1. Photosynthesis and Respiration
CELL ENERGY
Photosynthesis and Respiration

2. You should be able to…
Describe the role of ATP in biochemical reactions.
Describe the fundamental roles of chloroplasts and mitochondria in energy transformations.
Compare the basic transformation of energy during photosynthesis and cellular respiration.

3. A3 Vocabulary adenosine triphosphate (ATP) heterotroph autotroph
photosynthesis
pigment
chlorophyll
thylakoid
stroma
NADP+
light-dependent reactions
light independent reactions
aerobic
anerobic
cellular respiration
glycolysis
matrix
Kreb’s cycle
NAD+
fermentation
calorie

4. Chemical Energy and ATP
Energy = ability to do work
Energy comes in different forms (light, heat, electricity)
Cells need energy to do work
Cell energy comes from ATP (adenosine triphosphate)
Consists of adenine, a 5-carbon sugar and THREE phosphates
Phosphates are the key to ATP’s ability to store and release energy

5. Examples of ATP in action
Active transport
Protein pumps in cell membrane need ATP
Movement
Muscle contractions
Protein synthesis

6. How do cells release the energy stored in ATP?
Cells release energy from ATP when the bond between the second and third phosphate groups is broken
Phosphate released = energy released
ATP minus a phosphate group = ADP

7. Regenerating ATP
ADP (adenosine diphosphate) can be recharged by adding another phosphate group to become ATP again
Phosphate gained = energy stored
Cells regenerate ATP from ADP by using energy in food like glucose

8. Quick Check Where is the energy stored in the molecule of ATP?
How would you change the figure to show a molecule of ADP?

9. The connection between the food you eat and ATP…
Cells do not keep a lot of ATP
Food is digested and converted into ATP
Different foods give different amounts of ATP
Carbohydrate = 36 ATP
Lipid = 146 ATP
Proteins = broken down to make other proteins, not energy!!!!
Plants use photosynthesis to produce the carbs so their cells can get ATP

10. MODELING ATP
Activity

11. What are the green organelles inside the leaf cells?.
What is the function (job) of the chloroplast?

12. LIGHT Energy Mixture of different wavelengths (color)
Can be absorbed, transmitted or reflected
Absorbed energy can be used for photosynthesis
Reflected light is not used for photosynthesis
Absorbed by pigments (chlorophyll) in plant cell chloroplasts

14. Quick Check…look at the light absorption spectrum on the previous slide
What color light is least absorbed?
What color(s) of light are most absorbed?
What color of light can be used for photosynthesis?
How would a plant grow if only given green/yellow light?

15. What are the green organelles inside the leaf cells?.
What is the function (job) of the chloroplast?

16. CHLOROPLASTS

17. CHLOROPLASTS
Thylakoids = photosynthetic membranes (contain chlorophyll)
Arranged in stacks called grana
Stroma = space around the thylakoids

19. Photosynthesis – BIG PICTURE
Multi-step process
Energy from the sun is used to convert water and carbon dioxide (reactants) into high energy sugars and oxygen (products
Plants then use the sugars to make ATP (cell respiration…stay tuned)

20. High-Energy Electron Carriers
Chlorophyll absorbs light
Absorption of light produces high-energy electrons
Electrons picked up by NADP+ to become NADPH
NADPH carries the high-energy electrons to chemical reactions elsewhere in the cell

21. Photosynthesis - Details
Light dependent reactions
INPUT= sunlight, water, chlorophyll
OUTPUT = oxygen (waste), ATP, energy carriers (NADPH)
LOCATION = thylakoid

22. Photosynthesis - Details
Light Independent reactions (a.k.a. Calvin Cycle)
INPUT– carbon dioxide, energy carriers from light reactions
OUTPUTS – sugar (carbohydrate)
LOCATION - stroma

24. QUICK CHECK…
Where in the chloroplast do the light reactions take place?
Where in the chloroplast does the Calvin Cycle occur?
What is another name for the Calvin Cycle?
What are the reactants of photosynthesis?
What are the products of photosynthesis?
What is the role of energy carriers in photosynthesis?
How is energy transformed in photosynthesis?
Is photosynthesis energy absorbing or energy releasing?
What is the form of energy used by ALL cells called?
How are you connected to the process of photosynthesis?

