Cellular Respiration, Harvesting Chemical Energy Fermentation ...
Cellular Respiration, Harvesting Chemical Energy Fermentation ...
Cellular Respiration, Harvesting Chemical Energy Fermentation ...
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Chapter 9 – <strong>Cellular</strong> <strong>Respiration</strong>, <strong>Harvesting</strong> <strong>Chemical</strong> <strong>Energy</strong><br />
<strong>Fermentation</strong> enables some cells to produce ATP without the use of oxygen<br />
<strong>Cellular</strong> respiration requires O 2<br />
to produce ATP<br />
Glycolysis CitricOxidative<br />
acid phosphorylation:<br />
cycle electron transport<br />
ATP and ATPchemiosmosis<br />
H +<br />
Protein complex<br />
Intermembrane<br />
of electron<br />
space carriers<br />
Inner<br />
mitochondrial<br />
membrane<br />
Mitochondrial<br />
matrix<br />
I<br />
H +<br />
Q<br />
III<br />
II<br />
FADH 2FAD<br />
Cyt c<br />
Inner<br />
mitochondrial<br />
membrane<br />
NADH+ H + NAD +<br />
ADP + P<br />
(carrying electrons<br />
i ATP<br />
from food)<br />
H +<br />
Electron transport chain<br />
Chemiosmosis<br />
Electron transport and pumping of protons ATP (H + ), synthesis powered by the flow<br />
Which create an H + gradient Oxidative across phosphorylation<br />
the membrane of H + back across the membrane<br />
IV<br />
2H + + 1 /2 O 2<br />
H +<br />
H 2 O<br />
H +<br />
ATP<br />
synthase<br />
•Glycolysis can produce ATP with or without<br />
O 2<br />
(in aerobic or anaerobic conditions)<br />
pyruvate<br />
•Two common types are<br />
2 ATP<br />
2 ADP + 2 P i<br />
2 Pyruvate<br />
Glucose<br />
Glycolysis<br />
Alcohol <strong>Fermentation</strong><br />
2<br />
CO 2<br />
•In alcohol fermentation, pyruvate is converted to<br />
ethanol in two steps, with the first releasing CO 2<br />
2 Ethanol<br />
Alcohol fermentation<br />
2 NAD + 2 NADH<br />
+ 2 H +<br />
2 Acetaldehyde<br />
•This reaction regenerates NAD+ needed for the continuation of glycolysis.
Lactic Acid <strong>Fermentation</strong><br />
In lactic acid fermentation,<br />
Glucose<br />
2 ATP<br />
Glycolysis<br />
2 NAD +<br />
2 NADH<br />
+ 2 H +<br />
2<br />
CO 2<br />
2 ADP + 2 P i<br />
2 Pyruvate<br />
2 Lactate<br />
Lactic acid fermentation<br />
•Lactic acid fermentation by some<br />
fungi and bacteria is used to<br />
make cheese and yogurt<br />
Lactic Acid <strong>Fermentation</strong> in Human Muscle Cells<br />
•Human muscle cells use lactic acid fermentation to generate ATP when O 2<br />
is scarce<br />
When you walk to class, ATP powers muscles cells of your legs.<br />
<strong>Cellular</strong> respiration regenerates ATP supply to keep you going.<br />
If you start to run to class,<br />
In order to keep running, your muscles must generate ATP by the anaerobic process of fermentation.<br />
NAD+ must also be present as an electron acceptor for glycolysis to occur.<br />
2 pyruvate
Lactic Acid <strong>Fermentation</strong> in Human Muscle Cells<br />
NAD+ is present under aerobic condition of cellular respiration.<br />
NAD+ is regenerated by the cell<br />
NAD+ cannot be recycled by the cell under anaerobic conditions,<br />
2 pyruvate<br />
This addition of electrons produces the waste product, lactic acid.<br />
Glucose<br />
2 NAD + 2 NADH<br />
2<br />
+ 2 H +<br />
2 Pyruvate<br />
CO 2<br />
2 ADP + 2 P i 2 ATP<br />
