PAGE CONTENT

CONTENTS PAGES

TASK GIVEN

DECLARATION FORM

ACKNOWLEDGEMENT

PAGE CONTENT

INTRODUCTION

AEROBIC RESPIRATION

ESSAY MIND MAP

ANAEROBIC RESPIRATION

ESSAY

MIND MAP

DIFFERENTIATE BETWEEN AEROBIC

RESPIRATION AND ANAEROBIC

RESPIRATION

SIMILARITIES BETWEEN AEROBIC AND

ANAEROBIC RESPIRATION

DIFFERENCE BETWEEN AEROBIC AND

ANAEROBIC RESPIRATION

THE USAGE OF AEROBIC AND ANAEROBIC

RESPIRATION

CONCLUSION

REFLECTION

PLANNING EXPERIMENT

REFERENCE

APPENDICES

COLLABORATION FORM

BOOK SOURCES

INTERNET SOURCES

INTRODUCTION

Cellular respiration (internal/ cell/ tissue respiration) is a sequence of enzyme-

controlled biochemical reactions. It involves the breakdown of complex organic

molecules such as glucose into simpler molecules with release of energy. The

energy released is trapped in the ATP molecule. Cellular respiration is divided into

two types, there are aerobic respiration and anaerobic respiration.

Aerobic respiration means the oxidation of the organic compound that takes

place in the metabolism of the cell in the presence of oxygen. Aerobic respiration is

also known as cellular respiration and normally takes place in the cytoplasm and

mitochondria. Aerobic respiration can also be broken up into 4 stages:

a) glycolysis

b) Link reaction

c) Krebs cycle

d) Electron transport chain

Simplified equation:

C6H12O6 + 6O2 ------------ 6CO2 + 6H2O + energy (38 ATP molecules)

Besides that, anaerobic respiration is another type of cellular respiration.

Anaerobic respiration means the oxidation of the organic compounds that takes

places in the metabolism of the cell in the absence of oxygen. This enables the

organism to live in an oxygen-deficient environment. Two different anaerobic

fermentation pathways are alcoholic fermentation and lactate fermentation.

In plant cells:

C6H12O6 ----------------- 2C2H5OH + 2CO2 + small amount of energy (2 ATP

molecules)

In animal cells:

C6H12O6 --------------- 2CH3CH(OH)COOH + small amount of energy ( 2 ATP)

AEROBIC RESPIRATION

The pyruvate produced in glycolysis undergoes further breakdown through a

process called aerobic respiration in most organisms. This process requires oxygen

and yields much more energy than glycolysis. Aerobic respiration is divided into two

processes: the Krebs cycle, and the Electron Transport Chain, which produces ATP

through chemiosmotic phosphorylation. The energy conversion is as follows:

C6H12O6 + 6O<2 -> 6CO2 + 6H2O + energy (ATP)

The pyruvate molecules produced during glycolysis contain a lot of energy in

the bonds between their molecules. In order to use that energy, the cell must convert

it into the form of ATP. To do so, pyruvate molecules are processed through the Kreb

Cycle, also known as the citric acid cycle. Glycolysis produces two pyruvate

molecules from one glucose, each glucose is processes through the kreb cycle twice.

For each molecule of glucose, six NADH2+, two FADH2, and two ATP.

NADH2+ and FADH2 produced during the Krebs cycle have been reduced,

receiving high energy electrons from the pyruvic acid molecules. Therefore, they

represent energy available to do work. These carrier molecules transport the high

energy electrons and their accompanying hydrogen protons from the Krebs Cycle to

the electron transport chain in the inner mitochondrial membrane.

In a number of steps utilizing enzymes on the membrane, NADH2+ is oxidized

to NAD+, and FADH2 to FAD. The high energy electrons are transferred to ubiquinone

(Q) and cytochrome c molecules, the electron carriers within the membrane. The

electrons are then passed from molecule to molecule in the inner membrane of the

mitochondron, losing some of their energy at each step. The final transfer involves

the combining of electrons and H2 atoms with oxygen to form water. The molecules

that take part in the

The electrons that are delivered to the electron transport system provide

energy to "pump" hydrogen protons across the inner mitochondrial membrane to the

outer compartment. This high concentration of hydrogen protons produces a free

energy potential that can do work. That is, the hydrogen protons tend to move down

the concentration gradient from the outer compartment to the inner compartment.

