Lecture 3 Outline (Ch. 9, 10)

2. Lecture 3 Outline (Ch. 9, 10) • Recap of Glycolysis, Coenzyme Junction • Cellular Respiration continued • A. Citric Acid Cycle (aka Krebs/TCA cycle) • B. Electron Transport Chain (ETC) • C. Chemiosmosis • Anaerobic respiration • Respiration using other biomolecules • Introduction to Photosynthesis • A. Chloroplasts • B. Light wavelengths • VI. Preparation for next lecture

3. Steps of Respiration

4. Steps of Respiration • Stages of respiration: • Citric acid cycle • Mitochondrial matrix • e- transfer: redox

5. Cellular Respiration 2. Citric acid cycle • few ATP so far • now in mitochondrial matrix • 2 Acetyl CoA (2C) join oxaloacetate (4C) • 2 citrate (6C) converted several steps, 4C lost (CO2) • 2 ATP made • e- to carriers (NAD+, FAD)

6. Citric acid cycle -inputs: 2 Acetyl CoA (2C) -outputs: [2 oxaloacetate (4C)] 2 ATP 6 NADH 2 FADH2 4 CO2 (H2O = none) Where do outputs go?

7. Which step so far has loaded the most electron carriers? • Glycolysis • Coenzyme junction • Citric acid cycle • They are all equal so far • No electron carriers have been loaded yet

8. Steps of Respiration • Stages of respiration: • ETC • Proton Motive Force

9. Cellular Respiration 3. Electron transport chain (ETC) • lots of energy harvested • released in stages • so far, 4 ATP – made by substrate phosphorylation – not as efficient • now, many ATP – made by oxidative phosphorylation

10. Steps of Respiration • Stages of respiration: 4. Chemiosmosis ATP produced!

11. Cellular Respiration Electron transport chain (ETC) • ETC  e- collection molecules • embedded on inner mitochondrial membrane • accept e- in turn • e- ultimately accepted by O2 (O2 reduced to H2O)

12. Electron transport chain (ETC) -inputs: per glucose, 10 NADH 2 FADH2 -outputs: ATP (none yet) ~100 H+ (stored) 10 H2O Where do outputs go?

13. Cellular Respiration 4. Chemiosmosis • ATP synthase: inner mitochondrial membrane • H+ stock-piled in inner membrane space = gradient • chemiosmosis – ion gradient to do work

14. Cellular Respiration 4. Chemiosmosis • ATP synthase: enzyme that makes ATP using H+ gradient • H+ must enter matrix here • Generates 1 ATP per ~3.4 H+

15. Where is the electron transport chain located in the diagram? • Green area • Blue area • Yellow area • Pink area

16. Cellular Respiration Summary of respiration KNOW THIS DIAGRAM – EXCELLENT SUMMARY 

17. Cellular Respiration - anaerobic • no O2 – no oxidative phosphorylation • fermentation = extension of glycolysis

18. Cellular Respiration - anaerobic • Types of fermentation - 1. alcohol • brewing & baking • pyruvate converted to acetaldehyde • acetaldehyde accepts e- • ethanol produced

19. Cellular Respiration - anaerobic • Types of fermentation - 2. Lactic acid • muscle fatigue • pyruvate accepts e- • lactate produced

20. Cellular Respiration • Comparison of aerobic vs. anaerobic respiration: Aerobic Anaerobic • e- carriers loaded: • ATP per glucose: • initial e- acceptor: • final e- acceptor:

21. Cellular Respiration – other biomolecules • Glucose catabolism – one option • Proteins: Catabolized into a.a. Amino group removed (pee out in urine) • Fats: enter CAC or before • If have more glucose than needed, can run “backward” to store energy as glycogen or fats!

22. Self-Check

23. Which cells perform aerobic cellular respiration? • Plant cells only • Animal cells only • Bacteria only • Plant and animal cells • Plant, animal and bacterial cells

24. Photosynthesis - overview

25. Photosynthesis - overview Overall purpose: • photosynthesis: light chemical energy • complements respiration - light rxn: solar energy harvest - “dark” rxn: energy to organics

26. Cellular Respiration: (Exergonic) Photosynthesis: (Endergonic) Cellular Respiration vs. Photosynthesis

27. chloroplast recap Outer membrane Inner membrane Thylakoid membrane Intermembrane space Stroma Thylakoid space

28. Photosynthesis - overview Chloroplast model: • Photosynthesis - 1. light rxn: store energy & split water NADPH & ATP given off

29. CO2 + H2O + light energy C6H12O6 + O2 Redox Reactions Equation for photosynthesis synthesis photo

30. In photosynthesis, which of the following happens to H2O? • Oxidized to oxygen gas • Reduced to oxygen gas • Oxidized to glucose • Reduced to glucose

31. Photosynthesis – light absorption • visible light ~380 to 750 nm • chloroplast pigments – absorb blue-violet & red/orange - transmit and reflect green

32. Photosynthesis – light absorption • pigments: • chlorophyll a -energy-absorbing ring -hydrocarbon tail • accessory pigments - chlorophyll b - carotenoids - photoprotective

33. Photosynthesis – light absorption • chlorophyll a – abs blue-violet, red ~400-450, 650-700 • chlorophyll b & carotenoids – abs broadly blue-violet 450-500 & 600-650 • more wavelengths used for photosynthesis = more light energy absorbed

34. If a car is red, which light wavelengths are reflected (NOT absorbed)? • Green (500-550 nm) • Red (650-700 nm) • Blue (450-500 nm) • All wavelengths are reflected • All wavelengths absorbed

35. Things To Do After Lecture 3… • Reading and Preparation: • Re-read today’s lecture, highlight all vocabulary you do not understand, and look up terms. • Read chapter 9, focus on material covered in lecture (terms, concepts, and figures!) • Ch. 9 Self-Quiz: 1-7 (correct using the back of the book). • Skim next lecture. • “HOMEWORK”: • Draw a diagram similar to the cell on the next slide, and show where each step of cellular respiration occurs. • Match up the three boxes each for the citric acid cycle and oxidative phosphorylation (from last lecture). • Compare and contrast aerobic respiration and fermentation for three things that are similar/shared AND three things that are different! • Diagram a chloroplast labeling the three membranes and three spaces. • In the spectrum of visible light (380 to 750 nm), indicate which wavelengths (number AND color) are absorbed by chloroplasts and which are not absorbed.

36. Self-Check