Lesson 2.3.3
2.3.3 Enzyme mechanism, specificity and activation energy Quiz: Pearson Edexcel Biology, Unit 2
20 questions
In partnership with Revision Ninja
Lesson 2.3.3, Enzyme mechanism, specificity and activation energy: 20 multiple choice questions for the Pearson Edexcel Biology (9BI0), Unit 2: Genes and Health, written with Revision Ninja.
Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.
The 20 questions
-
How do enzymes increase the rate of chemical reactions in living organisms?
- Increasing activation energy
- Raising body temperature
- Increasing substrate concentration
- Lowering activation energy
-
What is activation energy?
- Maximum stored energy
- Minimum reaction energy
- Energy released overall
- Total kinetic energy
-
Which region of an enzyme directly binds to the substrate?
- Inhibitor site
- Allosteric site
- Active site
- Regulatory domain
-
Which enzyme model involves the active site changing shape slightly to fit the substrate?
- Lock and key model
- Allosteric activation model
- Induced fit model
- Competitive inhibition model
-
What feature of an enzyme's active site determines its substrate specificity?
- Linear primary structure
- Identical shape
- High activation energy
- Complementary shape
-
What process occurs when high temperatures disrupt an enzyme's tertiary structure?
- Hydrolysis
- Renaturation
- Phosphorylation
- Denaturation
-
Which of the following is an intracellular enzyme?
- Amylase
- Pepsin
- Catalase
- Trypsin
-
Which of the following is an extracellular enzyme?
- Catalase
- DNA polymerase
- ATP synthase
- Amylase
-
Why is the initial rate measured at the very start of an enzyme reaction?
- Temperature is highest
- Product is absent
- Substrate not limiting
- Enzyme is denatured
-
An enzyme catalyses a reaction and produces 20 cm^3 of gas in 40 seconds. What is the average rate of gas production?
- 0.05 cm^3 per second
- 800 cm^3 per second
- 2 cm^3 per second
- 0.5 cm^3 per second
-
At low substrate concentrations, how does increasing substrate affect reaction rate?
- Increases proportionally
- Stays constant
- Halves immediately
- Decreases rapidly
-
Why does reaction rate plateau at high substrate concentrations?
- Substrate breaks down
- Enzyme denatures
- Activation energy rises
- Active sites saturated
-
What happens to reaction rate when enzyme concentration doubles with excess substrate?
- Rate halves
- Rate doubles
- Rate decreases
- Rate stays constant
-
Why does increasing temperature up to the optimum increase reaction rate?
- Lower activation energy
- Active site expands
- More enzyme produced
- More kinetic energy
-
Why does reaction rate fall rapidly above the optimum temperature?
- Substrate evaporates
- Activation energy rises
- Molecules stop moving
- Enzyme denatures
-
How does a change in pH affect an enzyme's active site?
- Oxidises amino acids
- Alters R-group charges
- Increases kinetic energy
- Breaks peptide bonds
-
Which variable must be controlled when measuring the effect of enzyme concentration?
- Enzyme origin
- Product concentration
- Test tube volume
- Temperature and pH
-
Where does a competitive inhibitor bind to an enzyme?
- Allosteric site
- Coenzyme site
- Substrate site
- Active site
-
What shape is characteristic of globular proteins like enzymes?
- Rigid and linear
- Long and fibrous
- Compact and spherical
- Flat and sheet-like
-
How do enzymes lower the activation energy of a reaction?
- Raising collision frequency
- Orientating substrate molecules
- Increasing system temperature
- Altering overall enthalpy
Related quizzes
- Gas exchange surfaces and Fick's Law Quiz · 2.1.1 · 20 questions
- Cell membrane structure and the fluid mosaic model Quiz · 2.1.2 · 20 questions
- Osmosis, diffusion and membrane transport Quiz · 2.1.3 · 20 questions
- Nucleotides, DNA and RNA structure Quiz · 2.2.1 · 20 questions
- Transcription, translation, the genetic code and genes Quiz · 2.2.2 · 20 questions
- Amino acids, polypeptides and protein structure Quiz · 2.3.1 · 20 questions
- Globular and fibrous proteins: haemoglobin and collagen Quiz · 2.3.2 · 20 questions
- DNA replication and the Meselson and Stahl experiment Quiz · 2.4.1 · 20 questions
- Mutations and cystic fibrosis Quiz · 2.4.2 · 20 questions
- Monohybrid inheritance and pedigree diagrams Quiz · 2.5.1 · 20 questions