Plants’ source of food

Plants make their own food internally using carbon dioxide, water, and sun in a process called photosynthesis.

This is plants’ only source of food.

Plants take in their food from the outside environment. 

Plants have multiple sources of food.

Food made by green plants is matter that organisms can use as a source of energy. It is an energy-containing material.

Food is the stuff that organisms eat, chew, take into their bodies.

Function of food in plants

Food supplies the energy that each cell of a plant needs for internal life processes (functional explanation).

Food is need to keep plants alive, to grow (nonfunctional explanation).

Matter transformation (chemical change)

Water and carbon dioxide taken into plants is changed into new matter as a result of a chemical reaction.  In this chemical change, nonenergy-containing matter (carbon dioxide and water) is rearranged and recombined to make energy-containing food (glucose).

Movement of matter

Water and carbon dioxide travel to cells in the leaf where they are involved in one process -- photosynthesis.

Water and carbon dioxide travel throughout the plant where they are used for two separate processes -- eating/drinking the water and breathing the carbon dioxide.

Energy transformation

During photosynthesis, light energy from the sun is changed into chemical energy stored in the food that plants make.

Plants need sun to live, grow, to be green.  (No notion of energy being absorbed, needed, or changed)

OR

Plants get their energy directly from the sun -- this is their food. (No notion of light energy being transformed into food energy)

Importance of food-making process for plants

Most important product is food.  This food is the plant cells’ only source of energy.

The food-making process in plants is something they do for the benefit of people/animals.  Plants are important because they give us oxygen and food.

Importance of food-making process for people/animals

Animals depend on plants for food as well as oxygen.  Only green plants can change light energy from sun into chemical energy stored in food.  Thus, only green plants can make energy-containing food that all living things need.

Plants are important because they make oxygen for people and animals to breathe.  (Focus on oxygen production, not food production)

Plants are also an important source of food for animals, but they are not the only source.