NAME:_____________________

2.2.5 RESPIRATIONLearning Objectives

At the end of this section, students should be able to

1. Define of the term: aerobic respiration.2. Explain the role of aerobic respiration – what does it do for

organisms?3. Express aerobic respiration by a balanced equation of the overall

sequence of reactions for glucose. C6H12O6 + 6O2 ---> 6CO2 + 6H2O + Energy

4. Give a simple treatment of aerobic respiration of glucose by reference to a two-stage process.Stage 1 does not require oxygen and releases a small amount of energy. Stage 2 does require oxygen and releases a large amount of energy.

5. Define the term: anaerobic respiration.6. Know that anaerobic respiration may occur in the presence of

oxygen but does not use oxygen. It is therefore a first-stage process.

7. Know that the products of anaerobic respiration are lactic acid or alcohol and carbon dioxide.

8. State the nature and role of fermentation.9. Know that aerobic respiration uses oxygen and is described as a

two-stage process.10. State the cellular location of the first & second stage:

The first stage process occurs in the cytosol (the cytoplasm minus the organelles).The second stage process occurs in the mitochondrion.

11. Explain the role of microorganisms in industrial fermentation.12. Explain the role of microorganisms in bioprocessing with

immobilised cells 13. Explain the role of microorganisms in Bioreactors

Mandatory Activity: Prepare & show the production of alcohol by yeast

2.2.10.H RESPIRATION

1

[Extended Study]

Learning Objectives

At the end of this section students should be able to understand:

14. The first-stage process, referred to as glycolysis, converts a six-carbon carbohydrate to pyruvate with the generation and release of ATP.

15. Fermentation [anaerobic conditions] :the pyruvate molecule is converted or reduced to ethanol and carbon dioxideor the pyruvate molecule is reduced to lactic acid.

16. In the second-stage process, under aerobic conditions, a series of reactions occurs: the pyruvate molecule is broken down to one molecule of carbon

dioxide and a two-carbon acetyl group, Acetyl Co-enzyme A. this Acetyl Co. A enters a series called Krebs Cycle and leaves it

later as CO2 and H2O During this cycle an electron transport system operates to

remove electrons from the substrate intermediates electrons from the cycle are transferred through an electron

transport chain ultimately these are transferred to oxygen which combines with

hydrogen to form water

the energy released by these electrons through the chain is used in the production of ATP molecules.(Further biochemical references not required).

2.2.8 HRole of Adenosine Triphosphate (ATP) and Nicotinamide Adenine Dinucleotide (NAD/NADP+)

1. In order for photosynthesis and respiration to occur (both high energy reactions) the role of ATP and NAD/NADP+ needs to be understood.

2. Word structure of ATP.

2

3. Adenosine triphosphate has a special role in the trapping and transferring of energy for cell activities.

4. ADP + P ----> ATP + H2O, energy in.5. ATP + H2O ---> ADP + P, energy out.6. Role of NAD/NADP+

7. Nicotinamide adenine dinucleotide has a special role in trapping and transferring electrons and hydrogen ions in cell activities.

2.2.5 Respiration - NotesRespiration is the release of energy from food

Types of Respiration Aerobic Respiration – the release of energy from food in the

presence of oxygen Anaerobic Respiration The release of energy from food without

requiring the presence of oxygen

Equation for Aerobic Respiration:

C6H12O6 + 6O2 6CO2 + 6H2O + Energy

Glucose + Oxygen Carbon dioxide + water + 3

energy

Aerobic Respiration occurs in 2 stages:

Stage 1 - Glycolysis Stage 2 – Krebs (Citric Acid / tricarboxylic acid cycle (TCA cycle))

and Electron transport chain

Stage 1- Glycolysis Takes place in the cytosol (the cytoplasm without the organelles) as

enzymes are found here Does not require oxygen It only releases small amounts of energy Is the same for both aerobic and anaerobic respiration A 6 carbon carbohydrate (Glucose) is converted to two 3-molecules

called pyruvic acid, with the release of a small amount of energy Most of the energy in the glucose molecule remains stored in each

3- carbon molecule Some of the energy released forms 2 ATP molecules more of the

energy is used to form NADH

Stage 2

Krebs (Citric acid) cycle

In the presence of oxygen the pyruvic acid enters a mitochondrion It loses a carbon dioxide molecule to form a 2-carbon molecule

called Acetyl coenzyme A (Acetyl CoA for short)

4

Pyruvic acid also loses 2 high energy electrons that combine with NAD+ and a proton to form NADH

Each NADH will enter an electron transport system The Acetyl CoA enters a series of reactions called Kreb’s cycle