Glycolysis<br />
2 Lactate<br />
Lactic acid fermentation<br />
<strong>Fermentation</strong> and <strong>Cellular</strong> <strong>Respiration</strong> Compared<br />
•Both processes use glycolysis to oxidize glucose and other organic fuels to pyruvate<br />
2 ADP + 2 P i<br />
2 Pyruvate<br />
pyruvate<br />
Glucose<br />
2 ATP<br />
Glycolysis<br />
2 NAD +<br />
2 NADH<br />
+ 2 H +<br />
2<br />
CO 2<br />
2 Lactate<br />
Lactic acid fermentation
<strong>Fermentation</strong> and <strong>Cellular</strong> <strong>Respiration</strong> Compared<br />
The processes have different final electron acceptors:<br />
2 ADP + 2 P i<br />
2 Pyruvate<br />
Glucose<br />
2 ATP<br />
Glycolysis<br />
2 NAD +<br />
2 NADH<br />
+ 2 H +<br />
2<br />
CO 2<br />
Glucose<br />
2 ADP + 2 P i 2 ATP<br />
Glycolysis<br />
2 Pyruvate<br />
2 NAD + 2 Acetaldehyde<br />
2 NADH<br />
+ 2 H +<br />
2<br />
CO 2<br />
2 Lactate<br />
Lactic acid fermentation<br />
2 Ethanol<br />
Alcohol fermentation<br />
The processes have different final electron acceptors:<br />
Inner<br />
mitochondrial<br />
Glycolysis Citric Oxidative<br />
membrane<br />
acid phosphorylation:<br />
cycle electron transport<br />
ATP ATP and chemiosmosis ATP<br />
H +<br />
H +<br />
H +<br />
H<br />
Protein complex<br />
Cyt c<br />
+<br />
Intermembrane<br />
of electron<br />
space<br />
carriers<br />
Q<br />
IV<br />
I<br />
III<br />
ATP<br />
Inner<br />
II<br />
FADH 2H + + 1 /2 O<br />
mitochondrial<br />
2 FAD<br />
2 H 2 O<br />
synthase<br />
membrane<br />
NADH+ H + NAD +<br />
(carrying electrons<br />
ADP + P i ATP<br />
from food)<br />
H +<br />
Mitochondrial<br />
Electron transport chain<br />
Chemiosmosis<br />
matrix<br />
Electron transport and pumping of protons (H + ), ATP synthesis powered by the flow<br />
Which create an H + gradient<br />
Oxidative<br />
across the<br />
phosphorylation<br />
membraneof H + back across the membrane<br />
•<strong>Cellular</strong> respiration produces much more ATP<br />
Some organisms can carry out only fermentation (anaerobic respiration).<br />
Yeast and many bacteria are facultative anaerobes,<br />
Glucose<br />
In a facultative anaerobe,<br />
CYTOSOL<br />
Pyruvate<br />
No O 2 present<br />
<strong>Fermentation</strong><br />
O 2 present<br />
<strong>Cellular</strong> respiration<br />
Ethanol<br />
or<br />
lactate<br />
Acetyl CoA<br />
MITOCHONDRION<br />
Citric<br />
acid<br />
cycle
The Evolutionary Significance of Glycolysis<br />
Glycolysis occurs in nearly all organisms<br />
Membrane-bound organelles<br />
Accumulation of atmospheric<br />
oxygen from photosynthetic<br />
cyanobacteria<br />
Oldest prokaryotic fossils<br />
Earth cool enough for crust to solidify<br />
Origin of Earth<br />
Glycolysis and the citric acid cycle connect to many other metabolic pathways<br />
•Gycolysis and the citric acid cycle are major<br />
intersections to various catabolic and anabolic<br />
pathways<br />
The Versatility of Catabolism<br />
Catabolic pathways funnel electrons from many<br />
kinds of organic molecules into cellular respiration<br />
Proteins<br />
Carbohydrates<br />
Fats<br />
Proteins must be digested to amino acids;<br />
Amino<br />
acids<br />
Sugars<br />
Glycerol Fatty<br />
acids<br />
Glycolysis<br />
Glucose<br />
Glyceraldehyde-3- P<br />
NH 3<br />
Pyruvate<br />
Acetyl CoA<br />
Citric<br />
