Transcript Regents Biology

Cellular Respiration
Harvesting Chemical Energy
ATP
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Energy flow
 Energy enters an ecosystem as sunlight
 Photosynthesis converts this light energy
into chemical energy, stored in organic
compounds
 Cellular respiration is the release of
energy, in the form of ATP, from organic
compounds in cells in the presence of
oxygen
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Energy needs of life
 Animals are energy consumers

What do we need energy for?
 To make new compounds for body
 reproduction
 active transport
 movement
 temperature control
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Where do we get energy?
 Energy is stored in organic molecules
carbohydrates, fats, proteins (in the bonds)
Animals eat these organic molecules  food
 digest (break apart) food to get


 fuels for energy (ATP)
 raw materials for building more molecules
 carbohydrates, fats, proteins, nucleic acids
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What is energy in biology?
ATP
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What we all need to function:
Money and Energy
Change - - - - - - - - - - - - - - - - -ATP
Large bills - - - - - - - - - - - Simple Sugars
Checking
- - - - - - - - - - - - Disaccharides
Savings - - - - - - - - - - - - - -Starch, Lipids
stocks, investments- - - - - -- Lipids, Proteins
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Harvesting energy stored in food
 Cellular respiration

breaking down food to produce ATP
 happens in mitochondria
 requires oxygen
glucose + oxygen  carbon + water + energy
dioxide
C6H12O6 +
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6O2
 6CO2 + 6H2O + ATP + heat
What do we need to make energy?
 The “Furnace”

mitochondria
 Fuel

food
 carbohydrates,
fats, proteins
food
 The Helpers

oxygen
 “aerobic”

enzymes
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O2
ATP
“Burn fuels” to make energy
combustion
making heat energy by burning fuels in one step
fuel
(carbohydrates)
O2
CO2 + H2O + heat
respiration
making ATP energy (& some heat) by burning fuels
in many small steps in the presence of oxygen
ATP
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food
(carbohydrates)
O2
CO2 + H2O + ATP (+ heat)
Stepwise energy harvest
 If energy is released from a fuel all at once, it
cannot be harnessed efficiently for
constructive work
 For example, if a gasoline tank explodes, it
cannot drive a car very far.
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Efficiency:
 We can only use about 40% of the energy
contained in the food we eat
 Remaining 60% of energy in glucose is lost
as heat
 Very efficient: most cars use only 25% of
energy in gasoline
 WOW!!!
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Using ATP to do work?
Can’t store ATP
 too unstable
 only used in cell
that produces it
 only short term
energy storage
 carbohydrates & fats
are long term
energy storage
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ATP
work
ADP + P
A working muscle recycles over
10 million ATPs per second
A Body’s Energy Budget
food
intake
ATP
Kinetic energy
Potential energy
synthesis
storage
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{
{
{
• resting energy
• activity
• temperature
control
• growth
• reproduction
• glycogen
• fat
Now how do we actually break
apart this “glucose”?
 We break the 6-carbon glucose in half in a process
called Glycolysis
 Then if oxygen is:
absent
present
(anaerobic respiration) (aerobic respiration)
It starts to ferment
Or produce lactic acid
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it goes to the kreb’s cycle
and finishes popping off
carbons to get energy
LE 9-6_1
If oxygen IS present then …………
Glycolysis
Pyruvate
Glucose
Cytoplasm
ATP
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Mitochondria
LE 9-6_2
Glycolysis
Pyruvate
Glucose
Cytoplasm
ATP
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Kreb’s
cycle
Mitochondria
ATP
Electrons carried
via NADH
Electrons
carried
via NADH
Glycolysis
Pyruvate
Glucose
Cytoplasm
ATP
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Kreb’s
cycle
Electron
Transport
Chain
ETC
Mitochondria
ATP
ATP
What if something is missing?
 Can’t complete aerobic respiration

fermentation
 bacteria & yeast
 glucose  ATP + alcohol
 beer, wine, bread, yogurt

anaerobic respiration
 Animals and some bacteria
 glucose  ATP + lactic acid
 muscle fatigue
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Any Questions??
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