Introduction to Photosynthesis

Objectives

Overview

• Plants convert the energy of sunlight into the energy of chemical bonds of carbohydrates

Importance of Photosynthesis

But that’s not all..

But wait, there’s more..

History

Jan Van Helmont

Found the mass of a pot of soil and a seedling. Watered the seedling for five years. Found the mass again

Concluded that the increase in mass came from water

History

Joseph Priestly

Found that a candle goes out when placed in a jar. However, the candle keeps burning if a sprig of mint is also placed in the jar.

Concluded that plants produce [Oxygen]

History

Jan Ingenhousz

Showed that Priestley’s experiment only works in the light.

Concludes that light is necessary for plants to produce oxygen

History

Magic School Bus class

CO2+H20 C(H2O)+O2

Chemical basis of photosynthesis

Light

6CO2+6H20 C6H12O6+6O2

Balanced Equation

Light

CO2+H20 C(H2O)+ O2

Photosynthesis

Respiration

Sun Entropy

The BIG Picture

Leaf Structure – p.655

Leaf structure

Requirements for Photosynthesis

                        

Light

Mostly violet, blue and red wavelengths from the visible spectrum

Pigments

Energy Storing Compounds

Energy trapped by molecules can be used to lift electrons to a higher energy level.

From that higher energy level the electrons can fall down to their original energy level and do work along the way.

Example – a solar cell that powers a calculator

Or…

The high-energy electrons can be bound to an electron carrier.

Nicotinamide Adenine Dinucleotide Phosphate

NADP+ accepts a pair of high energy electrons and a Hydrogen ion to become NADPH

And of CourseATP – Adenosine Triphosphate

Energy storing compound used by every living cell

Provides the energy for almost all cellular functions

Function of ATP

Overview of Photosynthesis

• Light reactions

• Dark reactions – Calvin Cycle

Light Reactions

Calvin CycleProducts from the light reactions and CO2

from the atmosphere are used to produce carbohydrates

Objectives

1. Discuss energy flow through living systems

2. Identify the parts of a leaf

3. Outline the process of photosynthesis

Homework

See planner.

Have a nice day