cell respiration chapter 9. slide 2 of 33 why respire? living cells require energy transfusions to...

Cell Respiration

Chapter 9

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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

cell respiration chapter 9. slide 2 of 33 why respire? living cells require energy transfusions to...

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