Download 8.3 Cellular Respiration

Cellular Respiration
Harvesting Chemical Energy
ATP
“Burning fuels” to make energy
combustion
making heat energy by burning
fuels in one step
fuel
(carbohydrates)
O2
CO2 + H2O + heat
“Burning fuels” to make energy
Aerobic respiration
making ATP energy (& some heat) by
burning fuels in many small steps
ATP
O2
food
(carbohydrates)
ATP + CO2 + H2O (+ heat)
Energy needs of life
• Animals are energy consumers
• Why do we need energy?
• synthesis (building for growth)
• reproduction
• active transport
• movement
• temperature control (heat)
Where do we get energy?
• Energy is stored in organic molecules
• carbohydrates, fats, proteins
• Animals eat organic molecules  food
• digest food to get
• fuels for energy
ATP
• raw materials for building more
molecules
•carbohydrates, fats, proteins,
nucleic acids
What is energy in biology?
ATP
Adenosine TriPhosphate
Whoa!
HOT stuff!
Harvesting energy stored in food
• Cellular respiration
• breaking down food to produce ATP
• in mitochondria
• using oxygen
food
• “aerobic” respiration
• usually digesting glucose
• but could be other sugars,
fats, or proteins
ATP
O2
glucose + oxygen  energy + carbon + water
dioxide
C6H12O6 +
6O2
 ATP + 6CO2 + 6H2O
What do we need to make energy?
• The “Furnace” for making energy
• mitochondria
• Fuel
• food: carbohydrates, fats, proteins
• Helpers
• oxygen
• enzymes
food
enzymes
• Product
• ATP
• Waste products
• carbon dioxide
• then used by plants
• water
Make ATP!
Make ATP!
All I do all day…
And no one
even notices!
O2
ATP
CO2
H2O
Mitochondria are everywhere!!
animal cells
plant cells
Using ATP to do work?
Can’t store ATP
 too unstable
 used only in the cell that produces it
 short term energy storage
 carbohydrates & fats
are long term
energy storage
ATP
Adenosine TriPhosphate
Adenosine DiPhosphate
work
ADP
A working muscle recycles over
10 million ATPs per second
How organisms turn fuel into ATP
Fuel
(carbohydrates, lipids, proteins)
Oxygen present?
no
yes
Anaerobic
Cellular Respiration
Alcoholic
Fermentation
Aerobic
Cellular Respiration
Lactic Acid
Fermentation
ATP
ATP
Makes only a little ATP
ATP
ATP
ATP
ATP
Makes a LOT of ATP
Aerobic Cellular Respiration
3 Major Steps:
1. Glycolysis
2. Krebs Cycle
3. Electron
Transport Chain
1. Glycolysis
• Glyco = glucose lysis = splitting
• Where: in the cytoplasm
• Uses: NO oxygen
• Makes:
• Pyruvate (passed to Krebs Cycle)
• A little ATP
• NADH (electron bus… headed to the
Electron Transport Chain)
Glycolosis (no O2 required)
Glucose

G3P

2 Pyruvate
2. Krebs Cycle
• Where?
• in the mitochondrial matrix
• Uses:
- pyruvate (from glycolysis)
• Makes:
• NADH (electron bus)
• FADH2 (electron bus)
• A little ATP (energy)
• Carbon Dioxide (waste product)
Krebs Cycle
• 2 Acetyl CoA
enters cycle to
form Citric Acid
one at a time
3. Electron Transport
• Where?
• Inner mitochondrial membrane
• Uses:
• NADH & FADH2
• Remember these are like “electron buses” that drop off electrons
to the ETC (aka: electron transport chain)
• Oxygen
• Pulls electrons down the ETC and accepts them at the end of the
ETC
• This is why we die if we don’t get oxygen!
• Makes:
ATP
• Water (waste product)
• A BUNCH of ATP
• (whoohooo… big energy!)
Important!
Electron Transport
How does the ETC make so much energy (ATP)?
Answer = Chemiosmosis
Sound familiar? We learned it in photosynthesis too!
Electron Transport
• NADH & FADH2 drop off electrons
• Electrons move down the electron transport
chain
• pulled down the chain by oxygen
• Hydrogen ions diffuse from an area of high
concentration (outside the membrane) to an
area of low concentration (inner-membrane
space) through ATP synthase.
• ATP synthase is like an energy turbine,
producing lots of ATP!
Electron Transport
Anaerobic Respiration
We know that aerobic cellular respiration
requires oxygen, but what happens if
there is no oxygen available?
O2
Answer =
Anaerobic Cellular Respiration
Anaerobic Respiration
O2
• The anaerobic pathway that
follows glycolysis
• If there is no oxygen present and
an organism needs energy, the
cell may use anaerobic respiration
to continue producing ATP
Anaerobic Respiration
O2
• also known as fermentation
• alcohol fermentation
• lactic acid fermentation
• no oxygen
• no mitochondria (bacteria)
yeast
• makes very little ATP
• large animals cannot survive
bacteria
Anaerobic Respiration
O2
• Fermentation
• alcohol fermentation
• yeast
• glucose  ATP + CO2+ alcohol
• make beer, wine, bread
• lactic acid fermentation
• bacteria, animals
• glucose  ATP + lactic acid
• bacteria make yogurt
• animals feel muscle fatigue
Tastes good…
but not enough
energy for me!
Questions!
Number your paper 1 to 4
What is the overall purpose of cellular
respiration?
A. to make ATP
B. to produce H2O
C. to store glucose
D. to deliver oxygen
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
Which stage of cellular respiration is
the anaerobic process?
A. glycolysis
B. Krebs cycle
C. electron transport
Which molecule generated by the
Krebs Cycle is a waste product?
A. CoA
B. CO2
C. FADH2
D. NADH
Answers
1.
2.
3.
4.
A
B
A
B
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