Biology

Standard Level

Higher Level


General tips

Memorise the vocabulary - there is no way around that. Biology is a very vocabulary-intense course and you need to know key terms to get to understanding processes. For me, the most efficient way to do this was by noting down and then defining all terms that were newly discussed in class in my notes. I wrote hand-written notes and dedicated half of each page to definitions of all new terms (the other half was usually an image or a step-by-step procedure of a biological process.)

Also, in preparation for exams, I made a few vocabulary quizlets, which are available for those that become patrons via Patreon. My “Biology Key Terms” quizlet covers: Unit 1 (Cell Biology), Unit 2 (Molecular Biology), Unit 3 (Genetics), Unit 5 (Evolution), Unit 7 (Replication, Transcription, Translation), Unit 8 (Metabolism), and Unit 10 (Genetics & Evolution). My “Biology Ecology” quizlet covers unit 4 (Ecology), and My “Biology Option C” quizlet covers the Ecology Option.

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Understand the procedures - Biology is also a very procedure-based course, in the sense that there are a lot of step-by-step biological processes. Whether it be exocytosis, or DNA replication, or digestion, or even biological experiments, many of the biological processes need to be understood, rather than memorised. When taking notes, I would really recommend writing steps out almost like writing a recipe. This will allow you to categorise the process into simple steps that you can understand.

I usually wrote down my notes by hand very quickly (and roughly) in class, and then took the time to re-write them at home. About half of each page was dedicated to writing out the biological process and the other half was dedicated to defining vocabulary. Remember that Paper 2 Section B (which earns you the bulk of your marks) often asks very procedural-based questions for 6-8 mark questions - so it may be worth the effort to understand processes.

If you want to look at a specific unit from my notes, Patreons can write to me requesting a particular unit (as this will require me to take the trouble to scan and send my hand-written notes..

My IB Biology notes about Respiration (Unit 8). Click to enlarge the image.


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Apply your knowledge and understanding - Though this seems like a page straight out of an IB brochure, let me explain. There is only so much time you can dedicate to studying, because let’s face it - unless you’re that one kid that’s genuinely fascinated by Biology, you probably find Biology less attractive than let’s say YouTube videos. This was kind of similar for me, but I really enjoyed watching clips from David Attenborough’s documentaries, as well as reading about evolution. Apply your learning, because you find Biology everywhere in your life.

Also, this is useful in finding a good Experiment topic. I heard of a Korean kid that did an IA on osmosis (I mean come on - Osmosis is probably the most boring experiment) - but really made it his own by talking about how his mother removes water from the cabbages using salt before making Kimchi. My own IA was inspired by the corn vender outside my apartment, when I considered where the optimum temperature for respiration for corn and rice might be. I also linked my IA to climate change, suggesting that with increases in temperature, denaturation of respiration enzymes may occur.

So keep your eyes peeled, and hopefully you can find a suitable IA topic, and really make Biology feel relevant to your own life.


Suggested Reading

The Blind Watchmaker” by Emeritus Professor Richard Dawkins (Oxford) is a brilliant book in all accounts, and is certainly worth the read. He explains evolution by natural selection stunningly, so the book is really useful when studying for chapter 3, 5, and 10. Also, he explores the more molecular Biological processes involved in evolution, such as replication, transcription, and translation (though not in as much detail as the evolutionary processes), so in some way, chapters 2, 7, and 8 are covered. The level of English is not too bad, though I wouldn’t recommend for those struggling with English.


 

Biology Revision Videos

 

Introduction to Cell & Molecular Biology

Recommended Reading
1.1, 1.2 (Oxford Textbook)

Practice Questions
Explain the Cell Theory (3)

Describe the relationship between transcription and translation (3)

Identify structure labeled “D” (1)

Explain the function of the rER (2)

In this video, I give a very short introduction to some of the organelles in the cell, their functions in terms of the bigger-picture story of how proteins are synthesised from genetic code on the form of DNA.

