1. Cells and Energy How does a cell obtain energy?
How do some cells make food molecules?

2. Photosynthesis

3. The primary need of all cells is energy.
Sun-the ultimate source of energy used by living things

4. Some organisms are capable of absorbing light energy and converting it into stored chemical energy. This process is called photosynthesis.

5. Photosynthesis is a series of chemical reactions that convert light energy, water, and CO2 into the food-energy molecule glucose and give off oxygen.
photosynthesis
from Greek photo, means “light”; and synthesis, means “composition”

6. Photosynthesis is one of the most important biological processes - because it is the essential step between solar energy and life.

7. This process combines carbon dioxide, water, and light energy to form glucose (a sugar) and oxygen.

8. For photosynthesis to occur, special pigments, organelles, and enzymes must be present.
Pigments are colored substances that absorb light energy.

9. The chemical reactions of photosynthesis are powered by light energy.
In the chloroplasts of plants, pigments such as chlorophyll absorb light energy
Chlorophyll absorbs all colors except green light, which is reflected as the green color in leaves.

11. In order for photosynthesis to happen, catalysts must be present.
chlorophyll (a green-colored pigment) the primary catalyst of photosynthesis; most chlorophyll is located in chloroplasts

12. In addition to chlorophyll, plants and algae have other pigments (red, pink, yellow, brown, etc.) that also absorb light energy and may pass the energy on to chlorophyll.

13. Photosynthesis Equation
Carbon dioxide + water + light energy -----> glucose + oxygen + water

14. When an organism eats plant material it takes in food energy from the plant’s glucose.
An organism’s cells use the oxygen released during photosynthesis and convert the food energy into usable energy through cellular respiration.

16. Enzymes