Big Idea

Science Standard 7.1.d: Students know that mitochondria liberate energy for the work that cells do and that chloroplasts capture sunlight energy for photosynthesis. Paraphrase: Students will know how plants capture sunlight energy for photosynthesis.

photosynthesis: The process by which a cell captures energy in sunlight and uses it to make food. autotroph: An organism that makes it’s own food. heterotroph: An organism that cannot make it’s own food, including animals such as the zebra, and the lion. pigment: colored chemical compounds that absorb light. chlorophyll: the main photosynthetic pigment in chloroplasts. stomata: small openings on the undersides of leaves.

 the term photosynthesis comes from the Greek words photo, which means “light,” and synthesis, which means “putting together.”  Nearly all living things obtain energy either directly or indirectly from the energy of sunlight captured during photosynthesis.  Plants manufacture their own food through the process of photosynthesis.  an organism that makes it’s own food is known as an autotroph. (grass, plants)  an organism that cannot make it’s own food is called a heterotroph. (lions, zebras, etc)  Many heterotrophs obtain food by eating other organisms.  Some heterotrophs,such as fungi, absorb their food from other organisms.

Stage 1 : Capturing the Sun’s Energy  involves capturing the sun’s energy in sunlight  In plants, this process occurs mostly in the leaves  Light is absorbed by the pigments ( green organelles inside plant cells that absorb light)  The main photosynthetic pigment in chloroplasts is chlorophyll.  Chlorophyll captures the light energy and uses it to power the second stage of photosynthesis.

Stage 2 : Using Energy to make food  the cell uses captured energy to produce sugars  The cell needs two raw materials for this stage: water & carbon dioxide  Roots absorb water from the soil, and moves up through the plants stem to the leaves.  Carbon dioxide enters the plant through small openings on the undersides of the leaves called stomata  Once in the leaves the water and carbon dioxide move into the chloroplasts.  Inside the chloroplasts, the water and carbon dioxide undergo chemical reactions. The reactions are powered be the energy captured in the first stage. The products of these reactions are SUGARS and OXYGEN.

Write down two questions you have about this chapter!

Plants trap energy from sunlight during a process called photosynthesis and uses that energy to make sugars. Plants later break down those sugars, releasing the energy for cell use. The leaf has stored food that the plant made using energy from the sun. The substances that are needed for photosynthesis are carbon dioxide and water. The substances that are produced during photosynthesis are sugar and oxygen.

“The Cell in its Environment” Worksheet #1-112