Which statement about enzymes is correct?
Pick an answer to see the explanation
Biology is the third section of CEnT-S: 10 questions in 20 minutes. Questions sit at definition-and-mechanism level — you need precise vocabulary rather than long calculations.
Cell biology and genetics form the backbone. Compared with IMAT, plant biology and ecology are more visible, while human physiology is tested more lightly.
Question distribution analysis
CEnT-S Biology Topics: Frequency
Which topics demand your deepest attention? Below is the topic breakdown from our CEnT-S question data:
| Topic | Total | |
|---|---|---|
| Cell Cycle, Division & Inheritance | 3 | |
| Cell Biology | 2 | |
| Animal Anatomy & Physiology | 2 | |
| Biological Molecules | 2 | |
| Plant Biology & Ecology | 1 |
*Expected topic split of one 10-question Biology section, based on the CISIA syllabus and our exam-weight model.
Key Takeaways
- Genetics carries the highest weight: DNA → RNA → protein and Mendelian crosses.
- Cell biology: organelle functions, membrane transport and osmosis are reliable points.
- Plant biology & ecology appear more often than in IMAT — do not skip photosynthesis and food chains.
- Physiology is broad but shallow: know the function of each system, not every detail.
Difficulty analysis
Topic Difficulty & Recommended Study Allocation
Not all topics require the same time investment. Some need extensive problem-solving practice, others rely on precise conceptual recall:
Hard
Cell Cycle, Division & Inheritance 2 weeksMedium
Animal Anatomy & Physiology 1.5–2 weeksMedium
Cell Biology 1.5 weeksMedium
Plant Biology & Ecology 1 weekEasy
Biological Molecules 4–5 daysNot Sure Where to Begin Your Preparation?
Take the free CEnT-S diagnostic test: see your baseline in every section and get a personalised AI study plan.
Take Diagnostic TestOfficial syllabus breakdown
CEnT-S Biology Topics: How Each Is Tested
A topic-by-topic look at the Biology section of the official CISIA CEnT-S syllabus:
01
Biological Molecules Easy
- Water and its properties.
- Carbohydrates, lipids, proteins and nucleic acids: monomers and functions.
- Enzymes: activation energy, specificity, effect of temperature and pH.
How it appears on CEnT-S: Matching a molecule to its monomer or function; enzyme statements (they are not consumed and do not shift equilibrium).
02
Cell Biology Medium
- Prokaryotic vs eukaryotic cells.
- Plasma membrane, nucleus, ribosomes, endomembrane system, mitochondria, cytoskeleton.
- Plant-specific structures: cell wall, chloroplasts, vacuoles; osmosis and membrane transport.
How it appears on CEnT-S: ‘Where does process X take place?’ and osmosis scenarios (red blood cells in hypo-/hypertonic solutions).
03
Cell Cycle, Division & Inheritance Hard
- Genome characteristics; DNA and RNA coding.
- Replication, transcription and translation.
- Mitosis and meiosis; Mendelian inheritance and cross probabilities.
How it appears on CEnT-S: Phase-of-the-cell-cycle questions and simple monohybrid/dihybrid cross probabilities (e.g. 1/4, 3/16).
04
Plant Biology & Ecology Medium
- Plant anatomy: root, stem, leaf, flower, fruit, seed.
- Photosynthesis: inputs, outputs and location.
- Energy flow, ecosystems, food chains and biotic interactions.
How it appears on CEnT-S: Conceptual items on energy loss between trophic levels and on the light/dark phases of photosynthesis.
05
Animal Anatomy & Physiology Medium
- Tissue types.
- Musculoskeletal, digestive and respiratory systems.
- Circulatory, excretory and nervous systems.
How it appears on CEnT-S: Function-level questions: which organ does what, the path of blood, where digestion of each nutrient begins.
Official CISIA Syllabus
The full, official CEnT-S syllabus and test structure are published by CISIA:
cisiaonline.it — CEnT-S structure and syllabusSolved exam problems
CEnT-S Biology Sample Questions & Elimination Tactics
See how CEnT-S biology questions are built and how disciplined elimination avoids the −0.25 penalty:
A red blood cell is placed in distilled water. What is most likely to happen?
Pick an answer to see the explanation
During which phase of the cell cycle is nuclear DNA replicated?
Pick an answer to see the explanation
Candidate trap analysis
5 Most Common Mistakes in CEnT-S Biology
Recurring conceptual and tactical errors that cost students crucial points:
01
Mitosis vs meiosis
Know the chromosome number (2n/n) at every stage; most errors come from mixing up sister chromatids and homologous chromosomes.
02
Enzymes and equilibrium
Catalysts change the rate, never the equilibrium position or the yield.
03
Tonicity direction
Water moves toward the higher solute concentration. ‘Hypotonic solution’ means the cell swells.
04
Transcription vs translation
Transcription: DNA → mRNA in the nucleus. Translation: mRNA → protein at the ribosome.
05
Ignoring plant biology
CEnT-S tests photosynthesis and plant structures more than IMAT; students coming from IMAT material often skip them.
Study roadmap
10-Week Strategic Study Roadmap
Weeks 1–2
Diagnostic & Foundations
Take a timed diagnostic; rebuild the Foundation topics marked ‘Easy’ and note every error type.
Weeks 3–5
Core Topics
Work through the ‘Medium’ and ‘Hard’ topics in the order of the frequency table; 20–30 targeted questions per topic.
Weeks 6–7
Mixed Practice
Mixed sets under section timing (2 min/question). Keep an error log: concept, reading or calculation.
Weeks 8–9
Full Mocks
One full 65-question CEnT-S mock per week with real section timers; review every wrong and every guessed answer.
Week 10
Final Polish
Re-do your error log, revise traps, and practise the skip-or-guess rule for the −0.25 penalty.