Chemical Reactions and Enzymes PPT - Enfield High...

Lesson OverviewLesson Overview Chemical Reactions and EnzymesChemical Reactions and Enzymes

Chemical Chemical Reactions and Reactions and

EnzymesEnzymesEnzymesEnzymes


Number 1What is a chemical reaction?

A process that changes, or transforms, one set of chemicals into another by changing the chemical bonds that join atoms in compounds.


Number 2What is conserved during chemical transformations?

MASS

ENERGY


Number 3Compare / contrast reactants and products.

Both are parts of a chemical reaction and both can be elements or compounds

Reactants are the elements or compounds that enter into a Reactants are the elements or compounds that enter into a chemical reaction

Products are the elements or compounds produced by a chemical reaction


Number 4Reactants and products of the following…

2 Na + 2 HCl � 2 NaCl + H2REACTANTS PRODUCTS


Number 5What is changed in a chemical reaction?

The chemical bonds that join atoms in compounds are changed in a chemical reaction

Bonds can be either created or brokenBonds can be either created or broken


Number 6Why is the melting of ice not a chemical reaction?

New chemical bonds are not formed

The bonds between hydrogen and oxygen are not changed


Number 7Chemical reaction in your bloodstream

As CO2 enters the blood, it reacts with water to produce carbonic acid (H2CO3), which is highly soluble

This reaction enables the blood to carry the carbon dioxide to the lungsthe lungs

In the lungs, the reaction is reversed and produces carbon dioxide gas, which you exhale


Number 8How do plants get the energy needed to stay alive?

Plants trap and store the energy from sunlight in energy-rich compounds


Number 9How do animals get the energy needed to stay alive?

Animals consume plants or other animals to get their energy


Number 10What is activation energy?

The energy that is needed to get a reaction started

It is the difference between the required energy and the energy of the reactantsenergy of the reactants


Number 11Label the following…

A

C

B

A = Reactants

B = Activation Energy

C = Products

This is an energy-absorbing reaction (endothermic reaction)


Number 11Label the following…

A

C

B

A = Reactants

B = Activation Energy

C = Products

This is an energy-releasing reaction (exothermic)


Number 12What is a catalyst? Why are catalysts important?

A substance that speeds up the rate of a chemical reaction

Catalysts work by lowering the activation energy

Catalysts are important because some reactions that make life possible are too slow or have activation energies that are too high


Number 13What are enzymes?

Proteins that act as biological catalysts

Enzymes speed up chemical reactions that take place in cells


Number 14Steps of an enzyme-catalyzed reaction

1. The substrates bind to the enzyme on the active site

2. The substrates are converted into productsconverted into products

3. The products are released

4. The enyzme is ready for another reaction

The enzyme brings the substrate together which means less energy is required


Number 15Why is the enzyme-substrate complex compared to a lock and key?

The active site and the substrates have complementary shapes

The fit is very precise, much like a lock that can only be The fit is very precise, much like a lock that can only be opened by one key


Number 16What are some variables that can affect enzymes?

Temperature, pH, and regulatory molecules are all factors that can affect the activity of enzymes.

Enzymes work best at certain temperatures.Enzymes work best at certain temperatures.

� Enzymes produced by human cells generally work best at

temperatures close to 37 degrees Celcius, the normal

temperature of the human body.

Enzymes work best at certain pH values.

� For example, the stomach enzyme pepsin, which begins protein

digestion, works best under acidic conditions.

The activities of most enzymes are regulated by molecules that carry

chemical signals within cells, switching enzymes “on” or “off” as

needed.

Chemical Reactions and Enzymes PPT - Enfield High...

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