Biology- Chapter 2.4 Chemical Reactions and Enzymes

What happens to chemical bonds during chemical reactions?

Chemical reactions involve changes in the chemical bonds that join atoms in compounds. (Chem bonds break during reactions-> form compounds)

Chemical reaction

process that changes, or transforms, one set of chemicals into another

Reactants

elements or compounds that enter into a chemical reaction

Products

The elements or compounds produced by a chemical reaction.

What is conserved during chemical transformations, even in living organisms?

Mass and energy

How do energy changes affect whether a chemical reaction will occur?

Chemical reactions that release energy often occur on their own, or spontaneously. Chemical reactions that absorb energy will not occur without a source of energy.

How does a chem reaction in your bloodstream that enables carbon dioxide to be removed from the body work?

As it enters the blood, carbon dioxide reacts with water to produce carbonic acid (H2CO3), which is highly soluble. This reaction enables the blood to carry carbon dioxide to the lungs. In the lungs, the reaction is reversed and produces carbon dioxide gas, which you exhale

How is energy in the burning of hydrogen gas released?

in the form of heat, and sometimes—when hydrogen gas explodes—light and sound

What is one of the most important factors in determining whether a chemical reaction will occur.

Energy changes

Why must every organism have a source of energy to carry out chemical reactions?

Because matter and energy are conserved in chemical reactions

How do plants and animals get energy to carry out chemical reactions?

Plants- trapping and storing the energy from sunlight in energy-rich compounds
Animals- when they consume plants or others animals

How do humans release the energy needed to grow tall, to breathe, to think, and to even dream?

Through the chemical reactions that occur when we metabolize, or break down, digested food

Activation energy

Energy needed to get a reaction started

Is activation energy involved in chemical reactions that release or absorb energy?

Both

What role do enzymes play in living things and what affects their function?

Enzymes speed up chemical reactions that take place in cells.
Temperature, pH, and regulatory molecules can affect the activity of enzymes.

What process helps chemical reactions that are too slow or have activation energies that are too high occur?

Catalysts made by cells

Catalysts

substances that speed up the rate of a chemical reaction

How do catalysts work?

By lowering a reaction's activation energy

Enzymes

proteins that act as biological catalysts

Generally, how many chemical reactions does one enzyme catalyze?

1

How big an effect does enzymes have on reactions?

Consider the reaction in which carbon dioxide combines with water to produce carbonic acid.
CO2 + H2O H2CO3
-this reaction is so slow that carbon dioxide might build up in the body faster than the bloodstream could remove it.
-Your bloodstream contains an enzyme called carbonic anhydrase that speeds up the reaction by a factor of 10 million.
-With carbonic anhy- drase on the job, the reaction takes place immediately and carbon dioxide is removed from the blood quickly.

How do enzymes do their jobs?

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. If the reactants do not have enough energy they will be unchanged after the collision.
-Enzymes provide a site where reactants can be brought together to react.
-Such a site reduces the energy needed for reaction.

Substrates

the reactants of enzyme-catalyzed reactions

What do the active site and the substrate have in common?

Complementary shapes (lock and key)

What is the site the substrates bind to on the enzyme called?

The active site

What do enzymes play essential roles in?

Controlling chemical pathways, making materials that cells need, releasing energy, and transferring information

What temperature do enzymes generally work best at?

Close to 37 degrees Celsius

What is 37 degrees Celsius the normal temp of?

The human body

What certain conditions and values do enzymes work best at?

Ionic conditions and pH values

What conditions does the stomach enzyme pepsin work best at?

Acidic conditions

How are the activities of most enzymes regulated?

by molecules that carry chemical signals within cells, switching enzymes "on" or "off " as needed.