Joseph Geissler. Newark Science Park High School Mrs. Paulose

Transcription

1 Joseph Geissler Newark Science Park High School Mrs. Paulose

2 Structure of leaf Structure of a chloroplast Importance of photosynthesis General equation of photosynthesis Light vs dark reactions Definitions of ATP, NADP+, ATP synthase, electron transportation

3 Humans are heterotrops Animals, fungi and many bacteria Are there any organism that are able to make their own food? Autotrophs Plants, algae, and many bacteria

4

5 Thylakoid Membrane Intermembrane Space Stroma Cristae Matrix

6 Stroma Interior space of the chloroplasts Contains metabolic enzymes, as well a special set of ribosomes, RNA and DNA Thylakoid Membrane Network of flattened disclike sacs (thylakoids) which create a third internal compartment separate from the stroma The site of the light-capturing systems, the electron-transport chains, and ATP synthase

7 The process by which green plants make their own food using carbon dioxide and water in the presence of sun light. 6CO H 2 O + light energy C 6 H 12 O 6 + 6O 2

8 Objective: Investigate the rate of O 2 production and CO 2 consumption in an aquatic plant Methods: 1) Open LoggerPro exercise 31C in Vernier for Biology 2) Attach gas probe to computer (probe interface will load) 3) Place probe in beaker containing water and aquatic plant life 4) For the first part of the exercise, cover the biochamber, restricting its exposure to light --Using LoggerPro, collect data for 15 minutes 5) Next, collect 2.5 minutes of data while plant is covered. Then. remove the cover and continue collection for an additional 2.5 minutes (for a total of 5 minutes) 6) Finally, place the plant in front of lamp --Using LoggerPro, collect data for 5 minutes

9 Results: -- Determine the slope of the line generated in LoggerPro for each situation Conclusions: --How does the amount of oxygen in the aquatic environment compare among the thee recordings? How do the slopes compare? If different, by how much? Why do you think these values differ? --How does sunlight drive photosynthesis? Can photosynthesis occur without sunlight? --Describe the similarities and differences between mitochondria and chloroplasts.

10 Light absorbing pigment that plays a central role in photosynthesis Long hydrophobic tails (in yellow) anchor chlorophyll to the thylakoid membrane Light is absorbed by electrons within the bond network (in blue) Chlorophyll are arranged in and around photosystems embedded in the thylakoid membrane Electrons in chlorophyll molecules interact with photons from light are raised to a higher energy level

11 A. B. (A) Charge separation generated in pigmentprotein complex of a chlorophyll molecule to drive (B) the donation of a highenergy electron to the electron-transport chain Student photosystems demonstration

12

13 Photosystem II --Produces high-energy electrons to be propelled along the electron-transport chain --Electron transportation drives H+ pump creating a proton gradient --ATP synthase uses this gradient to drive ATP synthesis (video) Photosystem I --Finally, the highenergy electron arrives at photosystem I --Here, it will fill a positively charged hole which has been left in the reaction center of chlorophyll

14 Light reactions (photosynthetic electron-transfer reactions) Photosystems Energy from sun light excites electrons within chlorophyll, enabling electrons to move along an electron transport chain in the thylakoid membrane Electrons are obtained from the splitting of water molecules, which produces O2 as a byproduct Dark reactions (carbon-fixation reactions) Calvin Cycle ATP and NADPH generated from light reactions serve as a source of energy and reducing power, respectively, to drive the conversion of CO2 to carbohydrate, such as sucrose These organic molecules can then be exported to other tissues as a source of energy

15 Properly functioning chloroplasts Properly functioning chlorophyll molecules Well established electron transport chain Optimum exposure to sun light Steady supply of water and nutrients Steady removal of waste by products

16 Environmental conditions can strongly affect photosynthesis Light intensity Temperature Concentrations of CO 2 Concentrations of O 2 Foreign substances in soil

17 Which of the following is the correct formula which describes photosynthesis? A) O 2 + H 2 O + light C 6 H 12 O 6 + CO 2 B) C 6 H 12 O 6 + light CO 2 + H 2 O C) CO 2 + O 2 + light C 6 H 12 O 6 + O 2 D) CO 2 + H 2 O + light C 6 H 12 O 6 + O 2 + H 2 O Balance the equation of your answer

18 Which organelle in plants is the site for photosynthesis? A) Stroma B) Chlorophyll C) Chloroplast D) Mitochondria

19 What gas occupies the intercellular space of the mesoderm on a bright sunny day? A) Nitrogen B) Carbon Dioxide C) Hydrogen D) Oxygen

20 Which of the following events takes place during light reactions? A) Combination of H and CO 2 B) Combination of C and CO 2 C) Splitting of H 2 O D) Splitting of CO 2

21 Which of the following events takes place during dark reactions? A) Combination of H and CO 2 B) Combination of C and CO 2 C) Splitting of H 2 O D) Splitting of CO 2

22 From where does the low-energy electron responsible for releasing the high-energy electron come from? A) CO 2 B) NADPH C) ATP D) H 2 O E) None of the above

23 Molecular Biology of the Cell, Reference Edition Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter. New York: Garland Science; 2002.