Enzymes

What is a substance called if it speeds up a chemical reaction?

• reusable

• catalyst

• specific

• fragile

Answer explanation

A substance that speeds up a chemical reaction is called a catalyst. Catalysts increase the rate of reaction without being consumed in the process.

The graph shows how enzymes affect reactions in cells. Which statement best summarizes the information shown in the graph?

• Enzymes increase the energy of the reactants.

• Enzymes decrease the energy level of the products.

• Enzyme decrease the activation energy of the reaction.

• Enzymes reverse the direction of the reaction.

Answer explanation

The correct statement is that enzymes decrease the activation energy of the reaction, as shown in the graph.

Based on the graph, what is the optimal temperature for this enzyme? 

• 15^oC

• 40^oC

• 30^oC

• 35^oC

Answer explanation

The optimal temperature for the enzyme is 30°C as it shows the highest activity on the graph.

In the diagram, what is letter A? 

• product

• substrate

• enzyme-substrate complex

• active site

Answer explanation

In the diagram, letter A represents the enzyme-substrate complex, which is the correct choice based on the question.

Letter D...

• active site

• enzyme

• substrate

• products

Answer explanation

The correct choice is 'enzyme' because the letter D is commonly associated with the active site of an enzyme, where the substrate binds and the reaction occurs.

Letter B...

• active site

• enzyme

• substrate

• products

Answer explanation

The letter B typically represents the 'substrate' in the context of enzymes and their active sites. The substrate is the molecule upon which an enzyme acts.

Letter C...

• active site

• enzymes

• substrate

• products

Answer explanation

The active site is where enzymes bind to substrates to catalyze reactions. In this case, the correct answer choice related to the letter C is the active site.

Letter E...

• active site

• enzyme

• substrate

• products

Answer explanation

The correct answer is 'products' because the question is asking for the result of the enzyme action, which is the products formed after the reaction.

Which of the following conclusions can be drawn from this graph?

• The optimum pH of the enzyme is 6.6.
  

• The optimum pH of the enzyme is 5.8
  

• The enzyme’s activity increases as pH increases 5.0 to 9.0
  

• The enzyme’s activity is greater around pH of 8.0 .
  

Answer explanation

The optimum pH of the enzyme is 6.6.

Which of the following are not true about enzymes?

• Enzymes speed up chemical reactions.

• Enzymes react best at a specific temperature.

• Enzymes only control ONE type of reaction.

• Enzymes are made of fatty acids.

Answer explanation

Enzymes speed up chemical reactions, react best at a specific temperature, and can control multiple types of reactions, not just one. They are not made of fatty acids.