Cellular respiration 2012

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Cellular RespirationObjectives:(1) Define metabolism and give its significance to YOU(2) Identify the parts of mitochondria and give the function of each(3) Draw the complete equation of cellular respiration and its opposite reaction(4) Summarize how glucose is broken down in the first stage of cellular respiration.

Cellular RespirationObjectives:

(5)Describe how ATP is made in the stages of cellular respiration.

(6) Identify the role of and importance of fermentation in the second stage of cellular respiration.

(7) Evaluate the importance of oxygen in aerobic respiration.

is a series of reactions where fats, proteins, and carbohydrates, mostly glucose, are broken down to make CO2, water, and energy (ATP).

Cellular Respiration is a metabolic process like burning fuel

Releases much of the energy in food to make ATP

This ATP provides cells with the energy they need to carry out the activities of life.

C6H12O6+O2 6CO2 + 6H2O + ATP

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Glucose Breakdown: Summary Reaction

Electrons are removed from substrates and received by oxygen, which combines with H+ to become water.

Glucose is oxidized and O2 is reduced

+ + energy

Reduction

Oxidation

glucoseC6H12O6 6O

2

6CO2 6H2O+

Matrix: locationof the prepreaction and thecitric acid cycle

Cristae: locationof the electrontransport chain(ETC)

cristaeIntermembrane space

Inner membrane

matrix

Outer membrane

45,000

© Dr. Donald Fawcett and Dr. Porter/Visuals Unlimited

FOOD

Carbohydrates Fats Proteins

Simple sugars Fatty acids and glycerol

Amino acids

stages of CELLULAR RESPIRATION

stages of CELLULAR RESPIRATION

Simple sugars

Fatty acids and glycerol

Amino acids

fuels

Most of the energy from cell respiration is converted into ATP

ATP is a substance that powers most cell activities.

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glucose

2 pyruvate

2 acetyl CoA

Citric acidcycle

subtotal subtotal

glycolysis

2 CO2

4 CO2

NADH

NADH

NADH

FADH2

2

2

6

2

4 or 6

6

18

4

324

36 or 38total

6 O2 6 H2O

ATPP

ATP

ATP

ATP

ATP

ATP

ATP

ATP

ATPor 34

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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Cellular RespirationStage One: Breakdown of Glucose

•GlycolysisGlucose is broken down to pyruvate making 2 ATP.

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FERMENTATION

•the anaerobic conversion of sugar to carbon dioxide and alcohol/acid• Alcoholic Fermentation - yeasts• Lactic Acid Fermentation - humans, fungi, and bacteria

FERMENTATIONAlcoholic Fermentation

e.g. yeastsproduce alcohol and CO2• bread, beer, wine

Lactic Acid Fermentatione.g. humans, some bacteria & fungimuscle tissue ferments lactic acid

when O2 is not delivered to cells

Lactate producing bacteria – used in the production of cheese, yogurt, sauerkraut.

other products: acetic acid, butyric acid, isopropanol etc.

Where in the cell does gylcolysis occur?

Fate of glucose in the beginning of gylcolysis?

Explain “it takes energy to make energy”?

How much net ATP is made?

What else is made? 2 types of fermentation?

Cytoplasm

Fructose (isomer) Invest 2 ATP get

4

Net= 2 ATP CO2 + NADH Lactate or

alcohol

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Pyruvate is a pivotal metabolite in cellular respiration

If O2 is not available to the cell, fermentation, an anaerobic process, occurs in the cytoplasm. During fermentation, glucose is incompletely

metabolized to lactate, or to CO2 and alcohol (depending on the organism).

If O2 is available to the cell, pyruvate enters the mitochondria for aerobic respiration.

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© The McGraw Hill Companies, Inc./Bruce M. Johnson, photographer

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30



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Advantages Provides a quick burst of ATP energy for muscular activity.

Disadvantages Lactate and alcohol are toxic to cells. Lactate changes pH and causes muscles to fatigue.

▪ Oxygen debt Yeast die from the alcohol they produce by fermentation

Efficiency of Fermentation Two ATP produced per glucose of molecule during

fermentation is equivalent to 14.6 kcal. Complete oxidation of glucose can yield 686 kcal. Only 2 ATP per glucose are produced, compared to 36 or 38

ATP molecules per glucose produced by cellular respiration.

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Fermentationinputs outputs

2 lactate or2 alcohol and 2 CO2

glucose

2 ADP + 2 P net gainATP2


Pyruvate enters mitochondrion (matrix)

It is oxidized to 2 carbon acetyl groups

NADH is formedCO2 is removed (waste product)

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Connects glycolysis to the citric acid cycle

End product of glycolysis, pyruvate, enters the mitochondrial matrix

Pyruvate is converted to a 2-carbon acetyl group

Attached to Coenzyme A to form acetyl-CoA

Electron are picked up (as hydrogen atom) by NAD+

CO2 is released and transported out of mitochondria into the cytoplasm

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2 NAD+ 2 NADH

2 2 + 2 CoA + 2 CO2

2 pyruvate

O OHC

CH3

+ 2 CoA

CoA

CH3

pyruvatecarbondioxideacetyl CoA

C OC O

2 acetyl CoA + 2 carbondioxide


Cellular RespirationStage Two: Production of ATP

•Krebs Cycle is a series of reactions that produce energy-storing molecules during aerobic respiration.