(German scientist Hans Krebs) Takes place in the lumen of the mitochondria Requires Oxygen The Acetyl CoA is broken down into carbon dioxide and protons (H+

ions) The energy that was in the Acetyl CoA is released in a number of

steps in the form of high energy electrons These electrons along with protons (H+) combine with NAD+ to

form NADH The NADH enters an electron transport system Phosphorylation also occurs in Kreb’s cycle where a single ADP is

changed to ATP

Electron Transport Train

The NADH enters an electron transport chain5

Takes place in the cristae of the mitochondria Oxygen is necessary The foldings of the cristae increase the number of electron transport

systems that can fit in them Each electron transport system consists of a number of molecules

mainly proteins High energy electrons are passed from NADH to the first of these

molecules As electrons pass from molecule to molecule they lose some of their

energy Some of this energy is used to form ATP the rest is lost as heat At the end of each system the low energy electron is removed by

combining it with oxygen and hydrogen to form water The production of ATP by the electron transport system is called

Oxidative Phophorylation as it requires oxygen + phosphate The main significance of the electron transport system is that it

produces energy rich ATP Oxygen is essential as it accepts the low energy electron at the end

of the chain If oxygen is absent aerobic organisms may die as there is no oxygen

to accept the low energy electron and no ATP may be formed Chemicals such as cyanide may be fatal because they prevent some

of the proteins from receiving and passing on electrons meaning ATP cannot be produced

6

Anaerobic Respiration (Fermentation)

In stage 1 glucose is converted to 2 molecules of pyruvic acid 2 molecules of ATP and 2 molecules of NADH are produced in this

process In the absence of oxygen the pyruvic acid is converted to either

lactic acid or ethanol and carbon dioxide In each case the 2 NADH break down into 2 electrons and 2 protons

which combine with the pyruvic acid to form lactic acid or ethanol and carbon dioxide

As pyruvic acid gains electrons in both cases it is said to be reduced As only stage 1 is involved in anaerobic respiration it only occurs in

the cytosol Anaerobic Respiration is also known as Fermentation 2 types of fermentation

Lactic Acid Fermentation Alcohol Fermentation

7

Lactic Acid Fermentation This occurs in some anaerobic bacteria and fungi and in animal

muscles when there is not enough oxygen In this fermentation Lactic acid is produced Glucose 2Lactic Acid + small amount of energy Lactic acid forms when bacteria cause milk to go sour, when

bacteria respire on cabbage to form Sauerkraut, in silage production and in yoghurt production

When we exercise and get out of breath not enough oxygen can reach our muscles and anaerobic respiration takes place in the muscle this forms lactic acid which causes cramps, when you rest the lactic acid is broken down by the liver

Alcohol Fermentation Takes place in Bacteria and some fungi such as yeast and in plants

when they are deprived of oxygen Involves the partial breakdown of glucose Glucose 2Ethanol + 2Carbon dioxide + small amount of

energy The ethanol itself is high energy Alcohol fermentation has been used for centuries In baking yeast is used for alcohol fermentation, the alcohol

evaporates but the carbon dioxide causes the dough to rise Baking powder is used instead of yeast in very hot ovens

8

Industrial Fermentation

Biotechnology refers to the use of living things (such as microorganisms and enzymes) to carry our useful reactions

In industrial fermentation the microorganisms are placed in a container with a suitable substrate on which they can react

The vessel in which biological reactions can take place is called a Bioreactor

When the microorganisms are mixed with the substrate foam may be formed so a foam breaker is used

Oxygen is pumped in through a sparger Quality and amount of product depend on the quality of the

microorganism and substrate, the design of the bioreactor, a correct rate of mixing, a correct temperature and pH and elimination of contaminating microorganisms

Microorganisms used in bioprocessing

New mo/s are being produced by genetic engineering In general bacteria and fungi (especially yeast strains) Bacteria can be used to make yoghurts, antibiotics + enzymes Yeasts can be used to make Beer and wine, carbon dioxide for

baking and single cell protein Fungi can produce antibiotics and citric acid

Bioprocessing with Immobilised cells To ensure the microorganisms used in a bioreactor are not lost at

the end of every reaction they are often immobilised or fixed The microorganisms can be immobilised by bonding them to each

other bonding them to an insoluble support or suspending them in a gel or

In the treatment of sewage bacteria and fungi may be attached to sand and

In the production of alcohol yeast cells are immobilised with sodium alginate

Immobilisation is gentle it does not Immobilised cells can be easily Immobilised cells reduce the need for

filtration at the end of bioprocessing Immobilised cells can be reused

9

Differences between Aerobic and Anaerobic Respiration

Aerobic Anaerobic

Location Cytoplasm and Lumen and Cristae of mitochondria

Cytoplasm

Oxygen Requirements

Uses O2 Does not use O2

End Products CO2 + H2O Ethanol +CO2orLactic acid

Energy Produced Lots of energy(38 ATP)

