2.4 notes
What happens to the energy?
...In one direction the reaction produces energy, and in the other direction the reaction requires energy
The enzymes produced by human cells generally work best at temperatures close to?
37 degrees celsius, the normal temp of the human body
What do enzymes provide?
A site where reactants can be brought together to react, such a site reduces the energy needed for reaction
every organism must have what?
A source of energy to carry out chemical reactions because matter and energy is conserved.
Because enzymes are catalysts for reactions, what are enzymes affected by?
Any variable that influences a chemical reaction.
Where do enzymes work best?
At certain ionic conditions and pH values
Chemical reactions that release energy____
Do not always occur spontaneously.
Activation energy
Energy needed to get a reaction started. Activation energy is involved in chemical reactions regardless of whether the overall chemical releases or absorbs energy.
What else do chemical reactions involve?
Energy. Energy is released or absorbed whenever chemical bonds are formed or broken.
Anhydrase
Enzyme that speeds up the reaction of removing carbon dioxide by a factor of 1 million
In order to stay alive,
Organisms need to carry out reactions that require energy
How do plants get a source of energy to carry out chemical reactions?
Plants get that energy by trapping and storing the energy from sunlight in energy-rich compounds.
Enzymes
Proteins that act as biological catalysts. Enzymes speed up chemical reactions that take place in cells. Like other catalyst, enzymes act by lowering the activation energy, Lowering the activation energy has a dramatic effect on how quickly the reaction is completed.
An example of an energy releasing action
The burning of a hydrogen gas, in which hydrogen reacts with oxygen to produce water vapor. 2H2 + O2 --> 2H20 the energy released is a form of heat, when hydrogen gas explodes -light and sounds
An example of energy absorbing
When water is changed into hydrogen and oxygen gas, absorbs so much energy that it does not occur by itself.
Catalase
an enzyme that breaks down hydrogen peroxide
The activites of enzymes are regulated by molecules that?
carry chemical signals within cells, switching enzymes "on" or "off" as needed.
What do chemical reactions involve?
changes in the chemical bonds that join atoms in compounds Ex: an important chemical reaction in your blood stream enables carbon dioxide to be removed from the body
Product
element or compound produced by a chemical reaction
Reactant
element or compound that enters into a chemical reaction substrate
What is conserved during chemical transformations?
mass and energy
Chemical reaction
process that changes, or transforms, one set of chemicals into another set of chemicals
What do enzymes play essential roles in?
regulating chemical pathways, making materials that cells need, releasing energy, and transferring information
Catalyst
substance that speeds up the rate of a chemical reaction without any permanent damage. Can be reused. Catalysts lower a reaction activation energy. cells make catalyst. Can be reused
What can affect the activity of enzymes?
temperature, pH, and regulatory molecules
Humans release the energy needed to grow tall, to breathe, to think, and even to dream through____
the chemical reactions that occur wen we metabolize, or break down, digested food
For a chemical reaction to take place,
the reactants must collide with enough energy so that existing bonds will be broken and new bonds will be formed
Substrates
the reactants of enzyme-catalyzed reactions. The substrates bind to a site on the enzyme called the active sight, The active site and the substrates have complementary shapes. The fit is so precise that the active site and substrates are compared to a lock and key.
If the reactants don't have enough energy
they will be unchanged after the collision
Some chemical reactions that make life possible are?
too slow or have activation energies that are too high to make them practical for living tissue.
How do animals get their energy?
when they consume plants or other animals
Chemical reactions that absorb energy ____
will not occur without a source of energy
