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Warm-up Imagine that you are given 25 germinating pea seeds that have been placed in boiling water for 5 minutes. You place these seeds in a respirometer.

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Presentation on theme: "Warm-up Imagine that you are given 25 germinating pea seeds that have been placed in boiling water for 5 minutes. You place these seeds in a respirometer."— Presentation transcript:

1 Warm-up Imagine that you are given 25 germinating pea seeds that have been placed in boiling water for 5 minutes. You place these seeds in a respirometer and collect data. Predict the rate of oxygen consumption (i.e., cellular respiration) for these seeds, and explain your reasons.

2 Monday 10/29 Agenda Tutoring starts today! Analysis in lab packet
Share inquiry findings Take Lab Quiz Homework – Photosynthesis poster and CH. 10 online assignments due tomorrow One more week to do test corrections

3 10/30 Agenda Chloroplast structure and up to slide 25 (15 min)
Photosynthesis Light Reaction Calvin Cycle Homework – Study poster for open-poster quiz tomorrow Print and bring AP Lab 4 Photosynthesis (from my website) tomorrow, don’t need to read yet

4 ■Enduring Understandings
• 1B1: Organisms share many conserved core processes and features that evolved and are widely distributed among organisms today. • 2A1: All living systems require constant input of free energy. • 2A2: Organisms capture and store free energy for use in biological processes. • 2B3: Eukaryotic cells maintain internal membranes that partition the cell into specialized regions (e.g., mitochondria). • 4A2: The structure and function of subcellular components, and their interactions, provide essential cellular processes. • 4A6: Interactions among living systems and with their environment result in the movement of matter and energy.

5 Standard Deviation and Standard Error for first part of lab
Take each groups rates- find mean rate Calculate Standard Deviation from mean Calculate standard error Graph rates on bar graph Add standard error bars

6

7 Graph Average Rates with Error Bars

8 Lee, Richard E. “Using Microrespirometers to Measure O2 Consumption by Insects and Small Invertebrates.” The American Biology Teacher, vol. 57, no. 5, 284–85,

9 Chloroplasts: The Sites of Photosynthesis in Plants
Leaves are the major locations of photosynthesis Their green color is from chlorophyll, the green pigment within chloroplasts Chloroplasts are found mainly in cells of the mesophyll, the interior tissue of the leaf Each mesophyll cell contains 30–40 chloroplasts © 2011 Pearson Education, Inc. 9

10 Chloroplasts also contain stroma, a dense interior fluid
CO2 enters and O2 exits the leaf through microscopic pores called stomata The chlorophyll is in the membranes of thylakoids (connected sacs in the chloroplast); thylakoids may be stacked in columns called grana Chloroplasts also contain stroma, a dense interior fluid © 2011 Pearson Education, Inc. 10

11 Let’s look at model Figure 10.4 Leaf cross section Chloroplasts Vein
Mesophyll Stomata CO2 O2 Chloroplast Mesophyll cell Outer membrane Figure 10.4 Zooming in on the location of photosynthesis in a plant. Thylakoid Intermembrane space Stroma Granum 20 m Thylakoid space Inner membrane Let’s look at model 1 m 11 11

12 Photosynthesis as a Redox Process
Photosynthesis reverses the direction of electron flow compared to respiration Photosynthesis is a redox process in which H2O is oxidized and CO2 is reduced Photosynthesis is an endergonic process; the energy boost is provided by light © 2011 Pearson Education, Inc. 12

13 Energy  6 CO2  6 H2O C6 H12 O6  6 O2 becomes reduced
Figure 10.UN01 becomes reduced Energy  6 CO2  6 H2O C6 H12 O6  6 O2 becomes oxidized Figure 10.UN01 In-text figure, p. 188 13 13

14 The Two Stages of Photosynthesis: A Preview
Photosynthesis consists of the light reactions (the photo part) and Calvin cycle (the synthesis part) The light reactions (in the thylakoids) Split H2O Release O2 Reduce NADP+ to NADPH Generate ATP from ADP by photophosphorylation © 2011 Pearson Education, Inc. 14

