Chapter 3 Section 3

Energy for Life Chemical energy stored in food molecules is changed inside cells into forms needed to perform all the activities necessary for life All of the activities of an organism invole chemical reactions in some way Metabolism= the total of all chemical reactions in an organism

Enzymes Chemical reactions of metabolism need enzymes Enzymes assist reactions and causes a change, but the enzyme stays the same Enzymes can be used again and again

Living Things Divided into two groups: producers and consumers Producers- organisms that make their own food. Also called autotrophs consumers- organisms that cannot make their own food. Also called heterotrophs

Plants Are autotrophs Use the energy from sunlight to make their own food through photosynthesis Photosynthesis- when producers convert light energy into chemical energy, or sugars that can be used as food.

Where the Magic Happens…. Chlorophyll- a green pigment that is used in photosynthesis to capture light. They are found in chloroplasts

What Happens… Captured light energy powers a chemical reaction that turns carbon dioxide and water into oxygen and sugar Excess sugar is stored as starches or used to make other carbohydrates

Respiration The process in which chemical reactions break down food molecules into simpler substances and release stored energy

Respiration Begins in the cytoplasm Carbohydrates are broken down into glucose molecules

Next Moves into the mitochondria Two simpler molecules are broken down again, releasing more energy This process uses oxygen and produces carbon dioxide and water as waste

Fermentation Cells that do not have enough oxygen for respiration use fermentation to release some of the stored energy in glucose molecules Occurs in the cytoplasm Produces lactic acid, alcohol, and carbon dioxide as waste Also called anaerobic respiration

Lactic Acid Why your muscles hurt during tough workouts

Alcohol

Did You Know..? Bread is made using the process of fermentation Yeast, a fungi, is an ingredient in the bread dough that uses anaerobic respiration As the yeast eats up the sugar in the dough, it begins to release gas bubbles of carbon dioxide, and small amounts of ethanol alcohol, causing the bread to rise