Quiz Ch 6 What molecule does the human body use for energy for all it’s activities? Answers for question 2 and 3 include: carbon dioxide, oxygen, water,

Quiz Ch 6 What molecule does the human body use for energy for all it’s activities? Answers for question 2 and 3 include: carbon dioxide, oxygen, water, glucose, ATP 2. Name one of the molecules (reactants)that the body uses in respiration to make energy. 3. Name one of the products of respiration. 4. What organelle is important for cellular respiration? 5. T/F Redox reactions involve movement of electrons.

Space Plants The following is a transcript of the video clip, which is approximately 3.5 minutes in length. Video Transcript [Narrator] When the first mission to Mars is launched, people will live in space for extended lengths of time. They will need to produce food, water, and oxygen to survive. NASA scientists are experimenting on plants to develop onboard greenhouses that do just that. In one experiment, volunteer Nigel Packham spent two weeks in a pair of airtight containers. Instead of oxygen canisters, wheat plants provided all the air he needed to breathe. [Narrator] Plants absorbed the carbon dioxide Nigel breathed out and used it to produce the oxygen they both needed to survive. This exchange worked even when he exercised. As Nigel used up more oxygen and produced more carbon dioxide, the plants absorbed more carbon dioxide and produced more oxygen. [Packham] “The plants have performed wonderfully. They react very quickly to me being here and to changes in my metabolic output. For example, if I sit on the bicycle and start exercising for 30 minutes, and I tend to put out a lot more carbon dioxide, the plants react very, very rapidly to that. So, it’s almost as if they know I’m here.” [Narrator] After two weeks, the experiment ended and Nigel emerged in good health. The results show that people can depend on plants for oxygen in an artificial environment. Now scientists want to know how long that balance can last. In another experiment, a NASA team manipulates the growing conditions of vegetable-yielding plants. Using artificial nutrients and high-intensity lamps, David Bubenheim grows plants 10 to 20 times more densely then they occur in nature. This is helpful for producing food in very limited spaces. Based on this prototype, they determined the size of a greenhouse needed to support a crew headed for Mars. [Bubenheim] “This chamber is about 200 square feet and for a crew of four people, it would be able to supply and recycle all the air and water but it wouldn’t supply a 100 percent of the food in that case. To do that, you would need an area about four times this large or a chamber about this size per person.” [Narrator] Since areas that large aren’t practical in space, Bubenheim hopes that changing the color of light can solve the problem. Plants used in these experiments gather the energy they need from light rather than sunlight. Changing the color of this light will change the way the plants grow. [Bubenheim] “If you look at these wheat plants that are growing under white light, like plants would outside, where all colors of the spectrum are represented, you can see that there are a number of smaller side shoots that are grown.” [Narrator] Side shoots are waste that has to be recycled, but growing wheat under blue lights eliminates these shoots, leaving the important center shoot unharmed. Red light works in much the same way. [Narrator] Scientists now want to know if the color of light has the same effect on plants other than wheat. If so, they’ll be one step closer to an efficient plant-based system that can support life in space.

Space Plants Why are NASA scientists researching plants as a life-support system for long-term space flight? Why are we talking about plants and how they make oxygen? Checkpoint questions are intended to help your students review the basic terms, facts, and information presented in the video segment. Alternatively, you may find these questions helpful if you have a personal response system integrated into your classroom. Questions and Answers Why are NASA scientists researching plants as a life-support system for long-term space flight? b. Packaged food will require too much room.—Option b is the best answer. For long-term space travel, a life-support system that recycles will require less room and weight than carrying packaged food. Option a may be true, recycling carbon dioxide is only one consideration. Space travelers also require food and oxygen. Option c is not accurate. A plant-based life-support system will require a great deal of monitoring to maintain it at peak operating performance. Although true, Option d is not a serious consideration. Not just any plant will meet the conditions required by a working space station. Option e is not correct because Option b is a reasonable answer to the question.

