Cellular RespirationCellular Respiration

Overall reaction:Overall reaction:

A good cellular respiration animation!

click above!

3 stages of Cellular 3 stages of Cellular RespirationRespiration

1.1. GlycolysisGlycolysis - - occurs in cytosoloccurs in cytosol

2.2. Krebs CycleKrebs Cycle – – occurs in occurs in mitochondrionmitochondrion

3.3. Electron Electron TransportTransport – – occurs in occurs in mitochondrionmitochondrion

ATPATP

MitochondrionMitochondrionElectron micrograph of a mitochondrion in the pancreas of a bat.

3D drawing of a 3D drawing of a mitochondrionmitochondrion

Glycolysis

Conversion of pyruvic acid Conversion of pyruvic acid to acetyl CoA in a to acetyl CoA in a

mitochondrionmitochondrion

Krebs CycleKrebs Cycle (sometimes called the Citric (sometimes called the Citric

Acid Cycle)Acid Cycle)

How complex is the Kreb’s How complex is the Kreb’s Cycle?Cycle?

Another diagram of Another diagram of Krebs CycleKrebs Cycle

Electron Transport Chain

BiosyntheBiosynthesissis

Questions 1-2, page 115Questions 1-2, page 1151.1. How are cellular respiration and glycolysis How are cellular respiration and glycolysis

related?related?- Glycolysis breaks down glucose in the Glycolysis breaks down glucose in the

cytoplasm before cellular respiration occurs in cytoplasm before cellular respiration occurs in the mitochondrion. The aerobic processes in the mitochondrion. The aerobic processes in mitochondria use the products of glycolysis.mitochondria use the products of glycolysis.

2.2. Summarize the aerobic stages of cellular Summarize the aerobic stages of cellular respiration. Be sure to discuss the Krebs cycle respiration. Be sure to discuss the Krebs cycle and electron transport chain in your answer.and electron transport chain in your answer.

- Answers should indicate that the products of Answers should indicate that the products of glycolysis are broken down by the Krebs Cycle glycolysis are broken down by the Krebs Cycle to make energy-carrying molecules and carbon to make energy-carrying molecules and carbon dioxide. Energy from the Krebs Cycle is used dioxide. Energy from the Krebs Cycle is used by the Electron Transport Chain to make ATP.by the Electron Transport Chain to make ATP.

Questions 3-4, page 115Questions 3-4, page 1153.3. Analyze – Describe the relationship between Analyze – Describe the relationship between

cellular respiration and photosynthesis. cellular respiration and photosynthesis. Discuss the functions of chloroplasts and Discuss the functions of chloroplasts and mitochondria.mitochondria.

- The reactant and products of the overall The reactant and products of the overall processes are essentially the reverse of each processes are essentially the reverse of each other. The chloroplasts and mitochondria other. The chloroplasts and mitochondria also have approximately opposite functions. also have approximately opposite functions. Chloroplasts absorb energy and build Chloroplasts absorb energy and build carbon-based molecules and mitochondria carbon-based molecules and mitochondria break down carbon-based molecules to break down carbon-based molecules to release energy.release energy.

4.4. Apply – Is glucose a reactant in the aerobic Apply – Is glucose a reactant in the aerobic stages of cellular respiration? Explain.stages of cellular respiration? Explain.

- No, glucose is broken down during glycolysis, - No, glucose is broken down during glycolysis, which is an anaerobic process.which is an anaerobic process.

Question 5, p115Question 5, p115

5.5. Chemical Reactions – Is the process Chemical Reactions – Is the process of cellular respiration exothermic of cellular respiration exothermic or endothermic? Explain your or endothermic? Explain your answer.answer.

- Exothermic – energy is released as Exothermic – energy is released as heat and ATP.heat and ATP.

Questions 1-3, p 121Questions 1-3, p 1211.1. What is the role of pyruvate in cellular What is the role of pyruvate in cellular

respiration?respiration? pyruvate, produced by the breakdown of glucose, pyruvate, produced by the breakdown of glucose,

is needed for the Krebs Cycle, which is part of is needed for the Krebs Cycle, which is part of cellular respiration.cellular respiration.

2.2. Describe in your own words the function of the Describe in your own words the function of the Krebs Cycle.Krebs Cycle.

