Photosynthesis & Cellular Respiration

1. Photosynthesis & Cellular Respiration Cellular Energy Or Bioenergetics

2. How does energy from the sun become energy for life?

3. Organisms called producers convert light energy to chemical energy using a process called photosynthesis. Photosynthesis- Amoeba Sisters

4. The chemical energy produced in photosynthesis is in the form of sugar. • This allows producers to store the energy for later use.

5. Photosynthesis • Method of converting sun energy into chemical energy usable by cells • Autotrophs utilize this process • Photoautotrophs- light • Chemoautotrophs- chemicals • Equation 6CO2 + 6H2O + light → C6H12O6 + 6O2

6. Fill It In … The goal of photosynthesis is …

7. Photosynthesis takes place within the cell • In eukaryotic cells, organelles called chloroplasts are the site of photosynthesis

8. Photosynthesis takes place within the cell • Chloroplasts are filled with a pigment called chlorophyll. • This pigment allows the cell to “gather” energy from light waves.

9. Photosynthesis takes place within the cell • Some prokaryotic cells can photosynthesize, but they do NOT have chloroplasts. • They do, however, contain chlorophyll.

10. Photosynthesis is a metabolic pathway. This means it is a series of chemical reactions. All of these reactions can be simplified into one chemical equation: CO2 + H2O + sunlight (radiant energy) -> C6H12O6 + O2 (reactants)(products) http://www.youtube.com/watch?v=wj8TGhcCnxs

11. CO2 + H2O + sunlight (radiant energy) -> C6H12O6 + O2 • The reactants(things that are used) for photosynthesis are obtained from the environment. • The carbon dioxide enters the leaves from the air and the water enters the roots from the soil.

12. CO2 + H2O + sunlight (radiant energy) -> C6H12O6 + O2 • The products(things that are made) of photosynthesis include sugar and oxygen. • Sugar is stored in the cell and used as food. • Oxygen is released into the air.

13. Electron Carriers • Carrier molecule- a compound that can accept a pair of high-energy electrons and transfer them along with most of their energy to another molecule • Process: electron transport • Molecule: electron transport chain

14. NADP+: NADP+ accepts and holds 2 high-energy electrons along with H+ • When this occurs it becomes NADPH • NADPH can then carry high-energy electrons to chemical reactions elsewhere

15. Light-Dependent Reactions • Require light • Produce oxygen gas • Convert ADP and NADP into ATP and NADPH

16. Light-Dependent Reactions • Pigments in photosystem II absorb light • Energy is absorbed by electrons which are passed on to electron transport chain • Electrons come from breaking bonds between water molecules • Create 2 electrons, H+ ions, and oxygen

17. Light-Dependent Reactions 3. Electrons move through electron transport chain • from photosystem II to photosystem I • Energy is used to transport H+ ions from stroma to inner thylakoid 4. Pigments in photosystem I use energy from light to reenergize the electrons • NADP+ picks up high energy electrons and H+ ions • Becomes NADPH

19. Light-Independent Reaction • Calvin Cycle • Uses ATP and NADPH to produce high-energy sugars • Does not require light

20. Calvin Cycle • 6 CO2 molecules enter cycle • Combine with 6 5-carbon molecules • Result = 12 3-carbon molecules 2. 3-carbon molecules are converted into higher-energy forms (energy from ATP and NADPH) 3. 2 3-carbon molecules are removed from cycle • Used to produce sugars, lipids, amino acids, etc.. For metabolism and growth of plant

21. Calvin Cycle 4. Remaining 10 3-carbon molecules are converted back to 6 5-carbon molecules • Combine with 6 new carbon dioxide molecules to begin the next cycle

22. Factors affecting Photosynthesis • Water • Lack of water can slow or even stop photosynthesis • Desert plants have waxy coating to reduce water loss • Temperature • Enzymes function at particular temp ranges • Intensity of Light • Increasing light increases rate of photosynthesis • There is a maximum rate of photosynthesis

23. Fill It In … Reactants for photosynthesis: 1. 2. 3. Products of photosynthesis: 1. 2.

24. Photosynthesis provides no DIRECT source of energy for the cell. • The cell must convert the sugar produced to another form of energy: ATP

25. What is ATP, and why should I care? • ATP stands for adenosine triphosphate • This basically means that it is a chemical with three phosphate groups attached.

26. What is ATP, and why should I care? • The cell uses ATP for energy. • ATP is much smaller and faster to use than a larger molecule such as sugar. • The energy in ATP is in the bonds connecting the four parts together.

