A-Level Biology (OCR): Free Mock Test & Practice Questions

A-Level Biology (OCR)

Biological molecules, cells, exchange, genetics, energy, response. OCR board.

Weak on a topic? Drill just that one till it clicks, then move on.

Free practice questions

Try 3 real A-Level Biology (OCR) questions

Have a go, then reveal the worked explanation. A taster from a bank of 219 original questions — unlock for unlimited drills and full timed mocks.

Q1. Which property of water is most directly responsible for its use as a solvent for polar and ionic substances in living cells?

A. Water molecules are dipolar, with a slightly negative oxygen and slightly positive hydrogens
B. Water has a high specific heat capacity due to hydrogen bonding
C. Water has a high surface tension caused by cohesion between molecules
D. Water is less dense as a solid than as a liquid

Show answer & explanation

✓ Answer: A. Water molecules are dipolar, with a slightly negative oxygen and slightly positive hydrogens

Water's dipolar (polar) nature means the slightly negative oxygen and slightly positive hydrogens can surround and separate charged or polar solute particles, dissolving them. Specific heat capacity and surface tension are also consequences of hydrogen bonding but relate to thermal stability and cohesion, not solvent action. Ice being less dense is due to a fixed hydrogen-bond lattice, unrelated to solvency.

Q2. A student states that all ribosomes in the body are 80S. Why is this incorrect?

A. Mitochondrial and chloroplast ribosomes, like those of prokaryotes, are 70S
B. Ribosomes vary continuously in size with no fixed sedimentation value
C. Only ribosomes bound to rough ER are 80S; free ribosomes are 70S
D. 80S applies only to plant cells, animal cells have 70S ribosomes

Show answer & explanation

✓ Answer: A. Mitochondrial and chloroplast ribosomes, like those of prokaryotes, are 70S

Eukaryotic cytoplasmic ribosomes are 80S, but mitochondria and chloroplasts contain smaller 70S ribosomes, reflecting their prokaryotic evolutionary origin (endosymbiotic theory). Sedimentation values are not continuous or dependent on ER attachment.

Q3. Insects such as locusts exchange gases via a tracheal system rather than lungs. Which statement correctly describes how gases move in the tracheoles during periods of high activity?

A. Gases move entirely by mass flow driven by the heart pumping haemolymph
B. The ends of tracheoles fill with fluid which is withdrawn into tissues, increasing the air-filled surface area for diffusion
C. Gases move exclusively by active transport across the tracheole walls
D. Spiracles remain permanently open to allow continuous bulk airflow

Show answer & explanation

✓ Answer: B. The ends of tracheoles fill with fluid which is withdrawn into tissues, increasing the air-filled surface area for diffusion

During exercise, anaerobic respiration in muscle cells produces lactate, lowering the water potential of cells, which draws fluid out of the tracheole tips. This increases the surface area of air in contact with cells, speeding diffusion of oxygen. Mass transport of air by abdominal pumping also occurs, but is separate from this specific adaptation.

Start here

Ten questions to see where you stand

Two minutes, no timer, marked the moment you finish with every answer explained. Then you'll know which topics need the work before you sit a full mock.

Exam mode

Full mock exam

40 random questions, real timing, marked against the official pass mark. Different every time.

Create a free account for a full mock

No card needed. A free account unlocks a full timed mock and 3 drills on every exam.

Try it free

Topic drills

Ten quick questions on one topic, marked instantly with explanations.

1 free drill left — then a free account unlocks 3 + a full mock.

A-Level Biology (OCR) — common questions

Frequently asked

How many questions are in the A-Level Biology (OCR)?

The exam has 40 questions. Every Revision Robin mock uses the same 40-question format so your practice matches the real thing.

What is the pass mark for the A-Level Biology (OCR)?

You need 24 out of 40 correct to pass, which is about 60%. Our mocks mark you against this exact threshold.

How long do you get?

The test is timed at 60 minutes. Our full mock runs on the same clock so you can practise your pacing.

Are these the real exam questions?

No. Our questions are original and written to match the current syllabus, so they give realistic practice without copying the official paper. Every answer comes with a plain-English explanation. Always confirm current rules and content with OCR.