Sunlight energy ECOSYSTEM Photosynthesis in chloroplasts CO2 Glucose Together, these two processes are responsible for most of the energy needs of life on Earth Plants give off oxygen and we take in oxygen. We use this oxygen along with glucose to make ATP. ATP is one of the products of cellular respiration. + + H2O O2 Cellular respiration in mitochondria Figure 6.1 The connection between photosynthesis and cellular respiration. We all hlive together and actually help each other ATP (for cellular work) Heat energy

Energy flows into an ecosystem as sunlight and leaves as heat
Photosynthesis generates O2 and organic molecules, which are used in cellular respiration Cells use chemical energy stored in organic molecules to regenerate ATP, which powers work Main purpose of cellular respiration is to produce ATP Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Cellular Respiration Reaction
C6H12O6 + 6 O2 6 CO2 + 6 H2O + ATPs Glucose Oxygen Carbon dioxide Water Energy Cellular respiration is a process that releases energy from the bonds in glucose and captures the energy as ATP Cellular respiration produces 38 ATP molecules from each glucose molecule Figure 6.3 Summary equation for cellular respiration: C6H12O6 + 6 O2 6 CO2 + H2O + energy

6.5 Cells tap energy from electrons “falling” from organic fuels to oxygen
The energy necessary for life is contained in the arrangement of electrons in chemical bonds in organic molecules An important question is how do cells extract this energy? Gradually Energy must be added to pull an electron away from an atom, just as energy is required to push a ball uphill. Student Misconceptions and Concerns 1. Students should be cautioned against the assumption that energy is created when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics addressed in Module 5.11). 2. The advantage of the gradual degradation of glucose may not be obvious to some students. Many analogies exist that reveal the advantages of short and steady steps. Fuel in an automobile is burned slowly to best utilize the energy released from the fuel. A few fireplace logs release gradual heat to keep a room temperature steady. In both situations, excessive use of fuel becomes wasteful, reducing the efficiencies of the systems. Copyright © 2009 Pearson Education, Inc.

When the carbon-hydrogen bonds of glucose are broken, electrons are transferred to oxygen Oxygen has a strong tendency to attract electrons _ Remember water? Biochemists say that electrons “fall” to oxygen to indicate that the electrons move down an energy gradient. The shift of electrons from carbon and hydrogen to oxygen provides a more stable state for these atoms. Student Misconceptions and Concerns 1. Students should be cautioned against the assumption that energy is created when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics addressed in Module 5.11). 2. The advantage of the gradual degradation of glucose may not be obvious to some students. Many analogies exist that reveal the advantages of short and steady steps. Fuel in an automobile is burned slowly to best utilize the energy released from the fuel. A few fireplace logs release gradual heat to keep a room temperature steady. In both situations, excessive use of fuel becomes wasteful, reducing the efficiencies of the systems. + + Copyright © 2009 Pearson Education, Inc.

Energy can be released from glucose by simply burning it The energy is dissipated as heat and light and is not available to living organisms With burning, energy is released from glucose all at once, and cannot be harnessed for cellular work. Student Misconceptions and Concerns 1. Students should be cautioned against the assumption that energy is created when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics addressed in Module 5.11). 2. The advantage of the gradual degradation of glucose may not be obvious to some students. Many analogies exist that reveal the advantages of short and steady steps. Fuel in an automobile is burned slowly to best utilize the energy released from the fuel. A few fireplace logs release gradual heat to keep a room temperature steady. In both situations, excessive use of fuel becomes wasteful, reducing the efficiencies of the systems. Copyright © 2009 Pearson Education, Inc.

On the other hand, cellular respiration is the controlled breakdown of organic molecules Energy is released in small amounts that can be captured by a biological system and stored in ATP In respiration, organic fuels are broken down in a series of steps, each one catalyzed by an enzyme. Student Misconceptions and Concerns 1. Students should be cautioned against the assumption that energy is created when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics addressed in Module 5.11). 2. The advantage of the gradual degradation of glucose may not be obvious to some students. Many analogies exist that reveal the advantages of short and steady steps. Fuel in an automobile is burned slowly to best utilize the energy released from the fuel. A few fireplace logs release gradual heat to keep a room temperature steady. In both situations, excessive use of fuel becomes wasteful, reducing the efficiencies of the systems. Copyright © 2009 Pearson Education, Inc.