acid<br />
cycle<br />
Oxidative<br />
phosphorylation
Regulation of <strong>Cellular</strong> <strong>Respiration</strong> via Feedback Mechanisms<br />
•Feedback inhibition is the most common mechanism for<br />
control of glycolysis and the Krebs Cycle.<br />
If ATP concentration begins to drop, respiration speeds up;<br />
when there is plenty of ATP, respiration slows down<br />
Glucose<br />
–<br />
Glycolysis<br />
Fructose-6-phosphate<br />
Phosphofructokinase<br />
AMP<br />
Stimulates<br />
+<br />
–<br />
Inhibits<br />
Fructose-1,6-bisphosphate<br />
Inhibits<br />
Phosphofructokinase is an<br />
allosteric enzyme with receptor<br />
sites for specific inhibitors<br />
and activators.<br />
Fructose-6-phosphate<br />
ATP<br />
Phosphofructokinase<br />
Pyruvate<br />
ADP<br />
ATP<br />
Acetyl CoA<br />
Citrate<br />
Fructose-<br />
1, 6-bisphosphate<br />
Citric<br />
acid<br />
cycle<br />
Allosteric Regulation of Enzymes<br />
Oxidative<br />
phosphorylation<br />
Allosteric regulation is the term used to describe cases where a<br />
Allosteric regulation may either inhibit or stimulate an enzyme’s activity<br />
Allosteric enzyme<br />
with four subunits<br />
Active site<br />
(one of four)<br />
Allosteric activator<br />
stabilizes active form.<br />
Most allosterically regulated enzymes are made from polypeptide subunits<br />
Regulatory<br />
site (one<br />
of four)<br />
Active form<br />
Activator<br />
Stabilized active form<br />
Oscillation<br />
Allosteric inhibitor<br />
stabilizes inactive form.<br />
Nonfunctional<br />
active site<br />
Inactive form Inhibitor Stabilized inactive<br />
form<br />
Allosteric activators and inhibitors
Regulation of <strong>Cellular</strong> <strong>Respiration</strong> via Feedback Mechanisms<br />
–<br />
Glucose<br />
Glycolysis<br />
Fructose-6-phosphate<br />
Phosphofructokinase<br />
AMP<br />
Stimulates<br />
+<br />
–<br />
Inhibits<br />
Fructose-1,6-bisphosphate<br />
Inhibits<br />
Phosphofructokinase is also sensitive to citrate production<br />
in the Krebs Cycle.<br />
Pyruvate<br />
If citrate accumulates in the mitochondria,<br />
ATP<br />
Acetyl CoA<br />
Citrate<br />
Citric<br />
acid<br />
cycle<br />
Oxidative<br />
phosphorylation<br />
Study outline-Chapter 9-<strong>Cellular</strong> <strong>Respiration</strong><br />
-Understand the two common types of fermentation (Fig. 9.18)<br />
-alcohol fermentation<br />
-lactic acid fermentation<br />
-What types of processes use alcohol fermentation?<br />
-Understand how fermentation works in human muscle cells.<br />
-Know terms-anaerobic, fermentation<br />
-What metabolic pathway provides ATP during fermentation?<br />
-Why can’t NAD+ be recycled by the cell under anaerobic conditions?<br />
-What waste product that is produced in the fermentation process in muscle cells?<br />
-What waste products are produced in the fermentation of yeast?<br />
-Understand similarities and differences between fermentation and cellular respiration<br />
-Know terms-obligate anaerobes<br />
-facultative anaerobes (Fig. 9.19)<br />
-Understand the evolutionary significance of glycolysis<br />
-Understand how glycolysis and the citric acid cycle connect to other metabolic pathways (Fig. 9.20)<br />
-Understand the regulation of cellular respiration via feedback mechanisms (Fig. 9.21)<br />
-Know terms-allosteric enzymes