Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Energy and Organisms Organisms are
classified based on the kind of energy they use. Autotrophs Use the
energy from sunlight to make organic molecules (sugar) Use the
energy in the organic molecules to make ATP Heterotrophs Obtain
organic molecules by eating the autotrophs Use the energy in the
organic molecules to make ATP Autotrophs use photosynthesis. To use
the energy from light to make organic molecules All organisms use
cellular respiration. To harvest the energy from organic molecules
and use it to make ATP
Slide 3
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Energy Transformation
Slide 4
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Cellular Respiration Respiration is
a metabolic pathway of Redox Reactions Respiration oxidizes
carbohydrates and transfers the energy to produce ATP The type of
molecule that is reduced determines the type of respiration The
energy produced is in the form of ATP
Slide 5
5- Copyright The McGraw-Hill Companies, Inc. Permission
required for reproduction or display. Cellular Respiration Three
Types of Respiration 1. Aerobic Respiration - Oxygen is reduced to
produce water 2. Anaerobic Respiration - A molecule other that
oxygen is reduced - may produce acids, methane, etc. 3.
Fermentation - Another carbohydrate is reduced to produce
alcohols
Slide 6
5- Copyright The McGraw-Hill Companies, Inc. Permission
required for reproduction or display. 1. Aerobic Respiration
Glucose is Oxidized to become Carbon Dioxide Oxygen is reduced to
become water The protons and electrons from the oxidation of
glucose are used to produce ATPs
Slide 7
5- Copyright The McGraw-Hill Companies, Inc. Permission
required for reproduction or display. 1. Aerobic Respiration C 6 H
12 O 6 + 6 O 2 6 H 2 O + 6 CO 2 + Energy C 6 H 12 O 6 + 6O 2 + 38
ADP + 38 P 6 H 2 O + 6CO 2 + 38 ATP
Slide 8
5- Copyright The McGraw-Hill Companies, Inc. Permission
required for reproduction or display. 1. Aerobic Respiration
Aerobic Respiration is a three stage process: Stage 1: Glycolysis
Stage 2: The Krebs Cycle Stage 3: Oxidative Phosphorylation
(Electron Transport Chain) Each of these stages produce ATP At the
end of all three stages, there is a net gain of ~38 ATPs
Slide 9
Slide 10
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 1: Glycolysis Glycolysis is a
10 step metabolic pathway that cleaves glucose Glyo-lysis =
splitting glucose Glycolysis occurs in the cells cytoplasm
Slide 11
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 1: Glycolysis Glycolysis
splits glucose to make two pyruvate molecules Produces 4 ATP
molecules 4 ATP made -2 ATP invested = net production of 2 ATP
Reduces 2 NAD + to make 2 NADH
Slide 12
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 1: Glycolysis During
Glycolysis, Glucose (a 6 carbon molecule) is chopped up into 2
Pyruvates (pyruvate is a 3 carbon molecule) This is a 9 step
metabolic process
Slide 13
Figure 6_07
Slide 14
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- 9 Steps of Glycolysis Summary 1.
Glucose is phosphorylated - costs 1 ATP to become
Glucose-6-Phosphate 2. Glucose-6-P is converted to Fructose-6-P 3.
Fructose-6-P is phosphorylated - costs 1 ATP to become
Fructose-1,6-bisphosphate 4. Fructose-1,6-bisphosphate is split
into two molecules - each with 3 carbons and a phosphate:
Dihydroxyacetone (DHAP) Glyceraldehyde-3-Phoshate (G-3-P)
Slide 15
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- 9 Steps of Glycolysis Summary
G-3-PDHAP 5. G-3-P is phosphorylated to 5. DHAP is phosphorylated
to become 1,3-bisphosphoglycerate become 1,3 bisphosphoglycerate 6.
1,3-bisphosphglycerate gives up 6. 1,3-bisphosphoglycerate gives up
a a phosphate to an ADP, G-3-P left phosphate to an ADP, G-3-P left
7. G-3-P converted to 7. G-3-P converted to 2-Phosphoglycerate
2-Phospoglycerate 8. 2-Phosphoglycerate converted to 8.
2-Phosphoglycerate converted to Phosphoenolpyruvate
Phosphoenolpyruvate 9. Phosphoenolpyruvate gives up 9.
