Enzyme and Energy Review

Enzyme• Enzymes are catalytic molecules. That is, they speed

up specific reactions without being used up in the reaction. Enzymes are proteins.

• All enzymes have three special features in common:– 1. Enzymes do not create processes that would not take

place on their own. They just make the processes take place faster!

– 2. Enzymes are not permanently altered or used up in reactions.

– 3. Each enzyme catalyzes only one specific type of reaction, but can catalyze many of this particular reaction one after another.

Parts of an Enzyme• Substrates are molecules that a specific enzyme can chemically

recognize and to which it can bind. Substrates undergo chemical changes to form new substances called products.

• Each substrate fits into an area of the enzyme called the active site. It is like a lock-and-key mechanism. Once the enzyme-substrate complex is together, the enzyme holds the substrate in a position where the reaction can occur. Once the reaction is complete, the enzyme unlocks the product and the enzyme is free to facilitate another reaction.

Rate of the Reaction

• The rate of a reaction depends in part on the concentration of the enzyme. If the enzyme is diluted, its concentration is lowered, which slows the reaction rate.

• Rate of reaction also depends on the amount of energy present for the reaction to occur

• Temperature can also slow or speed up a reaction.

Energy- The Big IDEA• All life on Earth depends on the flow of energy. The primary source

of this energy is the Sun. • Plants and other photosynthetic organisms (for example,

cyanobacteria, or bluegreen algae) are the entry point for this flow of energy.

• The process of photosynthesis supports almost all life on Earth directly or indirectly.

• Photosynthesis is the process that converts solar energy to chemical energy in the form of carbohydrates.

• Carbohydrates are then broken down by the metabolism of the cells of these photosynthetic organisms or by the cells of other organisms, such as animals, fungi, or microbes that consume plant materials.

• In all cells, the processes of life are constantly moving and rearranging atoms, ions, and molecules. All this biological work requires energy.

ATP- Stored Energy• ATP, adenosine triphosphate, is a special molecule

that stores and releases the energy in its bonds in response to the energy need of the cell.

• Cells work constantly to maintain a vast supply of this energy storage molecule.

• The stored energy is released when ATP is split into ADP, adenosine diphosphate, and an inorganic phosphate.

Photosynthesis• Occurs in autotrophs who use chlorophyll (pigment

found in cholorplast) to absorb sunlight. • Must also have CO2 and H2O in order to work.• 6CO2 + 6H2O + energy -> C6H12O6 + 6O2 • The goal is to change the sun’s energy into a usable

stored form of sugar.

Cellular Respiration• Most all organisms have some sort of cellular respiration going on

inside their cells.• Mitochondria convert sugar and O2 into usable energy, ATP. • Two Main Reactions of Cellular Respiration:– 1. Krebs Cycle – Breaks down the products of Glycolysis to

produce molecules used in the electron transport chain. 2 ATP– 2. Electron Transport Chain – Consists of a series of proteins in the

mitochondrial membranes that convert ADP to ATP by transferring electrons. 34 ATP