Metabolism What is metabolism? What is metabolism? The sum of all chemical reactions occurring in the body. The sum of all chemical reactions occurring in the body. Why do we need all those chemical reactions? Why do we need all those chemical reactions? There are lots of jobs that must be done to keep us alive! Breathing, digestion, movement, thinking, immunity, growth, etc. There are lots of jobs that must be done to keep us alive! Breathing, digestion, movement, thinking, immunity, growth, etc. All those reactions require energy. Where do we get the energy? All those reactions require energy. Where do we get the energy?

Living things depend on the Sun! (stored in glucose) (wasted energy) (wasted) (Used for Movement)

2 Laws of Thermodynamics 1 st Law: Energy cannot be created or destroyed, but it can change from one form to another. 1 st Law: Energy cannot be created or destroyed, but it can change from one form to another. Solar, chemical, mechanical, heat energy, etc. Solar, chemical, mechanical, heat energy, etc. 2 nd Law: When energy changes forms, some of the energy is wasted or lost as… 2 nd Law: When energy changes forms, some of the energy is wasted or lost as… HEAT! HEAT!

Living things depend on the Sun! (stored in glucose) (wasted energy) (wasted) (Used for Movement)

Photosynthesis Solar energy + 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Solar energy + 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 (carbon (water) (glucose) (oxygen) (carbon (water) (glucose) (oxygen)dioxide) Photosynthesis transforms solar energy into the chemical energy of a carbohydrate. Photosynthesis transforms solar energy into the chemical energy of a carbohydrate. * Autotrophs

Respiration C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O (glucose) (oxygen) (carbon (water) C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O (glucose) (oxygen) (carbon (water)dioxide) * Heterotrophs

Solar energy can be converted to chemical energy. This chemical energy can be stored in the covalent bonds that hold together the atoms in a molecule of glucose. Chemical energy can be converted to mechanical energy. See Spot run! Spot the Dog Chemical energy is stored in each of these covalent bonds.

Before an organism can use the chemical energy in glucose, the energy must be stored in ATP. Before an organism can use the chemical energy in glucose, the energy must be stored in ATP. ATP is the “currency” of cellular energy. ATP is the “currency” of cellular energy. ATP directly supplies the energy necessary for nearly all chemical reactions in the body. ATP directly supplies the energy necessary for nearly all chemical reactions in the body.

ATP: Adenosine Triphosphate Very high energy bonds between phosphate groups (like charges repel)

ATP Chemical energy is stored in the high energy bonds that hold the phosphate groups together in the ATP molecule. Chemical energy is stored in the high energy bonds that hold the phosphate groups together in the ATP molecule. When ATP is broken down, a phosphate group is released along with free energy that can be used for metabolism. When ATP is broken down, a phosphate group is released along with free energy that can be used for metabolism.

Functions of ATP Chemical work: ATP supplies the energy needed to build organic molecules in the cell (DNA, RNA, proteins). Chemical work: ATP supplies the energy needed to build organic molecules in the cell (DNA, RNA, proteins). Transport work: ATP supplies the energy to pump substances across the cell membrane (active transport). Transport work: ATP supplies the energy to pump substances across the cell membrane (active transport). Mechanical work: ATP provides energy for movement. (muscle contraction, flagella, chromosome movement during mitosis, etc.) Mechanical work: ATP provides energy for movement. (muscle contraction, flagella, chromosome movement during mitosis, etc.)

So how & where is ATP formed?

Fun Facts The typical person will use their body weight in ATP over the course of the day! The typical person will use their body weight in ATP over the course of the day! Each ATP molecule can be recycled from times per day! Each ATP molecule can be recycled from times per day!

Big Picture Organisms require energy for metabolism. Organisms require energy for metabolism. That energy ultimately comes from the sun’s energy stored in the chemical bonds of glucose, produced by photosynthesis. That energy ultimately comes from the sun’s energy stored in the chemical bonds of glucose, produced by photosynthesis.