3.7 Core
8.1 Additional Higher Level

Animation-07-01 electron transport and ATP synthesis cell resp.swf

 The controlled release of energy from organic compounds in cells to form
ATP.
 Can take place w/ or w/o oxygen
 Either: 1 st stage is glycolysis

3.7.2 State that, in cell resp, glucose in the cytoplasm is broken down by glycolysis into pyruvate, with a small yield of ATP.
 1 Glucose  2 pyruvate + 2 net ATP
 In cytoplasm/cytosol
 No oxygen necessary
 Pyruvate = 3-C molecule

3.7.3 Explain that, during anaerobic resp, pyruvate can be converted in the cytoplasm into lactate, or ethanol and carbon dioxide, with no further yield of ATP.
GLUCOSE
GLYCOLYSIS in cytoplasm
Aerobic Resp in mitochondria
PYRUVATE + small amt ATP
Anaerobic Resp (only when no oxygen) in cytoplasm
Into CO
2
+ H
2
O
+ lots ATP in animals
(muscle)
Into lactate (3-C) in animals & bacteria, w/small amount ATP
Sprinting! Body doesn’t produce enough ATP to contract muscles w/the limited Oxygen...cramping
Into ethanol
(2-C) and CO
2 in yeasts and plants, w/small amount ATP
Mmm!

3.7.4 Explain that, during aerobic cell respiration, pyruvate can be broken down in the mitochondrion into carbon dioxide and water with a large yield of ATP.
 IF OXYGEN’S PRESENT!
 Pyruvate moves into mitochondrion
 Much more ATP produced
AEROBIC
SUMMARY:

8.1.1 State that oxidation involves the loss of electrons from an element, whereas reduction involves a gain of electrons; oxidation frequently involves gaining oxygen or losing hydrogen, whereas reduction frequently involves losing oxygen or gaining hydrogen.
• Redox (always go together)
• LEO GER or OIL RIG
– Oxidation is loss; reduction is gain
– Subst that’s been reduced has the power TO reduce other substances, becomes oxidized in the process
– NADH
Oxidation Reduction
Electrons Loss Gain
Oxygen Gain
Hydrogen Loss
Loss
Gain

• Oxidation:

• Reduction:

8.1.2 Outline the process of glycolysis, including phosphorylation, lysis, oxidation and ATP formation
• Glucose + 2ADP + 2P + 2NAD + 
2 pyruvate + 2ATP + 2NADH + 2H + + 2H
2
O
• Anaerobic, no O necessary
• Small amt ATP, NADH, H+ produced
• Oxidation of glucose; reduction of ADP to ATP
• Pyruvate (triose)
• ...

8.1.2 Outline the process of glycolysis, including phosphorylation, lysis, oxidation and ATP formation
• 1 st step: phosphorylation
– USE ATP to add P group to glucose
– 2 nd phosphorylation  hexose biphosphate
• 2 nd step: lysis
– 2 triose phosphate
• 3 rd step: oxidation phosphorylation
–  triose biphosphate
– Each 1 gives up a P group
•  ADP  ATP
• Repeat! (2 ATP)
– + 2: pyruvate, NADH, H+

8.1.3 DRAW and label a diagram showing the structure of a mitochondrion as seen in electron micrographs.
Eukaryotes only
Cells that need lots of energy have lots!
Ribosomes, mtDNA
Matrix, cristae, inner/outer membranes

Image source unknown

8.1.4 Explain aerobic respiration, including the link reaction, the Krebs cycle, the role of NADH + H+, the electron transport chain and the role of oxygen.
• Link reaction:
– b/w glycolysis & Krebs
– Reaction:
Pyruvate + CoA + NAD+ 
Acetyl CoA + CO2 + NADH + H+
– Decarboxylation of pyruvate (CO
2 is removed)

8.1.4 Explain aerobic respiration, including the link reaction, the Krebs cycle, the role of NADH + H+, the electron transport chain and the role of oxygen.
• Krebs Cycle:
– TCA (tricarboxylic citric acid) cycle
– In matrix
– Products, per 1 acetyl CoA:
3NADH + 3H+ + 1FADH2 + 1ATP + 2CO2
– Cyclic
– Start @ Acetyl CoA... (2-C; product of link)

4C
5C
Acetyl
CoA
(2C)
6C

• Krebs Cycle:
– Acetyl CoA + 4-C  6-C
– Decarboxylated  5-C & CO2
– “”  4-C & CO2
– Same one that reacts with Acetyl CoA!
– P.140

• One cycle – 1 Acetyl CoA  1 CoA, 2CO2
• Purpose????
• Produce energy!!!
• Also produce:
– 3 NADH, 3H+ (e- carrier/H+ acceptor/reduced)
– 1 FADH2 (e- carrier/H+ acceptor/reduced)
– 1 ATP

8.1.5 Explain oxidative phosphorylation in terms of chemiosmosis.
• OVERALL...1 glucose  6 CO2
• So far, no O2 used, little ATP produced
• LAST STAGE... E-carriers used to make
– AEROBIC!
– ETC, on cristae’s phospholipid bilayer
– ETC = proteins, pass e-, pump H+ from matrix to intermembrane space...to reduction of oxygen  water

• Proton gradient drives ADP + P  ATP
– ATP synthase
• “Chemiosmotic theory”
– Explains how synthesis of ATP is coupled to electron transport & proton movement

• Net result: p. 140
• Pass high energy e- down ETC, H pumped across inner membrane
• Build up of H+ in intermemb space
• [] gradient (proton-motive force) drives H+ through
ATP synthase (chemiosmotic channel), ATP is made.

• Energy from NADH, FADH2 transferred to
ATP
• H+ , e- + Oxygen  water
• Aerobic
• No oxygen: no water, no NAD+ or FAD, so no
Krebs cycle...
• Acetyl CoA builds up, no longer produced from pyruvate...
• Glycolysis ok; anaerobic resp

8.1.6 Explain the relationship between the structure of the mitochondrion and its function.
• Outer membrane
– Barrier to cytoplasm
• Inter-membrane space
– Higher [H+] b/c ETC
– Small volume
• Small amt H+  big difference
• Inner membrane
– Folds (cristae)...surface area for ETC, ATP synthase
– Impermeable to H+
• Matrix
– Enzymes for Krebs

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