However, the only path that the protons have is through enzyme complexes

within the inner membrane. The protons therefore pass through the channel lined

with enzymes. The free energy of the hydrogen protons is used to form ATP by

phosphorylation, bonding phosphate to ADP in an enzymatically-mediated reaction.

Since an electrochemical osmotic gradient supplies the energy, the entire process is

referred to as chemiosmotic phosphorylation.

Once the electrons (originally from the Krebs Cycle) have yielded their energy,

they combine with oxygen to form water. If the oxygen supply is cut off, the electrons

and hydrogen protons cease to flow through the electron transport system. If this

happens, the proton concentration gradient will not be sufficient to power the

synthesis of ATP.

Glucose + 2 NAD+ + 2 Pi + 2 ADP → 2 pyruvate + 2 NADH + 2 ATP +2H+ + 2 H2O

Process converts one molecule of glucose into two molecules of pyruvate, and makes ATP.

GLYCOLISIS

The pyruvate is oxidized to acetyl-CoA and CO2 by the Pyruvate dehydrogenase

In the process one molecule of NADH is formed per pyruvate oxidized, and 3 moles of ATP are formed for each mole of pyruvate.

OXIDATIVE DECARBOXYLATION

OF PYRUVATE

When oxygen is present, acetyl-CoA is produced. Once Acetyl CoA is formed, two processes can occur, aerobic or anaerobic respiration. When oxygen is present, the

ANAEROBIC RESPIRATION

Anaerobic respiration is carried out by certain bacteria that live in anaerobic

environments such as waterlogged soil, stagnant ponds or animal intestines.

Electrons are transferred from glucose to NADH, just as in aerobic respiration.

They are then passed down an electron transport chain that is linked to ATP

synthesis by chemiosmosis. However, oxygen is not the terminal electron acceptor. It

is replaced by an inorganic substances such as nitrate or sulphate. The end products

are carbon dioxide, one or more reduced inorganic substances and ATP. The

equation is C6H12O^ + 12 KNO3 ------- ^CO2 + 6H2O +12KNO2 + Energy.

Yeast are facultatives anaerobes. They have mitochondria and carry out

aerobic respiration when oxygen is available, but switch to alcohol fermentation when

facing a shortage of oxygen. This is an anaerobic pathway that does not involve the

electron transport chain. NADH molecules are generated in glycolysis from the

CITRIC ACID

If oxygen is not present, fermentation of the pyruvate molecule will occur. In the presence of oxygen, when acetyl-CoA is produced, the molecule then enters the citric acid cycle inside the mitochondrial matrix, and gets oxidized to CO2 while at the same time reducing NAD to NADH.

When oxygen is present, acetyl-CoA is produced. Once Acetyl CoA is formed, two processes can occur, aerobic or anaerobic respiration. When oxygen is present, the

OXIDATIVE PHOSPHORYLA

In eukaryotes, oxidative phosphorylation occurs in the mitochondrial cristae. It comprises the electron transport chain that establishes a proton gradient (chemiosmotic potential) across the inner membrane by oxidizing the NADH produced from the Krebs cycle

reduction of NAD+ molecules. NADH molecules transfer their hydrogen atoms to

organic molecules, thus regenerating NAD+ which then channelled back to keep

glycolisis going. Enzymes decarboxylate pyruvate, releasing carbon dioxide and

forming a two-carbon compound, acetaldehyde. NADH formed in glycolisis transfers

hydrogen atoms to acetaldehyde, reducing it to form ethanol.

Lactate fermentation also occurs in human muscle during strenuous exercise

when the amount of oxygen is insufficient to support aerobic respiration. This shift is

only temporary.

Certain fungi and bacteria carry out lactate (lactic acid) fermentation. In this

pathway, NADH produced during glycolisis transfers hydrogen atoms to pyruvate,

reducing it to lactic acid. Certain anaerobic bacteria such as lactic –acid bacteria

constantly produce lactate in this manner and helps in the manufacture of cheese.