25. Cellular Respiration CHAPTER 9
CELL ENERGY
Cellular Respiration
CHAPTER 9

26. What role do mitochondria have in bioenergetics?

27. Chemical Energy and “Food”
Autotrophs (plants) make their own food
Heterotrophs (animals) need to consume other organisms as food
Food represents chemical energy
Fats and carbohydrates are primary sources of energy
Energy stored in food is measured by the calorie
Amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius
The Calorie on food labels is actually a kilocolarie or calories

28. Mitochondria Site of Cellular Respiration
Similar structure to chloroplast
Double membrane
Inside of mitochondria = matrix
Folds of mitochondria = cristae
Increase surface area

29. Cellular Respiration
The process that converts food energy into cellular energy in the presence of oxygen
Consists of many chemical reactions and many enzymes

30. Stages of Cell Respiration
Glycolysis
Kreb’s cycle
Electron transport chain

31. Stages of Cell Respiration

32. Energy transformations begin with glycolysis
Anaerobic (doesn’t need oxygen)
Occurs in the cell cytoplasm
Glucose is “cut” in two
Small amount of ATP is made
Necessary for cellular respiration
Products of glycolysis are broken down further in the mitochondria C C

34. Kreb’s cycle Takes place in the mitochondrial matrix
Occurs twice for each glucose molecule that enters glycolysis
Cycle of chemical reactions, each catalzyed by a specific enzyme
Carbon dioxide released as waste
Electron carriers (NADH and FADH2) produced here are used in the next step

36. Electron Transport Chain (ETC)
Occurs across the inner mitochondrial membrane
Proteins hand off high energy electrons to pump hydrogen ions across the inner membrane against the concentration gradient
Hydrogen ions, at the end of the chain flow through ATP synthase, a protein channel equipped with an enzyme to make ATP
Oxygen is the final electron acceptor in the ETC
Without oxygen, the ETC does not run, ATP will not be produced

38. 1 glucose = 36 ATP ATP Production totals Glycolysis Kreb’s Cycle ETC

40. As long as oxygen is present, cellular respiration will occur in the mitochondria and much ATP will be made.
What happens if oxygen is not around?
How will a cell get ATP for its processes to continue working?

41. Fermentation
Recall that glycolysis, an anearobic process produced 2 ATP per molecule of glucose
If oxygen is present, cellular respiration will come next to produce much more ATP
If oxygen is not present, fermentation will begin to allow glycolysis to continue
Fermentation DOES NOT produce ANY ATP
Fermentation is anaerobic (oxygen not needed)
Two types of fermentation

42. 1. Lactic Acid Fermentation
Occurs in your muscle cells and some bacteria
Produces lactic acid (which makes your muscles “burn” during intense exercise)
Yogurt contains bacteria that undergo lactic acid fermentation – lactic acid gives yogurt its flavor

43. 2. ALCOHOLIC FERMENTATION
Occurs in yeast, some bacteria and certain types of plants
Produces alcohol and carbon dioxide as waste
Cheese, bread, beer and wine are examples of food made by fermentation
Bacteria which go through fermentation help animals digest food

44. Three main sources of ATP for use during exercise…
Stored ATP (only enough for short bursts)
ATP made by lactic acid fermentation (about 90 seconds worth)
ATP produced by cellular respiration (aerobic; requires oxygen)

45. Where does the ATP come from?
QUICK BURSTS of ACTIIVTY…
Stored ATP (a few seconds worth)
Lactic acid fermentation can supply cells with an additional 90 seconds worth of ATP
Builds up an “oxygen debt” that gets repaid by rapid breathing
EXTENDED EXERCISE (more than 90 seconds)
Cellular respiration (aerobic)
Stored carbohydrates (glycogen) used first to 20 minutes
Stored lipids next

46. Quick Check… Where does glycolyis occur? What does glycolysis produce?
Is glycolysis aerobic or anearobic?
Where do the products of glycolysis go if oxygen is present?
What happens after glycolysis if oxygen is not present?
Is Kreb’s cycle aerobic or anearobic?
Is the ETC aerobic or anaerobic?
What are the two forms of fermentation?
Give an example of lactic acid fermentation.
Give an example of alcoholic fermentation.
Does fermentation produce any ATP?

47. Another Quick Check… What is the role of the mitochondria?
Do plants have mitochondria?
Do plants do cell respiration?
How much ATP can be produced from one molecule of glucose?
Describe the energy transformations that are occuring in respiration.
What is the connection between breathing and cell respiration?
What does ATP synthase do?