- The Krebs Cycle breaks down and extracts energy The Krebs Cycle breaks down and extracts energy from carbon-based molecules, transfers it to the from carbon-based molecules, transfers it to the electron transport chain, makes a small amount of electron transport chain, makes a small amount of ATP, and releases carbon dioxide.ATP, and releases carbon dioxide.

3.3. Explain the functions of electrons, hydrogen ions, Explain the functions of electrons, hydrogen ions, and oxygen in the electron transport chain.and oxygen in the electron transport chain.

- The electron transport chain pumps hydrogen ions The electron transport chain pumps hydrogen ions across the inner mitochondrial membrane. across the inner mitochondrial membrane. Hydrogen ions then flow through a channel that is Hydrogen ions then flow through a channel that is bound to ATP synthase. Oxygen picks up bound to ATP synthase. Oxygen picks up electrons and hydrogen ions so that the electron electrons and hydrogen ions so that the electron transport chain can continue to function.transport chain can continue to function.

Questions 4-6 p 121Questions 4-6 p 1214.4. Compare and Contrast – Describe the similarities and Compare and Contrast – Describe the similarities and

differences between the Krebs Cycle and the Calvin Cycle.differences between the Krebs Cycle and the Calvin Cycle. Both occur in the interior space of their respective Both occur in the interior space of their respective

organelles, and both are cycles of chemical reactions. organelles, and both are cycles of chemical reactions. The Calvin Cycle builds larger carbon-based molecules in The Calvin Cycle builds larger carbon-based molecules in chloroplasts to store energy. The Krebs Cycle breaks chloroplasts to store energy. The Krebs Cycle breaks down carbon-based molecules in the mitochondria to down carbon-based molecules in the mitochondria to release energy.release energy.

5.5. Evaluate – Is oxygen necessary for the production of all Evaluate – Is oxygen necessary for the production of all ATP in your cells? Why or why not?ATP in your cells? Why or why not?

No, ATP is also formed during glycolysis, which can No, ATP is also formed during glycolysis, which can continue without oxygen.continue without oxygen.

6.6. Common Ancestry – Protein molecules called cytochromes Common Ancestry – Protein molecules called cytochromes are part of the electron transport chain. They are nearly are part of the electron transport chain. They are nearly identical in every known aerobic organism. How do these identical in every known aerobic organism. How do these molecules show the unity of life on Earth?molecules show the unity of life on Earth?

The similarity of cytochromes in many different organisms The similarity of cytochromes in many different organisms suggests a common ancestor.suggests a common ancestor.

Questions 1-3, p 125Questions 1-3, p 1251.1. What is the relationship between glycolysis and What is the relationship between glycolysis and

fermentation?fermentation? Glycolysis leads to fermentation if no oxygen is Glycolysis leads to fermentation if no oxygen is

available. NADavailable. NAD++ produced by fermentation allows produced by fermentation allows glycolysis to continue.glycolysis to continue.

2.2. Summarize the process of alcoholic fermentation in Summarize the process of alcoholic fermentation in yeast. yeast.

Sugars are broken down by glycolysis. Pyruvate and Sugars are broken down by glycolysis. Pyruvate and NADH enter alcoholic fermentation, producing NADH enter alcoholic fermentation, producing alcohol and carbon dioxide. NADalcohol and carbon dioxide. NAD++ is recycled back is recycled back to glycolysis.to glycolysis.

3.3. Compare and Contrast – How are lactic acid Compare and Contrast – How are lactic acid fermentation and alcoholic fermentation similar? fermentation and alcoholic fermentation similar? How are they different?How are they different?

Both are anaerobic processes that break down Both are anaerobic processes that break down glucose to make ATP and recycle NADglucose to make ATP and recycle NAD++ to glycolysis. to glycolysis. Lactic acid fermentation produces lactic acid; Lactic acid fermentation produces lactic acid; alcoholic fermentation produces alcohol and carbon alcoholic fermentation produces alcohol and carbon dioxide.dioxide.

Questions 4 & 5Questions 4 & 54.4. Compare and Contrast – Describe the Compare and Contrast – Describe the

similarities and differences between similarities and differences between cellular respiration and fermentation.cellular respiration and fermentation.

