IB Biology Unit 8 - Enzymes & Protein Structure (HL)

The first enzyme in the metabolic pathway that produces isoleucine is threonine deaminase.

Which graph illustrates the relationship between threonine deaminase activity and threonine concentration?

• A

• B

• C

• D

The graph shows the effect of substrate concentration on the rate of an enzyme-catalysed reaction with and without an inhibitor.

What do the curves J, K and L on the graph indicate?

• A

• B

• C

• D

Metabolic pathways are dependent on enzyme-catalysed reactions.

Which term corresponds with the description?

• A

• B

• C

• D

Tags

NGSS.HS-LS1-7

The graph shows the rate of an enzymatic reaction versus the substrate concentration, in the absence or presence of an enzyme inhibitor.

Which condition is indicated by lines Y and Z?

• A

• B

• C

• D

The graph shows an example of an enzyme-catalysed reaction.

What does the curve labelled X represent?

• No inhibition

• Competitive inhibition

• Non-competitive inhibition

• Reversible inhibition

In one of the curves in the graph, the rate of an enzyme-catalysed reaction has been plotted against the substrate concentration in presence of a small quantity of a competitive inhibitor.

Which curve represents competitive inhibition?

• A

• B

• C

• D

What describes non-competitive inhibition?

• Inhibiting molecule does not resemble substrate and binds to an area other than active site

• Inhibiting molecule resembles substrate and binds to active site

• Inhibiting molecule does not resemble substrate and binds to active site

• Inhibiting molecule resembles substrate and binds to an area other than active site

Consider the metabolic pathway shown in the diagram.

If there is end-product inhibition, which product (B to E) would inhibit which enzyme (1 to 4)?

• A

• B

• C

• D

Tags

NGSS.HS-LS1-3

What can reduce the effect of a competitive inhibitor of an enzyme?

• Decrease the temperature at which the reaction takes place.

• Increase the temperature at which the reaction takes place.

• Increase the substrate concentration.

• Add a non-competitive inhibitor.

In the enzyme controlled pathway shown below, which compound is most likely to inhibit enzyme (w)?

• I

• II

• III

• IV