Chapter 6: Cellular Respiration Obtaining Energy from Food

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Chapter 6 Cellular Respiration - Obtaining
Energy from Food
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What We Will Cover In Chapter 6

• We will define autotrophs and heterotrophs
• We will compare and contrast producers and
  consumers
• We will compare photosynthesis with cellular
  respiration
• We will look at the big picture of cellular
  respiration then focus on its three components
• 1. Glycolysis
• 2. The Citric Acid Cycle
• 3. The Electron Transport Chain
• 5. We will compare aerobic vs. anaerobic
  respiration in terms of energy production
• 6. Finally, we will look at the fermentation
  process in microorganisms that occurs in the
  absence of oxygen

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Energy Flow Autotrophs and Heterotrophs
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Autotrophs (Self Feeders) Organisms (mostly
plants) that make all their own
(bio_______________) _______________________ Prot
eins Lipids ______________________


Heterotrophs (Other Feeders) Organisms that
cannot make their own biomolecules. They get
their nutrients through the consumption of
_____________________________________.
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Chemical Cycling In the Environment
Photosynthesis and Cellular Respiration
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Plants combine _______________, ______________
and light energy in a process known as
photosynthesis to produce ___________ and
___________ (chapter 7). An animal consumes the
sugar in plants and combines the food with
_____________ to generate energy (_________),
water and heat in a process known as cellular
respiration (this Chapter).
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How Breathing is Related to Cellular Respiration
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Humans respire on two levels 1) System level
The _____________system exchanges carbon dioxide
for oxygen in the ____________. 2) Cellular
level In each cell, oxygen is exchanged for
carbon dioxide across the _______________
_____________.
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Both Plants and Animals Burn _____________ via
Cellular Respiration
The Relationship Between Photosynthesis and
Cellular Respiration
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First, plants make Glucose
Then
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The Role of Oxygen in Cellular Respiration
In a nutshell, the ________________ of sugar is
a controlled _________________reaction. High
temperature reactions such as wood burning or gas
exploding simply would not do inside a cell!
Cellular respiration is so ___________________
because it takes many intermediate steps
employing many different ____________to carefully
control the flow of ____________________.
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Analogy Cellular Respiration as an Electron
Relay
Cellular respiration, is just a controlled series
of ________________ _____________. A relay
race of sorts, where the baton, in the form of
_________________ are passed between molecules.
The starter in this relay is the food energy
molecule, ______________. The anchor in this
relay is ____________. Oxygen is required in
our lives as the final electron acceptor in the
conversion of glucose to cellular energy (ATP).

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NADH as Electron Carriers
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The first step or runner in the relay race is
the ion, nicotinamide adenine dinucleotide
(NAD). NAD accepts 2 electrons and one proton
() to become ____________.
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The Metabolic Pathway for Cellular Respiration
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There are over 20 different reactions involved
in converting glucose to ATP and each one is
catalyzed by a different _____________. For
convenience, the whole series of reactions we
call ___________ ________________ can be
divided into _______different stages.
Where does cellular respiration occur?

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The Metabolic Pathway for Cellular Respiration
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• The Big Three
• Glycolysis - Cytoplasm
• The citric acid cycle -mitochondrion
• The electron transport chain - mitochondrion

Total chemical energy released from cellular
respiration is 38 molecules of ATP from 1
molecule of glucose.
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Step 1. Glycolysis
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Glycolysis means splitting of _________.
Glycolysis splits a six carbon sugar in half
yielding two, 3-carbon molecules of ___________
_______________.
Glycolysis directly results in the formation of
ATP (which is the direct energy gain) and the
formation of NADH (which are electron carriers)
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Step 2 The Citric Acid Cycle
Pyruvic acid does not enter the citric acid
cycle as is first it must be chemically
prepared by converting it to ________
____________ . In the process, one ___________
__________must be stripped off. Acetic acid
is delivered into the citric acid cycle which
takes place in the ______________________ by
binding it to a carrier molecule called coenzyme
A forming Acetyl CoA. What happened to that
carbon atom?______________________________________
___.
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Step 2 The Citric Acid Cycle

Acetic acid (2 carbons) is further broken down
into CO2 (1 carbon). The energy released is used
to form __________, several _____________
molecules and a couple of _______molecules
(another high energy electron carrier).
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RECAP
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Glycolysis and the Citric Acid Cycle Steps 1
and 2 of Cellular Respiration (not much ATP
YET!)