A cellular respiration equation is helpful to show the changes in hydrogen atom distribution Glucose loses its hydrogen atoms and is ultimately converted to CO2 At the same time, O2 gains hydrogen atoms and is converted to H2O Loss of electrons is called oxidation Gain of electrons is called reduction The movement of electrons is called an oxidation-reduction or redox reaction. The combustion of gasoline in an automobile engine is also a redox reaction: the energy released pushes the pistons. Our main energy foods are carbohydrates and fats because they are reservoirs of large numbers of electrons associated with hydrogen. You may want to tell your students that a hydrogen atom consists of an electron and a proton, and although we have only considered the electron up to now, the proton becomes important later in the synthesis of ATP. Student Misconceptions and Concerns 1. Students should be cautioned against the assumption that energy is created when it is converted from one form to another. This might be a good time to review the principle of conservation of energy (the first law of thermodynamics addressed in Module 5.11). 2. The advantage of the gradual degradation of glucose may not be obvious to some students. Many analogies exist that reveal the advantages of short and steady steps. Fuel in an automobile is burned slowly to best utilize the energy released from the fuel. A few fireplace logs release gradual heat to keep a room temperature steady. In both situations, excessive use of fuel becomes wasteful, reducing the efficiencies of the systems. Redox Copyright © 2009 Pearson Education, Inc.

NADH ATP NAD+ + 2e– Controlled release of H+ energy for synthesis
of ATP H+ Electron transport chain Figure 6.5C In cellular respiration, electrons fall down an energy staircase and finally reduce O2. 2e– H+ 1  2 O2 H2O

Reduced or oxidized? NADH NAD+ ATP + 2e– Controlled release of energy for synthesis of ATP H+ Electron transport chain Figure 6.5C In cellular respiration, electrons fall down an energy staircase and finally reduce O2. 2e– H+ 1  2 O2 Reduced or oxidized? Redox reactions involve the transfer of electrons H2O

The Stages of Cellular Respiration: A Preview
Cellular respiration has three stages: Glycolysis (breaks down glucose into two molecules of pyruvate) The citric acid cycle (completes the breakdown of glucose) Oxidative phosphorylation/chemiosmosis (accounts for most of the ATP synthesis) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

High-energy electrons
NADH High-energy electrons carried by NADH Mitochondrion NADH FADH2 and GLYCOLYSIS OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis) CITRIC ACID CYCLE Glucose Pyruvate animation Cytoplasm Inner mitochondrial membrane Figure 6.6 An overview of cellular respiration. CO2 CO2 ATP ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation Oxidative phosphorylation

Glycolysis What goes in . . . What comes out . . . Net 2 ATP produced
2 Pyruvate + 2 ATP + 2 NADH Glucose Pyruvate and NADH will continue on in respiration to be the reactants of subsequent reactions i.e. - The Citric Acid Cycle The cell is very efficient and recycles molecules again and again

Glycolysis Know this figure Glucose 2 ADP 2 NAD+ + 2 P 2 NADH 2 ATP +
Figure 6.7A An overview of glycolysis. 2 Pyruvate

6.8 Pyruvate is chemically groomed for the citric acid cycle
The pyruvate formed in glycolysis is transported to the mitochondria, where it is prepared for entry into the citric acid cycle Acetyl CoA (coenzyme A) + CO2 Pyruvate Coenzyme A is abbreviated CoA and is the molecule that shuttles fuel into the citric acid cycle. Student Misconceptions and Concerns 1. Perhaps more than anywhere else in general biology, students studying aerobic metabolism may fail to see the forest for the trees. Students may focus on the details of each stage of aerobic metabolism and devote little attention to the overall process and products. Consider emphasizing the products and energy yields associated with glycolysis, the citric acid cycle, and oxidative phosphorylation before detailing the specifics of each reaction. 2. The location within a cell in which each reaction takes place is often forgotten in the details of the chemical processes, but it is important to emphasize. Consider using Figure 6.12 as a common reference to locate each stage as you discuss the details of cellular respiration. 3. Students frequently think that plants have chloroplasts instead of mitochondria. Take care to point out the need for mitochondria in plants when photosynthesis is not efficient or possible (such as during the night). Teaching Tips 1. The production of NADH through glycolysis and the Krebs cycle, as compared to the direct production of ATP, can get confusing for students. Help students understand that NADH molecules have a value to be cashed in by the electron transport chain. The NADH can therefore be thought of as casino chips, accumulated along the way to be cashed in at the electron transport cashier. Acetyl CoA enters the citric acid cycle CO2 is released by lungs Copyright © 2009 Pearson Education, Inc.

