Respiration

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Lesson 1

Respiration Respiration is the release of energy from food It is needed to provide energy for the human body Energy is needed for muscular activity and maintenance of body temperature The food involved in respiration is usually glucose Internal respiration is controlled by enzymes The reactions lead to the formation of molecules called ATP Energy from glucose is stored in ATP (Adenosine Triphosphate)

The 2 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

Aerobic Respiration AEROBES are living things that respire using oxygen The energy stored in bonds in glucose is released and used to make ATP

Equation for Aerobic Respiration C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + Energy Glucose + Oxygen Carbon dioxide + water + energy

Aerobic respiration is relatively efficient Any energy not used to produce ATP is lost as heat

Aerobic Respiration occurs in 2 stages  Stage 1: Glycolysis  Stage 2

Stage 1:Glycolysis Glycolysis is the breaking down of glucose (6 carbon ring)into two 3 carbon molecules, with the release of a small amount of energy Most of the energy in the glucose molecule remains stored in each 3- carbon molecule

Stage 1:Glycolysis Takes place in the cytosol because enzymes are present (respiration needs enzymes) Cytosol is the cytoplasm without the organelles Does not require oxygen Stage 1 occurs in both aerobic and anaerobic respiration

Learning Check 1. What is respiration? 2. There are two types of respiration what are they? 3. What is the difference between each type? 4. Where is the energy stored in cells? What are aerobes? 5. What does ATP supply for cells? 6. What is the balanced equation for respiration? 7. How efficient is aerobic respiration ? 8. What is the first stage of respiration called? 9. Where does this stage take place and why? 10. Does this stage require oxygen? 11. Does it release much energy? 12. What is the 6-carbon sugar broken into?

Lesson 1, can you….

Stage 2 Occurs in the mitochiondrian (as enzymes are present) Requires oxygen so only occurs in aerobic respiration Releases a large amount of energy The 3- carbon molecules are broken down to Carbon Dioxide and Water

Stage 2 The complete breakdown of the 3-carbon molecules releases a lot of energy There is very little energy left in Carbon Dioxide and Water

Aerobic respiration

Learning Check Where does the second stage take place? Why does it take place here? Does this stage require oxygen? Does it release much energy? Does it occur in aerobic respiration, anaerobic respiration or both? What is the 3-carbon sugar broken into?

Anaerobic Respiration Anaerobic respiration can occur in the presence of oxygen but it does not need to use it In anaerobic respiration Glycolysis occurs this means glucose is broken into two 3-carbon molecules A small amount of energy is released this way

Anaerobic Respiration There are different forms of anaerobic respiration where the 3 –carbon molecules are converted to different substances but no extra energy is released Anaerobic respiration is less efficient

Learning Checks Does anaerobic respiration require oxygen? What is glucose broken into? What process does this? Is there a lot or a little energy released by anaerobic respiration? Why is anaerobic respiration described as being less efficient than aerobic respiration?

Fermentation Anaerobic Respiration is also known as Fermentation 2 types of fermentation 1. Lactic Acid Fermentation 2. Alcohol Fermentation

Lactic Acid Fermentation In this fermentation Lactic acid is produced

Lactic Acid Fermentation Occurs in 1. Bacteria and milk: Lactic acid forms when bacteria cause milk to go sour

Lactic Acid Fermentation Occurs in 2. Bacteria and yoghurt production: yogurt bacteria is introduced into pasteurised milk at 40 degrees for 6 hours. Due to anaerobic respiration of the bacteria, lactic acid is produced and curdles the milk

Lactic Acid Fermentation Occurs in 3. Humans: 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

Learning Check What is fermentation? There are two types of fermentation what are they? Which type can occur in animal cells?

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

Alcohol Fermentation Used in 1. Brewing: yeast cells are immobilised (fixed) in sodium alginate beads and placed in a sugar solution in a bioreactor. They respire anaerobically to produce alcohol and carbon dioxide.

Alcohol Fermentation 2. Baking: yeast is used for alcohol fermentation, the alcohol evaporates but the carbon dioxide causes the dough to rise

Learning Check What are the end products of alcohol fermentation? What kind of organisms carry out alcohol fermentation? What is the benefit of alcohol fermentation in baking?

