How do living organisms fuel their actions Cellular

How do living organisms fuel their actions? Cellular respiration

Cellular Respiration Harvesting Chemical Energy ATP

Cellular Respiration (1) fuel and (2) oxygen. q Potential energy stored in chemical bonds of sugar, protein, and fat molecules. q Breaks bonds to release the high-energy electrons captured in ATP. q Oxygen is electron magnet. q Requires

Cellular Respiration

Photosynthesis Cellular Respiration Function Energy Storage Energy Release Location Chloroplasts Mitochondria Reactants CO 2 and H 2 O C 6 H 12 O 6 and O 2 Products C 6 H 12 O 6 and O 2 CO 2 and H 2 O Equation 6 CO 2 + 6 H 2 O C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O

Clarification - Two Types of Respiration • External – exchange of gases through breathing (O 2 in, CO 2 out) • Internal/Cellular – breakdown of food with or without O 2 to produce ATP for the cell

Conversion of Energy • Energy is the ability to do work • 1 st Law of Thermodynamics: Energy cannot be created or destroyed, but can be inter-converted

What is energy in biology? ATP HOT stuff!!!

• All organisms are energy consumers – What do we need energy for? • • • synthesis (building for growth) reproduction active transport movement temperature control (making heat)

Where do we get energy? • Energy is stored in organic molecules – carbohydrates, fats, proteins • Animals eat these organic molecules food – digest food to get • fuels for energy (ATP) • raw materials for building more molecules – carbohydrates, fats, proteins, nucleic acids • Plants break down the food they produced in photosynthesis ATP

What is Cellular Respiration? • The process in which organisms take molecules broken down from food and release the chemical energy stored in the chemical bonds of those molecules. • It’s important to remember that food is not the direct source of energy. • The energy that is released from chemical bonds during cellular respiration is stored in molecules of ATP.

Food Is Used to Power the Operations of Life 1. ATP is the energy unit of the cell. 2. Food is “burned” in the cell to produce ATP. 3. 3 mechanisms exist to produce ATP. 4. Different foods can be inter-converted and used for energy or stored.

Energy Is Created During Internal Respiration • True • False

When water moves through a hydroelectric power plant some of the energy of the water A. B. C. D. is lost is converted into electrical energy Is converted into ATP disappears

What do we need to make energy? • The “Furnace” for making energy – mitochondria • Fuel – food: carbohydrates, fats, proteins • Helpers – oxygen – enzymes food • Product enzymes – ATP • Waste products – carbon dioxide • then used by plants – water O 2 ATP CO 2 H 2 O

Mitochondria are everywhere!! animal cells plant cells

Using ATP to do work? Can’t store ATP § too unstable § only used in cell that produces it § only short term energy storage § carbohydrates & fats are long term energy storage ATP Adenosine Tri. Phosphate work Adenosine Di. Phosphate ADP A working muscle recycles over 10 million ATPs per second

ATP-ADP Interconversion Energy for Cell Adenine O P P Energy from Glucose Adenine O P P

A Body’s Energy Budget 1 make energy ATP eat food 2 3 synthesis (building) storage { { { • energy needed even at rest • activity • temperature control • growth • reproduction • repair • glycogen (animal starch) • fat

Which of the following is a form of energy used directly by organisms for its processes? A. B. C. D. NADH ATP Carbohydrates Fats

It is necessary for a cell to convert sugars into ATP and NADH because: A. B. C. D. Sugar is unstable in the cell ATP and NADH are easier to use by the cell The cell gains energy in this process The cell needs water and CO 2 that this process releases.

Food Can be “Burned” to Produce ATP Burning of Food to produce ATP is called

The Cellular Respiration Equation C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + energy (ATP) Glucose carbon dioxide water oxygen Notice that the cellular respiration equation is the breakdown of those molecules made through photosynthesis and that it also uses the waste products of photosynthesis. Notice that photosynthesis uses those products made by cellular respiration.

Cellular Respiration and Photosynthesis This is representative of a cycle.

• Overall, cellular respiration is a process that is aerobic. Aerobic means that it requires the presence of oxygen. • Some steps within the process of cellular respiration do not require the presence of oxygen and are therefore anaerobic.

Where does cellular respiration occur? • Cellular respiration takes place in the mitochondria of the eukaryotic cell. • Recall that the mitochondria is considered to be the “powerhouse” of the cell because it produces the majority of a cell’s ATP.

