OCR A-Level Biology A Active Recall Guide (H420)
OCR · A-Level
OCR A-Level Biology A Active Recall Guide
Every section of specification H420 written as exam-style questions with the answers printed after them. 1,833 questions across 26 sections and 151 subtopics, covering all six modules and the practical and mathematical requirements examined on the papers.
- OCR
- A-Level
- Specification H420
- 1,833 questions
Guide overview All 26 sections Sample questions Papers and weighting Look inside Questions and answers
What the exam asks of you
OCR A-Level Biology A is assessed by three written papers at the end of Year 13. Biological Processes and Biological Diversity are 2 hours 15 minutes and 100 marks each, worth 37 per cent apiece. Unified Biology is 1 hour 30 minutes and 70 marks, worth 26 per cent, and draws on all six modules at once.
The volume is the difficulty. Six modules, twenty-six sections, and a synoptic paper that can reach any of it. A guide that reads like a chapter cannot tell you which parts of that you can produce with the book shut. A list of questions can, on every subtopic, in twenty minutes.
| Paper | Covers | Length | Marks | Weighting |
|---|---|---|---|---|
|
Component 01 Biological Processes |
Module 1: Development of practical skills in biology Module 2: Foundations in biology Module 3: Exchange and transport Module 5: Communication, homeostasis and energy |
2 hours 15 minutes | 100 marks | 37% |
|
Component 02 Biological Diversity |
Module 1: Development of practical skills in biology Module 2: Foundations in biology Module 4: Biodiversity, evolution and disease Module 6: Genetics, evolution and ecosystems |
2 hours 15 minutes | 100 marks | 37% |
|
Component 03 Unified Biology |
All six modules | 1 hour 30 minutes | 70 marks | 26% |
|
Component 04 Practical Endorsement in Biology |
Practical activities carried out across the course | Non-exam assessment | Reported separately | Pass or Not Classified |
What is in the guide
All 26 sections
Every section has its own page with its subtopics, what it covers and sample questions.
Sample questions
Taken from the guide. Answer each one closed book first, then open the answer.
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Microscopy, slide preparation and staining
When preparing a microscope slide, what is the first step involving the specimen?
Show the answer
Place a thin specimen on a glass slide. -
The properties of water
Explain how water acts as a solvent for ionic compounds.
Show the answer
Water's polarity allows it to surround ions with hydration shells, separating and dissolving ionic compounds and other polar molecules. -
Nucleotide structure and the bases
Which pentose sugar is found in DNA nucleotides?
Show the answer
Deoxyribose. -
Enzyme action: lock and key and induced fit
Name an enzyme that catalyses intracellular reactions.
Show the answer
Catalase. -
Membrane structure and the fluid mosaic model
Explain how phospholipids are arranged in a membrane bilayer.
Show the answer
Phospholipids arrange with their hydrophilic (phosphate) heads facing outward towards the aqueous environments and their hydrophobic (fatty acid) tails facing inward, away from water. -
The cell cycle
What is the main event of the S phase?
Show the answer
DNA replication occurs, producing two identical copies of each chromosome. -
Surface area to volume and the features of an exchange surface
Why do multicellular organisms require specialised exchange surfaces?
Show the answer
Their lower surface area to volume ratio combined with higher metabolic activity means simple diffusion across the body surface is inadequate to supply sufficient oxygen and remove waste products. -
Why animals need transport systems
What defines a single circulatory system?
Show the answer
Blood passes through the heart once per complete circuit of the body.
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
-
Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Look inside
Questions for a subtopic print together and the answers for that section print after them.
- Cell Structure68
- Biological Molecules113
- Nucleotides and Nucleic Acids58
- Enzymes43
- Biological Membranes60
- Cell Division, Cell Diversity and Cellular Organisation80
- Exchange Surfaces64
- Transport in Animals103
- Transport in Plants56
- Communicable Diseases, Disease Prevention and the Immune System88
- Biodiversity70
- Classification and Evolution52
- and 14 more
- Why is water described as a polar molecule?
- What charge does the oxygen atom carry in a water molecule?
- What charge do the hydrogen atoms carry in a water molecule?
- How do hydrogen bonds form between water molecules?
- Explain how water acts as a solvent for ionic compounds.
- What is a hydration shell?
- Give two examples of how water functions as a transport medium in organisms.
- Why does water have a high specific heat capacity?
- How does water's high specific heat capacity help organisms?
- Water is polar because the oxygen atom has a slight negative charge and the hydrogen atoms have slight positive charges, creating an uneven distribution of charge across the molecule.
- A slight negative charge.
- Slight positive charges.
- Electrostatic attraction occurs between the slightly positive hydrogen atoms of one water molecule and the slightly negative oxygen atom of another water molecule, forming hydrogen bonds.
- Water's polarity allows it to surround ions with hydration shells, separating and dissolving ionic compounds and other polar molecules.
- A layer of water molecules that surrounds an ion due to the attraction between the polar water molecules and the charged ion.
- Water carries dissolved glucose in blood plasma of mammals and dissolved mineral ions in the xylem of plants.
- Large amounts of energy are needed to raise its temperature because energy is required to break the hydrogen bonds between water molecules.
- It buffers temperature changes, preventing rapid fluctuations in body temperature and maintaining stable conditions for metabolic reactions.
questions
Scroll sideways to turn through the pages.
Questions students ask first
I do OCR Biology. Is this the right specification?
OCR runs two A-Level Biology specifications. This guide is Biology A, H420. The other is Biology B, Advancing Biology, H422, and its content is organised completely differently.
The code is printed on your exam timetable and on the front of most endorsed textbooks. If yours says H422 you need the Biology B guide instead.
Does it cover all six modules?
Yes. The guide is cut into 26 sections across the six modules, 151 subtopics, 1,833 questions. Module 2 Foundations in Biology holds six of those sections, Module 5 holds seven and Module 6 holds six.
Module 1 has its own section, Practical Skills and Mathematical Requirements, with 104 questions on apparatus, uncertainty, presenting data, gradients and logarithmic scales, and the statistical tests.
Is the Practical Endorsement in it?
No. The Endorsement is Component 04, assessed by your teacher across the two years and reported as Pass or Not Classified alongside your grade. It is not examined on a paper.
The Module 1 content that is examined on the written papers is in the guide in full, because practical skills questions appear on all three components.
Component 03 is synoptic. Does the guide help with that?
Unified Biology draws on all six modules in one 1 hour 30 minute paper. Holding six modules at once is a recall problem before it is a technique problem, and the guide is the whole course in one file, so a synoptic round is a pass over every section rather than a hunt through six sets of notes.
OCR A-Level Biology A Active Recall Guide
Every question paired with its answer, grouped by section and subtopic, ready to work in three passes.