Biology Paper 2

Section A

Divide the Graph into several parts
Often, your first question in P2 Section A will be to describe a given graph. Depending on how many marks the question is allocated, you should divide the graph into several parts to give a good description. For instance, if the “describe the graph” question is two marks, you should try to divide the graph into two parts - perhaps there is an increase until 20 degrees, then a decrease - perhaps there is a linear increase until 10 degrees then an exponential increase from that point - the specifics will differ from question to question - but you will have to look at the number of marks allocated for the question and divide up your description of the graph accordingly.

Practise Analysing Data
The bulk of Section A is analysing data, rather than simply regurgitating content from the textbook. This is something I really liked about the IB course, as I felt it really seems to prepare us to be scientists. However, it can, admittedly, be quite a hassle. I recommend getting some extra practice on this through the textbook questions and the guide. Then, I also suggest looking at the results graph from your friends’ IA Lab Reports and asking each other critical questions about these - this can greatly enhance your skills in this section.

It’s often OK to be critical
Often with a question, you find that all the data they give you almost wants you to take a certain side. Purely hypothetically, let’s say you get an experiment where lactose-intolerant laboratory rats are given lactase by a pharmaceutical company. All the data seems to show that the rats given lactase are better at digesting milk-based products. Then the question asks, “Using all the data, evaluate if lactase is a suitable product for lactose-intolerant humans”. The previous parts of the question seem to support the view that the lab-rats were enhanced by lactase. However, as it is an “evaluate” question, you MUST note that humans and rats have different physiologies. You could also note that there may be unforeseen long-term consequences, which the experiment does not examine for humans. In this way, you are often required to be critical of the data you’re given and the premises of the experiment itself. You should NOT seek for the answer the question seems to be leading you towards, but rather critically examine every element of the question to find potential flaws as well as potential benefits of the experiment.

Correlation ≠ Causation
Often, the question seems to lead you to believe that there is a correlation between two aspects. You need to be very careful here to distinguish between correlation and causation. Often the question will ask you to “evaluate the claim that X causes Y” - in which case you would need to explain how the data leads you to believe that there is correlation, but that correlation does not equal causation. This fundamental principle of scientific analysis is vital to remember, and often earns you easy marks.

Section B

Memorise key processes
From my experience, biological processes make up the overwhelming majority of 6-8 mark questions. As such, when you make notes, I recommend condensing all the details in your textbook into several step-by-step procedures - just as though you’re writing a recipe.

For instance, in my hand-written notes, for a major process like Aerobic Respiration, I made a procedure, starting from the Link Reaction and ending in the Electron Transport Chain, with only essential details. I feel this approach was very successful, as the bulk of my marks in my IB exams, I suspect, came from this memorising of step-by=step procedures.

Practise drawing diagrams
Again, from my own experience, the bulk of 3-4 mark questions seem to ask the student to draw diagrams. You need to be very familiar with all the diagrams you need to draw. The following is a list of the drawings I feel were most necessary to learn:

1. Cell Biology
Prokaryotic Cell, Animal Cell, Plant Cell, Membrane Structure, Mitotic Stages, Mitochondria, Chloroplast
2. Biochemistry
Glucose, Ribose, Amino Acid, Condensation Reactions, Deoxyribose, Nucleotide, Fatty Acids, Water Molecule Hydrogen Bonds,
4. Ecology
Sigmoid Population Curve, Carbon Cycle, (For Option C) Nitrogen Cycle, Phosphorus Cycle
6. Human Physiology
Digestive System, Respiratory System, Heart, Neuron, Male Reproductive System, Female Reproductive System, Hormone Graph, Artery, Vein, Capillaries (HL Only) Elbow Joint, Sacromere, Kidney, Loop of Henlé. Sperm & Egg, Seminal Tube, Ovary
9. Plant Biology
Inside of a Leaf, Root Vascular Tissue, Stem Vascular Tissue, Flower, Seed