Cell Energy Chapter 3

Cells need energy in order to work properly Plant cells get energy through photosynthesis, which happens in the chloroplast Animal cells get energy through cellular respiration, which happens in the mitochondria.

How are photosynthesis and cellular respiration opposite or complementary processes? This means that one cannot happen without the other. The products of photosynthesis are the reactants of respiration and the products of respiration are the reactants of photosynthesis.

PHOTOSYNTHESIS Photosynthesis is the transformation of light energy from the sun into the chemical energy of glucose. Reactants Products 6 CO H 2 O + light  C 6 H 12 O O 2 carbon dioxide + water + light energy  glucose + oxygen

CELLULAR RESPIRATION Cellular respiration is the process of breaking down food (such as carbohydrates and other molecules) in order to release energy present in food. The energy molecule released in cellular respiration is ATP (adenosine triphosphate) Reactants Products C 6 H 12 O O 2  6 CO H 2 O + Energy Glucose + oxygen  carbon dioxide + water + ATP

Types of cellular respiration 1. Aerobic Respiration 2. Anaerobic Respiration.

Aerobic respiration Requires oxygen Glucose is completely broken down into CO 2 and H 2 O in the presence of O 2 to release energy from food It allows for the maximum amount of energy to be released from the glucose It occurs in the cytoplasm and the mitochondria of the cell in both plants and animals

Anaerobic respiration Does NOT require oxygen Glucose is broken down without oxygen to release energy It generates little energy for the cell. It occurs in smaller organisms and in larger organisms when oxygen is not present. It occurs in the cytoplasm of both plants and animals.

Lactic Acid Fermentation When lactic acid builds up in muscles and a person feels a stitch. This happens when glucose is broken down and makes lactic acid, instead of energy, because there is not enough oxygen available. Lactic acid builds up in muscles causing a burning/painful sensation. The muscle will return to normal after rest. C 6 H 12 O 6 2 CH 3 CHOHCOOH