CITRIC ACID CYCLE Acetyl CoA CoA CoA 2 CO2 3 NAD+ FADH2 FAD 3 NADH 
Figure 6.9A An overview of the citric acid cycle: Two carbons enter the cycle through acetyl CoA, and 2 CO2, 3 NADH, 1 FADH2, and 1 ATP exit the cycle. Asetil E as in pet FAD 3 NADH  3 H+ ATP ADP + P

Citric Acid Cycle What goes in . . . What comes out . . .
Net 2 ATP produced (1 per each Acetyl CoA molecule) 1Acetyl CoA + 1Oxaloacetate 1Oxaloacetate + 1ATP + 3NADH + 1 FADH + 2CO2 Oxaloacetate is the reactant for the next cycle of the citric acid cycle NADH and FADH will continue on in respiration to be reactants of the next reaction i.e. – Oxidative Phosphorylation

So far, from 1 molecule of glucose,
We have produced 10 NADH (2 from glycolysis, 2 from pyruvate processing, 6 from citric acid cycle) 2 FADH 4 ATP NADH and FADH are our electron carriers that we have been building up in order to enter oxidative phosphorylation phase They will now enter that process and fulfill their purpose: They have been carrying high energy electrons. They will now donate these electrons to produce ATP

NADH High-energy electrons carried by NADH Mitochondrion NADH FADH2 and GLYCOLYSIS OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis) CITRIC ACID CYCLE Glucose Pyruvate animation animation Cytoplasm Inner mitochondrial membrane Figure 6.6 An overview of cellular respiration. CO2 CO2 ATP ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation Oxidative phosphorylation

Electrons: Stair Stepping Down in Energy
As each electron is passed from protein complex to protein complex it loses energy The energy is used to pump H+ ions across the membrane to form a gradient Each electron steps down an “energy stair” with each passage Until it reaches its final destination and it accepted by oxygen Oxygen will simultaneously accept the electrons and the H+ ions to form water

of ATP H+ Electron transport chain Figure 6.5C In cellular respiration, electrons fall down an energy staircase and finally reduce O2. 2e– H+ 1  2 O2 H2O

During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis
Following glycolysis and the citric acid cycle, NADH and FADH2 account for most of the energy extracted from food These two electron carriers donate electrons to the electron transport chain, which powers ATP synthesis via oxidative phosphorylation For the Cell Biology Video ATP Synthase 3D Structure — Side View, go to Animation and Video Files. For the Cell Biology Video ATP Synthase 3D Structure — Top View, go to Animation and Video Files. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Know this figure NADH NAD+ ATP + 2e– Controlled release of energy for synthesis of ATP H+ Electron transport chain Figure 6.5C In cellular respiration, electrons fall down an energy staircase and finally reduce O2. 2e– H+ 1  2 O2 H2O

The Pathway of Electron Transport
The electron transport chain is in the cristae of the mitochondrion The carriers accept and donate electrons Electrons are finally passed to O2, forming H2O Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The electron transport chain generates no ATP
Electrons are transferred from NADH or FADH2 to the electron transport chain The electron transport chain generates no ATP The chain’s function is to break the release of energy into smaller steps that release energy in manageable amounts Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Chemiosmosis: The Energy-Coupling Mechanism
Electron transfer in the electron transport chain causes proteins to pump H+ from the mitochondrial matrix to the intermembrane space H+ then moves back across the membrane, passing through channels in ATP synthase ATP synthase uses the exergonic flow of H+ to drive phosphorylation of ATP This is an example of chemiosmosis, the use of energy in a H+ gradient to drive cellular work Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

i INTERMEMBRANE SPACE H+ Stator Rotor Internal rod Cata- lytic knob
Fig. 9-14 INTERMEMBRANE SPACE H+ Stator Rotor Internal rod Cata- lytic knob Figure 9.14 ATP synthase, a molecular mill ADP + P ATP i MITOCHONDRIAL MATRIX