Yeasts generate alcohol and carbon dioxide, which makes bread rise. Both alcohol

fermentation and lactate fermentation are highly inefficient because the fuel is only

partially oxidised and producing only two ATPs from each molecule of glucose. A

large supply of fuel is also required.

Glycolysis, a series of enzymatic steps in which the six-carbon glucose molecule is degraded to yield two three-carbon pyruvate molecules.

Fermentation is an anaerobic process by which glucose or other organic nutrients are degraded into various products to obtain ATP.

In some animal tissues, pyruvate is reduced to lactate during anaerobic periods, such as during vigorous exercise, when there is not enough oxygen available to oxidize glucose further. This process, called anaerobic glycolysis.

Because glycolysis occurs in the absence of oxygen, and living organisms first arose in an anaerobic environment, anaerobic catabolism was the first biological pathway to evolve for obtaining energy from organic molecules.

Anaerobic glycolysis also serves to oxidize glucose to lactic acid with the production of ATP in anaerobic microorganisms. Such lactic acid production by bacteria sours milk and gives sauerkraut its mildly acidic taste.

A third pathway for pyruvate produced by glycolysis produces ethanol and CO2 during anaerobic glycolysis in certain microorganisms, such as brewer's yeast—a process called alcoholic fermentation.

ANAEROBICRESPIRATION

DIFFERENTIATE BETWEEN AEROBIC AND ANAEROBIC RESPIRATION

Similarities between Aerobic Respiration and Anaerobic Respiration1. Cellular respiration2. Involve in the breakdown of glucose3. Release energy that is stored in the ATP molecules4. Are catalysed by enzyme

Differences between Aerobic and Anaerobic RespirationAerobic Respiration Aspects of differences Anaerobic RespirationOxygen is present Availability of oxygen Oxygen is absentComplete oxidation of glucose

Oxidation of glucose Incomplete oxidation of glucose

Carbon dioxide, water, and energy

Products of respiration Lactic acid and energy (in muscle) or ethanol, carbon dioxide and energy (in yeast)

38 molecules of ATP Number of ATP molecules released per glucose molecule

2 molecules of ATP

A large amount of energy is released per mole of glucose (2898 KJ)

Amount of energy released per mole of glucose

A small amount of energy is released per mole of glucose, that is 210 kJ (during fermentation) and 150 kJ (during anaerobic respiration in the muscle cells)

In all organsms: C6H12O6 + 6O2 -------- 6CO2 + 6H2o z= 2898 kJ

Chemical equation In muscle cellsC6H12)6 ---------------- 2C3H6O3 + 150 kJ

In yeastC6H12O6 ---------------- 2C2H5OH + 2CO2 + 210 kJ

Mitochondria Where the process takes place

Cytoplasm

1) Glycolysis2) Link Reaction3) Krebs Cycle4) Electron transport

chain and chemiosmosis hypothesis

Stages/process involve Fermentation

THE USAGE OF AEROBIC RESPIRATION

Aerobic respiration is our daily life is the respiration that are carried out which means

the inhalation of Oxygen and exhalation of carbon dioxide.

THE USAGE OF ANAEROBIC RESPIRATION

The fermentation process is applied widely in industry, especially in the food

industry. Some common industrial applications of fermentation are baking of cakes

and bread,

The common process is baking of cakes and breads. In this process, the flour

is mixed with yeast. Carbon dioxide gas produced from the fermentation process

causes the dough to rise and gives the soft texture of cakes or bread when it is

baked in the oven.

Next, the manufacture of beer, wine and other alcoholic beverages, the

enzyme diastase in the malt derived from cereals or fruit juices, converts starch or

other complex sugars into maltose. A yeast mixture is then added to allow

fermentation to take place. During fermentation, the enzyme maltase converts

maltose into glucose. Glucose is then converted by the enzyme zymase into ethanol

and carbon dioxide. The fermented mixture is then distilled to produce beer or wine

of various ethanol concentrations.

Other than that, the making of dairy products such as yoghurt and cheese. In

this process, the enzyme lactase from bacteria such as Lactobacillus acts on lactose

(milk sugar) to produce lactic acid. The lactic acid produced gives milk a sour taste

and turns it into a curd called yougurt. Various flavours can be added to produce a

variety of yougurt with different tastes and flavours. The milk curd can be solidified

and pressed to produce cheese. Yougurt and cheese are rich in calcium, vitamin B

and D.

