Photosynthesis & Cellular Respiration

Photosynthesis Photo = light Synthi = to put together

Science as a Process Greeks believed that plants derive their substance from soil. Van Helmont showed that the materials that make up plants does not come from the soil.

Science as a Process Willow tree gained 164 lbs, but the soil only lost a few ounces. Plants must make their own food!

What is Photosynthesis? Photosynthesis is a chemical reaction. It is the most important chemical reaction on our planet.

What is the Chemical Equation for the Chemical Reaction of Photosynthesis?

Photosynthesis Basics Photosynthesis uses CO2, water, and light to produce glucose and O2.

What is the equation for the chemical reaction of photosynthesis? Six molecules of carbon dioxide react with six molecules of water to form 1 molecule of glucose and six molecules of oxygen.

Where do the reactants come from? Enters through pores in the leaf’s underside called stomata. Water Acquired by roots and transported to leaves Light Energy From the sun!

Describe Photosynthesis The process of changing light energy to chemical energy Chemical Energy stored as sugar (glucose) Occurs in plants and algae Takes place in the chloroplasts, using chlorophyll, the green pigment in plants

What happens during photosynthesis? Plants capture light energy and use that energy to make glucose Sunlight provides the energy needed by chlorophyll to change molecules of carbon dioxide and water into glucose Oxygen is also released in this reaction

What happens during photosynthesis? Carbon dioxide enters the leaf through holes called stomata

What happens during photosynthesis? The sugar is moved through tubes in the leaf to the roots, stems and fruits of the plants Some of the sugar is used right away by the plant for energy; some is stored as starch; and some is built into plant tissue

Why is this important to us? Animals can not make their own food (glucose, energy), they must get our food from plants. Plants are the first step in the food chain. The oxygen released during photosynthesis is necessary for life.

STOMATA Stomata are located on the abaxial surface (underside) of leaves. They are part of the epidermal tissue. Carbon dioxide enters the leaf through the stomata. Water also exits the leaf through the stomata in a process called TRANSPIRATION. This helps to cool the leaf and provides a gradient to move water from the roots up into the vine. Impression of abaxial (underside) of 2 leaves using nail polish peel technique (polarized light) A stoma is composed of a pore surrounded by two guard cells (red arrow in image at left). The guard cells adjust the opening of the pore. When the guard cells become turgid (swollen), the pore is opened and gas exchange and transpiration can occur. As the guard cells lose their turgidity, the pore becomes closed

Cellular Respiration How the glucose is used

What is Cellular Respiration? The release of chemical energy for use by cells. Once the energy that was in sunlight is changed into chemical energy by photosynthesis, an organism has to transform the chemical energy into a form that can be used by the organism. This process is cellular respiration.

Describe Cellular Respiration The breakdown of glucose molecules to release energy Takes place in all living things Happens in the cell’s mitochondria

What is the chemical equation for cellular respiration?

What is the chemical equation for cellular respiration? + Energy 38(ATP) + Energy 38(ATP)

= Glucose = ATP ATP=Energy Currency *Before we can use the glucose, we need convert it to spendable energy currency