Enzymes-

Enzymes

Biological Catalysts

Enzymes are Biological Catalysts

• They are proteins

• Catalysts speed up chemical reactions

• Structure = Function: Enzymes are specific to their Substrate (reactants). Active site of the enzymes fits together with the substrate(s)

• Different reactions require different enzymes

Enzymes speed up chemical reactions (Catalysts)

• Activation energy is the energy needed to start a chemical reaction.

• The less activation energy needed (smaller hill to climb) the faster the reaction will happen

• Enzymes speed up reactions by lowering the activation energy

Enzyme Specificity - The shape of the enzyme (structure) fits it's substrate (function)

The induced-fit model is the more accurate model

Factors affecting reaction rates

• Substrate concentration

• Enzyme concentration

• pH, temperature, and ion concentrations

Denaturation = to lose shape

• Structure (shape) = function

• If enzymes lose their shape they no longer function correctly

• Lower enzyme function = slower reaction rates

• Factors that can affect shape & function of enzymes: Temperature, pH, salinity (ion concentration)

Multiple Choice

The diagram below illustrates a biochemical process that occurs in organisms. What is another name for the substance labeled "catalyst"?

• Enzyme
• inorganic compound
• Hormone
• Antibody

Multiple Choice

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.

Optimal Enzyme Function

When the reaction rate is the highest!

Multiple Choice

Which enzyme is most efficient in a basic solution?

• A
• B

Multiple Choice

What happens when enzymes are heated to a high temperature?

• The enzymes die.
• The shapes of the enzyme are altered denature
• The enzymes' amino acid sequence changes.
• The enzymes remain the same

Multiple Choice

Letter c...

• active site

• enzyme

• substrate

• products

Multiple Choice

An enzyme speeds up a chemical reaction in the cell but can only be used once.  True or False? 

• true

• false

Multiple Choice

What happens when enzymes are heated to a high temperature?

• The enzymes die.

• The shapes of the enzyme are altered denature

• The enzymes' amino acid sequence changes.

• The enzymes remain the same

Multiple Choice

Enzymes are _______________ that _____________________ chemical reactions by ____________ the amount of activation energy required to start the reaction.

• carbohydrates, slow down, lowering

• proteins, speed up, increasing

• lipids, speed up, lowering

• proteins, speed up, lowering

Multiple Choice

What is the optimal temperature of this enzyme?

• 60

• 40

• 70

• 30

Multiple Choice

What is the optimal pH for this enzyme?

• 6

• 10

• 9

• 7

Multiple Choice

What 3 letters do enzymes typically end in?

• -ose
• -ase
• -ese
• -tic

Multiple Choice

Which of these is NOT true?

• Enzymes can denature (change shape) when the temperature gets too high.
• Enzymes can only be used once in a chemical reaction. 
• Extreme pH can denature enzymes.
• Enzymes speed up chemical reactions. 

Multiple Choice

Which of these is most likely an enzyme?  

• Sucrose

• Galactose

• Fructose

• Amylase

Multiple Choice

Enzymes are...

• nucleic acids
• proteins
• lipids
• carbohydrates

Multiple Choice

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 .
  

Multiple Choice

Any substance that is acted upon by an enzyme is called a(n)?

• Coenzyme
• Substrate
• Vitamin
• Polypeptide

Multiple Choice

In the diagram, what is letter A? 

• product
• substrate
• enzyme-substrate complex
• active site

Multiple Choice

Each enzyme only has 1 substrate that will fit its active site.  What is this called?

• reusablility
• denaturation
• specificity
• fragility

Multiple Choice

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

• reusable
• catalyst
• specific
• fragile

Multiple Choice

Which of the following best explains why enzymes are necessary for many cellular reactions?

• Enzymes supply the oxygen necessary for the reactions
•  Enzymes change reactants from solid to liquids during the reactions.
• The reactions take up too much space in the cell if the enzymes are missing.
• The reactions are too slow to meet the needs of the cell if enzymes are missing.