Chapter 8

© 2006 W.W. Norton & Company, Inc. DISCOVER BIOLOGY 3/e

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Photosynthesis and

Respiration

Chapter 8 Lecture Outline


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Class Policies Attendance:

Attend both lab and lecture regularly and on time. You CANNOT make up labs. If you miss a lab, you should read the lab manual

carefully and make sure you understand the lab. If you miss more than two labs, you may be dropped from the course If you miss more than two lectures, you may be dropped from the course (this includes

sleeping in class) Academic Integrity: the highest standards of academic integrity are expected

Students must do their own work on homework assignments, tests, quizzes, and laboratory write-ups.

If academic dishonesty occurs, you will receive a zero for that assignment and you may be dropped from the course with an F.

Make-up exams: I will not allow make-up exams except for in EXTREME circumstances. All make-up

exams will consist primarily of essay questions. It is NOT POSSIBLE to make-up a Lab Practical. You will receive a zero for that grade

Cell phones: Please turn phones off during class.


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Grade Points

Assignment Points

Lecture Exams (100 points each) 400 Lab Exams (100 points each) 300 Lab Reports (5 points each) 50 Project Presentation 100 Total 850


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Respiration

Getting energy from food


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Energy Carrier Molecules

Temporarily store and transfer energy ATP stores energy in phosphate bonds

Transfers this energy with phosphate

Phosphorylation


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Hydrogen – proton and electron

Proton – positively charged (+)

Electron – negatively charged (-)


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Other Energy Carriers

NADP+ and NAD+

Pick up electrons and become reduced NADPH and NADH

Donate these electrons and energy


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Mitochondrion: Aerobic Respiration Citric acid cycle & oxidative phosphorylation Electron Transport Chain (ETC) Mitochondrial Matrix

ETC


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Gaining Energy from Sugar


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Catabolic Reactions – breaking down molecules, capturing energy

Aerobic metabolism: three steps Glycolysis, Citric Acid Cycle, Oxidative Phosphorylation

Releases the most energy


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Glycolysis Glucose is split into 2 molecules of pyruvate 2 ATP and 3 NADH are made


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Glucose is split

Count the Carbon atoms 6 Carbons in Glucose 3 Carbons in Pyruvate


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Catabolic Reactions - More

Anaerobic metabolism: two steps Glycolysis & Fermentation Releases much less energy

Does NOT use Oxygen Does not use the Citric Acid Cycle Does not use mitochondria


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Fermentation – Does NOT use oxygen Anaerobic Respiration

Energy production in the absence of O2

In yeast and bacteria, CO2 is formed Ethyl alcohol is a byproduct

In animals, lactic acid is the byproduct


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Anaerobic Respiration

Used in making beer, bread


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Anaerobic Respiration – more

Used in making yogurt, kefir


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The Citric Acid Cycle

Pyruvate broken down to release CO2

Acetyl CoA added to OAA to form citrate

3 NADH and 1 ATP are made

NADH passed to the ETC


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Ox/Phos Electrons passed

from NADH to ETC ETC produces H+

gradient O2 accepts electrons

and becomes 2 H2O ATP synthase makes

ATP from H+ gradient


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Websites

http://vcell.ndsu.nodak.edu/animations/atp

gradient/movie.htm

http://vcell.ndsu.nodak.edu/animations/etc/movie.htm


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Stop Here


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Capturing Energy Sun is primary source of energy Energy flows through life systems

Producers

Primary consumers

Secondary

consumers

Photosynthesis

Sugars out

O2 out

Respiration

CO2 and H2O out


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Structure of the Chloroplast Double membrane – intermembrane space Stroma Thylacoid disks - Thylacoid space

Stroma

Inner membrane

Outermembrane

Granum (stack of thylacoids)

ChloroplastThylacoid disk

Stroma

Thylacoid membrane Thylacoid spaceIntermembrane space


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Light and Dark Reactions Light reactions capture light energy

Take place in thylacoids Use chlorophyll Charge energy transfer molecules & make O2

Dark reactions make sugars Occur in the stoma Use the energy from transfer molecules Produce glucose


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Light Reactions Chlorophyll antennae capture energy from

light Pass it to Photosystems I and II (ETCs)

Chlorophyllmolecules

Reactioncenters

Photosystem II Photosystem I

Thylacoid space

Thylacoid membrane

Antennacomplex

Stroma


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Photosystem II Electrons stripped from

H2O Energized by light &

passed H+ remains inside

thylacoid space Energy used to pump H+

into thylacoid More H+ accumulates in

thylacoid space


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Process Animation 8.1bPhotosynthesis: Overview of Reactions

Macintosh

Windows


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Electron Transport ChainPhotosystem I (look familiar?)


