Today: Today:

• Photosynthesis Photosynthesis and and RespirationRespiration

• LunchLunch

• Quiz 5Quiz 5

Step 1: Step 1:

• Capture your Capture your thoughts and thoughts and questions…questions…

Let’s start with

Photosynthesis

An Overview of Photosynthesis

LIGHT used in Photosynthesis

So What is this Plant Doing?

LIGHT used in Photosynthesis

When PHOTONS hit a Chlorophyll Molecule they EXCITE ELECTRONS

Redox Reactions

The Gain and Loss of Electrons through REDOX reactions allows

for

ELECTRON TRANSPORT CHAINS

Noncyclic electron flow generates

ATP and NADPH

What is NADPH?What is NADPH?

I carry electrons

!

What is ATP?

Cartoon Schematic

of NONCYCLICELECTRON

FLOWin the LIGHT

REACTIONS

More on Making ATP…

Something More Familiar?

What Should We Do With the ATP and Electrons (NADPH)??

The Light-The Light-Independent Independent

ReactionsReactions

The Calvin Cycle

What Might a Plant Do With These Sugars?

Grow new leaves?Grow new leaves? Store it for Store it for

winter?winter? Build a fruit?Build a fruit? Use it to generate Use it to generate

the energy to the energy to support life!support life!

Onto Onto Respiration! Respiration!

Note that Energy Note that Energy Flow is Flow is

Directional, but Directional, but Matter is CycledMatter is Cycled

Cellular RESPIRATION: An Overview

Step 1: Step 1: GlycolysisGlycolysis

http://instruct1.cit.cornell.edu/courses/biomi290/ASM/glycolysis.dcr

Step 2: The Citric Acid Cycle

The Citric Acid (Kreb’s)

Cycle: A Friendly View

Step 3: The Electron Transport Chain

So far, only 4 molecules of ATP from each Glucose

Where’s the rest of the energy??

How can we capture it??It’s in the electrons!! So we need an electron transport

chain!!

The ETC pumps H+ into the The ETC pumps H+ into the intermembrane space, creating a intermembrane space, creating a

concentration gradientconcentration gradient

ATP Synthase is a Molecular

Turbine!

http://www.sp.uconn.edu/%7Eterry/images/movs/synthase.mov

Energetic Summary of Cellular Respiration:

Efficiency = ~40%

Can we generate ATP under Can we generate ATP under anaerobic conditions?? How??anaerobic conditions?? How??

Aerobic = oxygen present

Anaerobic = without oxygen

Glycolysis!

Can this proceed

indefinitely? Why or why

not?

Anaerobic Respiration: Alcohol Fermentation

Anaerobic Respiration: Lactic Acid Fermentation

Applying Your Understanding Applying Your Understanding of Photosynthesis and of Photosynthesis and

RespirationRespiration

What does it mean What does it mean to be a carbon to be a carbon source? source?

What does it mean What does it mean to be a carbon sink?to be a carbon sink?

What IS the Carbon Cycle?

Applying Your Understanding of

Photosynthesis and Respiration

Is the Amazon Basin a carbon

source, or a carbon sink? How could

you find out?