Phosphoenolpyruvate gives up its phosphate to an ADPits phosphate
to an ADP
Slide 16
Glucose Pyruvate1 Pyruvate 2 2 ATP 4 ATP, 2 NADH
Slide 17
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- NAD +, NADH NAD + is an electron
carrier for the redox reactions of cellular respiration NAD +
accepts 2 electrons and 1 proton to become NADH Functions of NAD +,
NADH NAD + is reduced so Redox reactions can occur NAD + is used to
carry electrons from one part of the cell to another NAD + keeps
protons out of solution
Slide 18
NAD +, NADH
Slide 19
NAD + Reduced to NADH
Slide 20
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- FAD, FADH 2 FAD is very similar to
NAD + It has the same functions of collecting and carrying
electrons and protons FAD can carry 2 Hydrogen atoms FAD is Reduced
to FADH 2
Slide 21
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 2: Krebs Cycle Also known as
The Citric Acid Cycle or the Tricarboxylic Acid (TCA) Cycle The
Krebs cycle is a metabolic pathway that further oxidizes pyruvate
The Krebs Cycle occurs in the Cell membrane of Prokaryotic Cells
and in the mitochondria of Eukaryotic Cells In mitochondria, a
multienzyme complex called pyruvate dehydrogenase catalyzes the
reaction
Slide 22
Slide 23
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 2: Krebs Cycle The Krebs
Cycle begins with pyruvate (from Glycolysis) Remember, there are 2
pyruvates made from each Glucose, so there are 2 Krebs Cycles for
every glucose molecule During a Krebs Cycle the pyruvate (a 3
carbon molecule) will be completely oxidized to become 3 carbon
dioxide molecules (one carbon atom each)
Slide 24
5- Copyright The McGraw-Hill Companies, Inc. Permission
required for reproduction or display. Cellular Respiration C 6 H 12
O 6 + 6O 2 6H 2 O + 6CO 2 + Energy Glucose Oxygen Water Carbon
Dioxide The Krebs Cycle produces the CO 2 that we exhale
Slide 25
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 2: Krebs Cycle Important
steps in the Krebs Cycle Pyruvate is converted to acetyl-CoA
Acetyl-CoA combine with Oxaloacetate (in the mitochondria) to make
Citrate The cycle ends with the production of oxaloacetate, ready
for anther turn of the cycle
Slide 26
Figure 6_05
Slide 27
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 2: Krebs Cycle During the
Krebs Cycle enough energy is released from one pyruvic acid
molecule to produce: 1 ATP 4 NADH from 4 NAD + 1 FADH 2 from 1
FAD.
Slide 28
Figure 6_08
Slide 29
Glucose Pyruvate1 Pyruvate 2 2 ATP 4 ATP, 2 NADH 2 ATP 1 ATP, 2
CO 2 4 NADH, 1 FADH 2 Pyruate converted to Acetyl Co-A
Slide 30
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 2: Krebs Cycle After
glycolysis and the Krebs cycle glucose has been completely oxidized
to form: 6 CO 2 ~5 ATP ~10 NADH ~2 FADH 2 We are still short of our
36-38 ATP goal The third stage of cellular respiration uses the
protons and electrons of the hydrogens on the NADHs and FADH 2 s
that were produced during the first 2 stages
Slide 31
Glucose Pyruvate1 Pyruvate 2 2 ATP 4 ATP, 2 NADH 2 ATP 2 ATP,
CO 2 8 NADH, 2 FADH 2 Electron Transport Chain NADH, FADH 2 34 ATP
Pyruate converted to Acetyl Co-A
Slide 32
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 3: Electron-Transport System
The electron transport chain (ETC) is a series of membrane-bound
electron carrier molecules called cytochromes embedded in the
mitochondrial inner membrane Electrons from NADH and FADH 2 are
transferred to cytochromes of the ETC Each cytochrome transfers the
electrons to the next cytochromes in the chain
Slide 33
Fig. 7.13a
Slide 34
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 3: Electron-Transport System
As the electrons are transferred, some electron energy is released
with each transfer This energy is used by the cytochromes to pump
protons (H + ) across the membrane from the matrix to the inner
membrane space A proton concentration gradient is established
Slide 35
Stage 3: Electron Transport Chain
Slide 36
Figure 6_06
Slide 37
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Stage 3: Electron-Transport System
There are other channel proteins in the membrane known as ATP
synthases ATP synthases provide a channel for protons to rush
through by diffusion The rushing protons provides the energy for
ATP synthase to phosphorylate ADP to ATP
Slide 38
Slide 39
Figure 6_06
Slide 40
40
Slide 41
41
Slide 42
Figure 6_09
Slide 43
5- Copyright The McGraw-Hill Companies, Inc. Permission
required for reproduction or display. Cellular Respiration Recall
Three Types of Respiration 1. Aerobic Respiration - Oxygen is
reduced to produce water 2. Anaerobic Respiration - A molecule
other that oxygen is reduced - may produce acids, methane, etc. 3.
