January 8, 2014! Welcome Back! Bellringer: Photosynthesis … Pass back exams Go over EVERY question Diagnose Wrong Answers Start Photosynthesis Notes HW:

January 8, 2014!

Welcome Back! Bellringer: Photosynthesis … Pass back exams

Go over EVERY question Diagnose Wrong Answers

Start Photosynthesis Notes HW:

Draw and Define the parts of the Chloroplast (pg. 111)

Photosynthesis!!!

1/9/14 Bellringer: 6…5…4… Check off HW

Photosynthesis Notes

HW: Read 114-116

(or at least the chapter summary)

6…5…4There are 6 schooldays until finals (& Final Grades).

Create and Fill out the following table

Photosynthesis

What does it mean to photosynthesize?

Who Photosynthesizes?

Name the reactants and products of photosynthesis.

Photosynthesis Photosynthesis: When light energy is used

by producers/autotrophs to make sugars and other food molecules ~75% performed in the ocean Temperature, light intensity, water and carbon

dioxide supply affect the efficiency

Photosynthesis Equation

6CO2 + 6H2O

Energy from sunlight (in chlorophyll)

C6H12O6 + 6O2

Photosynthesis Reactants/Products

Reactants: CO2: Let into the leaf through pores called stomata H2O: Taken in through the roots

Catalyst: Chlorophyll: Pigment in chloroplast that catches sunlight

Products: O2: Used by plants/animals for cellular respiration Glucose: Used by the plant (or by an animal that eats the

plant!) for energy (C6H12O6)

Oxidation-Reduction Reactions Reactions that give or take electrons are

called “oxidative-reduction reactions” or Redox rxns

Oxidation = Molecules lose electrons or hydrogen

Reduction: Molecules gain electrons or hydrogen

In organisms, each electron travels with a proton (an H atom)…

Cont’d

Photosynthesis IS a Redox reactionH2O is oxidized

CO2 is reducedElectrons gain energy

Light/Color (Just Listen!!!)

Increasing energy

Gammarays

X-rays UV InfraredMicro-waves

Radiowaves

Visible light

380 400 500 600 700 750

Wavelength (nm)

650nm

10–5 10–3nm 1 nmnm 103 nm 106 nm 1 m 103 m

Light

Reflectedlight

Absorbedlight

Chloroplast

Transmittedlight

Why do we see certain colors?

Why do we see this red sweatshirt as red?

Answer: When all colors (ROYGBIV) hit it, all colors are absorbed but red, which is reflected back to our eyes!

Why do white things LOOK white?

Because all the colors (ROYGBIV) are hitting the object, and all the colors are reflecting back into your eyes

Why do black things LOOK black?

Because all the colors (ROYGBIV) are hitting the object, and all the colors are being absorbed

Pigments (start writing notes

again) Pigments: The natural coloring matter of

organisms Several pigments are built into the thylakoids of

chloroplasts These absorb some wavelengths of light; reflect or

transmit others Chlorophyll a:

Absorbs blue-violet and red light, reflects green light

Participates directly in the light reactions

Light

Reflectedlight

Absorbedlight

Chloroplast

Transmittedlight

Cont’d Chlorophyll b:

Absorbs blue and orange light, reflects yellow-green

Gives absorbed energy to chlorophyll a Carotenoids:

Yellow-orange pigments Pass energy to chlorophyll a or protect it by

dissipating excessive light energy Xanthophylls:

Yellow pigments

Stage 1: Light Reactions The light reaction takes place in the

thylakoid (disc inside the chloroplast

Chloroplast

Thylakoid

1/10/14 Bellringer: PHOTO REVIEW

CONTINUE PHOTOSYNTHESIS NOTES

HW: PHOTOSYNTHESIS GRAPHING

Photo Review

1) What is the formula for photosynthesis? (should know this by memory)

2) What are the four pigments in chlorophyll?

3) Why aren’t plant’s roots green?

Photosynthesis RXNs

Photosynthesis takes place in two stages: Light-Dependent Stage: Light-Independent/Calvin Cycle:

Stage 1: Light Reactions When photosynthesizers absorb sunlight, it

boosts their electrons to higher energy levels It EXCITES them

The electron now has more energy

PARTS OF THE LIGHT RXN

1) Photosystem: First part of the light reaction that gathers light. Contains the following:

A.Pigment Molecules: these absorb sunlight and give their energy to Chlorophyll a

B.Chlorophyll a Reaction Center: The molecule whose electron gets excited, and moves on to…

C.Primary Electron Acceptor: These take the electron from the reaction centerThere are 2 photosystems in the light reaction

A. Photosystem II: (P680), and Photosystem I: (P700)

Electron Transport Chain (ETC)

Electron transport chain(ETC): Series of proteins in the thylakoid membrane that makes the products of the light reaction

Takes the high energy electrons from the photosystems

Uses the electrons’ energy is to make ATP and NADPH ATP: Made from ADP NADPH: Carries electrons to the light-

independent reaction, made from NADP+

Steps of the Light Reaction

1. Light excites an electron (e-)in Photosystem II’s reaction center, and it goes to the Electron Transport Chain

2. A water molecule replaces the lost electrons3. e- moves down ETC (electron transport

chain),and this makes ATP4. Light excites an electron in Photosystem I’s

reaction center, and it goes to the second Electron Transport Chain

5. e- moves down ETC, which makes NADPH

LIGHT RXN SUMMARY

What do plants enter the light reaction with? Energy from sunlight and pigments to absorb it

What do plants leave the light reaction with? ATP and NADPH

WHAT DO WE HAVE LEFT TO DO? Actually build the glucose molecule!!!

The Light-Independent Reaction/Dark Reaction/Calvin Cycle

2nd part of Photosynthesis, and occurs in the stroma

Uses carbon atoms from CO2 to make the backbone of a sugar molecule (glucose) Glucose is made

ATP is used to get the energy for this (recycling)

Molecules of NADPH donate electrons and become NADP+ (recycling)

Fig. 10.17.3

THE OVERALL LIGHT-INDEPENDENT REACTION!!!

What do plants enter with? ATP, NADPH, and CO2

What do plants leave the light reaction with? Glucose

Bellringer What is the equation

for photosynthesis? What products have

we made thus far? Where does the light

reaction take place?

Bellringer What part of the chloroplast does the light

reaction take place in In the Light Reaction of photosynthesis,

what happens in the photosystems? What happens in the electron transport

chains?