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

A bioreactor is a vessel where biological reactions take place

Nutrients and micro- organisms added here Gas out here Oxygen (if required) in here Stirrer Sparger Bioreactor for Batch Food Processing Product is released at the end of the process

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 quality of the microorganism quality of the substrate, design of the bioreactor, correct temperature and pH etc.

Microorganisms used in bioprocessing New mo/s are being produced by genetic engineering In general bacteria and fungi (especially yeast strains) OrganismProduct BacteriaYoghurt YeastEthanol- beer and wine FungiCitric Acid – food additive in soft drinks

Immobilisation If enzymes are used freely dissolved in a vessel it can be very wasteful as they are lost at the end of the process To prevent this problem enzymes are often immobilised or fixed Immobilised: Enzymes are attached to each other or an inert substance and used repeatedly 36

From the animation, list the physical and chemical ways to immobilise enzymes certificate-biology-plus/#ebookresources certificate-biology-plus/#ebookresources Book Page

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How to immobilise enzymes Trapped in a gel, sodium alginate. This allows substrates in and products out. Gel beads (with immobilised enzymes) are placed in a long column. Substrate is poured over beads and product is collected at the bottom. 39

Advantages of Immobilised Enzymes Immobilised enzymes: can be reused (cuts costs) efficiency is not affected can be easily removed to obtain a pure sample of product become more stable 40

Learning Check What is biotechnology? What is a bioreactor? Why is a foam breaker needed? What is oxygen pumped in through? Name a few factors that affect quality and amount of product What types of microorganisms are used in bioprocessing? What are the advantages of immobilising cells?

AerobicAnaerobic Location Cytoplasm and Lumen and Cristae of mitochondria Cytoplasm Oxygen Requirements Uses O 2 Does not use O 2 End Products CO 2 + H 2 OEthanol +CO 2 or Lactic acid Energy Produced Lots of energy (38 ATP) Little energy (2 ATP) Differences between Aerobic and Anaerobic Respiration

Syllabus Can You?.... Definition of the term: aerobic respiration. Explain the role of aerobic respiration – what does it do for organisms? Express aerobic respiration by a balanced equation. State the nature of respiration from syllabus – what stages are involved, where do these take place, what happens? Definition of the term: anaerobic respiration. Express anaerobic respiration by a balanced equation. State the nature and role of fermentation. State the cellular location of the first & second stage. Explain the role of microorganisms in fermentation. Explain the role of microorganisms including bioprocessing and Bioreactors

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To prepare and show the production of alcohol by yeast watch?v=znhalRdr5Zs watch?v=znhalRdr5Zs

Step 1 Prepare a glucose solution by adding 5 g of glucose to 1000cm 3 of water and boil. Boiling removes gases from the solution causing anaerobic conditions

Step 2 Add 5 g of yeast to one flask. The second flask contains no yeast – this acts as a control.

Step 3 Label the flasks: ‘Yeast + Glucose’ and ‘Control’

Step 4 Cover the liquid in the flask with oil. This prevents oxygen re-entering the solution

Step 5 Half fill the fermentation locks with lime water and put one on each flask.

Step 6 Stand the flasks in a water bath at 30°C for 24 hours.

Result: Fermentation is complete when the bubbles stop. The bubbles eventfully stop because the alcohol produced kills the yeast.

Step 6 Filter the contents of each flask into separate boiling tubes.

Step 7 Add 3 ml potassium iodide to each boiling tube.

Step 8 Add 5 ml sodium hypochlorite to each boiling tube. The solution goes brown to orange

Step 9 Place boiling tubes in a water bath at 60°C for 4-5 minutes.

Expected result Yellow crystals shows alcohol is present.

Table of results: Flask Original colour of filtrate Final colour of filtrate Other changes Yeast + Glucose solution Control (no yeast)

The 2 Different ways it can be set up

2004 HL Q7

(b) Diagram [must include evidence of anaerobic conditions and two correct labels for 3 marks] 3, 0 Sugar or named sugar or starch 3 Carbon dioxide or any product of glycolysis 3 Yeast absent (or dead) in same set up 3 Comparison or purpose described 3 No more gas given off (no more bubbles) 3 *NB - To test for alcohol – All candidates who attempt Q 3 Water (allow other correct product from Kreb’s cycle) 3

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