Fermentation - Another carbohydrate is reduced to produce
alcohols
Slide 44
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- 1. Aerobic Respiration Oxygen is
the final molecule to receive the electrons as they are passed down
the Electron Transport Chain Oxygen is reduced with two electrons
and picks up two protons The result is water: 2O 2 + 8e - s and 8H
+ s 4H 2 O Oxygen is the Final Electron Acceptor in Aerobic
Respiration
Slide 45
The Electron Transport Chain
Slide 46
Glucose Pyruvate1 Pyruvate 2 2 ATP 4 ATP, 2 NADH 2 ATP 2 ATP,
CO 2 8 NADH, 2 FADH 2 Electron Transport Chain NADH, FADH 2 30+ ATP
And H 2 O Pyruate converted to Acetyl Co-A
Slide 47
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Aerobic Cellular Respiration:
Overview
Slide 48
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Total Yields for Aerobic Cellular
Respiration per Glucose Molecule Glycolysis 2 ATP 2 NADH (converted
to 2 FADH 2 ) Krebs cycle 2 ATP 8 NADH 2 FADH 2 Electron transport
chain Each NADH fuels the formation of 3 ATP. 8 NADH x 3 ATP = 24
ATP Each FADH 2 fuels the formation of 2 ATP. 4 FADH2 x 2 ATP = 8
ATP Total ATP=2+2+24+8=36 ATP made from the metabolism of one
glucose molecule.
Slide 49
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- 2. Anaerobic Cellular Respiration
Some cells do not require O 2 as the final electron acceptor for
the electron transport chain These cells perform Anaerobic
Respiration Anaerobic Respiration produces fewer ATPs per glucose
molecule compared to Aerobic Respiration it is not as efficient and
the exact amount of ATP production depends on the organism and the
electron acceptors that are used
Slide 50
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- 2. Anaerobic Cellular Respiration
Anaerobic respiration by methanogens methanogens use CO 2 CO 2 is
reduced to CH 4 (methane) Anaerobic respiration by sulfur bacteria
inorganic sulphate (SO 4 ) is reduced to hydrogen sulfide (H 2
S)
Slide 51
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- 3. Fermentation Fermentation
reduces organic molecules as the final electron acceptors Ethanol
fermentation occurs in yeast fermentation of sugars produces
alcohol Lactic acid fermentation occurs in animal cells (especially
muscles) electrons are transferred from NADH to pyruvate to produce
lactic acid
Slide 52
Figure 6_10
Slide 53
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Alcoholic Fermentation Starts with
glycolysis Glucose is metabolized to pyruvic acid. A net of 2 ATP
is made. During alcoholic fermentation Pyruvic acid is reduced to
form ethanol. Carbon dioxide is released. Yeasts do this Leavened
bread Sparkling wine
Slide 54
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Lactic Acid Fermentation Starts
with glycolysis Glucose is metabolized to pyruvic acid. During
lactic acid fermentation Pyruvic acid is reduced to form lactic
acid. No carbon dioxide is released. Muscle cells have the enzymes
to do this, but brain cells do not. Muscle cells can survive brief
periods of oxygen deprivation, but brain cells cannot. Lactic acid
burns in muscles.
Slide 55
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Metabolizing Other Molecules Cells
will use the energy in carbohydrates first. Complex carbohydrates
are metabolized into simple sugars. Cells can use the energy in
fats and proteins as well. Fats are digested into fatty acids and
glycerol. Proteins are digested into amino acids. Cells must
convert fats and proteins into molecules that can enter and be
metabolized by the enzymes of glycolysis or the Krebs cycle.
Slide 56
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Fat Respiration Fats are broken
down into Glycerol Fatty acids Glycerol Converted to
glyceraldehyde-3-phosphate Enters glycolysis Fatty acids Converted
to acetylCoA Enter the Krebs cycle Each molecule of fat fuels the
formation of many more ATP than glucose. This makes it a good
energy storage molecule.
Slide 57
Preparatory Steps Amino Acids Lipids
Slide 58
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Protein Respiration Proteins are
digested into amino acids. Then amino acids have the amino group
removed. Generates a keto acid (acetic acid, pyruvic acid, etc.)
Enter the Krebs cycle at the appropriate place
Slide 59
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- The Interconversion of Fats,
Carbohydrates and Proteins
Slide 60
Copyright The McGraw-Hill Companies, Inc. Permission required
for reproduction or display. 6- Energy Resources Carbohydrates,
fats and proteins can all be used for energy. Glycolysis and the
Krebs cycle allow these types of molecules to be interchanged. If
more calories are consumed than used The excess food will be
stored. Once the organism has all of the proteins it needs And its
carbohydrate stores are full The remainder will be converted to and
stored as fat.