Cellular Respiration

1. Cellular Respiration AP Biology

2. Why do we need Cellular Respiration? If we released all of the energy from glucose all at once (transfer electrons directly to oxygen), so much heat would be released that we would explode or at least denature all of our proteins.

3. Cellular Respiration Overview Taking the high energy electrons out of sugar and releasing the energy from the electrons in small steps, eventually returning the electrons and protons (H+) to oxygen making water AND making ATP using the energy released from the electrons

4. ATP

5. ATP Release Energy To do work From glucose ADP

6. Use Energy in ATP to do work • Work in living things: • Transport • Chemical reactions • Muscle Contraction • Active Transport, Endo and Exocytosis

7. Mitochondria Structure

9. e.t.c. Enzymes (Krebs), DNA, RNA, ribosomes

10. Making ATP Oxidative Phosphorylation: Phosphorylating ADP as the result of the e.t.c. in the mitochondria (chemiosmosis) Substrate Level Phosphorylation: An enzymatic transfer of Phosphate onto another molecule (usually ATP)

11. Overview of the reactions

12. Overview of the reactions Chemical reaction to make acetate (mitochontrial matrix) Krebs cycle (mitochondrial matrix) Electron Transport Chain (inner-mitochondrial membrane) With oxygen Glycolysis Cytoplasm Anaerobic Aerobic Without oxygen 38 Fermentation Cytoplasm Still Anaerobic 2 ATP

13. Glycolysis: first step of cellular respiration Glucose Pyruvate Pyruvate 2 ATP (substrate level phosphorylation) 2 carriers with H+ and high energy electrons (NADH)

14. No Name Step (first step in mitochondrial matrix – aerobic) CO2 released and H with its high energy electrons get put on a carrier (NAD+) Pyruvate Acetate + Coenzyme A Acetyl CoA

15. The Kreb’s Cycle (The Citric Acid Cycle):Series of Chemical Reactions in Mitochondrial Matrix Acetate gets broken down to 2 CO2 and all 4 of the H with their high ENERGY electrons get put onto carriers 2 ATP’s are made (substrate level) For each glucose, there are 2 acetates!

16. Krebs Cycle

17. Electron Transport ChainLocated in the inner membrane • Electron Transport Chain – series of carriers – each one more electronegative (attracted to electrons) than the previous one • As the electrons are passed from carrier to carrier – they are pulled closer to the atomic nucleus which causes them to lose energy • The energy is lost a little bit at a time

18. The Electron Transport Chain

19. Steps of the E.T.C. • STEP 1: the electron carriers that picked up electrons in glycolysis, no name step, and the Kreb’s cycle pass their electrons to the first molecule of the electron transport chain • STEP 2: with each successive pass to other carriers, the electronslose energy • STEP 3: The energy lost by the electrons is used to makeATP’s (34/ glucose) by chemiosmosis • STEP 4: The Hydrogens and their electrons which now have the normal amount of energy (lost the extra absorbed by the sun during the e.t.c) combine with oxygen to form water. There isn’t a big energy change all at once so there is no explosion just the loss of a reasonable amount of heat

20. Summary • Break the sugar apart back into CO2 and H which combine with O to make H2O • The excess energy stored in the electrons of H is slowly released and used to make ATP before they combine with the O • Therefore, the energy that came from the sun and was stored in the organic molecule sugar, is now temporarily stored in ATP until the energy is used to transfer the last phosphate to a motor protein, muscle protein, active transport channel, or substrate to do work

21. Fermentation Pyruvates + NADH (2 of them) Yeast Cell Animal Cell Alcohol + CO2 + NAD+ Lactic Acid + NAD+ All are waste products, so most of the energy stored in the sugar ends up not getting used by the organism Purpose is regenerate the NAD+

22. Anerobic Activities • No activity can be totally anaerobic and be compatible with life – it just means you can’t get enough Oxygen to stay totally aerobic (your need for ATP is greater than you can supply the oxygen for) • Anaerobic activities include anything that makes you breathe excessively heavy – sign you’re not getting enough oxygen • Sprinting, swimming really fast, biking really fast, etc., lifting really heavy weights • You will make lactic acid and run out of ATP – can’t keep going for very long

23. Making Wine and Bread • Yeast using the sugar provided by grapes or flour and added sugar to do cellular respiration • Sugar diffuses into yeast cells, if not enough oxygen, do some aerobic and some anaerobic respiration • As a result of anaerobic, they make alcohol and CO2 • In wine, CO2 evaporates and left with alcohol in the grape juice • In bread, baking the bread makes the CO2 and alcohol evaporate leaving behind holes where CO2 was making the bread fluffy

24. How to use Fat and Protein for Energy • Each fatty acid is broken up and rearranged to form many acetates which enter the Kreb’s Cycle • Amino acids contain very few C-H bonds but the amino and acid groups can be clipped off, and the rest can also be rearranged to enter glycolysis or the Kreb’s Cycle