Little energy(2 ATP)

10

Useful videos and websites

http://youtu.be/i8c5JcnFaJ0

http://leavingbio.net/RESPIRATION-(higher%20level).htm

Revision diagrams:

11

12

13

14

15

16

Exam questions:

2013 Q14 b

2012 Q12 c

2011 Q6

17

2009 Q12 a, b

2008 Q5

18

19

2.2.5 Respiration TestName: ________________

Class: ________________

1. The benefit of respiration is the production of ___________________. (10)

2. Aerobic respiration produces _________________________ energy than anaerobic respiration because it involves a ________________________________ breakdown of glucose. (2(5))

3. State the end product(s) of each of the following:

(a) glycolysis in yeast __________________________________

(b) glycolysis in humans __________________________________

(c) fermentation in yeast ___________________________________

(d) lactic acid fermentation __________________________________

(e) aerobic respiration ____________________________________ (5(2))

4. Name a precise location in a cell for the location of each of the following:

(a) Kreb’s cycle ___________________________________

(b) stage 1 of respiration ___________________________________

(c) the use of oxygen in respiration ___________________________________

(d) an electron transport system ______________________________________

(e) the formation of acetyl coenzyme A ___________________________________ (2(5))

5. In preparing a cell immobilisation:

(a) The gel must be impermeable to ___________________________.

20

(b) The calcium chloride solution is stirred (when adding the gel and cells) in order to_____________________________________________________. (2(5))

6. Name the reagent used in each case to test for the products of fermentation in yeast___________________________and ________________________ _________________________. (2(5))

7. The molecule that carries high-energy electrons to the electron transport system is _________________. (10)

8. In oxidative phosphorylation, _____________ is converted to ____________ by the addition of a _______________________________.

This process requires ______________ and takes place on the ________________________ of a mitochondrion. (5(2))

9. At the end of the electron transport system, electrons are combined with _________________ and hydrogen to form ____________________. (2(5))

10. In anaerobic respiration (which is a stage _____ process), _______________________ acid is converted to ____________________ ________________ in mammals or to __________________and _____________________ ________________________ in yeast. (5(2))

2.2.5 RespirationSelf-Assessment

Where is your learning at?

Green : I know it allOrange : I have some idea – study the sections in more detail Red : I need to start studying this section

Can You Green Orange Red

21

1 Define the term Aerobic respiration2 Explain the role of aerobic respiration in

living things3 Express aerobic respiration by a balanced

equation4 Explain why aerobic respiration is a two

stage process5 State what happens during stage 16 State where in the cell stage 1 takes place7 State what happens during stage 28 State where in the cell stage 2 takes place9 State the difference between the cytosol and

the cytoplasm10 Define the term Anaerobic respiration11 Explain why anaerobic respiration is a one

stage process12 Name the products of anaerobic respiration13 Say which type of respiration releases more

energy?14 Explain the term fermentation15 State what type of microorganisms play a

role in fermentation16 Explain what a bioreactor is17 Outline how microorganisms are used in

bioprocessing18 Explain the advantages of bioprocessing

with immobilised cells19 Describe how to investigate the production

of alcohol by yeast20 Draw a labelled diagram to show how you

would carry out this investigation

22

2.2.10.H Respiration

Extended Study

Self Assessment

Where is your learning at?

Green : I know it allOrange : I have some idea – study the sections in more detail Red : I need to start studying this section

Can You Green Orange Red

1 S ta t e wha t i s me an t by G lyco l ys i s2 S ta t e whe re g lyco l y s i s t akes p l a ce3 S ta t e t he e nd p roduc t s o f g lyco l y s i s4 S ta t e t he e nd p roduc t s o f

f e rme n ta t i on [ anae rob ic cond i t i ons ] o f t he py ruva t e m o lecu l e i n p l an t s and yea s t

5 S ta t e t he e nd p roduc t s o f f e rme n ta t i on [ anae rob ic cond i t i ons ] o f t he py ruva t e m o lecu l e i n a n ima l s and bac t e r i a

6 S ta t e whe re t he s ec ond - s t age p roces s , unde r ae rob i c cond i t i ons , occu r s

7 S ay wha t tw o mo l ecu l e s t hethe py ruva t e m o lecu l e i s b roken down t o

8 De sc r ibe w ha t ha ppens du r ing the Kre bs ' cyc l e

9 S ta t e wha t u l t ima te ly ha ppens t he e l e c t rons r emove d f rom the subs t r a t e i n t e rm ed ia t e s i n K rebs ' cyc l e

10 S ta t e wha t u s e i s made o f t he e ne rgy r e l e a s ed by the s e e l ec t rons t h rough the e l ec t ron t r ans po r t c ha in

23

24

25

Cellular Respiration - True or False

Name___________________ Class______________ Date________

Write true if the statement is true or false if the statement is false.