OXIDATIVE PHOSPHORYLATION
Potential energy from electrons is used to synthesize ATP Electrons in NADH and FADH contain potential energy. This energy is used to pump H+ ions across the membrane. The H+ gradient contains potential energy. This energy is used to activate ATP synthase. ATP synthase converts this energy and stores it in the form of ATP. H+ H+ H+ H+ H+ Protein complex of electron carriers H+ H+ Electron carrier H+ H+ ATP synthase Intermembrane space Inner mitochondrial membrane Figure 6.10 Oxidative phosphorylation, using electron transport and chemiosmosis in the mitochondrion. FADH2 FAD Electron flow NADH NAD+ 2  1 O2 + 2 H+ H+ Mitochondrial matrix H+ ADP + H+ P ATP H2O H+ Electron Transport Chain Chemiosmosis OXIDATIVE PHOSPHORYLATION

Many poisons and antibiotics affect the electron transport chain.
What would happen to a human or a bacteria if you stopped ATP synthase? One of the electron transporters?

Reviewing the big picture
C6H12O6 + 6 O2 6 CO2 + 6 H2O + ATPs Glucose Oxygen Carbon dioxide Water Energy Know the overall equation for cellular respiration Where do each of these reactants get consumed? Where are the products produced? 38 ATP from each glucose molecule in aerobic respiration Oxygen consumed as last electron acceptor Co2 produced in pyruvate grooming and citric acid cycle H2O produced when O2 accepts electrons and H come across gradient 2ATP produced in glycolysis, 2 ATP in cirtic acid and 34 atp in electron transport NADH = 3 ATP FADH = 2 ATP

How many calories are released when 1 gram of glucose is completely broken down in the presence of oxygen? Each gram of sugar can provide 1.2 X ATP or 4 calories Each gram of fat can provide 2.7 X ATP or 9 calories So. . . it is much harder to burn off a pound of fat because it can contain so many calories. It produces more than two times the amount of ATP.

How many calories do you have to burn to lose a pound?
It is commonly said that a gram of fat contains 9 calories. But there are 454 grams in a pound, and 9 x 454 = 4086 calories, not 3500. The reason for the discrepancy is that body fat, or adipose tissue, contains not only fat, but also other substances including protein, connective tissue, and water. The dietary fat referred to in the nutritional analysis of food is pure.

Counting Calories

Low carb diets Low carb diets are based on the theory that restricting the amount of carbohydrates you eat will cause your body to burn fat to obtain the energy it needs. When we eat, our bodies convert digestible carbohydrates into blood sugar (glucose), our main source of energy, which is stored in our liver as glycogen. When we greatly restrict our intake of carbohydrates, to the point where our liver's store of glycogen is depleted and our bodies do not find the usual source of energy readily available, they turn to our fat stores.

Low carb diets Through a process called ketosis, our body fat is "burned" or turned into fuel to provide the energy we need. Our bodies run on ketones instead of blood sugar. Ketosis is related to halitosis (acetone) Do low carb diets work in the long run? Huge amounts of fat and protein Increased cholesterol, kidney stones, decreased bone density In the first week or two of a low-carbohydrate diet a great deal of the weight loss comes from eliminating water Body can still use proteins and fats that you are eating for energy

At Atkins, we believe in science - the science it took to develop our program, the science that backs it up and the scientific approach we use to continually improve everything we do. Our NEW and evolved diet is not the often perceived "all you can eat -- bacon, egg, and cheese diet” or the "NO CARBS DIET" as some would have you believe; but instead; Atkins is a diet rooted in the science of eating fewer refined carbohydrates and refined sugars – what we refer to as “bad carbs.” As you will discover, the new Atkins Diet is an optimally balanced lifetime eating plan with the flexibility to meet each individual’s unique physical condition addressing factors such as age, gender, level of physical activity, and metabolic rate. The lifetime eating plan incorporates "ALL" food groups while focusing on eating some of the best foods on earth.

Dr Atkins dies in 2003 He is credited with revolutionizing the diet world with his theory that you can lose weight by eating fat, and his followers hailed him as a pioneer. His critics accused him of selling a dangerous idea, but Atkins dismissed their claims. Atkins' diet books were some of the best-selling books of all time. "See, that's a big mistake ... to tell people to restrict calories," Atkins told CNN in January. "They lose the weight, they feel fine, then they get to their goal weight and they still have 60 more years to live, and are they going to go hungry for all 60 years?" Atkins was a cardiologist and businessman, selling supplements and food on his Web site and at the Atkins Center for Complementary Medicine. All of his best-selling diet books promoted the same philosophy: a diet high in fat and protein and low in carbohydrates is a sure way to lose weight. "It's not that it needs to be low-calorie. As long as you cut out the carbohydrate the weight loss is automatic," Atkins said.

