What is metabolism?• The sum of all chemical reactions occurring in
the body. 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.
All those reactions require energy. Where do we get the energy from?
1st Law: Energy cannot be created or destroyed, but it can change from one form to another.• Solar, chemical, mechanical, heat energy,
etc.
2nd Law: When energy changes forms, some of the energy is wasted or lost as…• HEAT!
Solar energy + 6CO2 + 6H2O C6H12O6 + 6O2
(carbon (water) (glucose) (oxygen)
dioxide)
Photosynthesis transforms solar energy into the chemical energy of a carbohydrate.
The photosynthetic process takes place with organelles called chloroplasts.
Energy for cells is stored in the chemical bonds of organic molecules (lipids, proteins and carbohydrates)
These are the “fuels” that power organisms
The carbohydrate “glucose” is the primary source of energy for the cell
C6H12O6 + 6O2 6CO2 + 6H2O +ATP(Cellular Respiration)
ATP directly supplies the energy necessary for nearly all chemical reactions in the body.
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.
ATP is the energy-carrier molecule in all cells
Think of ATP like a rechargeable battery The battery “releases” its energy to run
a radio/flashlight. (ATP ADP) When its energy has been used the
battery has to be recharged by adding energy to it (ADP + P ATP)
What are carbs and why do we always refer to them when discussing Cellular Respiration?!?!
How do we go from eating a sandwich to using the glucose to create usable energy for our cells?
Chemical work: ATP supplies the energy needed to build organic molecules in the cell.
Transport work: ATP supplies the energy to pump substances across the cell membrane.
Mechanical work: ATP provides energy for movement. (muscle contraction, flagella, chromosome movement during mitosis, etc.)
Organisms require energy for metabolism.
That energy ultimately comes from the sun’s energy stored in the chemical bonds of glucose, produced by photosynthesis. (We eat plants/glucose)
Mitochondria within cells have the machinery necessary to turn that glucose into ATP that the cell can use for energy.
The products of photosynthesis (sugar and oxygen) are used by cells during respiration.
The by-products of respiration (carbon dioxide and water) are used by cells performing photosynthesis.
And so it continues, with sunlight being put in as energy at the photosynthesis stage, and cellular energy (ATP) derived from glucose at the respiration stage.