Photosynthesis

• Science
• 6th Grade

Photosynthesis

How are we feeling today?

I can explain the role of photosynthesis in the cycling of matter and the flow of energy into and out of organisms.

Virtual Lab

Photosynthesis

gizmos.explorelearning.com

Photosynthesis is a process by which plants, algae, and certain microorganisms transform light energy from the sun into the chemical energy of food. During photosynthesis, energy from sunlight is harnessed and used to convert carbon dioxide and water into organic compounds—namely sugar molecules—and oxygen. The process enables photosynthetic organisms to change light energy into a form of energy—the chemical energy in sugars—that their cells can store and use to grow and thrive. This chemical energy is transferred to animals that eat plants as well as other photosynthetic organisms, and to the animals that eat other animals. The oxygen produced through photosynthesis is released into the atmosphere.

Photosynthesis proceeds through a series of steps. Water enters the plant through the roots and travels up to the leaves. Carbon dioxide enters the leaves through tiny pores called stomata. Inside the chloroplasts, chlorophyll captures energy from sunlight; this energy then drives a series of chemical reactions between carbon dioxide and water, changing them into glucose and oxygen.

All photosynthesis in plants takes place within the chloroplasts, which are concentrated in the cells of leaves.

The importance of photosynthesis to life on Earth cannot be overstated. Photosynthesis directly and indirectly supplies the food we eat and the air we breathe. Without it, the Earth’s fundamental food supply would not be replenished. With less food available, most organisms would disappear, and the planet would become devoid of oxygen.

Photosynthesis is a chemical process in which light energy from the sun drives a series of chemical reactions between carbon dioxide and water, forming glucose and oxygen as end products. 

The overall process can be expressed as follows:

carbon dioxide + water + light energy → glucose + oxygen. The reaction requires chlorophyll, a green pigment found in all that can undergo photosynthesis. Chlorophyll plays a critical role in capturing energy from incoming sunlight and transferring it to the chemical compounds involved in photosynthesis. The chlorophyll in plant cells is contained in organelles called chloroplasts.

The oxygen produced in photosynthesis is released into the air as a waste product. The plant may burn some of the glucose immediately for energy to power cellular activities (see cellular respiration). Some glucose molecules may be converted to other sugars, such as fructose or sucrose, or linked together to form cellulose—a large complex carbohydrate needed to build and repair cell walls. Most of the glucose produced in photosynthesis is linked together to form starch, a large complex carbohydrate. Plants store starch in their tissues and break it down into glucose molecules when they need energy.

-Encyclopedia Britannica Kids, Inc.

Sunlight 

(energy)

Exit Ticket:

Please answer:

What is photosynthesis?

Where in the plant does photosynthesis happen?

What part of the plant makes it look green?