Food, such as peanuts Carbohydrates Fats Proteins Sugars Glycerol
Fatty acids Amino acids Amino groups OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis) Figure 6.15 Pathways that break down various food molecules. CITRIC ACID CYCLE Acetyl CoA Glucose G3P Pyruvate GLYCOLYSIS ATP

Is fermentation your friend?
Figure 6.13C Fermentation vats for wine.

6.13 Fermentation enables cells to produce ATP without oxygen
Fermentation occurs if there is not enough oxygen to undergo cellular respiration It is Plan B for our cells and used as a last resort because it is less efficient at producing ATP Fermentation is an anaerobic (without oxygen) energy-generating process It takes advantage of glycolysis, producing two ATP molecules and reducing NAD+ to NADH The trick is to oxidize the NADH without passing its electrons through the electron transport chain to oxygen Fermentation captures significantly less energy from a glucose molecule than is captured from glucose through respiration. Student Misconceptions and Concerns 1. Perhaps more than anywhere else in general biology, students studying aerobic metabolism may fail to see the forest for the trees. Students may focus on the details of each stage of aerobic metabolism and devote little attention to the overall process and products. Consider emphasizing the products and energy yields associated with glycolysis, the citric acid cycle, and oxidative phosphorylation before detailing the specifics of each reaction. 2. The location within a cell in which each reaction takes place is often forgotten in the details of the chemical processes, but it is important to emphasize. Consider using Figure 6.12 as a common reference to locate each stage as you discuss the details of cellular respiration. 3. Students frequently think that plants have chloroplasts instead of mitochondria. Take care to point out the need for mitochondria in plants when photosynthesis is not efficient or possible (such as during the night). 4. Students may expect that fermentation will produce alcohol and maybe even carbon dioxide. Take the time to clarify the different possible products of fermentation and correct this general misconception. Teaching Tips 1. The text notes that some microbes are useful in the dairy industry because they produce lactic acid. However, the impact of acids on milk may not be obvious to many students. Consider a simple demonstration mixing about equal portions of milk (skim or 2%) with some acid (vinegar will work). Notice the accumulation of strands of milk curd (protein) on the side of the container and stirring device. 2. Dry wines are produced when the yeast cells use up all or most of the sugar available. Sweet wines result when the alcohol accumulates enough to inhibit fermentation before the sugar is depleted. 3. Exposing fermenting yeast to oxygen will slow or stop the process, because the yeast will switch back to aerobic respiration. When fermentation is rapid, the carbon dioxide produced drives away the oxygen immediately above the wine. However, as fermentation slows down, the wine must be sealed to prevent oxygen exposure and permit the fermentation process to finish. Copyright © 2009 Pearson Education, Inc.

Your muscle cells and certain bacteria can oxidize NADH through lactic acid fermentation NADH is oxidized to NAD+ when pyruvate is reduced to lactate In a sense, pyruvate is serving as an “electron sink,” a place to dispose of the electrons generated by oxidation reactions in glycolysis Fermentations are used by the dairy industry to make cheese and yogurt, while other industries produce soy sauce and sauerkraut through fermentation reactions. Student Misconceptions and Concerns 1. Perhaps more than anywhere else in general biology, students studying aerobic metabolism may fail to see the forest for the trees. Students may focus on the details of each stage of aerobic metabolism and devote little attention to the overall process and products. Consider emphasizing the products and energy yields associated with glycolysis, the citric acid cycle, and oxidative phosphorylation before detailing the specifics of each reaction. 2. The location within a cell in which each reaction takes place is often forgotten in the details of the chemical processes, but it is important to emphasize. Consider using Figure 6.12 as a common reference to locate each stage as you discuss the details of cellular respiration. 3. Students frequently think that plants have chloroplasts instead of mitochondria. Take care to point out the need for mitochondria in plants when photosynthesis is not efficient or possible (such as during the night). 4. Students may expect that fermentation will produce alcohol and maybe even carbon dioxide. Take the time to clarify the different possible products of fermentation and correct this general misconception. Teaching Tips 1. The text notes that some microbes are useful in the dairy industry because they produce lactic acid. However, the impact of acids on milk may not be obvious to many students. Consider a simple demonstration mixing about equal portions of milk (skim or 2%) with some acid (vinegar will work). Notice the accumulation of strands of milk curd (protein) on the side of the container and stirring device. 2. Dry wines are produced when the yeast cells use up all or most of the sugar available. Sweet wines result when the alcohol accumulates enough to inhibit fermentation before the sugar is depleted. 3. Exposing fermenting yeast to oxygen will slow or stop the process, because the yeast will switch back to aerobic respiration. When fermentation is rapid, the carbon dioxide produced drives away the oxygen immediately above the wine. However, as fermentation slows down, the wine must be sealed to prevent oxygen exposure and permit the fermentation process to finish. Copyright © 2009 Pearson Education, Inc.