DNA Replication in the Nucleus

Recommended Reading
2.6, 2.7, 7.1, 3.1, 3.2 (Oxford Textbook)

Practice Questions
Explain the process of DNA Replication (8)

Describe the structure of DNA (4)

Contrast the structure of DNA and RNA (3)

Explain the leading and lagging strands (4)

Draw and label a DNA nucleotide (3)

Explain the semi-conservative replication of DNA (3)

Describe the Polymerase Chain Reaction (3)

In this video, I explain how DNA Replication occurs in the nucleus. Important to note is that memorising the enzymes and each process is very important, as it can be asked in exams. Also, remember that DNA Polymerase III, DNA Polymerase I, and RNA Polymerase all add nucleotides at the 3’ end.

Transcription of DNA into mRNA in the Nucleus

Recommended Reading
2.6, 7.2 (Oxford Textbook)

Practice Questions
Describe the process of transcription (4)

Draw a ribose molecule (2)

Define polysome (1)

Describe post-transcriptional modification of mRNA (3)

In this video, I explain that DNA needs to be transcribed in the nucleus by RNA Polymerase, which both separates the hydrogen bonds between the DNA strands of the particular gene and adds the RNA nucleotides. I then explain the additional HL material of polysome, as well as post-transcriptional modification, whereby introns are removed to keep only the exons.

Translation in the rER and by Free Ribosomes

Recommended Reading
7.3, 3.1 (Oxford Textbook)

Practice Questions
Describe the process of translation (8)

Explain how gene expression occurs in the cell (3)

Outline the role of tRNA in translation (3)

Identify the amino acid the start codon codes for (1)

This video explains how gene expression is the process by which proteins are synthesised from the DNA code. Translation is when each codon triplet of mRNA is used to code for an anti-codon in the tRNA, and each amino acid connects together to form peptide bonds. With a continuous repetition and elongation of this amino acid chain, eventually a long, linear polypeptide is formed, which we call the “primary structure” of the protein. As we will learn in the next video, this structure spontaneously coils itself to become a more complex, three-dimensional structure.

Recommended Reading
2.4, 2.5, 7.3, 3.1 (Oxford Textbook)

Practice Questions
Draw two amino acid being joined by a condensation reaction (4)

Describe four ways functions of proteins giving a named example for each (8)

Explain the quaternary structure of a protein (3)

Explain the tertiary structure of a protein (3)

After translation has occurred, immediately, a primary structure is formed, which spontaneously folds itself into a more complex structure. The most immediate structural element that forms is hydrogen bonds, which lead either to Alpha Helices or Beta Pleated Sheets. Fibrous proteins, such as silk and keratin, insoluble and useful in maintaining structure, stop here and do not become tertiary or quaternary structures. Globular proteins, such as enzymes, soluble and easily transported, fold even further, with interactions between R Groups such as sulphur bridges, and with the surrounding medium. Quaternary structures extend further than this with interactions with other proteins.

Membrane Transport (Neurons as an example)

Recommended Reading
1.4, 1.5, 6.5 (Oxford Textbook)

Practice Questions
Compare and contrast passive and active transport using one example for each (4)

Explain the sodium potassium pump and its significance in the neuron (3)

Identify four functions of proteins (4)

Explain the process of exocytosis (3)

Explain how neurotransmitters are used (4)

After the proteins have been translated, and have coiled themselves into a specific 3-dimensional shape, if they need to be exported, they are packaged into vesicles. The contents of these vesicles can be transported out of the cell via the process of exocytosis. Indeed, at the membrane, however, it is possible to find various other processes of membrane transport, including diffusion, active transport, osmosis, and endocytosis. For example, a paramecium needs to conduct both pinocytosis (cell drinking) and phagocytosis (cell eating) via its oral groove for its nutrition. Also, the neuron requires both maintaining of resting potential (especially via the sodium potassium pump), as well as when necessary, a propagation of action potential (via simple diffusion, then via facilitated diffusion). These examples provide practical examples of the necessary functions of membrane transport.

Respiration (both anaerobic and aerobic)

Recommended Reading
2.2.8, 8.1, 8.2 (Oxford Textbook)

Practice Questions
State the chemical formulae for anaerobic respiration in humans and in yeast (2)

Explain 3 industrial uses for anaerobic respiration (3)

Explain the process of glycolysis (5)

Explain the link reaction (3)

Describe the Krebs Cycle (6)

Explain the electron transport chain in respiration (8)