Biology exam technique

When answering questions that are 2 or 3 marks and there is no obvious mark points as to where the marks are allocated, it's often the case that the points are in the answer in your head, but you need to be clear on them.

The way around this is to breakdown your answer into individual components. For example

Q: The sinoatrial node (SAN) is in the right atrium of the heart.  Describe the role of the sinotarial node. (2)

A: - The sinoatrial node sends out electrical impulses. (1)

    - This stimulates the heart to beat (1)

    - by causing the atria to contract (1)

Really, this should be done for all questions to maximise mark gain.

There are 2 types of graph questions. Description and explanation.

Description graphs

There are 4 main things you are looking to describe when describing a graph. these being

- corellation

- changes

- overall interpretation

- places of significant change

It must be noted that these are not all used when describing a single graph, as often the case it is specific to the question. For example, you could describe a grpah as: 

Starting at 10, it sharply decreases to 3 before plateauing at 1. This shows a negative correlation between x and y.

By doing this you basically cover all the bases for any dexcription of a graph. Remeber, if it asks you to describe, you are not saying why the changes occur or why the shape is the way it is.

Explaining graphs

When explaining graphs, it is vital that if they ask you to use the graph, you must refer to it in your answer.

It is also key to remember some of the facts that often come up. For any enzyme question, if you are asked to explain any sudden plateau, you need to remember your 

- Denaturation (1) 

- Change in bonds/ H bonds broken --> change in tertiary structure (1)

- change in active site --> no enzyme - substrate complexes formed. (1)

These are low hanging fruit. Given you can remember all the main components of each process, there is often not much they can test you on. The topics in previous papers have been (unit 1)

- role of enzymes in the breakdown of starch

- Absorption of glucose

- Difference between prokaryotes and eukaryotes

- advantages and disadvantages of TEM and SEM microscopes

- ORS

- movement across the cell membrane

- description of how the lungs are specialized for gas exchange

- Phagocytosis

- vaccines

The way to go at these is to try and minimise the "waffle" bullet points are helpful. Try and split it into distinct parts when answering the questions, and logically move through the question. For example.

Explain how a a pathogen is destroyed by a macrophage. (5)

- The pathogen releases chemoatrractants that stimulate the macrophage and cause it to move towards it. (1)

- The macrophage then proceeds to form a vesicle around the pathogen (1)

- This vesicle is called a phagosome (1)

- The macrophage contains lytic enzyme (1)

- Lytic enzymes destroy the pathogen in the phagosome by destroying cell membrane, causing the pathogen to burst by osmotic lysis (1)