Glucose 2 NAD+ 2 ADP During intense exercise, this lactic is produced faster than is can be removed from the muscles, used to be thought this is what made you sore the next day  2 P GLYCOLYSIS 2 ATP 2 NADH 2 Pyruvate 2 NADH Figure 6.13A Lactic acid fermentation oxidizes NADH to NAD+ and produces lactate. 2 NAD+ 2 Lactate Lactic acid fermentation

Lactic Acid Fermentation
What goes in . . . What comes out . . . Net 2 ATP produced How many ATP are produced with respiration? 1 glucose+ 2 NAD+ 2 Lactate + 2ATP + 2NADH Compare this to respiration in which 38 ATP are produced for each molecule of glucose

Are you a better sprinter or distance runner?
It is generally accepted that muscle fiber types can be broken down into two main types: slow twitch muscle fibers and fast twitch muscle fibers Human muscles contain a genetically determined mixture of both slow and fast fiber types, usually about 50/50 but the percentage of muscle fiber type varies from person to person

Nick Harrison wins the Melbourne Marathon
Distance runners The slow twitch muscles are more efficient at using oxygen to generate more ATP This allows continuous, extended muscle contractions over a long time They fire more slowly than fast twitch fibers and can go for a long time before they fatigue Therefore, slow twitch fibers are great at helping athletes run marathons and bicycle for hours Nick Harrison wins the Melbourne Marathon theage.com What type of energy making process are slow twitch muscles using?

Sprinters/body builders
Fast twitch fibers use anaerobic metabolism to create fuel Much better at generating short bursts of strength or speed than slow muscles. They fatigue more quickly. Fast twitch fibers generally produce the same amount of force per contraction as slow muscles, but they get their name because they are able to fire more rapidly. They are not effective in longer-term training, but are very useful in brief, high-intensity training like we see in sprinting, bodybuilding, or powerlifting What type of energy making process are slow twitch muscles using? Fermentation or respiration?

Are Athletes Born or Built? Can Training Change Fiber Type?
Fiber type is part of a great athlete's success, but it alone is a poor predictor of performance. There are many other factors that go into determining athleticism, including mental preparedness, proper nutrition and hydration, getting enough rest, and having appropriate equipment and conditioning. Genetically determined lugn capacity and cardiac output Jury is still out on whether certain types of traing can change muscle fiber type

Do you like the white or the dark meat?
Chickens have fast and slow twitch muscle, too Dark meat, like in the drumstick, is mostly made up of slow twitch fibers Chickens use their legs for walking and standing, which they do for extended periods White meat, like in chicken wings and breasts, is mostly made up of fast twitch muscle They use their wings for quick bursts of flight

White or dark meat? WikiAnswers
Are chicken wings considered dark meat? White vs. Dark Chicken Meat Chicken wings, like the breast, are white meat. Chicken wings are white meat. I worked at KFC (management) for nearly 10 years. Wings are white meat!