Energy Carriers Found in Cellular Respiration • ATP • NADH (similar to NADPH in photosynthesis) • FADH 2

In eukaryotic cells, respiration has three stages: • Glycolysis Glucose 2 Pyruvate 2 NADH 2 ATP • Kreb’s Cycle Pyruvate • Electron Transport Chain 34 ATP NADH/FADH 2 4 NADH 1 FADH 2 2 ATP Oxygen not required Oxygen required

Cellular Respiration Cellular respiration breaks down into these major steps. 1. Glycolysis (anaerobic) 2. Krebs Cycle (aerobic) 3. Electron Transport Chain (aerobic)

The first step of cellular respiration: glycolysis is the universal energy-releasing pathway. Glycolysis: the universal energy-releasing pathway

1. Glycolysis Glyco - glucose/sugar Lysis – to break • • • Makes ATP in all cells that use glucose for food Glycolysis takes place in the cytoplasm of the cell Energy in glucose bonds is captured in several steps Each step is catalyzed by an enzyme Energy is stored in chemical bonds of ATP, NADH and pyruvate • Oxygen is not required.

A glucose molecule has bonds that contain a lot of energy

The energy of glucose bonds is stored in different chemicals in the cell Pyruvate NADH ATP Glycolysis – step by step breaking of glucose bonds

In eukaryotic cells, respiration has three stages: • 1. Glycolysis Glucose 2 Pyruvate 2 NADH 2 ATP • 2. Kreb’s Cycle Pyruvate • 3. Electron Transport Chain NADH/FADH 2 4 NADH 1 FADH 2 2 ATP 34 ATP Oxygen not required Oxygen required

The second step of cellular respiration: the Krebs cycle extracts energy from sugar.

What moves on to the next Stage? Pyruvic acid is the main goal of glycolysis and these molecules will move on to the Krebs Cycle. Pyruvic Acid NADH ATP Krebs Cycle ETC (Electron Transport Chain) Usable Energy

Though the Krebs cycle does not directly require oxygen, it can only take place when oxygen is present because it relies on by-products from the electron transport chain, which requires oxygen. The Krebs cycle is therefore an aerobic process.

In eukaryotic cells, respiration has three stages: • Glycolysis Glucose 2 Pyruvate 2 NADH 2 ATP • Kreb’s Cycle Pyruvate • Electron Transport Chain 34 ATP NADH/FADH 2 4 NADH 1 FADH 2 2 ATP Oxygen not required Oxygen required

The third step in cellular respiration: ATP is built in the electron transport chain.

FIGURE 4. 36

What is the starting point of glycolysis? A. B. C. D. E. Glucose Oxygen ATP Pyruvate C and D

What is the ending point of glycolysis? A. B. C. D. E. Glucose Oxygen ATP Pyruvate C and D

When glucose is broken down, where does its energy go? A. B. C. D. It is lost Into the cell Into other energy containing compounds Into the mitochondria

What types of cells use glycolysis? A. B. C. D. All types Eukaryotic cells only Only those that use glucose for food Prokaryotic cells only

Practice Questions 1 1. 2. 3. 4. 5. 6. 7. 8. 9. What are the four main points in how energy is obtained from food? Describe an example of the 1 st Law of Thermodynamics. What are the functions in an organism that require ATP? How do external and internal respiration differ? How are they similar? What are three stages of cellular respiration? What is the purpose of glycolysis and where does it occur? What are the beginning and ending substances in glycolysis? If a starch molecule containing 100 glucose units is fully broken down by glycolysis, how many ATP molecules will be produced? What is the relationship between glucose, ADP and ATP, and glycolysis?

After Glycolysis What Happens? Glycolysis If O 2 is not present Fermentation If O 2 is present Krebs Cycle Aerobic Respiration

Anaerobic Respiration and Fermentation • Glycolysis does not require oxygen and so is known as ANAEROBIC respiration. • It is only able to capture some of the energy of glucose. • Many organisms continue to break down the glucose even more using oxygen • But some organisms cannot do this and so further processes to extract more energy from glucose after glycolysis. This is called FERMENTATION

Chemical Formula of Fermentation C 6 H 12 O 6 + 6 O 2 6 CO 2 + ATP + Lactic Acid or Ethanol

Lactic Acid When you are exercising and your muscles begin to burn, it is because your cells are not getting enough oxygen and they are producing ATP by fermentation. The burn you feel is lactic acid buildup.