15 The Calvin cycle (in the stroma) forms sugar from CO2, using ATP and NADPH
The Calvin cycle begins with carbon fixation, incorporating CO2 into organic molecules © 2011 Pearson Education, Inc. 15

16 Calvin Cycle Light Reactions [CH2O] (sugar)
Figure H2O CO2 Light NADP ADP + P i Calvin Cycle Light Reactions ATP Figure 10.6 An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle. NADPH Chloroplast [CH2O] (sugar) O2 16 16

17 While light travels as a wave, many of its properties are those of a discrete particle, the photon.
Photons are not tangible objects, but they do have fixed quantities of energy and amount depends on wavelength.

18 Figure 10.10 RESULTS Chloro- phyll a Chlorophyll b
Absorption of light by chloroplast pigments Carotenoids (a) Absorption spectra 400 500 600 700 Wavelength of light (nm) Rate of photosynthesis (measured by O2 release) Figure Inquiry: Which wavelengths of light are most effective in driving photosynthesis? (b) Action spectrum 400 500 600 700 Aerobic bacteria Filament of alga Engelmann’s experiment (c) 400 500 600 700 18 18

19 The action spectrum of photosynthesis was first demonstrated in 1883 by Theodor W. Engelmann
In his experiment, he exposed different segments of a filamentous alga to different wavelengths Areas receiving wavelengths favorable to photosynthesis produced excess O2 He used the growth of aerobic bacteria clustered along the alga as a measure of O2 production © 2011 Pearson Education, Inc. 19

20 Chlorophyll a is the main photosynthetic pigment
Accessory pigments, such as chlorophyll b, broaden the spectrum used for photosynthesis Accessory pigments called carotenoids absorb excessive light that would damage chlorophyll © 2011 Pearson Education, Inc. 20

21 When a molecule absorbs a photon, one of that molecule’s electrons is elevated to an orbital with more potential energy. The electron moves from its ground state to an excited state. The only photons that a molecule can absorb are those whose energy matches exactly the energy difference between the ground state and excited state of this electron. Because this energy difference varies among atoms and molecules, a particular compound absorbs only photons corresponding to specific wavelengths. Thus, each pigment has a unique absorption spectrum.

22 Excited electrons are unstable.
Generally, they drop to their ground state in a billionth of a second, releasing heat energy. Some pigments, including chlorophyll, release a photon of light, in a process called fluorescence, as well as heat. Fig

23 Photon (fluorescence)
Figure 10.12 Excited state e Heat Energy of electron Photon (fluorescence) Photon Figure Excitation of isolated chlorophyll by light. Ground state Chlorophyll molecule (a) Excitation of isolated chlorophyll molecule (b) Fluorescence 23 23

24 Fig. 10.9

25 Figure 10.18 STROMA (low H concentration) Cytochrome complex
NADP reductase Photosystem II Photosystem I Light 3 Light 4 H+ NADP + H Fd Pq NADPH 2 Pc H2O 1 1/2 O2 THYLAKOID SPACE (high H concentration) +2 H+ 4 H+ To Calvin Cycle Figure The light reactions and chemiosmosis: the organization of the thylakoid membrane. Thylakoid membrane ATP synthase ADP + P i ATP STROMA (low H concentration) H+ 25 25

26 A Photosystem: A Reaction-Center Complex Associated with Light-Harvesting Complexes
A photosystem consists of a reaction-center complex (a type of protein complex) surrounded by light-harvesting complexes The light-harvesting complexes (pigment molecules bound to proteins) transfer the energy of photons to the reaction center © 2011 Pearson Education, Inc. 26

27 THYLAKOID SPACE (INTERIOR OF THYLAKOID)
Figure 10.13 Photosystem STROMA Photon Light- harvesting complexes Reaction- center complex Primary electron acceptor Chlorophyll STROMA e Thylakoid membrane Thylakoid membrane Figure The structure and function of a photosystem. Transfer of energy Special pair of chlorophyll a molecules Pigment molecules Protein subunits THYLAKOID SPACE (INTERIOR OF THYLAKOID) THYLAKOID SPACE (a) How a photosystem harvests light (b) Structure of photosystem II Each photosystem consists of chlorophylls, accessory pigments, and proteins. The black arrows represent photons being passed like a wave to reaction center chlorophylls that actually donate their electrons. 27 27