The manufacture of ethanol. Ethanol, apart from carbon dioxide direct product

of alcoholic fermentation. Ethanol is widely used as a solvent, especially in the

pharmaceutical industry, and to manufacture various organic compounds such as

ethanoic acid (acetic acid in vinegar) and esters.

Some local foods and beverages produced from the fermentation process

include fermented beans, tapai, tempe, dadih, budu and cincalok which are

favourites among local people.

CONCLUSION

Cellular respiration (internal/ cell/ tissue respiration) is a sequence of enzyme-

controlled biochemical reactions. It involves the breakdown of complex organic

molecules such as glucose into simpler molecules with release of energy. The

energy released is trapped in the ATP molecule. Cellular respiration is divided into

two types, there are aerobic respiration and anaerobic respiration.

Aerobic respiration means the oxidation of the organic compound that takes

place in the metabolism of the cell in the presence of oxygen. Aerobic respiration is

also known as cellular respiration and normally takes place in the cytoplasm and

mitochondria. Aerobic respiration can also be broken up into 4 stages:

a) glycolysis

b) Link reaction

c) Krebs cycle

d) Electron transport chain

Simplified equation:

C6H12O6+6O2 ------------ 6CO2 + 6H2O ^ H = 28880 KJ

Glycolysis means the breakdown of glucose (6C) molecule in a number of

enzyme-controlled steps into two molecules of pyruvate (3C). The process occurs in

the cytoplasm and doesn’t require oxygen. In order to initiate the process, 2

molecules of ATP are consumed, 4 molecules of ATP and 2 molecules NADH are

produced.

Equation of glycolysis:

Glucose + 2NAD+ + 2Pi + 2ADP ------------- 2 Pyruvate + 2NADH + 2ATP + 2H+ +

2H2O

Whereas, link reaction takes place when oxygen is available. Pyruvate is

transported into the matrix of mitochondrion from cytoplasm. Pyruvate (3C) formed at

the end of glkycolisis is decarboxylated and is oxidised to form two carbon acetate

(2C). The acetate combines with coenzyme A (COA) to form two carbon-

acetylcoenzyme A (acetyl-COA) which then enters into Krebs Cycle. The process is

called oxidative decarboxylation to Krebs Cycle.

Equation Link reaction:

Pyruvate + COA + NAD+ --------------- acetyl COA + CO2 + NADH+ + H+

Krebs Cycle means the continuing series of reactions in cellular respiration

that produces carbon dioxide, NADH, and FADH2.It is also known as tricarboxylic

acid cycle. A Series of ten enzymatic reactions, where a 4C organic molecules,

oxaloacetate, is recycled back into the cycle. As each molecules of Acetyl-COA runs

through the Kreb Cycle, it combines with the 4C molecules to make citric acid. These

2 citric acid molecules are oxidised, and the hydrogen ions are bound to NAD to form

NADH and to FAD to form FADH2. Oxaloacetate is produced when the last carbon is

released in the form of CO2.

Other than that, electron transport chain is the process in which high-energy

electron are transferred along a series of electron=carrier molecules in a membrane.

The electrons are removed from the molecules in glycolysis and citric acid follow a

series of cytochromes on the mitochondrial membrane, while the hydrogen ions are

pumped across the inner membrane of mitochondria. These protons flow through

ATP synthase enzyme molecules, and thereby release energy which drives the

formation of ATP molecules.

Besides that, anaerobic respiration is another type of cellular respiration.

Anaerobic respiration means the oxidation of the organic compounds that takes

places in the metabolism of the cell in the absence of oxygen. This enables the

organism to live in an oxygen-deficient environment.

At the beginning stage it involves stage of the respiration process called

glycolysis which takes place in the cytoplasm of the cell. Whereby in the process, it

convert glucose and carbon dioxide (as in yeast cells or lactic acid (as in animal

cells). Facultative anaerobes like yeast and intestinal parasitic worms which can

respire anaerobically or carry out anaerobic respiration when oxygen is limiting.

