Where does the mass come from to turn an Acorn into an Oak Tree? Explain the process as you think it happens!

Photosynthesis: Energy from theSun!

Photosynthesis• Photosynthesis: Process to

convert light energy into organic material.

• Photos = light

• Synthi = to put together

Photosynthesis

• Photosynthesis cannot occur without the help of chloroplasts.

• Chloroplasts are disc shaped organelles found in certain plant cells that carry out the process of photosynthesis.

Photosynthesis• The balanced equation for Photosynthesis is

6H2O + 6CO2 C6H12O6 + 6O2

• Remember that matter must be conserved. (Law of Conservation)• Therefore what is on one side of the chemical equation must equal the other

Light

Energy

Reactant + Reactant → Product + Product

Draw lines to match the image to the answer:

Carbon Dioxide

Light Energy

Glucose

Water

Oxygen

What organisms are able to photosynthesize?

❖ Plants

❖ Bacteria

❖ Some protists

Question:

Where does photosynthesis take place?

• C?: How is cellular transport related to homeostasis?

In Plants• Autotrophs – produce their own food

(glucose)

• Occurs in the leaves (where

chlorophyll is):

a. stoma - pores

b. mesophyll cells (in

chloroplasts)

Stoma

Stoma (stomata (plural))Pores in a plant’s cuticle through which water

vapor and other gases (CO2 & O2) are exchanged between the plant and the atmosphere.

Guard CellGuard CellCarbon Dioxide

(CO2)

Oxygen

(O2)

Found on the underside of leaves

Stoma

Draw or type to label the diagram (use the words: Oxygen, Carbon Dioxide, Guard Cells, Stoma):

1.

2.

3.

4.

Photosynthesis happens in chloroplasts

= sac-like photosynthetic membranes inside chloroplast

THYLAKOIDS

GRANUM (pl. grana)= stack of thylakoids

THYLAKOID

SPACESTROMA

cytoplasm

Gel-filled space

Inside the

thylakoid

sac

Gel-filled space inside

chloroplast surrounding

thylakoid sac

Gel-filled space OUTSIDE chloroplast but inside the cell membrane

Proteins that are part of the thylakoid

membrane organize light absorbing pigments into clusters called Photosystems

The mesophyll layer has many chloroplasts…

Draw or type to label the diagram:

1.

2.

3.

4.

5.

Question:

Why are plants green?

They contain a pigment called

chlorophyll

Pigments●In addition to water,

carbon dioxide, and light energy, photosynthesis requires Pigments

●•Chlorophyll is the primary light-absorbing pigment in autotrophs

•Chlorophyll is found inside chloroplasts

Pigments●Located in the thylakoid

membranes

●Chlorophyll have Mg+ in the center

•Chlorophyll pigments harvest energy (photons) by absorbing certain wavelengths (blue-420 nm and red-660 nm)

•Plants are green because the green wavelength is reflected, not absorbed.

Wavelength of Light

Absorption of Light by Chlorophyll

WAVELENGT

H

ABSORPTION

violet blue green yellow orange red

Chlorophyll absorbs blue-violet & red light best

Green is

REFLECTED! so

plants appear

GREEN!

What does Chlorophyll do?

Question:

So how does photosynthesis work?

PhotosynthesisLight-Dependent

Reaction

Light-Independent

Reactions

Light &

Water

Oxygen

ATP

NADPH

• Requires ______________

• Pigments that absorb light are part of

______________________

• Made up of ___________________________

• Connected by ______________________ &

______________

• Uses light energy to create _______ & ________

• Breaks apart ______ molecules and

releases _____________

• The next two slides illustrate this process

LIGHT

ATP

Thylakoid membranesPHOTOSYSTEMS II & I

Electron transport chain

NADPHH20oxygen

ATP synthase

LIGHT DEPENDENT REACTION

LIGHT-DEPENDENT REACTIONS

PHOTOSYSTEM IIATP SYNTHASE

↓

PHOTOSYSTEM I

ELECTRON TRANSPORTSYSTEM

↓INSIDE THYLAKOID SPACE

OUTSIDE THYLAKOID IN STROMA

PHOTOSYSTEM II

LIGHT-DEPENDENT REACTIONSA. PSII: absorbs light

energy, creates high

energy electron, and

splits water into hydrogen

ions (protons) and oxygen

(this is the oxygen we

breathe!!!)

B. Electron transport system:

electron travels down

losing energy and

pumping protons (from

water) to the inner

thylakoid space

C. PSI: absorbs more light

energy and converts

NADP+ into NADPH

D. Hydrogen ions drive ATP

Synthase (concentration

gradient)

E. ATP Synthase makes

ATP!

