Photosynthesis

From Light to Life

Definition

• The process by which plants use CO2 and water, along with the sun’s energy to create glucose, a simple sugar, oxygen and water.

Where does photosynthesis occur?

Chloroplasts- Thylakoids- Stroma

Chlorophyll absorbs the violet, blue and red waves of sunlight and uses it. It reflects the green wavelengths, which is why we see leaves as green.

Chlorophyll is a truly amazing substance!

It is present in all green plants and is responsible for light absorption, which provides energy for photosynthesis. Photosynthesis generates oxygen—a source of life for our planet. This flask contains chlorophyll extracted from spinach leaves. When a beam of light passes through the extract, the chlorophyll absorbs the energy, which is the first step in photosynthesis. Because the chlorophyll in this flask has been isolated from the plant, energy cannot be converted and stored. Instead the energy is released as heat and red fluorescence.

The Process of Photosynthesis- Two Phases

Light Phase- takes place in the thylakoids

Light Reactions-REQUIRE LIGHT1. Light is absorbed by

chlorophyll and the molecules become energized

2. Adenosine diphosphate becomes adenosinetriphosphate

3. The energy splits the water (photolysis)

4. The hydrogen from water bonds with NADP (H)

Results of Light Phase

• ATP and NADPH are produced for use as energy during the dark phase

• Oxygen (from H2O)is released into the atmosphere

Dark Phase Takes Place in the Stroma

Dark Reactions- DO NOT REQUIRE LIGHT

1. Carbon dioxide combines with RuBP

2. RuBP splits into two molecules of PGA

3. The ATP and hydrogen/electrons from light phase change PGA to PGAL (a higher energy molecule

Results of Dark Phase

• Some of the PGAL molecules go on to form glucose

• The rest will continue through the cycle and repeat the process

Dark Reactions also known as-The Calvin Cycle

Really Now- Don’t you agree that photosynthesis is an amazing process?

Hebrews 11:3 By faith we understand that the universe was formed at God's command, so that what is seen was not made out of what was visible.

BE AMAZED!