Both produce ATP through the Both produce ATP through the breakdown of carbon-based molecules, breakdown of carbon-based molecules, and both allow glycolysis to continue by and both allow glycolysis to continue by recycling electron acceptors. Cellular recycling electron acceptors. Cellular respiration requires oxygen and respiration requires oxygen and produces much more ATP than produces much more ATP than fermentation.fermentation.

5.5. Aerobic Respiration – How is the role of Aerobic Respiration – How is the role of oxygen in cellular respiration similar to oxygen in cellular respiration similar to the role of NADthe role of NAD++ in fermentation? in fermentation?

Both oxygen and NADBoth oxygen and NAD++ pick up electrons pick up electrons and allow ATP production to continue.and allow ATP production to continue.

FermentationFermentation In the absence of oxygen, entire process of In the absence of oxygen, entire process of

cellular respiration stops (oxygen is a final cellular respiration stops (oxygen is a final electron acceptor). See – page 409 – BSCSelectron acceptor). See – page 409 – BSCS

During strenuous exercise, muscles may not During strenuous exercise, muscles may not get enough Oget enough O22, thus , thus fermentationfermentation occurs. occurs.

Lactic Acid FermentationLactic Acid Fermentation - pyruvic acid - pyruvic acid produced in glycolysis converted into lactic produced in glycolysis converted into lactic acid (and NADH gives up hydrogen atoms to acid (and NADH gives up hydrogen atoms to become NADbecome NAD++ (goes back to glycolysis) (goes back to glycolysis)

Lactic acid – produces muscle stiffness. As Lactic acid – produces muscle stiffness. As muscles recover, lactic acid is converted muscles recover, lactic acid is converted back to pyruvic acid (cellular respiration back to pyruvic acid (cellular respiration continues)continues)

Fermentation - continuedFermentation - continued Lactic acid bacteria can ferment milk sugar Lactic acid bacteria can ferment milk sugar

lactose to lactic acid (help make yogurt)lactose to lactic acid (help make yogurt) Alcohol fermentationAlcohol fermentation – yeast cells, in the – yeast cells, in the

absence of oxygen, convert pyruvic acid from absence of oxygen, convert pyruvic acid from glycolysis into ethanol and carbon dioxideglycolysis into ethanol and carbon dioxide

Bread making – COBread making – CO22 produces the air pockets produces the air pockets in the bread, causes bread to leaven (rise)in the bread, causes bread to leaven (rise)

Production of Alcohol – making beer, wine, etc. Production of Alcohol – making beer, wine, etc. – ethanol produced, along with CO– ethanol produced, along with CO22 (the (the bubbles)bubbles)

Fermentation is helpful in the industrial Fermentation is helpful in the industrial production of various useful products such as production of various useful products such as alcohol, antibiotics, vitamins, organic acids, alcohol, antibiotics, vitamins, organic acids, bakery and dairy products, tanned leather, etc. bakery and dairy products, tanned leather, etc.

PhotosynthesisPhotosynthesis

Overall Reaction:

ChloroplastsChloroplasts

Photosynthesis SummaryPhotosynthesis Summary

Light ReactionLight Reaction

Another good light reaction animation!One more!

Light Reaction SummaryLight Reaction Summary

Dark ReactionDark Reaction

More complicated More complicated illustrations of the Dark illustrations of the Dark

ReactionReaction

Plant BiosynthesisPlant Biosynthesis

Great Biology Great Biology AnimationsAnimations

1.1. Light ReactionLight Reaction

2.2. Another Light Reaction animationAnother Light Reaction animation

3.3. Dark Reaction (Calvin Cycle) – see Dark Reaction (Calvin Cycle) – see top link!!top link!!

Questions 1-3, p 105Questions 1-3, p 1051.1. What are the roles of chloroplasts and chlorophyll What are the roles of chloroplasts and chlorophyll

in photosynthesis?in photosynthesis? Photosynthesis occurs in chloroplasts, powered by Photosynthesis occurs in chloroplasts, powered by

energy captured by chlorophyll. Chlorophyll is a energy captured by chlorophyll. Chlorophyll is a light-absorbing molecule located in chloroplasts.light-absorbing molecule located in chloroplasts.

2.2. Describe the stages of photosynthesis. Use the Describe the stages of photosynthesis. Use the terms thylakoid, light-dependent reactions, and terms thylakoid, light-dependent reactions, and light-independent reactions in your answer.light-independent reactions in your answer.