28 Linear Electron Flow Figure 10.14-5 Electron transport chain
Primary acceptor Primary acceptor 4 7 Electron transport chain Fd Pq e 2 e 8 e e H2O NADP 2 H Cytochrome complex NADP reductase + H + 3 1/2 O2 NADPH Pc e e P700 5 P680 Light 1 Light 6 ATP Figure How linear electron flow during the light reactions generates ATP and NADPH. Pigment molecules Photosystem I (PS I) Photosystem II (PS II) 28 28

29 Mill makes ATP NADPH ATP Photosystem II Photosystem I e e e e e
Figure 10.15 e e e Mill makes ATP NADPH e e e Photon Figure A mechanical analogy for linear electron flow during the light reactions. e ATP Photon Photosystem II Photosystem I 29 29

30 Cyclic Electron Flow Cyclic electron flow uses only photosystem I and produces ATP, but not NADPH No oxygen is released Cyclic electron flow generates surplus ATP, satisfying the higher demand in the Calvin cycle © 2011 Pearson Education, Inc. 30

31 Primary acceptor Primary acceptor Fd Fd NADP + H Pq NADP reductase
Figure 10.16 Primary acceptor Primary acceptor Fd Fd NADP + H Pq NADP reductase Cytochrome complex NADPH Pc Figure Cyclic electron flow. Photosystem I Photosystem II ATP 31 31

32 A Comparison of Chemiosmosis in Chloroplasts and Mitochondria
Chloroplasts and mitochondria generate ATP by chemiosmosis, but use different sources of energy Mitochondria transfer chemical energy from food to ATP; chloroplasts transform light energy into the chemical energy of ATP Spatial organization of chemiosmosis differs between chloroplasts and mitochondria but also shows similarities © 2011 Pearson Education, Inc. 32

33 In mitochondria, protons are pumped to the intermembrane space and drive ATP synthesis as they diffuse back into the mitochondrial matrix In chloroplasts, protons are pumped into the thylakoid space and drive ATP synthesis as they diffuse back into the stroma © 2011 Pearson Education, Inc. 33

34 Electron transport chain
Figure 10.17 Mitochondrion Chloroplast MITOCHONDRION STRUCTURE CHLOROPLAST STRUCTURE H Diffusion Intermembrane space Thylakoid space Electron transport chain Inner membrane Thylakoid membrane Figure Comparison of chemiosmosis in mitochondria and chloroplasts. ATP synthase Matrix Stroma ADP  P i ATP Key Higher [H ] H Lower [H ] 34 34

35 ATP and NADPH are produced on the side facing the stroma, where the Calvin cycle takes place
In summary, light reactions generate ATP and increase the potential energy of electrons by moving them from H2O to NADPH © 2011 Pearson Education, Inc. 35

36 Let’s watch animation of Phase I

37 Concept 10.3: The Calvin cycle uses the chemical energy of ATP and NADPH to reduce CO2 to sugar
Carbon enters the cycle as CO2 and leaves as a sugar named glyceraldehyde 3-phospate (G3P) For net synthesis of 1 G3P, the cycle must take place three times, fixing 3 molecules of CO2 The Calvin cycle has three phases Carbon fixation (catalyzed by rubisco) Reduction Regeneration of the CO2 acceptor (RuBP) © 2011 Pearson Education, Inc. 37

38 The Calvin cycle has three phases
Carbon enters the cycle as CO2 and leaves as a sugar named glyceraldehyde 3-phospate (G3P) For net synthesis of 1 G3P, the cycle must take place three times, fixing 3 molecules of CO2 The Calvin cycle has three phases Carbon fixation (catalyzed by rubisco) Reduction Regeneration of the CO2 acceptor (RuBP) © 2011 Pearson Education, Inc. 38

