Photosynthesis & Cellular Respiration Seventh Grade Science

What is Photosynthesis? Photosynthesis is an endothermic reaction wherein energy is absorbed from the sun and utilized to convert carbon dioxide (CO2 ) and water (H2O) into glucose (C6H12O6) and oxygen (O2). 6 CO2 + 6 H2O → 6 C6H12O6 + 6 O2 The energy stored in the glucose molecules is ready to be used when needed.

Vocabulary Photosynthesis- A process by which plants convert sunlight, water, and carbon dioxide into food energy (sugar), oxygen and water. Chloroplast- An elongated cell organelle containing chlorophyll where photosynthesis takes place. Chlorophyll- A green molecule which uses light energy from sunlight to change water and carbon dioxide gas into sugar and oxygen

The chlorophyll absorbs the sunlight. Chlorophyll is the green pigment inside the chloroplasts of plant cells that makes leaves green

Chlorophyll then uses sunlight to change water, carbon dioxide and, nutrients from the soil. CO2

What is Cellular Respiration? Cellular respiration is the reverse reaction of photosynthesis: the combustion of glucose to form carbon dioxide and water Cellular respiration is an exothermic reaction. 6 C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

Vocabulary Respiration- The process by which the chemical energy of "food" molecules is released and changed into ATP. (chemical energy cells use) Mitochondria- Rod-shaped organelles (small part of a cell with a specific function) with a double membrane which converts the energy stored in glucose into ATP (energy) for the cell.

Plants and Animals Rely on Each Other Animals use: Sugar (from producers/plants) Oxygen (from producers/plants) Plants use: Carbon dioxide (from animals)

Examining the Reactants and Products Photosynthesis Reactants: 6 CO2 + 6 H2O Products: 6 C6H12O6 + 6 O2 Cellular Respiration Reactants: 6 C6H12O6 + 6 O2 Products: 6 CO2 + 6 H2O

Comparing & Contrasting Photosynthesis and cellular respiration have the exact same components in the chemical equation The reactants of photosynthesis are the same as the products of cellular respiration The products of photosynthesis are the same as the reactants of cellular respiration

Quick Quiz What is meant by “reverse reaction” when discussing photosynthesis and cellular respiration? How do the reactants and products of photosynthesis and cellular respiration compare? What is the formula for glucose?