Chapter 8 Photosynthesis
Chapter 8 Section 1 Energy and Life Autotrophs and Heterotrophs
Plants and some other types of organisms are able to use light energy from the sun to produce food. Autotrophs Organisms such as plants, which make their own food. Heterotrophs (Impalas and Leopard) Other organisms, such as animals, cannot use the sun's energy directly.
To live, all organisms, including plants, must release the energy in sugars and other compounds

Autotrophs vs. Heterotrophs -Autotrophs use light energy from the sun to produce food. -Heterotrophs eat grass to get their energy while, a leopard gets its energy by eating other animals. Chemical Energy and ATP Energy comes in many forms, including light, heat, and electricity. -Energy can be stored in chemical compounds, too. -The high-energy bonds are replaced by low-energy bonds between these atoms and oxygen. When the electrons in those bonds are shifted from higher energy levels to lower energy levels, the extra energy is released as heat and light. Adenosine Triphosphate (ATP) -One of the principal chemical compounds that cells use to store and release energy.
Those three phosphate groups are the key to ATP's ability to store and release energy.
Structure of Adenosine Triphosphate
ATP is used by all types of cells as their basic energy source. Storing Energy Adenosine Diphosphate (ADP) Is a compound that looks almost like ATP, except that it has two phosphate groups instead of three. ATP vs. ADP -This difference is the key to the way in which living things store energy. When a cell has energy available, it can store small amounts of it by adding a phosphate group to ADP molecules, producing ATP. In a way, ATP is like a fully charged battery, ready to power the machinery of the cell. Releasing Energy -Simply by breaking the chemical bond between the second and third phosphates, energy is released. Because a cell can subtract that third phosphate group, it can release energy as needed. ATP has enough energy to power a variety of cellular activities, including active transport across cell membranes, protein synthesis, and muscle contraction.
The characteristics of ATP make it exceptionally useful as the basic energy source of all cells. Using Biochemical Energy One way cells use the energy provided by ATP is to carry out active transport. ATP produces movement, too, providing the energy for motor proteins that move organelles throughout the cell. Energy from ATP powers other important events in the cell, including the synthesis of proteins and nucleic acids and responses to chemical signals at the cell surface. The energy from ATP can even be used to produce light. ATP is such a useful source of energy that you might think the cells would be packed with ATP to get them through the day, but this is not the case. In fact, most cells have only a small amount of ATP, enough to last them for a few seconds of activity. Even though ATP is a great molecule for transferring energy, it is not a good one for storing large amounts of energy over the long term. EX. A single molecule of the sugar glucose stores more than 90 times the chemical energy of a molecule of ATP. Therefore, it is more efficient for cells to keep only a small supply of ATP on hand. Cells can regenerate ATP from ADP as needed by using the energy in foods like glucose. As you will see, that's exactly what they do.
Chapter 8 Section 2 Photosynthesis: An Overview Photosynthesis The key cellular process identified with energy production. In the process of photosynthesis, plants use the energy of sunlight to convert water and carbon dioxide into high-energy carbohydrates—sugars and starches—and oxygen, a waste product. Investigating Photosynthesis Van Helmont’s Experiment Van Helmont's Experiment In the 1600s,