HESI A2 biology often surprises students who expect only basic science recall. The section can cover cell structure, genetics, and body systems at a level closer to an intro college course than a high school review.
This guide covers 7 key HESI A2 biology topics, common question types and how to study them efficiently.
What Does the HESI A2 Biology Section Cover?
Biology is one of the optional science sections some nursing programs require. It generally tests general biology concepts rather than advanced coursework, but exam versions and required topics can vary by school, so confirm with your program.
7 Key HESI A2 Biology Topics
1. Cell Structure and Function
Know the major organelles and their roles: the nucleus, mitochondria, ribosomes, cell membrane and cytoplasm. Understand the difference between plant and animal cells, and how substances move across the cell membrane through diffusion, osmosis and active transport.
2. DNA, RNA and Protein Synthesis
Review the structure of DNA and RNA, and the basic steps of transcription and translation. Know how DNA carries genetic instructions and how that information becomes a protein.
3. Genetics and Heredity
Expect questions on dominant and recessive traits, Punnett squares and basic inheritance patterns. Practice predicting offspring traits from parent genotypes.
4. Cellular Respiration and Photosynthesis
Understand the basic inputs and outputs of both processes. Cellular respiration converts glucose and oxygen into energy, carbon dioxide and water. Photosynthesis does the reverse in plants, using sunlight to produce glucose and oxygen.
5. Human Body Systems
HESI A2 biology often touches on major body systems, including circulatory, respiratory, digestive and nervous systems, at an introductory level. This overlaps with the Anatomy & Physiology section, so studying both together saves time. See our HESI A2 Anatomy & Physiology study guide for a deeper review.
6. Homeostasis
Know what homeostasis means and how the body maintains stable internal conditions, such as temperature and pH, through feedback mechanisms.
7. Basic Ecology and Classification
Review levels of classification, from kingdom to species, and basic ecological concepts like producers, consumers and energy flow through an ecosystem.
Common HESI A2 Biology Question Types
- Definition-based questions: Identify the correct term for a described process or structure.
- Diagram questions: Label or interpret a cell or body system diagram.
- Process questions: Put steps of a process, like protein synthesis, in the correct order.
- Application questions: Apply a concept, such as osmosis, to a real-world scenario.
How to Study HESI A2 Biology Efficiently
- Start with a diagnostic. Use our free practice tests to see which biology topics need the most review.
- Study one topic at a time. Spend a session on cells, then genetics, then body systems, rather than mixing everything together.
- Use diagrams. Draw and label a cell or a body system from memory to check your understanding.
- Practice with questions immediately. After each topic, answer practice questions before moving on.
- Review missed questions. Note whether you missed a definition, a process step or an application, and revisit that specific weak spot.
Best Resources for HESI A2 Biology
Our 9-in-1 HESI A2 study bundle includes a biology guide with explanations for every major topic above, alongside the other science sections.
FAQ
Is HESI A2 biology hard?
It depends on your science background. Students with a recent high school or college biology course often find it manageable. If it’s been a while, budget extra review time for cell structure and genetics.
Does every nursing program require HESI A2 biology?
No. Biology is often an optional section that some programs choose to include. Confirm your program’s required sections on its admissions page.
Master HESI A2 Biology One Topic at a Time
HESI A2 biology rewards a topic-by-topic approach: cells, genetics, body systems and the processes that connect them. Study one area, test yourself, and move to the next.
For a full science review alongside every other section, explore our complete HESI A2 study bundle, and ask questions anytime in our HESI A2 study group on Facebook.
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