Good things can be made by fermenting micro-organisms Bread rises because of CO 2 produced by yeast Yeast produces ethanol (alcohol) in wine and beer

4. 16 Beer, wine, and spirits are by -products of cellular metabolism in the absence of oxygen.

Take-home message 4. 16 q Oxygen deficiency limits the breakdown of fuel because the electron transport chain requires oxygen as the final acceptor of the electrons generated during glycolysis and the Krebs cycle.

Take-home message 4. 16 q When oxygen is unavailable, yeast resort to fermentation, in which they use a different electron acceptor, pyruvate, generating ethanol in the process, the alcohol in beer, wine, and spirits.

4. 17 Eating a complete diet: cells can run on protein and fat as well as on glucose.

Take-home message 4. 17 q Humans and other organisms have metabolic machinery that allows them to extract energy and other valuable chemicals from proteins, fats, and carbohydrates in addition to the simple sugar, glucose.

Anaerobic respiration is a type of process that: A. B. C. D. Requires oxygen Produces a great deal of ATP Occurs only in complex organisms Requires no oxygen

The purpose of fermentation is to: A. Capture more energy from glucose B. Make alcohol and lactic acid C. Completely break down glucose into carbon dioxide. D. Allow people to make bread and beer

Which of the following is NOT a part of the fermentation process? A. B. C. D. Oxygen Carbon Dioxide Lactic acid ATP

After Glycolysis What Happens? Glycolysis If O 2 is not present Fermentation If O 2 is present Krebs Cycle Aerobic Respiration

The Aerobic Pathway

Glycolysis and fermentation cannot produce enough ATP to sustain complex organisms To get all the energy out of the bonds of glucose, organisms have evolved a process which uses oxygen to fully oxidize glucose – AEROBIC respiration.

Aerobic Respiration • Occurs in the mitochondria of all eukaryotic cells • Requires oxygen • Produces 36 ATP for each molecule of glucose used • Consists of Kreb’s Cycle and the Electron Transport Chain (ETC)

Mitochondrion – where aerobic respiration occurs

Kreb’s Cycle • Starts with pyruvate from glycolysis • Completes the breakdown of glucose into carbon dioxide • Captures energy of glucose molecule in NADH, FADH 2 and ATP

Kreb’s (Citric Acid) Cycle NADH Sugar + O 2 NADH FADH 2 NADH CO 2+ H 2 O Results: 1 cycle = 3 NADH 2 + 1 FADH 2

In what organelle does aerobic respiration take place? A. B. C. D. Nucleus Lysosome Ribosome Mitochondrion

Which of the following is not a part of aerobic respiration? A. Glycolysis B. Kreb’s Cycle C. Electron Transport Chain

Which of the following is NOT an end product of Kreb’s Cycle? A. B. C. D. Pyruvate FADH 2 NADH CO 2

What is the function of Kreb’s Cycle? A. B. C. D. To produce CO 2 To efficiently extract energy from pyruvate To quickly burn glucose To prevent fermentation from happening

Electron Transport Chain

What is the purpose of the electron transport chain? A. B. C. D. To produce ATP To produce water To produce CO 2 To produce glucose

Which of the following chemicals are not required for ATP production in the electron transport chain? A. B. C. D. Pyruvate NADH FADH 2 Hydrogen ions

Practice Questions 2 1. 2. 3. 4. 5. 6. 7. 8. 9. What is the relationship between Kreb’s Cycle and Glycolysis? Where does Kreb’s Cycle occur? What is the overall purpose of Kreb’s cycle? What is the relationship between Kreb’s Cycle the Electron Transport Chain? Compare the amount of energy captured by each of the three stages of respiration. Why is it essential for complex organisms like humans to use aerobic respiration? Compared to a skin cell, a muscle cell has a huge density of mitochondria. Propose a logical reason to explain this. In what ways is a hydroelectric dam a good analogy for a mitochondrion? Explain how respiration is a much more useful way for living things to release energy from carbohydrates compared to fire.

Cellular Respiration ATP Tally 1. Glycolysis – 2 ATP 2. Krebs Cycle – 2 ATP 3. ETC – up to 34 ATP Grand Total = 36 -38 ATP

1. 2. 3. 4. 5. 6. Questions What is the real benefit of fermentation? What is the cellular respiration equation? What factor determines the pathway that pyruvic acid takes after leaving glycolysis? What is the importance of cellular respiration to us? Explain how cellular respiration complements photosynthesis. What is the ultimate end product of cellular respiration?