MDCAT Enzymes MCQs
Customize your practice drill: select target topics, configure your question limit (up to 180 MCQs per test), and choose your mode.
Total Topics
4
Selected Topics
1
Available MCQs
110
Question Limit
Up to 180
Select Topics to Practice
Questions will be drawn only from checked topics.
Test Configuration
Configure question count (limit 180) and testing mode.
Selected topics have 110 total questions. Test will draw 50 shuffled MCQs.
Sample Enzymes MCQs with answers
Try these questions, then open the answer to check your reasoning. Use the quiz above for more topics and a complete review.
Enzyme Basics
1. An activated enzyme consisting of polypeptide and cofactor is called as
- A. Activator
- B. Apoenzyme
- C. Holoenzyme
- D. Coenzyme
View answer and explanation
Answer: C. Holoenzyme
An active enzyme consisting of its polypeptide plus its non-protein cofactor is called the holoenzyme (apoenzyme + cofactor). The apoenzyme is the protein alone (inactive) and the coenzyme is the non-protein part alone.
Enzyme Inhibitors
2. A competitive inhibitor is added while substrate concentration is unchanged. Which immediate change is expected?
- A. Fewer enzyme–substrate complexes form
- B. The enzyme's equilibrium constant increases
- C. More active sites appear
- D. All substrate molecules are destroyed
View answer and explanation
Answer: A. Fewer enzyme–substrate complexes form
Inhibitor occupancy reduces the number of active sites available to substrate.
Enzyme Factors
3. The linear increase in reaction rate with enzyme concentration occurs because:
- A. More active sites are available to catalyse reaction.
- B. Temperature of solution increases.
- C. Activation energy is raised.
- D. Substrate molecules move faster.
View answer and explanation
Answer: A. More active sites are available to catalyse reaction.
With substrate in excess, each added enzyme molecule contributes more active sites working in parallel, so the rate rises in direct proportion to enzyme concentration — a linear relationship. Temperature, activation energy, and substrate speed are unchanged. More active faster rate.
About this unit
MDCAT Enzymes — Unit 6
817 practice MCQs covering Enzyme Basics, Enzyme Action, Enzyme Factors, Enzyme Inhibitors. Select custom topics and sit tailored tests up to 180 questions per drill.
Common questions about Enzymes practice
How many Enzymes MCQs are available on DIFF. MDCAT?
The current Enzymes question bank contains 817 practice MCQs across 4 topics. This is the bank size, not the length of one test. Choose your topics and a question count from 1 to 180, limited by the questions available in those topics.
Which topics does the Enzymes quiz cover?
The selectable topics are Enzyme Basics, Enzyme Action, Enzyme Factors, Enzyme Inhibitors. Use Select all for a broad chapter drill, Clear to start a focused selection, or choose individual topics. Questions are drawn from your chosen topics, so you can target a weak concept before returning to a wider test.
How do I build a custom Enzymes test?
Open the chapter builder, select one or more topics, enter your question count, and choose Tutor Mode or Timed Exam. The available-question total updates with your selection. Start Test generates a shuffled drill; you do not have to follow a fixed Quiz 1 or Quiz 2 sequence.
What is the difference between Tutor Mode and Timed Exam?
Tutor Mode gives feedback and an explanation after you choose an option, and you can change or clear that choice. Timed Exam runs a countdown and keeps explanations hidden until submission. Both modes let you move between questions, use the paper map, and submit for a complete review.
How do I review and download my Enzymes quiz?
Select Submit Quiz, then Submit & View Explanations. The review includes every question in your test, all options, your selection, the marked correct answer when a key is available, and the explanation. Download PDF saves a paginated review; Download Review saves an HTML copy you can open in a browser. The review also includes DIFF. MDCAT community links.
How should I use Enzymes MCQs to improve?
Start with a short tutor drill on one of these topics: Enzyme Basics, Enzyme Action, Enzyme Factors. Read the explanation for incorrect and uncertain answers, revise the relevant textbook section, and retry before taking a timed drill. Compare your reasoning with the answer key rather than memorising the option letter.