR
RESPIRATION
AEROBIC
CellularRESPIRATION
Respiration
• The formula for aerobic cellular respiration is
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy (ATP)
• The “word” equation for this is:
CellularRESPIRATION
Respiration
AEROBIC
• Aerobic cellular respiration has 3 stages.
1. Glycolysis
2. Krebs cycle
3. Electron Transport Chain, or ETC
Step 1: GLYCOLYSIS
Glucose is Broken Down
• Inputs:
– 1 Glucose
– 2 ATP
• Outputs:
– 2 Pyruvate
– 2 NADH
– 2 ATP Net (4 ATP made but 2 used = 2 left)
Occurs in the CYTOPLASM
Step 1: GLYCOLYSIS
Per 1 molecule of glucose and 2 molecules of
ATP, how many….
ATP are made (net)?
NADH are made?
Pyruvate are made?
Where does pyruvate come from?
Where does glycolysis take place?
Step 2: KREB’S
CYCLE
AEROBIC
RESPIRATION
• The step in which pyruvate is broken down
• Inputs:
– 2 Pyruvate
• Outputs:
– 2 ATP
– 8 NADH
– 2 FADH2
– 6 CO2
• Occurs in the mitochondria
Step 2: KREB’S
CYCLE
AEROBIC
RESPIRATION
Step 3:
ELECTRON TRANSPORT CHAIN
• In this step, the breakdown of Glucose is
completed.
• Inputs:
– 8 NADH
– 2 FADH2
– 6 O2
• Outputs:
– 32 ATP
– 6 H2O
• Occurs in the mitochondria
Step 3:
ELECTRON TRANSPORT CHAIN
Animation
•
The mitochondrial electron transport chain is similar to that used in chloroplasts for
photosynthesis. NADH and FADH2 molecules formed during Glycolysis and Krebs
Cycle carry their electrons to the electron transport chain. The electron transport
chain creates a proton gradient that ultimately leads to the production of a large
amount of ATP.
WOW! MY BRAIN HURTS!
Maybe a Video Will Help
http://www.youtube.com/watch?v=00jbG_cf
GuQ
Summary of Aerobic Respiration
• Glycolysis breaks down glucose into pyruvate.
2 ATP Made
• Pyruvate is further broken down in the Kreb’s
Cycle. 2 ATP Made
• The electron transport chain finishes breaking
down glucose and makes 32 ATP
• CO2 and H2O are wastes (or byproducts).
C6H12O6 + 6O2  6CO2 + 6H2O + ATP
36 ATP MADE TOTAL
Cellular Respiration
2
36
Where does Glycolysis take
place?
Glycolysis
What does Glycolysis require?
What is step 2 of cellular
respiration?
Glycolysis
Where does the Krebs Cycle
take place?
Glycolysis
What does the Krebs Cycle
Make?
What does the ETC Use?
What does the ETC Make?
Cellular Respiration – Part II
Anaerobic Respiration
Fermentation
Cellular respiration when oxygen is NOT present is called
ANAEROBIC RESPIRATION
ANAEROBIC - NO OXYGEN!!
• Some cells can function for a little while
without oxygen.
• Other Cells may go their entire life without
oxygen.
But they still need ENERGY!!
CELLULAR
ANAEROBICRESPIRATION
RESPIRATION
• Can release energy when
oxygen is not present but...
• It’s far less efficient.
• Begins with glycolysis followed
by fermentation.
Step 1: GLYCOLYSIS
Same as Before: Glucose is Broken Down
• Inputs:
– Glucose
– 2 ATP
• Outputs:
– 2 Pyruvate
– 2 NADH
– 4 ATP
Occurs in the CYTOPLASM
Special Note:
 Glycolysis can produce thousands of
ATP molecules in milliseconds.
But quickly fills all available NAD+
(electron carriers) with electrons and
the process stops, so it’s only good
for short-term energy.
ANAEROBIC
RESPIRATION
Step 2: FERMENTATION
1. Type of anaerobic respiration that
releases energy without oxygen
2. If oxygen is not present, the next
step is either
a. Lactic acid fermentation
b. Alcoholic fermentation
ANAEROBIC
RESPIRATION
Step 2: FERMENTATION
Lactic Acid Fermentation
– Converts pyruvic acid into lactic acid
and CO2
– Responsible for food production using
microbes (Swiss cheese)
– Causes muscle fatigue/burning
ANAEROBIC
RESPIRATION
Step 2: FERMENTATION
Alcoholic Fermentation
– Converts pyruvic acid into alcohol and
CO2
– Responsible for food production using
microbes (sourdough bread)
Summary Of Fermentation
Glycolysis  Fermentation
02+ C6H12O6  6CO2 + 6H2O + ATP + alcohol
or lactic
acid
Advantage of Aerobic
Respiration
Yields 66% more energy
36 net ATP
That’s nearly 20 times more ATP than glycolysis alone.
Energy Yield without oxygen
Glycolysis  2 ATP
Fermentation+ 2 ATP
= 4 net ATP
(that’s
32 less ATP than aerobic respiration)
Chapter
8
Cellular Energy
8.3 Formative
Questions
What is the overall purpose of cellular
respiration?
A. to make ATP
B. to process H2O
C. to store glucose
D. to deliver oxygen
Chapter
8
Cellular Energy
8.3 Formative
Questions
Which represents the general sequence of
cellular respiration?
A. TCA cycle
chemiosmosis
B. glycolysis
Krebs cycle
C. electron absorption
phosphorylation
D. aerobic pathway
fermentation
glycolysis
electron transport
catalysis
anaerobic pathway
Chapter
8
Cellular Energy
8.3 Formative
Questions
Which stage of cellular respiration is the
anaerobic process?
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?
A. CoA
B. CO2
C. FADH2
D. NADH
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
D. an increased
demand for ATP