MDCAT Biological Molecules MCQs
Customize your practice drill: select target topics, configure your question limit (up to 180 MCQs per test), and choose your mode.
Total Topics
8
Selected Topics
1
Available MCQs
132
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 132 total questions. Test will draw 50 shuffled MCQs.
Sample Biological Molecules 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.
Biomolecules
1. Splitting of water in sunlight is called
- A. Lysis
- B. Photolysis
- C. Condensation
- D. Hydrolysis
View answer and explanation
Answer: B. Photolysis
Photolysis means splitting by light. In the light-dependent reactions of photosynthesis, light energy splits water molecules into protons, electrons and oxygen at photosystem II, which is the photolysis of water. Lysis is general breakdown, condensation joins molecules with loss of water, and hydrolysis splits molecules by adding water, so none of these describes the sunlight-driven split.
Carbohydrates
2. It is not a monosaccharide:
- A. Fructose
- B. Glucose
- C. Sucrose
- D. All are monosaccharides
View answer and explanation
Answer: C. Sucrose
The correct answer is Sucrose. Sucrose is a disaccharide, meaning it consists of two monosaccharide units: glucose and fructose. This distinguishes it from fructose and glucose, which are monosaccharides, or single sugar units. Option D is incorrect because not all listed options are monosaccharides; sucrose is a disaccharide.
Water Properties
3. When water enters in roots due to diffusion, is termed as
- A. Osmosis
- B. Passive absorption
- C. Endocytosis
- D. Active absorption
View answer and explanation
Answer: B. Passive absorption
Passive absorption is the process by which water enters plant roots primarily due to diffusion and transpiration pull, without the plant using energy. In contrast, active absorption requires the plant to use energy to uptake water and nutrients. Osmosis, while involved in water movement, refers specifically to movement across membranes based on solute concentration gradients, not the broader process described in passive absorption. Endocytosis is not related to water uptake in plants, as it involves engulfing substances rather than absorbing water from the soil.
About this unit
MDCAT Biological Molecules — Unit 3
2113 practice MCQs covering Biomolecules, Water Properties, Carbohydrates, Proteins, Lipids, RNA, Conjugated Molecules, DNA Structure. Select custom topics and sit tailored tests up to 180 questions per drill.
Common questions about Biological Molecules practice
How many Biological Molecules MCQs are available on DIFF. MDCAT?
The current Biological Molecules question bank contains 2,113 practice MCQs across 8 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 Biological Molecules quiz cover?
The selectable topics are Biomolecules, Water Properties, Carbohydrates, Proteins, Lipids, RNA, Conjugated Molecules, DNA Structure. 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 Biological Molecules 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 Biological Molecules 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 Biological Molecules MCQs to improve?
Start with a short tutor drill on one of these topics: Biomolecules, Water Properties, Carbohydrates. 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.