Biology unit 5.5: enzymes

What is the first step to starting chemical reactions?

Weakening the chemical bonds in the molecules of the reactants

How can we weaken the bonds between the molecules of the reactants of a chemical reaction?

We need an activation energy

What is activation energy

The start-up energy to a chemical reaction

How can we provide the activation energy

Heating and catalysts(enzymes)

How does heating provide activation energy?

Hotter molecules will collide faster between one another making them break their bonds more easily

Why can’t we use heat to heat up a cell in a cellular reaction?

It would make the delicate structures of the cell break, possibly killing it

How is activation energy provided in cellular reactions?

By catalysts

What are catalysts

Compounds that speed up chemical reactions

What are enzymes?

The main catalysts for chemical reactions in living organisms

How does an enzyme provide a way for the chemical reactions to occur with the cell being its normal temperature?

It lowers the energy requirement so the reaction can proceed at the normal temperature

How does an enzyme catalyze only one type of reactions?

The shape of each enzyme fits the shape of only particular reactant molecules

What is an enzyme substrate

A specific reactant acted upon by an enzyme is the enzyme’s substrate

What is an active site?

The substrate fits into a particular region of the enzyme called the active site

How does the active site match its function

It changes its shape to fit the enzyme’s substrate more tightly, and also makes certain function groups in the substrate in the position of chemical reactions. It might also weaken the bonds of the reactants

Write the cycle of the action of sucrase

1. Enzyme is available with active empty cells

2. Substrate binds to enzyme and reacts with the water being added to it

3. It forms products

4. Glucose and fructose are produced

What is another way that an enzyme can lower the energy requirement for a chemical reaction?

By accepting 2 reactant molecules into adjacent sites, used fir catalyzing the formation of larger molecules from small ones

What surrounding factors can affect how good an enzyme works?

Temperature and pH