Animals respire anaerobically during periods of excessive exertion as in

running. Whereas, plant roots survive anaerobically in water-logged soil

condition.Obligate anaerobes such as closhidium perfringens can only live in places

hwere there is low or no oxygen and only respire anaerobically.

In prokaryotes, anaerobic respiration defined as membrane-bound biological

process coupling the oxidation of electron donating substrates (ex. sugar and other

organic compounds), but also inorganic molecules like hydrogen, sulphur, ammonia,

metals or metals ion ) to the reduction of suitable external electron acceptors other

than molecular oxygen.

Fermentation in prokaryotes: the oxidation of molecules is coupled to the

reduction of an internally-generated electron acceptor, usually pyruvate.

Fermentation in other organism:

In some plant cells and yeast fermentation produces carbon dioxide and ethanol. The

conversion of pyruvate to acetaldehyde generates carbon dioxide and the conversion

of acetaldehyde to ethanol regenarate NAD+.

Finally at the ending stage it ends with the transformation of pyruvic acid into

ethanol or lactic acid is called fermentation which extracts only a very small portion of

energy (about 5%) present in the original glucose. Most of the energy remains in the

ethanol or lactic acid (terminal product of fermentation)

Equation:

In plant cell can be represented as:

C6H12O6 ------ 2C2H5OH + 2CO2 + 2ATP

(Glucose) (Ethanol) (carbon dioxide) (energy)

In animal can be represented as:

C6H12O6 ---------- 2C3H6O3 + 2 ATP

(glucose) (lactic acid) (energy)

REFLECTION

Firstly, we are grateful because we managed to finish our project in duration

time given. During this period of time, we learned many things such as cooperation

among friends, working in a team and how to analyse and interpreting the data.

Honestly, we are happy to work as a team because we can change our view and

opinions regarding respiration topics. This project also acts as tutorial and revision to

us in order to remember facts and understanding more about respiration

Secondly, during to complete this project, we are having some difficulties and

problems. We are confusing about aerobic and anaerobic respiration. We cannot

differentiate between them and do not know how the process work. Those processes

are really complicated and makes us to search for a guider. Luckily, we get a guide

and a teach from our lecturer, Dr Faridah to explain all those confusing things. Know,

we more understanding the processes and can distinguish both of them properly.

Thirdly, we are having trouble with the experiment. For the first time we get the

task, we do not know how to start the project and conduct the experiment by

ourselves. We are looking the experiment that we can do with simplest and do not

have cost too much. After we are discussing with our group members and lecturer for

a few times, we managed to comes out with a simple experiment. This is a new thing

for us because it is the first time to conduct the experiment. We felt happy and really

enjoy because we faced the experience like scientist although we know it is not too

difficult compare to them.

Lastly, we felt satisfied with all the works that we had done through completing

this project. It is really exciting experiences and we love to tried it. We hope our

project will get a high grades and become the best project that have been carried out

in our class. Thanks you to all that helped us.

REFERENCE

Ching, L. (2005) Text Pre-U Biology Volume 1 (pp.194-204) Selangor : Pearson

Malaysia Sdn. Bhd.

Year,G.W. (2007) Success Biology SPM (pp.210-215) Selangor : Oxford Fajar

Sdn. Bhd.

L.S. Ching, L.S. Leong, Nalini B., Jacquelina R.S. (2005) Biology Matriculation

Semester 1 Second Edition (p.p 170-172) Selangor : Oxford Fajar Sdn. Bhd.

Aerobic Respiration (n.d) .Retrieved on August

11, 2008, from http://ntri.tamuk.edu/cell/mitochondria/glycpics.html

Anaerobic Respiration (n.d). Retrieved on

August 11, 2008, from the STS Wiki: http://en.wikipedia.org/wiki/Anaerobic

_respiration

Cellular respiration. (n.d). Retrieved on August

11, 2008, from the STS wiki:http://en.wikipedia.org/wiki/cellular_respiration

Cellular respiration and Fermentation. (n.d).

Retrieved on August 11, 2008, from http://biology.clc.uc.edu/courses/bin

104/cellresp.htm

Chart of Important Metabolic Products.

(n.d)Retrieved on August 11, 2008, from http://depatments

.oxy.edu/bio130/lectures_2000/metabolic_products.htm