39 Figure Input 3 (Entering one at a time) CO2 Phase 1: Carbon fixation Rubisco 3 P P Short-lived intermediate 3 P P 6 P Ribulose bisphosphate (RuBP) 3-Phosphoglycerate 6 ATP 6 ADP 3 ADP Calvin Cycle 6 P P 3 ATP 1,3-Bisphosphoglycerate 6 NADPH Phase 3: Regeneration of the CO2 acceptor (RuBP) 6 NADP 6 P i Figure The Calvin cycle. 5 P G3P 6 P Glyceraldehyde 3-phosphate (G3P) Phase 2: Reduction For every one net G3P, requires 9 ATP and 6 NADPH from the light reaction. 1 P G3P (a sugar) Glucose and other organic compounds Output 39 39

40 Photosynthesis is the biosphere’s metabolic foundation
In photosynthesis, the energy that enters the chloroplasts as sunlight becomes stored as chemical energy in organic compounds. - About 50% of the organic material made is consumed as fuel for cellular respiration in plant mitochondria. Rest is stored or used to build other organic compounds.

41 On a global scale, photosynthesis is the most important process to the welfare of life on Earth.
Each year photosynthesis synthesizes 160 billion metric tons of carbohydrate per year.

42 10/31 Agenda Finish photosynthesis Review posters while I check them
Photosynthesis quiz (20 minutes) – open poster Statistical analysis - standard deviation and standard error (standard error bars on graph) (20 min) I check lab packet from yesterday while you work in groups Intro Lab 4 and assign cuvettes Homework – Prelab worksheet for Lab 4, skip part A, be ready to do part B tomorrow – Read Lab, part B only Unit Test next Tuesday 11/6 covers chapters 6-10 – BE STUDYING!!!!

43 11/1 Agenda Intro and Set up 4B (25 min) Run Lab 4B (20 min)
Slides on spectrophotometer Set up blanks together. Calibrate spec and review how to use. Assign jobs – recorder, timekeeper, cuvette mixer, spec operator (all help setup) Assign cuvettes – each group does one of the four plus an inquiry tube Inquiry choices = screens, colored light, acid, base, salt, ice etc. Run Lab 4B (20 min) I check prelabs during this make use of your wait time by setting up graph Clean up and share data (10 min) Dump contents of cuvettes down the drains, then use test tube brush to clean out. Dry with paper towel. Wipe sides down with Kimwipes and put back in flask in bucket. Homework Do 4B Analysis – all of Analysis should be done for me to check tomorrow, including graph Unit Test next Tuesday 11/6 covers chapters 6-10 you should be putting in at least a half hour of study/review per night!!!

44 When light meets matter, it may be reflected, transmitted, or absorbed.
Different pigments absorb photons of different wavelengths. A leaf looks green because chlorophyll, the dominant pigment, absorbs red and blue light, while transmitting and reflecting green light. Fig. 10.6

45 SPECTROPHOTOMETER TECHNIQUE Refracting prism Chlorophyll solution
Photoelectric tube White light Galvanometer 605 nm is wavelength absorbed by DPIP High transmittance (low absorption): Chlorophyll absorbs very little green light. Slit moves to pass light of selected wavelength. Green light Figure 10.9 Research Method: Determining an Absorption Spectrum Low transmittance (high absorption): Chlorophyll absorbs most blue light. Blue light 45 45

46 Each year Make 3 copies of the next slide – put in separate powerpoint, have kids record data and to them

47 Clean up and share data with your side of the room (5 min) Dump contents of cuvettes down the drains, then use test tube brush to clean out. Dry with paper towel. Wipe sides down with Kimwipes and put back in flask in bucket.

48 11/2 Agenda Hand back quizzes Quick review prelab
Analysis and post lab discussion – I check while you present (also last lab packet) Lab bench quiz for Lab 4 Homework – Do conclusion only (use rubric) for Photosynthesis lab in your notebook – due Monday Unit Test next Tuesday 11/6 covers chapters 6-10 Free response questions due Monday


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