2. Chapter 8 Cellular Energy *Photosynthesis *Cellular Respiration Cellular Energy Cellular Energy

3. ENERGY - is the ability to do work ALL ORGANISMS – need and use energy!!!!

4. Where do organisms get the energy that they need? it comes from food, however, the ultimate source of most of our energy is the SUN

5. Law of Thermodynamics Energy cannot be created or destroyed, but it can be converted into other forms Energy cannot be created or destroyed, but it can be converted into other forms

6. Metabolism The sum of a cell’s chemical reactions The sum of a cell’s chemical reactions Metabolism = Catabolism + Anabolism Metabolism = Catabolism + Anabolism Catabolism: to break down Catabolism: to break down Ex: cellular respiration Ex: cellular respiration Anabolism: to build up Anabolism: to build up Ex: photosynthesis Ex: photosynthesis *This results in a continuous flow of energy within an organism.

7. organisms meet their energy needs in different ways in different ways AUTOTROPHS – plants, some bacteria & protists produce their own food chemoautotrophs go through chemosynthesis chemoautotrophs go through chemosynthesis photoautotrophs go through photosynthesis photoautotrophs go through photosynthesis HETEROTROPHS – fungi, animals, some bacteria & protists cannot produce their own food must obtain energy from the foods they consume must obtain energy from the foods they consume

8. ENERGY energy comes in many forms – light, heat, electricity, nuclear, kinetic,… energy comes in many forms – light, heat, electricity, nuclear, kinetic,… Some organisms consume foods in order to get the stored energy out of them Some organisms consume foods in order to get the stored energy out of them

9. ATP cellular activities require the use of energy cellular activities require the use of energy one of the main chemical compounds that cells use to store energy is ATP (adenosine triphosphate) one of the main chemical compounds that cells use to store energy is ATP (adenosine triphosphate) ATP consists of : 1. a N-containing part – called adenine 1. a N-containing part – called adenine 2. a 5-Carbon sugar - called ribose 2. a 5-Carbon sugar - called ribose 3. three phosphate groups (P and O) 3. three phosphate groups (P and O)

10. Metabolic Pathway of ATP and ADP Metabolic Pathway of ATP and ADP form a cycle of releasing and absorbing energy form a cycle of releasing and absorbing energy ATP ADP releases Energy requires (absorbs) energy

11. ATP and Glucose most cells have only a small amount of ATP (enough to last for a few seconds of activity) most cells have only a small amount of ATP (enough to last for a few seconds of activity) more is made as needed by using the stored energy (glycogen) more is made as needed by using the stored energy (glycogen)

12. 2 processes of great importance that enable living things to meet their energy needs – 1. PHOTOSYNTHESIS – the production of organic compounds 2. CELLULAR RESPIRATION – the break down of organic compounds

13. PHOTOSYNTHESIS PHOTOSYNTHESISCELLULARRESPIRATION ATP- ADP CYCLE Light Energy Chemical Energy (organic compounds) ATP’s ADP’s + P groups + energy (that can be used to do cellular activities) ADP’s + P groups + energy (that can be used to do cellular activities)

14. Photosynthesis process by which a cell captures light energy (photons) and uses it to make food (usually carbohydrates, like glucose) photosynthesis occurs in photoautotrophs: plants algae some bacteria (prokaryotes)

15. PHOTOSYNTHESIS - process in which water, carbon dioxide, and light energy are converted into oxygen and organic compounds the ORGANIC COMPOUNDS made during photosynthesis are usually carbohydrates (sugars and starches)

16. PHOTOSYNTHESIS – general equation 6 CO 2 + 6 H 2 O + light (energy) C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + light (energy) C 6 H 12 O 6 + 6 O 2 What are the reactants? What are the products? Where does the light energy come from? Where does the H 2 O come from? Where does the CO 2 come from?

17. Photosynthesis - Overview

18. most photosynthetic organisms are eukaryotes, therefore, photosynthesis occurs inside the CHLOROPLAST prokaryotes lack chloroplasts, in these organisms, photosynthesis occurs in the cytoplasm

19. PIGMENTS ALL photosynthetic organisms contain PIGMENTS (light absorbing substances) the principal photosynthetic pigment is (green) CHLOROPHYLL in addition to chlorophyll there are other pigments called ACCESSORY PIGMENTS (ex. Carotenoids)

20. Chloroplast Structure chloroplasts contain disc like structures called THYLAKOID DISKS these are arranged in stacks called GRANA PIGMENTS are found inside the thylakoid disks a fluid called STROMA surrounds the thylakoid disks

21. PHOTOSYNTHESIS – consists of 2 major sets of reactions 1. LIGHT DEPENDENT REACTIONS 1. LIGHT DEPENDENT REACTIONS 2. LIGHT INDEPENDENT REACTIONS 2. LIGHT INDEPENDENT REACTIONS (or CALVIN CYCLE) What do the names indicate about these reactions?

