Cellular Respiration Chapter 9

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Cellular RespirationChapter 9

• Objectives
• 3.0 Identify reactants and products associated
  with photosynthesis and cellular respiration and
  the purposes of these two processes.
• AOD B.3.1 Identify the function of photosynthesis
  and cellular respiration.
• AOD B.3.2 Describe photosynthesis and cellular
  respiration, including their reactants and
  products.
• AOD B.3.3 Recognize the relationship between
  reactants and products associated with
  photosynthesis and cellular respiration.
• AOD B.3.4 Recognize a given formula as either
  photosynthesis or cellular respiration.

2
Overview

• Fill in the major steps in cellular respiration
  while watching the following video clip
  http//www.youtube.com/watch?vaXC9jMNIRnE

3
Section 9-1

• What is the function of the mitochondria?
• What types of cells contain mitochondria?
• All eukaryotic cells

Source http//adamsewall.com/blog/happy-mitochond
ria-happy-gonads/629/
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• Mitochondria release the energy from glucose and
  other food compounds.
• Step 1 Glycolysis
• Step 2
• If glycolysis takes place in the presence of
  oxygen, then the Krebs cycle and electron
  transport chain work to produce lots of ATP.
• Without oxygen, fermentation occurs.

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Cellular Respiration

• Made up of all three processes glycolysis,
  Krebs cycle, and electron transport chain
• Occurs in the presence of oxygen
• C6H12O6 6O2 6CO2 6H2O
  energy
• Glucose, if converted all at once, would set the
  cells on fire!

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Glycolysis

• Breaks 1 glucose molecule in half, producing 2
  molecules of pyruvic acid (a 6-carbon molecule
  becomes 2 3-carbon molecules).
• Requires 2 molecules of ATP to break the glucose
  molecule.
• At the end, the cell will have 4 ATP molecules
  --- a gain of 2 ?

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NADH Production in Glycolysis

• 4 high-energy electrons and 2 Hs attach to 2
  electron carriers called NAD (comparable to
  NADP in photosynthesis), converting it into
  NADH.
• Glysolysis yields low energy amounts, but
  extremely rapidly, and with or without oxygen.

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Overview/Review
http//faculty.clintoncc.suny.edu/faculty/michael.
gregory/files/bio20101/bio2010120lectures/cellu
lar20respiration/cellular.htm
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Fermentation (Anaerobic Respiration)

• Releases energy from food particles by producing
  ATP in the absence of oxygen.
• Cells convert NADH back to NAD by passing
  electrons back to pyruvic acid. This allows
  glycolysis to continue producing ATP.

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2 Types of Fermentation

• Alcoholic fermentation
• Yields ethyl alcohol and CO2
• Pyruvic acid NADH alcohol CO2
  NAD
• What types of cells?
• Lactic acid fermentation
• Yields lactic acid
• Pyruvic acid NADH lactic acid
  NAD
• What types of cells?

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Bellringer/Assessment

• Refer to the Overview/Review for glycolysis,
  and Figures 9-3 and 9-4, as needed, to create a
  simple flowchart for
• Glycolysis
• Alcoholic fermentation
• Lactic acid fermentation
• (Remember, flowchart instructions/example are
  found on p.1065)

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Section 9-2

• What are the waste products of cellular
  respiration?
• How do we get rid of these waste products?
• Quick Lab How does exercise affect disposal of
  wastes from cellular respiration? (p.231)

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Section 9-2

• The aerobic (in air or oxygen) pathway after
  glycolysis consists of 2 main portions
• The Krebs cycle
• The electron transport chain

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Krebs Cycle

• Discovered by Hans Krebs in 1937.
• Breaks pyruvic acid (from where???) into
  (ultimately) carbon dioxide

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Krebs Cycle Steps

1. Pyruvic acid enters the mitochondrion.
2. One carbon atom breaks off and forms carbon
   dioxide. The other 2 carbon atoms, 1 oxygen atom,
   and 3 hydrogen atoms form an acetyl group that
   attaches to coenzyme A to form acetyl-CoA.

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Krebs Cycle Steps

1. Acetyl-CoA adds the acetyl group to a 4-carbon
   molecule, forming a 6-carbon citric acid
   molecule. (This is why it is also called the
   citric acid cycle.)
2. 2 carbons are removed (individually) to form CO2,
   and electrons are added to energy carrier
   molecules (???).

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Krebs Cycle Steps

• After 2 carbons have been removed, how many
  carbons are left?
• This 4-carbon molecule is now ready to accept
  another acetyl group.

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Krebs Cycle Steps

• 6. For each cycle, an ATP molecule is produced
  --- as citric acid is being reduced to a 4-carbon
  molecule.
• 7. Additionally, 5 pairs of high-energy electrons
  are transferred to electron carriers, changing
  NAD to ??? and FAD to FADH2.

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Krebs Cycle Products

• CO2
• ATP
• NADH and FADH2
• What happens to each of these products?

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Electron Transport Chain

• So what do you think happens here?
• Electrons from the Krebs cycle are used to
  convert ADP to ATP.
• How do electrons get from the Krebs cycle to the
  transport chain?
• Attached to NADH and FADH2 ?

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• NADH and FADH2 release Hs and electrons.
• The electrons are passed down the transport chain
  until they join with oxygen and Hs to form
  water (H2O).
• Every time 2 electrons are transported down the
  chain, a H is transported across the membrane.

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• How do the Hs generate energy for the cell?
• They cross ATP synthase to reestablish an
  equilibrium of charges, and convert ADP to ATP.
• They join with oxygen and electrons to form water
  (H2O).
• What happens to the NADH and FADH2?
• Converted to NAD and FAD to be reused
  (where????).

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Total Production

• Glycolysis 2 ATP
• This is ALL the ATP produced without oxygen.
• WITH oxygen
• Krebs cycle electron transport chain 34 ATP
• Total 36 ATP ---- 18x more than anaerobic
  respiration!!!!

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Comparing Photosynthesis and Cellular Respiration
Photosynthesis Cellular Respiration
Function
Location
Reactants
Products
Equation