The first stage of photosynthesis is the light-The first stage of photosynthesis is the light-dependent reaction that takes place in the dependent reaction that takes place in the thylakoids. Energy is absorbed from sunlight and thylakoids. Energy is absorbed from sunlight and transferred through the thylakoid membrane. The transferred through the thylakoid membrane. The energy is used in the light-independent reactions energy is used in the light-independent reactions to produce sugars.to produce sugars.

3.3. Apply – Supposed you wanted to develop a light to Apply – Supposed you wanted to develop a light to increase plant growth. What characteristics increase plant growth. What characteristics should the light have? Why?should the light have? Why?

The light should emit the optimal wavelengths, The light should emit the optimal wavelengths, such as blue and red, to be absorbed by the such as blue and red, to be absorbed by the pigments of the plants.pigments of the plants.

4.4. Analyze – Explain why photosynthesis Analyze – Explain why photosynthesis is important for building the structure is important for building the structure of plants cells.of plants cells.

In plants, the cell wall is responsible In plants, the cell wall is responsible for structure and support. Cell walls for structure and support. Cell walls are made from cellulose, which is a are made from cellulose, which is a carbohydrate that is built up from carbohydrate that is built up from sugars produced during sugars produced during photosynthesis.photosynthesis.

5.5. Chemical Reactions – Overall, do you Chemical Reactions – Overall, do you think photosynthesis is endothermic think photosynthesis is endothermic or exothermic? Explain your answer.or exothermic? Explain your answer.

Endothermic – it absorbs energy to Endothermic – it absorbs energy to produce sugars.produce sugars.

Questions 4-5, p 105Questions 4-5, p 105

1.1. How do the two photosystems work together to How do the two photosystems work together to capture energy from sunlight?capture energy from sunlight?

Photosystems II absorbs energy and energizes Photosystems II absorbs energy and energizes electrons. The electrons are passed along to electrons. The electrons are passed along to photosystem I, which absorbs more energy and adds photosystem I, which absorbs more energy and adds it to the electrons.it to the electrons.

2.2. Explain the relationship between the light-dependent Explain the relationship between the light-dependent and light-independent reactions.and light-independent reactions.

The light-dependent reactions absorb energy from The light-dependent reactions absorb energy from sunlight and transfer the energy to the light-sunlight and transfer the energy to the light-independent reactions that produce sugars.independent reactions that produce sugars.

3.3. Connect – Explain how the Calvin Cycle is a bridge Connect – Explain how the Calvin Cycle is a bridge between carbon in the atmosphere and carbon-based between carbon in the atmosphere and carbon-based molecules in the food you eat.molecules in the food you eat.

Carbon dioxide is removed from the atmosphere by Carbon dioxide is removed from the atmosphere by plants for photosynthesis. The carbon is incorporated plants for photosynthesis. The carbon is incorporated into sugars and other carbon-based molecules that into sugars and other carbon-based molecules that are eaten by other organisms.are eaten by other organisms.

Questions 1-3, p 112Questions 1-3, p 112

4.4. Explain why the chemical equation for Explain why the chemical equation for photosynthesis (below) is a highly simplified photosynthesis (below) is a highly simplified representation of the process. How is the representation of the process. How is the equation accurate? How is it inaccurate?equation accurate? How is it inaccurate?

6CO6CO22 + 6H + 6H22O → CO → C66HH1212OO66 + 6O + 6O22

The equation shows the general reactants and The equation shows the general reactants and products in the process. However – it does not products in the process. However – it does not show intermediate steps. For example, water and show intermediate steps. For example, water and carbon dioxide do not actually react with each carbon dioxide do not actually react with each other.other.

5.5. Cell Functions – Explain how both passive Cell Functions – Explain how both passive transport and active transport are necessary for transport and active transport are necessary for photosynthesis to occur.photosynthesis to occur.

Active transport moves the hydrogen ions against Active transport moves the hydrogen ions against the concentration gradient in photosystem II. the concentration gradient in photosystem II. Passive transport occurs when hydrogen ions flow Passive transport occurs when hydrogen ions flow through the channel bound to ATP synthase.through the channel bound to ATP synthase.

Questions 4-5, p 112Questions 4-5, p 112