9.1 Energy and Life Notes

Stored in chemical compounds

Breaking and forming chemical bonds releases energy

All living things store energy in chemical bonds of of certain compounds

ATP (Adenosine Triphosphate) - compound used by cells to store and release energy

• Composed of adenine, ribose, and 3 phosphate

ADP (Adenosine Diphosphate)

• Consists of adenine, ribose, and 2 Phosphates

Difference between ATP and ADP is how energy is stored

Add a phosphate to ADP to store energy

Cells release energy in ATP by the controlled breaking of the chemical bonds between atoms in the second and third phosphate groups

• energy is used to add a phosphate to ADP

• energy is released when a phosphate is split off and released

ATP can release and store energy by breaking and re-forming the bonds between the phosphates

This characteristic of ATP makes it exceptionally useful as a basic energy source for all cells

Cells use energy provided by ATP

• Active transport

  • 20-40% of energy used by the cell

• Enable cells to move

  • flagella-cilia- white blood cells

• Protein synthesis, movement within cells, responding to signals, producing light

Most animals obtain energy from food - heterotrophs

• Some eat plants- herbivores

• Some eat other animals that eat plants - carnivores

• Some can obtain energy from both - omnivores

• Some obtain energy from decomposition - fungi

All energy in food comes from the sun

• Some organisms use energy from sunlight to make food - autotrophs

  • plants

  • algae

  • some bacteria - cyanobacteria

• Nearly all life on earth depends on the sun

• Photosynthesis is the process by which plants convert the energy of the sun into chemical energy stored in the bonds of carbohydrates.