Photosystem II

Electron transport system

Photosystem I

ATP synthase

Draw lines to match the boxes to the part of the light dependent reaction they are associated with (some answers will have more than one line!):

absorbs light

Makes NADPH

Makes ATP

releases Hydrogen

ions

Sets up hydrogen ion

gradient

releases Oxygen

Absorbs more light!

PhotosynthesisLight-Dependent

Reaction

Light-Independent

Reactions

Light &

Water

Oxygen

ATP

NADPH Made from light

dependent reaction

and sent to light

independent

reactions!

PHOTOSYNTHESIS OVERVIEW

Pearson Education Inc; Publishing as Prentice Hall

Light INDEPENDENT:

(also known as

dark reaction

and calvin cycle)

H2O

Calvin Cycle (light independent)CO2 Enters Here

Sugars are generated here

Energy in the form of ATP &

NADPH enter

hereEnergy is

used to

make more RuBP

(5 carbon

ring)

• ____________ require ____________

• Happens in the ____________ between thylakoids

• NADPH donates ________________________

• ATP donates _________________

• CO2 donates ____________________ to make ___________

• This is __________ ____________, the process where carbon atoms are incorporated into organic molecules

• To produce glucose it takes 6 turns, which uses 18 ATP and 12 NADPH.

LIGHTLIGHT INDEPENDENT

ENERGY

STROMAHydrogen + electrons

Carbon & oxygenGlucose

Does notCALVIN CYCLE (also called _________________)

Carbon fixation

Summary

of

Photosynthesis

What is carbon fixation and when does it occur in plants? Why is it so important?

Review of the Calvin Cycle

https://ed.ted.com/lessons/nature-s-smallest-factory-the-calvin-cycle-cathy-symington#watch

Question: What are factors that affect Photosynthesis?

Factors that Affect Photosynthesis:_________________________

More light increases rate of

photosynthesis up to a certain

level until plant

reaches its maximum

rate of photosynthesis

1. LIGHT INTENSITY

Factors that Affect Photosynthesis

Photosynthesis enzymes function best between 0° C - 35° C

At temperatures above or below this range, photosynthesis will slow or stop

Conifers in winter may carry out

photosynthesis occasionally

2. TEMPERATURE

Factors that Affect Photosynthesis

____________________

Water is one of the raw materials needed, so a shortage of water can ____________ photosynthesis

3. Amount of water

Desert plants and conifers that live in dry conditions have a waxy coating on their leaves to prevent water loss.

slow or stop➔ Plants shut stomata to avoid losing water

➔ However, shutting the stomata will also deprive the

plant of CO2

Factors that Affect Photosynthesis

4. Wavelength of light

➔Photosystem I absorbs

energy most efficiently at 700

nm and Photosystem II at 680

nm.

➔Light with a high proportion of

energy concentrated in these

wavelengths will produce a

high rate of photosynthesis.

Enzymes work BEST at a certain

___ and __________.

Conditions that are TOO ACIDIC

or TOO HOT cause proteins

to unwind or _________

This can affect photosynthesis!

pH temperature

DENATURE

Recall Enzymes:

PHOTORESPIRATION: wastes energy and steals carbon

➢ Side reaction that uses carbon instead of fixing it!

➢ The enzyme RuBP oxygenase-carboxylase (rubisco),

incorporates carbon dioxide into an organic molecule during

the first stage of the Calvin cycle.

➢ Rubisco also has a major flaw: it sometimes picks up oxygen

Kahn academy images

Photorespiration occurs with hot and

dry conditions

Unless plants have special adaptations!

C3 Plants● Most plants

● no

adaptations

to combat

photo-

respiration

C4 Plants● minimize

photorespiration by

separating CO2 fixation

and the Calvin cycle in

space

● performing these steps

in different cell types.

CAM plants ● Crassulacean acid

metabolism

● minimize

photorespiration and

saves water by

separating these steps

in time, between night

and day.

Examples: Corn, Sugarcane Examples: Cacti, Agave

Comparison of C3, C4 and CAM plants

Explain why cacti are well adapted for the desert?

Question:

During the fall, what causes the leaves to change colors?

Fall Colors

• During the fall, the green

chlorophyll pigments are

greatly reduced

revealing the other

pigments

• Carotenoids are

pigments that are either

red, orange, or yellow

• In addition to the chlorophyll pigments,

there are other pigments present

Fall Colors

• During the fall, the green

chlorophyll pigments are

broken down revealing

the other pigments

• Temperature, light, and

water supply influence

the degree & the

duration of fall color

• In addition to the chlorophyll pigments,

there are other pigments present

Now that you have learned about photosynthesis, answer the question: Where does the mass come from to turn an Acorn into an Oak Tree? Explain the process!