Photosynthesis…it doesn’t involve taking photo

• All cells need energy to carry out their functions such as making proteins and transporting substances into and out of the cell.

• Photosynthesis—the process by which a cell captures energy in sunlight and uses it to make food. • Photo—Greek for “light” and

syntithenai means “putting together”

More Photosynthesis

• Nearly all living things obtain energy either directly or indirectly from the energy of sunlight that is captured during photosynthesis. –This happens due to the food chain

Producers & Consumers

• Autotroph (producer)—an organism that makes its own food–i.e. plants

• Heterotroph (consumer)—an organism that can’t make it’s own food–i.e. zebras lions, humans• They eat other organisms (some absorb food

from other organisms (fungi))

The Process of Photosyn.

• During photosynthesis, plants and some other organisms absorb energy from the sun and use the energy to convert carbon dioxide and water into sugars and oxygen–Happens in two stages

• Stage 1 (capturing energy)–Captures energy from the sunlight in the leaves–Chlorophyll—the main pigment for

photosynthesis in chloroplasts• Think of solar cells in a solar-powered calculator• water in chloroplasts is split into hydrogen and

oxygen–Oxygen is a waste product while hydrog. is used

Stage 2: Energy used to make food• Stage 2 cells produce sugar• Cells use hydrogen and carbon dioxide (CO2)

from the air which enters on underside of leaves–Two gases react and produce sugars• One important type is glucose…which cells use to

carry out vital functions–Oxygen gas exits a leaf through the openings on

its underside –Almost all the oxygen in the atmosphere comes

from this process

Photosyn. Equation

• Raw materials on left…products on left• Arrow means “yields”• Energy not a raw material