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Completes the breakdown of glucose Takes the pyruvate (3-carbons) and breaks it

down, the carbon and oxygen atoms end up in CO2 and H2O

Hydrogens and electrons are stripped and loaded onto NAD+ and FAD to produce NADH and FADH2

Production of only 2 more ATP but loads up the coenzymes with H+ and electrons which move to the 3rd stage

CO2 & H2ONADH & FADH

2 more ATP

What are the reactants?

What is produced?

What is NADH? FADH?

What is CoA and why is it important?

Pyruvate (C3)

2 ATP, CO2, NADH, FADH

Energy carriers

Escort molecule to Krebs cycle

Goal: to break down NADH and FADH2, pumping H+ into the outer compartment of the mitochondria

Where: Cristae of the mitochondria

Electron Transport Phosphorylation typically produces 32 ATP's

Electron carriers loaded with electrons and protons from the Kreb’s cycle move to this chain-like a series of steps (staircase).

As electrons drop down stairs, energy released to form a total of 32 ATP

Oxygen waits at bottom of staircase, picks up electrons and protons and in doing so becomes water

ATP is generated as H+ moves down its concentration gradient through a special enzyme called ATP synthase

http://www.uic.edu/classes/bios/bios100/lectf03am/ATPase.jpg

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Glycolysis: 2 ATP Krebs Cycle: 2 ATP Electron Transport Phosphorylation: 32 ATP

Each NADH produced in the conversion of pyruvate to acetyl COA and Krebs Cycle is worth 3 ATP (8 x 3 = 24)

Each FADH2 is worth 2 ATP (2 x 2 = 4) 4 + 24 + 4 = 32

Net Energy Production: 36 ATP from one glucose molecule

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Net yield per glucose: From glycolysis – 2 ATP

From citric acid cycle – 2 ATP

From electron transport chain – 32 or 34 ATP

Energy content: Reactant (glucose) 686 kcal

Energy yield (36 ATP) 263 kcal

Efficiency is 39%

The rest of the energy from glucose is lost as heat

36 ATP for aerobic vs. 2 ATP for anaerobic

Glycolysis 2 ATP

Kreb’s 2 ATP

Electron Transport 32 0r 34 ATP 36 or 38 ATP

Occurs in the chlorophyll-bearing cells of plants

Needs the presence of lightWater and carbon dioxide are usedOxygen is given off as a waste

productFood is built or synthesized The weight of the plant is increasedEnergy is stored

I. Draw and label the parts of a mitochondrion. Give the function of each part.

II. Complete the table below on cellular respiration.

PHASE/PROCESS LOCATION PRODUCTS ATP

PRODUCED

___________________ matrixNADH's,

2FADH2's, acetyl coA and 2 CO2

Glycolysis________________ _______________

2

________________ _________________ Water, NADH, FADH

_____________

Preparatory reaction _________________ NADH and

releases CO2

_____________

Fermentation*Organism involve________________________________

Alcohol & CO2

_______________

_________

Net total of ATP produced/glucose molecule = __________

I. Draw and label the parts of a mitochondrion. Give the function of each part.II. Complete the table below on cellular respiration.

1. In aerobic respiration carbohydrates are ultimately broken down into:

A. acetyl-CoA B. CO2 C. H2O D. O2

2. In the process of catabolism, protein is broken into

A. sugar B. amino acids C. glucose D. fatty acids 3. Which process of aerobic respiration takes

place in the cytoplasm and NOT in the mitochondria?

A. glycolysis B. Krebs cycle C. fermentation D. ATP synthesis

4. In the presence of oxygen, all cells synthesize ATP via the process of glycolysis. Many cells also can metabolize pyruvate if oxygen is not present, via the process of:

A. fermentation B. oxidative phosphorylation C. aerobic respiration D. photophosphorylation

5. The final electron acceptor in cellular respiration is

A. ATP. D. NADPH. B. oxygen. E. carbon dioxide. C. glyceraldehyde-3-phospate (G3P)

6. Which of the following does not occur in fermentation?

A. carbon dioxide is produced B. sugar is broken down C oxygen is formed D. energy is released 7. What is the net total of ATP

produced during aerobic respiration A. 2 ATP C. 36 ATP B. 32 ATP D. 39 ATP

8. Which process of aerobic respiration takes place in the cristae of mitochondria?

A. Glycolysis B. Citric Acid Cycle cycle C. Preparatory reaction D. Electron Transport Chain

9. All of the following are common to respiration and fermentation except one

A. energy is released B. carbon dioxide is produced C. sugar molecules are broken down D. alcohol is formed

Education

Cellular respiration 2012