IB biology 2.5 and 8.1 (enzymes and metabolism)

What is an advantage of using lactase in an immobilised state in the food manufacturing industry?

• It functions within cells

• It dissolves in multiple solvents

• It converts cellulose to glucose

• It is less likely to become denatured

Metabolic pathways are dependent on enzyme-catalysed reactions. Which term corresponds with the description?

• Allosteric inhibition: The inhibitor binds to the active site of the enzyme

• Competitive inhibition: The maximum rate of a reaction is lowered as the substrate concentration increases

• Non-competitive inhibition: raises the maximum rate of reaction of a given enzyme reaction

• End-product inhibition: The end-product in a metabolic pathway binds to an allosteric site of the first enzyme

Which enzyme does isoleucine inhibit?

• Enzyme E₁

• Enzyme E₂

• Enzyme E₃

• Enzyme E₅

The graph shows the effect of changing the substrate concentration on the early stages of an enzyme-catalysed reaction. What can be interpreted about the rate of reaction from the graph?

• Rate of reaction increases up to a point and then stays constant

• Rate of reaction increases linearly with increasing substrate concentration

• Rate of reaction increases non-linearly with increasing substrate concentration

• Rate of reaction is not affected by the substrate concentration

Tags

NGSS.HS-PS1-2

Living organisms control pH within their tissues. What is the reason for regulating pH?

• All parts of the body must have the same pH in order to survive

• Many reactions can only happen at specific pH levels

• pH affects osmosis

• Control of active transport is achieved by pH

Tags

NGSS.HS-LS1-3

The graph shows the effect of substrate concentration on the rate of an enzyme-catalysed reaction with and without an inhibitor. What do curves J, K and L on the graph indicate?

• J: Competitive inhibitor, K: Non-competitive inhibitor, L: Normal enzyme activity

• J: Normal enzyme activity, K: Competitive inhibitor, L: Non-competitive inhibitor

• J: Non-competitive inhibitor, K: Normal enzyme activity, L: Competitive inhibitor

• J: Normal enzyme activity, K: Non-competitive inhibitor, L: Competitive inhibitor

The graph shows the results of an investigation into the activity of turnip peroxidase. The accumulation of the product of the reaction catalysed by the enzyme is shown at different pH values. Based on the data, what is the optimum pH for this enzyme?

• Between 3 and 5

• Between 10 and 11

• Between 7 and 8

• Between 9 and 10

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

In which processes are macromolecules broken down into monomers?

• Anabolism and catabolism

• Catabolism and hydrolysis

• Hydrolysis and reduction

• Reduction and anabolism

What effect do changes in pH have on enzymes?

• All enzymes increase in activity as pH increases

• The activity of all enzymes is reduced by a pH below or above 7

• Low pH causes irreversible denaturation in all enzymes

• Extreme pH can alter the active site of all enzymes