Metabolic Pathways Test Review

Which of the following is true for anabolic pathways?

• they do not depend on enzymes
• they are usually spontaneous chemical reactions
• they consume energy to build polymers from monomers
• They release energy as they degrade polymers to monomers

What is an example of anabolism?

• Formation of peptides after protein digestion

• Formation of glucose and fructose from sucrose

• Formation of maltose from two glucose molecules

• Formation of glycerol and fatty acids from triglycerides

The graph shows how the activity of the enzyme varies with the concentration of polysaccharide. What is the reason for the curve levelling off?

• There is insufficient substrate for the enzyme to act on.

• The product acts as an enzyme inhibitor.

• The enzymes have all been consumed in the reaction.

• All the enzyme active sites are occupied by substrate.

Cells can only work if their enzymes are functioning. What can you infer from the graph?

• Cells function best at low pH values

• Cells function fine at all pH values

• Cells function best at high pH values

• Cells do not function well if the pH is too high or too low

The activity of amylase from two bacterial species and a fungus was measured at different pH levels and constant temperature. The results are shown in the graph. Which statement about the effect of pH on amylase can be concluded?

• A. oryzae amylase has the highest optimum pH.

• B. A change in pH affects amylase most in B. licheniformis.

• C. The optimum pH is 6 in B. subtilis.

• D. Amylase activity at pH 8 is the lowest in B. licheniformis.

What is the optimal pH of enzyme A?

• 8
• 2
• 5.7-10
• 10

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 .
  

How does temperature affect enzyme-catalyzed reactions?

• Temperature has no effect on enzyme activity.

• Enzyme activity increases indefinitely with temperature.

• Enzyme activity decreases after reaching an optimum temperature.

• Low temperatures permanently denature enzymes.

The graph shows the progress of the same enzyme-controlled reaction at two different temperatures. Which statement is clearly supported by the data?

• The amount of product produced initially occurs at a lower rate at 40 °C

• The optimum temperature for the reaction is 40 °C

• The lower the temperature, the slower the rate of the reaction

• The enzyme is denatured at 40 °C

Enzymes have a specific shape. It will only fit a special _________ in order to begin a chemical reaction.

• substrate

• key

• sugar