1. 1 Respiration The controlled release of energy from glucose, within a cell - 24 hour process.

2. 2 Contents Aerobic respiration Stage 1 Stage 2 Anaerobic respiration Aerobic – Biochemistry Aerobic Vs Anaerobic Industrial Fermentation Yoghurt Manufacture Beer Manufacture Use of Immobilised yeast

3. 3 Aerobic respiration The controlled release of energy from glucose, within a cell, using oxygen. In general (aerobic respiration): Glucose + oxygen  Energy + waste products Waste products = carbon dioxide + water

4. 4 Balanced equation for Aerobic Respiration C 6 H 12 0 6 + 6O 2  Energy + 6CO 2 + 6H 2 0 2820 kJ

5. 5 Respiration – a one or two stage process Stage 1 does not require oxygen and releases a small amount of energy – called glycolysis. - glucose (6 carbon carbohydrate) broken down into two 3 carbon compounds (pyruvate or pyruvic acid) in the cytosol (cytoplasm minus the organelles) of the cell, with the release of ATP. -this process releases very little energy (2 ATP).

6. 6 Stage one – aerobic & anaerobic respiration

7. 7 Respiration – a one or two stage process Stage 2 does require oxygen and releases a large amount of energy. -this process takes place in the mitochondria of the cell. Note: the rate of both processes are controlled by enzymes.

8. 8 Anaerobic Respiration The controlled release of energy from glucose, within a cell, without using oxygen. Oxygen may be present but oxygen will not be used. This is a Stage 1 process. In general (anaerobic respiration): Glucose  Energy + waste products

9. 9 Anaerobic Respiration – waste products Waste products = lactic acid Occurs in humans – causes cramps OR Waste products = carbon dioxide + ethanol Occurs in yeast – fermentation

10. 10 Balanced equations for Anaerobic Respiration C 6 H 12 O 6  Energy + 2CH 3 CH(OH)COOH 150 kJLactic acid C 6 H 12 O 6  Energy + 2C 2 H 5 OH + 2CO 2 210 kJEthanol

11. 11 Anaerobic respiration – summary chart OR

12. 12 Aerobic respiration – Stage 2 (1/3) Oxygen must be present. The pyruvate molecule (3C) enters a mitochondrion The pyruvate is broken down to one molecule of CO 2 (1C) and Acetyl Co- enzyme A (2C).

13. 13 Aerobic respiration – Stage 2 (2/3) Acetyl Co-enzyme A enters a series of chemical reactions, Kreb’s Cycle where it is broken down to CO 2 and H. During Kreb’s Cycle an electron transfer system operates to remove electrons from the hydrogen (H + + e - ) Electrons from the cycle are transferred through an electron transport chain

14. 14 Aerobic respiration – Stage 2 (3/3) The energy released by the transport of the electrons is used to make ATP from ADP and P. ADP + P  ATP Finally the electrons are transferred to oxygen which combines with hydrogen to form water

15. 15 Stage two – summary chart

16. 16 Types of Respiration – comparison AerobicAnaerobic See slide 27 for solution Complete this yourself – a minimum of four points

17. 17 Industrial fermentation Fermentation is important in the food and drink industries. Brewing, baking, yoghurt and cheese making all depend on micro-organisms fermenting the original food to produce the desired product. These are examples of biotechnology.

18. 18 Complete this table Original food Micro- organism used Desired product Brewing Baking Yoghurt making Cheese making

19. 19 Completed table Original food Micro- organism used Desired product Brewing Starch, sugar yeastAlcohol BakingStarchyeast Carbon dioxide Yoghurt making MilkBacteriaLactic acid Cheese making MilkBacteria e.g. Danish blue

20. 20 Yoghurt Manufacture (1/2) Made from milk. Sugar and/or powdered milk may be added. Skimmed milk use for making low-fat yoghurt. Milk pasteurised – kills pathogenic (disease causing) bacteria e.g. Tuberculosis bacillus, and stops growth of bacteria that sours milk.

21. 21 Yoghurt Manufacture (2/2) Milk cooled to 46°C and a starter culture of lactic acid bacteria is added. Yoghurt cooled after 4 to 5 hours at 46°C – to allow growth of yoghurt microbes. Fruit added – in a starch and sugar suspension. Colours & flavours added. Packed, cool and store in fridge.

22. 22 Industrial production of Yoghurt

23. 23 Beer Manufacture (1/2) Made from grain – barley – food stored as starch in grain – contains the enzyme amylase – enzyme produces as it germinates. Grain dampened, kept warm and allowed to germinate (= malting) – malt dried and stored. Malt ground with water – allows amylase convert starch to sugar – more barley can be added to increase starch supply.

24. 24 Beer Manufacture (2/2) Solution boiled to stop amylase activity. Mixture filtered. Hops added – for flavour and to reduce the growth of unwanted bacteria. Yeast (fungus) is added – Saccharomyces cerevisiae – fermentation begins. Yeast removed after about a week – by filtering. Beer bottled for distribution and sale.

25. 25 Industrial production of Beer

26. 26 Use of immobilised yeast Yeast cells are immobilised in sodium alginate beads. Sugar solution passed down through a bioreactor of S. cerevisiae containing beads. Alcohol produced and runs out the bottom of the column. Bioreactor can be used continuously – do not have to stop to separate yeast from alcohol.

27. 27 Advantages of immobilised yeast Gentle procedure Easily recovered Reduction in filtration procedure Reusable

28. 28 Types of Respiration – comparison Aerobic Oxygen necessary Produces a lot of energy Occurs in cytosol and mitochondria Consists of two stages Produces energy, CO2 and H2O Anaerobic Oxygen not necessary Produces very little energy Occurs in cytosol only Consists of one stage only Produces energy, ethanol + CO2 or energy +lactic acid Back to slide 15

29. 29 END