_____ 1. Like photosynthesis, cellular respiration begins with an electron transport chain.

_____ 2. Cellular respiration that proceeds in the presence of oxygen is called aerobic respiration.

_____ 3. Oxygen is the final electron acceptor during anaerobic respiration.

_____ 4. Cellular respiration occurs in the mitochondria.

_____ 5. Mitochondria posses their own DNA and ribosomes.

_____ 6. Just like the chloroplast, the stroma separates the inner and outer membranes of the mitochondria.

_____ 7. The Krebs cycle comes after glycolysis, during cellular respiration.

_____ 8. Cellular respiration begins with the absorption of sunlight by the mitochondria photosystems.

_____ 9. One molecule of glucose holds enough energy to produce up to 38 ATP.

_____ 11. Whereas plants perform photosynthesis, plants and animals perform cellular respiration.

Cellular Respiration - Multiple Choice

Name___________________ Class______________ Date________

Circle the letter of the correct choice.

1. Glycolysis(a) uses 2 ATPs and makes 2 ATPs, 2 NADHs, and 2 pyruvates.

26

(b) uses 2 ATPs and makes 4 ATPs, 2 NADHs, and 2 pyruvates.(c) uses 4 ATPs and makes 2 ATPs, 2 NADHs, and 2 pyruvates.(d) uses 2 ATPs and makes 4 ATPs, 4 NADHs, and 2 pyruvates.

2. Cellular respiration in the presence of oxygen is called(a) anaerobic respiration.(b) glycolysis.(c) aerobic respiration.(d) oxygen respiration.

3. The correct order of stages of cellular respiration is(a) glycolysis - the Calvin cycle - electron transport.(b) the light reactions - glycolysis - the Krebs cycle.(c) glycolysis - the Krebs cycle - electron transport.(d) electron transport - glycolysis - the Krebs cycle.

4. Where are the electron transport chains of cellular respiration located?(a) in the inner membrane of the mitochondrion(b) in the matrix of the mitochondrion(c) in the intermembrane space of the mitochondrion(d) in the outer membrane of the mitochondrion

5. The final electron acceptor at the end of cellular respiration is(a) hydrogen.(b) oxygen.(c) water.(d) ATP synthase.

6. The chemical formula of cellular respiration is(a) 6CO2 + 6H2O → C6H12O6 + 6O2.(b) C6H12O6 + O2 → CO2 + H2O.(c) CO2 + H2O → C6H12O6 + O2.(d) C6H12O6 + 6O2 → 6CO2 + 6H2O.

7. In the presence of oxygen, one glucose molecule has the energy to make up to(a) 4 FADH2.(b) 12 NADH.(c) 38 ATP.(d) all of the above

Cellular Respiration – Vocabulary I

Name___________________ Class______________ Date________

Match the vocabulary word with the proper definition.Definitions_________________________ 1. channel protein and enzyme that makes ATP

_________________________ 2. also known as the Krebs cycle

_________________________ 3. end product of glycolysis

_________________________ 4. cellular respiration in the absence of oxygen

_________________________ 5. energy-carrying compound involved in stage I and stage II of cellular respiration

27

_________________________ 6. stage II of cellular respiration

_________________________ 7. “folds” created by the mitochondria inner membrane

_________________________ 8. glucose splitting

_________________________ 9. involved in stage III of cellular respiration

_________________________ 10. cellular respiration in the presence of oxygen

Termsa. aerobic respirationb. anaerobic respirationc. ATP synthased. citric acid cyclee. cristaef. electron transport chaing. glycolysish. Krebs cyclei. NADHj. pyruvate

Cellular Respiration - Vocabulary II

Name___________________ Class______________ Date________

Fill in the blank with the appropriate term.

1. The reactions of cellular respiration can be grouped into three stages: ____________, the _____- ______ cycle, and electron transport chain.

2. Cellular respiration in the absence of oxygen is called ____________ respiration.

3. The last two stages of cellular respiration occur in the ____________.

4. Most of the ATP is produced in the __________________________ of cellular respiration.

5. ____________ is the final electron acceptor at the end of the electron transport chain, when water is formed.

