Photosynthesis

Photosynthesis: An Overview

Photosynthesis Plant’s use sunlight to convert water (H2O) and carbon

dioxide (CO2) into high energy carbohydrates, mainly glucose (C6H12O6), and oxygen (O2).

Other examples of high energy carbohydrates include: Other carbon based sugars like ribose, sucrose, cellulose, etc. Starches

NOTE: Oxygen (O2) is a “waste” product.

Plants obtain the CO2 they need from the air or from the water (aquatic plants) in which they grow.

Example: kelp, Anacharis sp., Elodea sp., Cabamba sp.

Plants also use the sugar they make as an energy source to produce complex carbohydrates such as starches.

Photosynthesis: The Early Years 1643 – Jan van Helmont concluded trees gain

most of their mass from water.

1771 – Joseph Priestly concluded plants release a substance that can keep a candle burning.

1779 – Jan Ingenhousz concluded that plants need sunlight to produce oxygen.

Those 3, plus others, finally discovered that in the presence of light plants transform carbon dioxide and water into carbohydrates while releasing oxygen.

Photosynthesis: The Elementary School Years(Or what I should have learned in 5th grade)

Carbon dioxide + water sugars + oxygen

light

light

CO2 +6 H2O6 O2C6H12O6 +6

Balanced ?Now Balanced ?

Now, where in the “cell” does all this take place?

Here’s Where. . .

* In the leaf of every autroph

* Through the stomates

* Into every cell

* Into the thousands of chloroplasts

* On the grana of each chloroplast

(TEM of grana) * On each thylakoid of every grana

NOTHIN’ BUT NET!!!

. . . I mean C6H12O6

(Ahemmmmm . . . .)

The Sequel . . .Every Autotroph in the World!!

So . . . Who are the playas?

(that’s ghetto talk for “players!”)

Let There Be Light . . . The main Playa!

Photosynthesis uses the energy of sunlight to convert CO2 into sugar and oxygen.

Light comes in various “wave-lengths” making up the visible spectrum of all colors Remember my friend Roy G Biv?

Chlorophyll . . . Another playa!

Chlorophyll (the “filling”) inside of each chloroplast predominantly absorbs the blue-violet to red colors of the spectrum very well and reflects the green color. That is why leaves appear green.

Plants gather the sun’s energy with light absorbing pigments . . . Predominantly chlorophyll a and chlorophyll b

Any compound that absorbs light, absorbs the energy in light!!

When chlorophyll absorbs sunlight, much of the energy of the light is transferred directly to the electrons in the chlorophyll molecule, And when those electrons have their energy level raised . . .

Whoooaaaaa . . . Every molecule gets excited . . .

And when molecules get excited . . .

crazy things start happening!! (to be continued)

Home Preparation Read pages 204 - 207 Find 3 examples of aquatic plants

other than those listed in lecture and give their Genus species

Get a picture and state the organisms habitat

This must be typed!! Study for pfe 8-2