27. Energy and ATP • ATP • Adenosine triphosphate • Adenine, 5-carbon sugar, 3 phosphate groups • ADP • Adenosine diphosphate • Adenine, 5-carbon sugar, 2 phosphate groups

28. Fill It In … ATP is used for …

29. What is ATP, and why should I care? ENERGY • When the cell needs energy from ATP, it uses enzymes to break the third phosphate off of the molecule. • The energy released is used for things in the cell such as active transport • Removing the third phosphate creates ADP and a loose phosphate

30. What is ATP, and why should I care? • ATP can be recycled. • When more energy is available, a third phosphate is added to ADP to make more ATP.

31. ADP and ATP • Storing energy • When a cell has energy available, it can store small amounts by adding a phosphate group to ADP, producing ATP • Releasing energy • Breaking bonds between the 2nd and 3rd phosphate groups • Powers several cellular activities • Active transport, protein synthesis, muscle contraction

32. How do cells use the sugar to make ATP? Cellular Respiration- Amoeba Sister • All cells must use a process called cellular respirationto create ATP. • Cellular respiration converts sugar (produced in photosynthesis) to create ATP • Cellular respiration takes place in the Mitochondria

33. Fill It In … The goal of cellular respiration is …

34. Cellular respiration takes place within the cell • In eukaryotic cells, organelles called mitochondria are the sites of cellular respiration

35. Cellular respiration takes place within the cell • Mitochondria use many enzymes to break down sugar (glucose) and store the energy in the chemical bonds of ATP

36. Cellular respiration takes place within the cell • Prokaryotes also use cellular respiration, but the do NOT have mitochondria. • Instead, prokaryotes use parts of their cell membrane.

37. Fill It In … Types of organisms that use cellular respiration:

38. Cellular respiration is also a metabolic pathway. The simplified equation for cellular respiration is: C6H12O6 + O2-> CO2 + H2O + ATP (reactants)(products)

39. C6H12O6 + O2-> CO2 + H2O + ATP • The reactants of respiration are glucose and oxygen. • The sugar (glucose) is obtained from the vacuole (in plant cells) or from ingestion (eating) of food. • If oxygen is used, it is obtained from the air.

40. C6H12O6 + O2-> CO2 + H2O + ATP • The products of respiration are ATP, water, and carbon dioxide. • The water and carbon dioxide are released into the environment as waste products. • ATP is kept in the cell for use as an energy molecule.

41. Cellular Respiration • Breakdown of glucose to produce energy • 1g of sugar releases 3811 calories of heat energy • Calorie- amount of energy needed to raise the temp of 1g of water 1˚ Celsius 6O2 + C6H12O6→ 6CO2 + 6H2O + energy • Steps: • Glycolysis • Krebs Cycle • Electron Transport Chain

42. Glycolysis • Process in which one molecule of glucose is broken in half, producing 2 molecules of pyruvic acid (3-carbon compound) • In cytoplasm • 2 ATP → 4 ATP • NAD+ = electron carrier • Accepts 4 high-energy electrons • Becomes NADH

43. Glycolysis • Energy yield is small but happens very fast • Does not require oxygen • Problem: NAD+ molecules fill up with electrons; without NAD+ ATP production stops

44. Fill It In … Reactants of cellular respiration: 1. 2. Products of cellular respiration: 1. 2. 3.

45. There are two types of cellular respiration: aerobic and anaerobic

46. There are two types of cellular respiration: • Aerobic respirationrequires the use of oxygen and makes A LOT of ATP

47. Krebs Cycle • Pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions • Aerobic- requires oxygen • AKA citric acid cycle – because citric acid is the first compound produced • In mitochondrion

48. Krebs Cycle

49. Krebs Cycle • Pyruvate Oxidation: • Pyruvic acid enters mitochondrion • A carbon atom is removed to form CO2 • The other 2 carbon atoms are joined to coenzyme A to form acetyl-CoA A. Acetyl-CoA adds to a 4-carbon molecule producing a 6-carbon molecule called citric acid

50. Krebs Cycle B. -Citric acid is broken down to produce a 5-carbon chain - CO2 is released - electrons transferred to energy carriers C.- 5-carbon chain is broken down into a 4 carbon chain - CO2 is released - ATP is produced D. – 4 carbon chain is ready to accept acetyl CoA to start cycle all over - FAD is converted to FADH2 - NAD+ is converted to NADH