Download AP Biology (An Introduction)

Cell Respiration
Chapter 9
Why Respire?
 Living cells require energy transfusions to perform most
of their tasks
 From external sources
 Assembling polymers
 (what is the general reaction called?)
 Pumping substances across their gradient
 (what is the generic reference for this process? Where did
we see this in Lab 1?)
 Moving
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Notes on Previous Slide
 Energy flows into an ecosystem as sunlight
 Leaves as heat
 Why can’t energy just be created?
 Which Law of Thermodynamics helps explain this flow?
 Essential chemical elements of life are recycled
 Photosynthesis (plants) make Oxygen and Sugars
 Cellular respiration take oxygen and sugars, make CO2
and H2O & energy
 The products of respiration (CO2 and H2O) are the raw
materials of photosynthesis
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Cellular Respiration
 Cellular respiration is catabolic
 Catabolic processes are exergonic
 Energy release from glucose is used to phosphorylate
ADP  ATP
 So cellular respiration burns fuels and uses the energy
to regenerate ATP
 Life processes constantly consume ATP
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Respiration Overall
 Food  Glucose  NADH  ATP
 Glycolysis  Pyruvate Oxidation  Kreb’s Cycle 
Oxidative Phosphorylation
 Cytoplasm  Mitochondrion  Matrix  Inner
Mitochondrial Membrane
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2 Respiration Pathways
 Cell Respiration
 Called Aerobic Respiration
 Requires Oxygen
 Generates 36 or 38 ATP per glucose
 Fermentation
 Called Anaerobic Respiration
 Oxygen NOT needed
 Ethanol or Lactic Acid forms
 Generates 2 ATP per glucose
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3 Stages of Respiration
 Glycolysis
 Decomposes glucose
 6-Carbon to 2 (3-Carbon molecules)
 Occurs in cytosol
 Citric Acid Cycle
 Continues decomposing 2-Carbon into CO2
 Mitochondrial matrix
 Oxidative Phosphorylation
 ETC + Chemiosmosis
 Powered by redox rxns
 Method of ATP synthesis
 Across inner mitochondrial membrane
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Cellular Respiration
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Questions
 Is respiration exergonic or endergonic? Why?
 Is fermentation exergonic or endergonic? Why?
 Does respiration require enzymes?
 What are the 2 catabolic pathways?
 How do they differ?
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Questions (Page 2)
 What are the 4 parts of cellular respiration?
 Which of the parts produce ATP?
 Which of the parts produce NADH?
 Which part(s) of cellular respiration require oxygen?
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Glycolysis
 Splitting of glucose
 Cytosol (cytoplasm)
 6-Carbon molecule  2 (3-Carbon molecules)
 2 Phases
 Energy Investment (Consumes 2 ATP)
 Energy Payoff (Produces 4 ATP)
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Pyruvate Oxidation
 Pyruvate  Acetyl CoA
 3-Carbon  2-Carbon
 Needs to get into the mitochondrion
 Transport protein
 Produces
 NADH or FADH2
 CO2
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Citric Acid Cycle
 Called Kreb’s Cycle OR TricarboxylicAcic Cycle (TCA)
 Mitochondria
 Produces
 CO2
 NADH
 FADH2
 ATP (Actually GTP  ATP)
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Questions
 What is Glycolysis?
 What is produced in Glycolysis?
 Where does Glycolysis occur in a eukaryotic cell?
 Where does it occur in a prokaryotic cell?
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Oxidative Phosphorylation
 2 Parts:
 Electron Transport Chain
 Chemiosmosis
 Electron Transport Chain
 Embedded in inner mitochondrial membrane
 Pumps Protons out of the matrix into the
intermembrane space
 Establishes electrochemical gradient
 Chemiosmosis
 ATP Synthase makes ATP
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A Different Perspective
 Glycolysis & Citric Acid Cycle
 Redox rxns
 Decompose glucose into CO2
 Transfers electrons from Glucose to NAD+ (NADH is
formed)
 Oxidative Phosphorylation
 Accepts electrons from NADH and uses them to drive
ATP synthesis
 Series of steps
 O2 is the final electron acceptor, forms H2O
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Questions
 What are the 4 Parts of Cellular Respiration?
 What is the purpose of Pyruvate Oxidation?
 What is produced in Pyruvate Oxidation?
 For each glucose, how many pyruvate oxidations occur?
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Questions (Page 2)
 Where does the TCA cycle occur in a eukaryotic cell?
 Where does it occur in a prokaryotic cell?
 What are the 2 alternate names for the TCA cycle?
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Questions (Page 3)
 For each glucose, how many turns of the TCA cycle
occur?
 Each turn of the TCA cycle produces how much:
 CO2?
 ATP?
 NADH?
 FADH2?
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Fermentation
 2 Forms
 Lactic Acid fermentation (2 ATP)
 Alcoholic fermentation (2 ATP + 2 CO2)
 Glycolysis + 1 extra step (Recycles NAD+)
 Does NOT require oxygen
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Fermentation
 Lactic Acid Fermentation
 3-Carbon  3-Carbon
 3-carbon = Lactate or Lactic acid (What functional group?)
 Muscles
 Alcoholic Fermentation
 3-Carbon  2-Carbon
 2-Carbon = Ethanol (What functional group?)
 CO2
 Beer or wine
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