Photosynthesis & Cellular Respiration

Objectives

1. Identify the reactants and products of photosynthesis and cellular respiration

2. Understand the recycling of chemicals between photosynthesis and cellular respiration

3. Understand the role of pigments with the reflection, absorption, and transmission of light.

The Power of Green• All life on earth is driven

by the sun & the power of green. Where’s the green come from?

• Chlorophyll!• 8 minutes for a photon to

travel 93 million miles from sun to earth.

• A green plant needs only seconds to capture that energy, process it, and store it as chemical bonds.

• What’s this called?

Photosynthesis Overview

Photosynthesis

• Light energy converted to chemical energy

The Formula• carbon dioxide + water + light energy ---> glucose +

oxygen

• 6CO2 + 6H2O + light energy -------------------> C6H12O6 + 6O2

Notice the balance on both sides of the equation

Cellular Respiration Overview

Cellular Respiration: Harvesting Energy

• Animals, including bats, harvest this energy stored in foods through a process called cellular respiration.

Glucose + Oxygen ---> Carbon Dioxide + Water + ATP

C6H12O6 + 6O2 -------> 6CO2 + 6H2O + ATP (Energy!)

What do you notice about the reactants of cellular respiration?

Cellular Respiration vs. Photosynthesis

• 6CO2 + 6H2O + light energy --> C6H12O6 + 6O2

• C6H12O6 + 6O2 ------------------> 6CO2 + 6H2O + ATP

What do you notice??

The products of one are the reactants for the other.

The Recycling of Energy

• Photosynthesis and Cellular Respiration recycle a common set of chemicals

• How does this work?• Let's Check it Out! (A

ctivity 7.1)

Electromagnetic Spectrum and Pigments

• Light is small part of spectrum

• Less than 1%• Pigment:

– chemical compound that determines color

• Light can be absorbed, transmitted, or reflected

Chlorophyll

• What color do we see when looking at a plant with chlorophyll?

• Is this the reflected or absorbed light?

• We see REFLECTED light!• Plants absorb red and blue light --> reflect green.