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WorksheetsENZYME
Total questions: 10
Worksheet time: 5mins
Which statement about enzymes is true?
Most enzymes are proteins.
All enzymes have an optimum temperature of about 38 0C.
Enzymes are denatured at low temperatures.
Enzymes are killed at high temperatures.
Which statement is not true for all enzymes?
Enzymes break down large molecules to small ones.
Enzymes remain unchanged at the end of a reaction.
Enzymes are affected by pH.
Enzymes catalyse reactions.
Where are enzymes found?
Only in the digestive system
in animals but not in plants
in all living cells
in plants but not in animals
Some catalase was added to some hydrogen peroxide. Bubbles of oxygen were given off. After a while, the reaction stopped.
Why did the reaction stop?
The catalase was all used up.
The catalase was denatured by the reaction.
The hydrogen peroxide was all broken down.
The oxygen given off inhibited the catalase.
Which types of enzymes digest starch?
catalase
amylase
lipase
protease
A student investigated the effect of temperature on the rate of activity of a protease enzyme. Which variable should she change, and which should she keep constant?
Change: Enzyme concentration; Keep constant:substrate concentration
Change: substrate concentration; Keep constant: temperature
Change: temperature; Keep constant: pH
Change: pH; Keep constant: enzyme concentration
Catalase catalyses a reaction in which hydrogen peroxide is
broken down to water and oxygen.
What are the substrate and product in this reaction?
Substrate: catalase; Product: hydrogen peroxide
Substrate: hydrogen peroxide; Product: water and oxygen
Substrate: oxygen and water; Product: catalase
Substrate: water; Product:oxygen
What is an active site?
A gland that secretes a particular enzyme
A part of an enzyme molecule into which a substrate molecules fits
A part of the substrate to which an enzyme molecules attaches
A place in the body where an enzyme works
Why does the rate of an enzyme-catalysed reaction increase as temperature is raised from 0–40 °C?
The enzyme and substrate molecules have more kinetic energy, so they collide more frequently.
The shape of the active site changes so that the substrate fits into it better.
Enzymes are denatured at low temperatures.
The shape of the substrate changes at high temperatures.
Why does pH affect enzyme activity?
Changes in pH affect the shape of the active site.
Changes in pH affect the frequency of collisions between enzyme and substrate.
Changes in pH affect enzyme concentration.
Changes in pH affect the enzyme's optimum temperature.