The baking and winemaking industry have used alcohol fermentation for thousands of years Yeasts are single-celled fungi that not only can use respiration for energy but can ferment under anaerobic conditions They convert pyruvate to CO2 and ethanol while oxidizing NADH back to NAD+ The carbon dioxide provides the bubbles in beer and champagne and also the bubbles in dough that cause bread to rise. Student Misconceptions and Concerns 1. Perhaps more than anywhere else in general biology, students studying aerobic metabolism may fail to see the forest for the trees. Students may focus on the details of each stage of aerobic metabolism and devote little attention to the overall process and products. Consider emphasizing the products and energy yields associated with glycolysis, the citric acid cycle, and oxidative phosphorylation before detailing the specifics of each reaction. 2. The location within a cell in which each reaction takes place is often forgotten in the details of the chemical processes, but it is important to emphasize. Consider using Figure 6.12 as a common reference to locate each stage as you discuss the details of cellular respiration. 3. Students frequently think that plants have chloroplasts instead of mitochondria. Take care to point out the need for mitochondria in plants when photosynthesis is not efficient or possible (such as during the night). 4. Students may expect that fermentation will produce alcohol and maybe even carbon dioxide. Take the time to clarify the different possible products of fermentation and correct this general misconception. Teaching Tips 1. The text notes that some microbes are useful in the dairy industry because they produce lactic acid. However, the impact of acids on milk may not be obvious to many students. Consider a simple demonstration mixing about equal portions of milk (skim or 2%) with some acid (vinegar will work). Notice the accumulation of strands of milk curd (protein) on the side of the container and stirring device. 2. Dry wines are produced when the yeast cells use up all or most of the sugar available. Sweet wines result when the alcohol accumulates enough to inhibit fermentation before the sugar is depleted. 3. Exposing fermenting yeast to oxygen will slow or stop the process, because the yeast will switch back to aerobic respiration. When fermentation is rapid, the carbon dioxide produced drives away the oxygen immediately above the wine. However, as fermentation slows down, the wine must be sealed to prevent oxygen exposure and permit the fermentation process to finish. Copyright © 2009 Pearson Education, Inc.

Alcoholic Fermentation
What goes in . . . What comes out . . . Net 2 ATP produced How many are produced with respiration? 1 glucose+ 2 NAD+ 2 Ethanol + 2 CO2+ 2ATP + 2NADH Compare this to respiration in which 38 ATP are produced for each molecule of glucose

Glucose 2 ADP 2 NAD+  2 P 2 ATP 2 NADH 2 Pyruvate 2 NADH 2 CO2
GLYCOLYSIS 2 ATP 2 NADH 2 Pyruvate 2 NADH 2 CO2 released Figure 6.13B Alcohol fermentation oxidizes NADH to NAD+ and produces ethanol and CO2. 2 NAD+ 2 Ethanol Alcohol fermentation

Alcoholic Beverages Made by fermentation Beer, wine
The chemical reaction of yeast on sugars Harvesting hops Beers Most beers are made from barley malt Ground up malt is added to barley to make mash Mash is combined with the flavoring, hops, and fermentation begins The fermentation can last for several weeks Can use open fermentation and rely on vigorous yeast action to produce a protective CO2 blanket The average beer is somewhere between 2-6% alcohol

Wine Made from grapes Crush grapes Ferment the juices Most wines are ferment for 4 years or more Contain 7-24% alcohol Why do beer/wine fermentation reactions have to take place in areas without oxygen? Why does wine have a higher alcohol percentage than beer?

Wine Made from grapes Crush grapes Ferment the juices Most wines are ferment for 4 years or more Contain 7-24% alcohol If oxygen were present than yeast would use the far more efficient mechanism of respiration The yeasts differ. Most beer yeasts cannot tolerate high concentrations of alcohol. When a brewer wants to ferment a high-alcohol beer, he uses a champagne yeast or specially-bred yeast to finish the fermentation.

There will be a quiz next class. It will cover chapters 5 and 6.

Quiz Ch 6 What molecule does the human body use for energy for all it’s activities? Answers for question 2 and 3 include: carbon dioxide, oxygen, water,

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Presentation on theme: "Quiz Ch 6 What molecule does the human body use for energy for all it’s activities? Answers for question 2 and 3 include: carbon dioxide, oxygen, water,"— Presentation transcript:

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Quiz Ch 6 What molecule does the human body use for energy for all it’s activities? Answers for question 2 and 3 include: carbon dioxide, oxygen, water,

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Presentation on theme: "Quiz Ch 6 What molecule does the human body use for energy for all it’s activities? Answers for question 2 and 3 include: carbon dioxide, oxygen, water,"— Presentation transcript:

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About project

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