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Photosystem I

Electrons passed to photosystem I

Light used to recharge electrons

This energy used to make NADPH

Making NADPH decreases H+ outside


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Process Animation 8.1cPhotosynthesis: The Light Reactions

Macintosh

Windows


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ATP Synthase

H+ gradient represents stored energy

Used by ATP synthase

H+ released to phosphorylate ADP


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Dark Reactions: Carbon Fixation Rubisco catalyzes CO2 fixation to ribulose

Begins the carbon fixation cycleRubisco

CARBON FIXATION

Glucose

Unstable 6CCompound

Ribulose1,5 bisphosphate Glyceraldehyde

3-phosphate


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Process Animation 8.1dPhotosynthesis: Carbon Fixation Reactions

Macintosh

Windows


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Three turns of cycle produce a 3C sugar:

glyceraldehyde 3-phosphate Most is used by mitochondrion: energy Two can be combined to give 6C: Glucose Can be stored or used for structure

Dark Reactions: Carbon Fixation


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Photosynthesis and Aerobic Respiration An exchange of molecules and energy


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Similarities between respiration and photosynthesis

Electron TransportChemiosmosisPhosphorylation


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Similarities between respiration and photosynthesis

ELECTRON TRANSPORT Aerobic respiration Glucose is oxidized (Lose Electrons Oxidation) Electrons are passed to the electron transport chain in

the inner mitochondrial membrane.Photosynthesis Chlorophyll a is oxidized by light (photo-oxidized),

(Lose Electrons Oxidation) Electrons are passed to the electron transport chain in

the thylakoid membrane.


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Electron transport Chain


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Similarities between respiration and photosynthesis CHEMIOSMOSIS the energy released by the

electrons as they pass through the electron transport chain is used to create a proton gradient across a membrane Across the inner mitochondrial membrane into the

intermembrane space in mitochondria, Across the thylacoid membrane into the thylacoid

lumen in chloroplasts. Both are impermeable to hydrogen ions. Diffusion

occurs only via specific transport proteins.


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Proton gradient – chemiosmosis and Oxidative Phosphorylation Generates Proton

gradient Provides energy for

ADP—>ATP Occurs in:

Respiration Photosynthesis


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Similarities between respiration and photosynthesis PHOSPHORYLATION

Both the inner mitochondrial membrane and the thylacoid membrane are impermeable to hydrogen ions. Diffusion occurs only via specific transport proteins.

Transport protein is an enzyme called ATP synthase. As the hydrogen ions (protons) diffuse through ATP synthase, ATP is produced from ADP and inorganic phosphate.


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Laboratory Preparation

Experiment 8C Paper ChromatographyExamine various photosynthetic pigments

Measure PhotosynthesisObserve O2 production

Design an Experiment for next class


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ELECTROMAGNETIC SPECTRUM


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Visible Spectrum


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Concept Quiz

A common feature of both chloroplasts and mitochondria is

A. The use of chlorophyll

B. Production of CO2

C. Use of an Electron Transport Chain

D. Presence in all cells


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Photosystem II differs from photosystem I in that it produces

A. NADPH

B. O2

C. A proton gradient

D. ATP

Concept Quiz


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Concept Quiz

Most of the ATP produced by aerobic respiration comes from

A. Glycolysis

B. The citric acid cycle

C. Oxidative phosphorylation

D. Fermentation


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Process Animation 8.1aPhotosynthesis: The Flow of Energy

Macintosh

Windows


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Process Animation 8.2aCatabolism: Glycolysis

Macintosh

Windows


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Process Animation 8.2bCatabolism: The Citric Acid Cycle

Macintosh

Windows


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Process Animation 8.2cCatabolism: Oxidative Phosphorylation

Macintosh

Windows


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Process Animation 8.2dCatabolism: Aerobic vs. Anaerobic Respiration

Macintosh

Windows

Chapter 8

Documents

Transcript of Chapter 8