22. Light Dependent Reactions (occur in thylakoid disk containing chlorophyll) Light Independent Reactions (occur in stroma)

23. Light dependent reaction: What are the reactants? products? Light independent reaction (Calvin Cycle)? What are the reactants? products? Light dependent reaction: What are the reactants? products? Light independent reaction (Calvin Cycle)? What are the reactants? products?Calvin CycleCalvin Cycle

24. Alternative Pathways Used when water and/or carbon dioxide are not present or in insufficient amounts Used when water and/or carbon dioxide are not present or in insufficient amounts 2 types: 2 types: The C 4 pathway The C 4 pathway Sugar cane, corn Sugar cane, corn The CAM pathway The CAM pathway Pineapple, cacti, orchids Pineapple, cacti, orchids

25. Factors Affecting Photosynthesis availability of water availability of water availability of carbon dioxide availability of carbon dioxide temperature temperature light intensity light intensity

26. Biochemical (Metabolic) Pathway

27. PHOTOSYNTHESIS PHOTOSYNTHESISCELLULARRESPIRATION ATP- ADP CYCLE ATP- ADP CYCLE Light Energy Light Energy Chemical Energy Chemical Energy (organic compounds) (organic compounds) ATP’s ATP’s ADP’s + P groups + energy (that can be used to do cellular activities) ADP’s + P groups + energy (that can be used to do cellular activities)

28. Cellular Respiration Cellular Respiration process that releases energy (in the form of ATP’s) from food (organic compounds) All living things undergo some form of cellular respiration, but remember living things differ so this process may differ

29. There are 2 possible ways in which a cell can accomplish cellular respiration and harvest energy from food…. (aerobic) Cellular Respiration = oxidative respiration ellular Respirationellular Respirationor FermentationFermentation (anaerobic respiration) Fermentation *both start with the same first step GLYCOLYSIS

30. (aerobic) Cellular Respiration or Oxidative Respiration (aerobic) Cellular Respiration or Oxidative Respiration releases energy (in the form of ATP’s) from food (organic compounds) ~in the presence of oxygen~

31. 3 steps of (aerobic) Cellular Respiration 1. Glycolysis 2. Kreb’s Cycle 3. Electron Transport Chain

32. 1. Glycolysis 1. Glycolysis  occurs in the cytoplasm  anaerobic  “splitting of glucose” into pyruvic acid (pyruvate)  net gain of 2 ATP and 2 pyruvate

33. 2. Kreb’s Cycle 2. Kreb’s Cycle  occurs in mitochondrion (of eukaryotes)  aerobic  breaks down pyruvic acid  produces CO 2 and a net gain of 2 ATP

34. 3. Electron Transport Chain 3. Electron Transport Chain  occurs in mitochondria(of eukaryotes)  aerobic  uses electrons to release energy and produce ATP  produces H 2 O and up to 34 ATP

35. How many ATP’s from (aerobic) Cellular Respiration? Glycolysis (2) Kreb’s Cycle (2) Electron Transport Chain (maximum 34) possible 38 ATP’s possible 38 ATP’s the actual number of ATP’s varies from cell to cell the actual number of ATP’s varies from cell to cell most eukaryotic cells produce 36 ATP’s most eukaryotic cells produce 36 ATP’s

36. General Equation for (aerobic) Cellular Respiration C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + ATP (energy) What are the reactants? What are the products?

37. if no oxygen is present….. glycolysis is followed by fermentation Fermentation (anaerobic respiration) releases energy (in the form of ATP) from food (organic compounds) ~in the absence of oxygen~

38. 2 steps of Fermentation (anaerobic respiration) 1. Glycolysis 2. Fermentation

39. 1. Glycolysis  occurs in the cytoplasm  anaerobic  “splitting of glucose” into pyruvic acid (pyruvate)  net gain of 2 ATP and 2 pyruvate

40. 2. Fermentation  occurs in the cytoplasm  anaerobic  the break down of pyruvic acid in the absence of oxygen  net gain of 0 ATP

41. How many ATP’s from FERMENTATION? Glycolysis (2) Fermentation (0) possible 2 ATP possible 2 ATP * fermentation is not nearly as efficient in releasing energy from food as is (aerobic) Cellular Respiration

42. 2 common types of Fermentation LACTIC ACID FERMENTATION converts pyruvic acid into lactic acid converts pyruvic acid into lactic acid process used to make yogurt, cheese, sour cream occurs in some fungi and some bacteria occurs in skeletal muscle cells of animals = lactic acid or sore muscles

43. 2 common types of Fermentation ALCOHOLIC FERMENTATION converts pyruvic acid into ethanol (ethyl alcohol) converts pyruvic acid into ethanol (ethyl alcohol) process used in the making of bread and alcoholic beverages - wine, beer,… occurs in yeasts, some bacteria, some plants ethanol is added to gasoline to make gasohol ethanol is added to gasoline to make gasohol

44. Visualizing Cellular Respiration

45. Let’s see the process again…

46. Photosynthesisand Cellular Respiration are a metabolic (biochemical) pathways BECAUSE…..

47. The products of photosynthesis are used as the reactants in cellular respiration The products of photosynthesis are used as the reactants in cellular respiration The products of cellular respiration are used as the reactants in photosynthesis The products of cellular respiration are used as the reactants in photosynthesis

48. Cellular Respiration Virtual Lab Cellular Respiration Virtual Lab Cellular Respiration Virtual Lab Cellular Respiration Virtual Lab