Wednesday 16 January 2019

Leaving Cert Biology

Careful timing and understanding the marking system help

The Leaving Certificate Biology course consists of three units:


There are 22 mandatory experiments which need to be completed and a record kept of them. They cover various aspects from the three units. All the experiments need to be completed in your class under the supervision of your teacher. A record needs to be kept of the experiment in the experiment workbook or you can keep your own record in an experiment copy.

> Format for experiment book



Materials: Make a list of materials that you used including chemicals etc.

Method: This should be in clear bullet points that are easy to follow.

Diagram: This needs to be drawn in pencil and labelled clearly.

Results: Results that you obtained. If it involved a graph this needs to be drawn on graph paper and in pencil. The graph should also be labelled clearly.

Conclusion: Conclusion of your finds - how it relates to the theory that you have learned.

Structure of the paper

There are three sections to the Leaving Certificate Biology paper.

Section A Six short questions; two from each unit of the biology course. Answer five.

Section B Six questions about the 22 mandatory experiments. Answer two.

Section C Six long questions from the different units of the biology course. Answer four.


Timing is very important in the Leaving Certificate and vital in Biology as you have quite a lot of questions to complete, so you need to make sure that you are familiar with the time that you are required to spend on each question and stick to it. On the day of the exam, ensure that you check the timing before you begin.

Total time: Three hours

Start Spend 10 minutes reading the paper thoroughly. Mark the questions that you are going to complete, this will also help you recall information that you have learned.

Section A Answer five short questions in 30 minutes - this gives you six minutes per question.

Section B Answer two experiment questions in 20 minutes —this allows you 10 minutes per question.

Section C Answer four questions in 110 minutes - 27.5 minutes per question.

Finish Allow 10 minutes at the end to read over your paper and ensure that you are satisfied that you have answered all the questions to the best of your ability.


It is important to look at the marks available for the questions before you begin, as this will determine how much information is required.

Total marks available: 400.

Section A 100 marks, 20 for each question.

Section B 60 marks, 30 for each question.

Section C 240 marks, 60 for each question.

Exam tips

> Make sure to start by reading through the paper, this will help you to remain calm and also aid with recalling information.

> Preparation is key so make sure that you have enough revision done. A study plan is a useful way to organise your revision so you know what topics you have revised and what you need to do.

> Timing is very important, so make sure that you keep to the time allotted for each question.

> Read the questions very carefully and make sure you answer the question that is being asked.

> Definitions are important, so make sure that you have learned them off by heart.

Sample question

A (i) What is the primary role of chlorophyll in photosynthesis?

The role of chlorophyll is to trap sunlight energy. (three marks)

(ii) Write an equation to summarise photosynthesis.

6CO2 + 6H2O = C6H12O6 + 6O2 (six marks)

B The second stage of photosynthesis is called the dark stage or light-independent stage. (i) why is the dark stage given the alternative name of the light-independent stage?

It is given this alternative name as light is not required but it can occur in the presence of light. (three marks)

(ii) Name a gas that is essential for the dark stage.

Carbon dioxide is essential for the dark stage. (three marks)

(iii) Two products of the light stage are vital for the dark stage. Name each of them.

Two products of the light stage: ATP and NADPH. (six marks)

(iv) State the precise role in the dark stage of each of the substances you named in (iii) ATP supplies the energy for the dark stage to make glucose.

NADPH supplies the protons and electrons needed for the dark stage. (six marks)

(v) To what group of biomolecules do the main products of the dark stage belong?

Glucose is a carbohydrate. (three marks)

C (i) Water is essential for photosynthesis. Briefly outline how water from the soil reaches the leaf.

Any six of the following are accepted: Concentration gradient, osmosis, root hair, root pressure, xylem, cohesion, adhesion, capillarity, evaporation, transpiration. (6x3=18 marks)

(ii) What happens to water molecules when they reach the sites of photosynthesis?

Water molecules are split by photolysis (three marks).

Products: protons, electrons, oxygen (six marks).

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