4 molecules of ATP (energy molecules) 10 NADH
molecules (high energy electron carriers) and 2
FADH (another electron carrier) as well as some
CO2 gas (we think of this as waste that is
exhaled)
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Step 3 the Electron Transport Chain

• First, the purple/blue circular structures
  represent ____________complexes known as the
  electron _______ chain. So, you may ask, what
  electrons are they transporting ? The answer, the
  electrons in ___________ originally captured
  from the breakdown of ___________.

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The Electron Transport Chain
The mitochondria consists of two membranes an
____ and an ____ membrane. ----------------------
----------- The electron transport chain
separates the hydrogen atom to actively transport
(pile up) H between these membranes.
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Remember (H) is equivalent to an (-) and a ()
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The Electron Transport Chain
2. The energy in electrons are used to actively
transport the resulting (_________) across the
inner membrane of the mitochondria. This sets
up a situation where the (H) will diffuse back
across the inner membrane if it can find a place
to pass.
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The Electron Transport Chain

• The only opening available for the (H) to flow
  back across the membrane are through the passage
  in the enzyme _______ ________________which uses
  the energy in the protons (H) to connect an
  inorganic _____________to ADP forming ATP as a
  result.

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The Electron Transport Chain

• The electrons at the end of the electron
  transport chain are accepted by oxygen which
  combines with H (protons) to make electrically
  neutral ____________ which is a harmless
  byproduct. Where did the (H) come from?

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A Summary of ATP Yielded During Cellular
Respiration
The take home message is that 1 molecule of
glucose can produce 38 molecules of ATP, more
energy in the form of heat, and CO2 gas as a
result of cellular respiration
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Energy From Food
The _____________ resulting from the digestion of
_______________, __________, and ____________ can
all serve as fuel for cellular respiration.
Comment on this.
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Fermentation Anaerobic Harvest of Food Energy

• Fermentation is sort of like cellular respiration
  but takes place in the absence of oxygen.
• Fermentation produces 2 ATP through glycolysis
  (Slide 12)
• The trick is to reform NAD in order to accept
  electrons which is usually the job of
  _________________.
• The cell does this by donating electrons to
  pyruvic acid resulting in the production of
  _____________ acid in humans and other animals.
  

Feel the burn !!
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Fermentation in Microorganisms
In microorganisms such as __________fermentation
results in the formation of _______
__________. The fermentation of sugars by
yeasts produces beer.
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Fermentation in Microorganisms
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Humans use microbial fermentation to our
advantage to manufacture ____________,
____________, ______________, soy sauce and other
food items we use on a daily basis. Food
microbiology is a popular class in large biology
departments.
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What You Need to Know

• That ATP is generated from the enzymatic
  breakdown of glucose
• That the process of making ATP from glucose is
  called cellular respiration
• Be able to write the chemical equation for
  cellular respiration
• That cellular respiration is divided into 3
  parts
• Glycolysis cytoplasm
• Citric acid cycle mitochondria
• Electron transport chain mitochondria
• Know that electrons are stripped from glucose as
  it is broken down and that these electrons are
  carried to the electron transport chain in the
  form of NADH to make most of the ATP
• Know that the entire process converts 1 molecule
  of glucose to 38 molecules of ATP mainly through
  the enzyme ATP synthase.
• Know that oxygen is needed to accept the
  electrons after they have been through the
  electron transport chain and that the oxygen and
  its accepted electrons eventually form harmless
  metabolic water.
• Know that fermentation is a less efficient method
  of getting energy (ATP) from glucose when oxygen
  is not available and that lactic acid in animals
  and ethyl alcohol in microbes is the result of
  fermentation.

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Thats All for Chapter 6
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