DO NOW

Please hand in homework into
the bin.

Then Answer
◦ How do we see colors?
◦ Which color has the longest
wavelength? The shortest?
◦ What pigments are in leaves? What
colors do they reflect?
◦ What pigment do you think is in the
graph?
Photosynthesis Intro Video

https://www.youtube.com/watch?v=eo5X
ndJaz-Y
Overview Of Photosynthesis
Objectives

To be able to list the inputs and outputs of
photosynthesis.

To be able to identify the structures in a
chloroplast.

To be able to summarize light-dependent
reactions.
Photosynthesis

Light energy ------> chemical energy

Used by autotrophs to produce food

All of our energy starts as light energy!
◦ Plants use sunlight to make food animals
eat plants other animals eat those animals
Photosynthetic Organisms

Go through Photosynthesis to produce
GLUCOSE…

Autotrophs -“Producers” in the food web

Consist of plants, protists, cyanobacteria
Photosynthesis

Occurs in CHLOROPLASTS!!

Requires the pigment chlorophyll to
capture energy from light.

Rearrange molecules of water and CO2
into new products
The Chloroplast
Structures within a
chloroplast

Thylakoids:
 flattened sac-like membranes arranged in
stacks (stacks are called grana).
 Light-dependent reactions take place here.
 Electron transport occurs in the thylakoid
membrane

Stroma:
 Fluid filled space outside the grana.
 Light-independent reactions take place here.
Starting Materials
1.
Carbon Dioxide
2.
Water
3.
Sunlight
Products!
1.
Oxygen
2.
Glucose! (C6H12O6)

**Plants don’t immediately use all the glucose they make:
◦ Stored as STARCH!!
Overall Chemical Equation
Glucose
Phase Overview

1) Light dependent Reactions
◦ Light energy is absorbed and converted into
chemical energy in the form of ATP and
NADPH. (also produces Oxygen!)

2) Light Independent Reactions:(Calvin
Cycle)
◦ CO2 ATP and NADPH are used to make
glucose.
*Glucose is the basic building block for more complex sugars such as starch.*
Do Now

Hand in your lab into the bin. Please make sure
your name and your partners name is on it!

Also grab four pieces of construction paper
from my desk. Any color(s) of your choosing!

Then answer:
◦ What are the reactants and products of
photosynthesis?
◦ What is the equation for photosynthesis?
Light Dependent Reactions Intro

https://www.youtube.com/watch?v=BK_cj
d6Evcw
Light Dependent Reactions

Step 1: Light energy reaches
photosystem II causing the water
molecule to split
H
H
O
H 2O
H+
+
O2
*H+ is released to the electron
transport system.
* O2 is given off as a byproduct.

Step 2: Light energy reaches
photosystem I and electrons flow from
photosystem II to photosystem I. (to
replace the electrons lost)

Step 3: HYDROGEN IONS (protons)
are pumped across the membrane into
the thylakoid space as the electrons move
through the electron transport chain.

Step 4: Electrons from photosystem I move
to a protein called FERRODOXIN
**Ferrodoxin =
“helper” protein**

Step 5: Ferrodoxin transfers electrons to
NADP+ forming NADPH. (Electron Carrier)
◦ We need this for the next part of photosynthesis!

Step 6: Hydrogen ions move through the ATP
SYNTHASE because of the concentration gradient,
creating ATP. (Chemiosynthesis)
To Calvin Cycle
Chemosynthesis

Mechanism in which ATP is produced as a
result from the flow of electrons down a
concentration gradient.
◦ Ex: Light reactions (H+ ions and ATP synthase)
Light Dependent Reactions
Location: Thylakoid Membrane in Chloroplasts!
Inputs
Outputs
Light
H₂O
O₂
ADP
ATP*
NADP+
NADPH*
**Goal Products!
O₂ is only a byproduct!!
Light Dependent Reactions
Lets see it altogether now!
https://www.youtube.com/watch?v=joZ1Es
A5_NY
Do Now

Please garb the worksheet off my desk,
and begin working on it individually.
Do Now

What are the steps of light dependent
reactions? (yay light!) 

What is the equation for photosynthesis?
Objectives

List the inputs and outputs of the Calvin Cycle

Define chemiosmosis and it’s role in
photosynthesis.

Summarize light – independent reactions

Perform chromatography to identify the
pigments of green leaves.
Intro Video for Calvin Cycle

https://www.youtube.com/watch?v=E_XQ
R800AgM
Light Independent Reactions
(Calvin Cycle)

Takes place in the stroma

Functions like a sugar factory within a chloroplast
◦ **Regenerates the starting material with each turn

Uses NADPH and ATP from Phase I (light dependent
reactions)

Needs CO2!!!

Produces GLUCOSE 
Light Independent Reaction
Calvin Cycle
Step 1:
Carbon dioxide molecules breakdown by
combining with RuBP. (Carbon Fixation)
Calvin Cycle
Step 2:
ATP and NADPH transfers energy and electrons to
this molecule to create another three carbon molecule
called G3P.
Calvin Cycle
Step 3:
2 G3P molecules will leave the cycle to create
glucose.
Calvin Cycle
Step 4:
An enzyme (Rubisco) converts the remaining G3P
molecules into RuBP.
◦ RuBP will combine with new carbon dioxide molecules to continue
the cycle.
Calvin Cycle
Inputs
6 CO2
- 18 ATP
- 12 NADPH
-
Outputs
- 2G3P (1 glucose- GOAL!)
- 18 ADP
- 12 NADP+
Location: Stroma of the Chloroplast
QUICK!

Which contains more energy, one
molecule of NADP+ or one molecule of
NADPH?

What is the name of the three carbon
molecule that is a product of the Calvin
Cycle?
Animation
https://www.youtube.com/watch?v=joZ1Es
A5_NY
Let’s try some examples

How many glucose molecules are made
from 108 ATP in the calvin cycle?

How many carbon dioxide molecules are
needed to make 8 glucose molecules?
Factors that can affect the rate of
photosynthesis!

Light Intensity (Amount)

Rainfall Amount

Temperature

CO₂ Concentration
Stomata can also affect the rate of
photosynthesis!

Stomata- openings (pores) on the underneath leaves that
allow the exchange of carbon dioxide, oxygen, and water.

More water available will open up stomata, less water will
cause them to close to reduce water loss.