6. During glycolysis, enzymes split a molecule of glucose into two molecules of ____________.

7. ____________ releases the energy in glucose to make ATP.

8. During the Krebs cycle, energy is captured in molecules of ____________, ____________, and FADH2.

28

9. ____________ is the molecule that enters the Krebs cycle.

10. During glycolysis, ____________ molecules of ATP are used, and ____________ molecules of ATP are made.

11. ____________ is the enzyme that produces ATP during the final stage of cellular respiration.

12. In all three stages of aerobic respiration, up to ____________ molecules of ATP may be produced from a single molecule of glucose.

Anaerobic Respiration - Multiple Choice

Name___________________ Class______________ Date________

Circle the letter of the correct choice.1. Complete this sentence: Most living things use ____________ to make ____________- from glucose.(a) oxygen, ATP(b) ATP, oxygen(c) NADH, NAD+(d) oxygen, NAD+

2. Which of the following organisms can perform alcoholic fermentation? (1) yeast, (2) humans, (3) bacteria.(a) 1 only(b) 1 and 2(c) 1 and 3(d) 1, 2, and 3

3. Which of the following is true about anaerobic respiration?(a) It is a very fast process.(b) It allows organisms to live in places where there is little or no oxygen.(c) It evolved before aerobic respiration.(d) All of the above are true.

4. In alcoholic fermentation(a) carbon dioxide is released.(b) NADH is recycled.(c) lactic acid is produced.(d) all of the above

5. Fermentation involves which stages of cellular respiration? (1) glycolysis, (2) the Krebs cycle, (3) electron transport.(a) 1 only(b) 1 and 2(c) 2 and 3(d) all three stages

6. In lactic acid fermentation29

(a) carbon dioxide is released.(b) NADH is recycled.(c) lactic acid is produced.(d) all of the above

7. After intense activity, your muscles feel sore because of(a) the accumulation of NAD+.(b) the accumulation of lactic acid.(c) the accumulation of ATP.(d) the accumulation of carbon dioxide.Anaerobic Respiration - Vocabulary I

Name___________________ Class______________ Date________

Match the vocabulary word with the proper definition.

Definitions_____ 1. an important way of making ATP without oxygen_____ 2. respiration in the absence of oxygen_____ 3. makes your muscles feel tired and sore after intense exercise_____ 4. recycles during fermentation_____ 5. perform cellular respiration in the presence of oxygen_____ 6. can use lactic acid fermentation for energy_____ 7. can use alcoholic fermentation for energy_____ 8. stage of cellular respiration that occurs with or without oxygen_____ 9. product of glycolysis_____ 10. energy in the cell_____ 11. fermentation in which pyruvic acid from glycolysis changes to lactic acid_____ 12. fermentation in which pyruvic acid changes to alcohol and carbon dioxideTermsa. aerobic organismsb. alcoholic fermentationc. anaerobic respirationd. ATPe. fermentationf. glycolysisg. lactic acidh. lactic acid fermentationi. muscle cellsj. NAD+k. pyruvic acidl. yeast

30

Anaerobic Respiration - Vocabulary II

Name___________________ Class______________ Date________

Fill in the blank with the appropriate term.

1. A way of making ____________ without oxygen is called fermentation.

2. During lactic acid fermentation, NAD+ cycles back to allow ____________ to continue.

3. Fermentation involves ____________, but not the other two stages of cellular respiration.

4. Aerobic respiration evolved after ____________ was added to Earth’s atmosphere.

5. In ____________ fermentation, pyruvic acid changes to alcohol and carbon dioxide.

6. Organisms that can make ATP without oxygen include some plants and ____________ and also of many bacteria.

7. In ____________ fermentation, pyruvic acid from glycolysis changes to lactic acid.

8. The small holes in bread are formed by bubbles of ____________ gas, which is produced by alcoholic fermentation in yeast.

9. Without oxygen, organisms can just split glucose into ____________ molecules of pyruvate.

10. ____________ in bread dough use alcoholic fermentation and produce carbon dioxide gas.

11. Aerobic respiration produces much more ____________ than anaerobic respiration.

12. Most organisms use oxygen to make ____________ from glucose.

Anaerobic Respiration - Critical Writing

Name___________________ Class______________ Date________

Thoroughly answer the question below. Use appropriate academic vocabulary and clear and completesentences.

31

Compare aerobic and anaerobic respiration, and discuss the advantages of each.

Respiration Keywords:

32

2.2.5 Respiration TestInstructions: Answer all questions into your answer booklet.

33

34