Genetic Change is a topic new to the HSC Biology syllabus. It is the syllabus’ effort in putting a greater focus on genetics and genetic techniques when, previously, genetics didn’t have such a dedicated section.
In the previous module, Module 5: Heredity, you may have gone through concepts such as DNA replication, protein synthesis, the applications of genetic knowledge and genetic variation.
But when we say genetic variation and genetic change, what do we mean?
In this brand-spanking new syllabus, Genetic Change explores the ways in which new genotypes can be introduced into the population, including mutation, environmental pressures and induced with biotechnology.
Get ready to ace the HSC and get that Band 6 in HSC Biology!
Content Focus for HSC Biology Module 6: Genetic Change
Although Genetic Change may seem like a short module, it focuses on a few, complicated concepts. Let’s look at the Content Focus straight from the syllabus:
We can see from the content focus that:
- Mutations can be cause naturally or from humans, each having its own cause and effects
- Pressure from the environment can lean towards certain mutations, which can lead to the evolution of a species
- Biotechnology can be used to change the genome and applied in agriculture, industry and medicine
- Biotechnology has a clear consequence on biological diversity
The main topics of the Genetic Change module are:
- Genetic Technologies
If you’re looking for some learning resources for these topics, make sure you check out HSC Together which has FREE video resources on every single HSC Biology dot point so that you can grasp concepts and revise effectively!
So let’s jump in and find out what they’re all about!
Inquiry question: How does mutation introduce new alleles into a population?
A great way to address the topic of mutations is to use the 5 Ws: who, what, where, when and why.
1. WHO: The Mutagen
A mutagen is anything that can cause mutations. A few examples of mutagens include:
- Electromagnetic Radiation e.g. X-rays, ultraviolet light and gamma rays (also ionising radiation)
- Chemical e.g. smoking
- Naturally occurring e.g. radon gas from uranium in soil and rocks
Each has its own mechanism of mutating DNA so make sure that you understand processes such as DNA replication and repair, DNA structure and transcription.
2. WHAT is the effect of the mutation?
What happens to DNA and why is it so bad that it happens?
Mutations are constantly occurring in our cells every day. Usually cell mechanisms fix these mutations, but sometimes these cell mechanisms fail. If these mutations occur in a portion of the cell that encodes for a protein, this can cause misfolding of the protein.
There are also different types of mutations, which you will learn more about through the Genetic Change module.
For example, if a mutation occurs in the gene encoding for haemoglobin, an oxygen carrying globular protein, then this can cause anaemia due to the misfolding of an essential protein.
For example, in Sickle Cell Anaemia (a blood disorder) there is a mutation which results in the substitution of one protein for another and prevents proper red blood cell formation:
3. WHERE is the location of the mutation?
This question might seen trivial, but is really important in practice.
Are they in ‘coding’ or ‘non-coding’ regions of DNA? If the mutation is in a coding region of the DNA, then this is going to have an effect on the function of the protein it codes for.
If the mutation is in a non-coding area of the DNA it might not have any effect at all! Although this can get a bit more complicated as you get deeper into the structure and function of DNA…
4. WHEN do the mutation/s occur?
Does the mutation occur (or is the mutation expressed) when the organism is all grown up in somatic cells? Do they occur during fertilisation or meiosis?
When the mutation is expressed is important in relation to its effect on function and disease pathogenesis.
5. WHY is the mutation important?
Why is genetic mutation biologically important, why do we need mutations, why do mutations exist if they seem so bad?
These are all important biological questions which relate to extremely fundamental aspects of biology, that you’ll explore in Module 6: Genetic Change.
Mutations must exist for a reason, after all, even if they seem to only cause disease or dysfunction!
Inquiry question: How do genetic techniques affect Earth’s biodiversity?
For the Biotechnology topic, you will be using secondary sources, to explore the impact of biotechnology.
Our past, present and future plans to use biotechnology have/will have ethical, social, economic, genetic consequences because we are ‘playing with nature’.
We can expand the bullet points like so:
- What are some past uses of biotechnology? How do they compare to current uses?
- What are some plans for future uses of biotechnology? How do they improve current uses of biotechnology? What are some limitations of current uses?
- What are some current uses of biotechnology? Can you use them in the medical field? In industry?
- What social benefits have uses of biotechnology had? Why would people’s health get better with biotechnology?
- What are some ethical difficulties using biotechnology? In what cases would it be ethically concerning to apply/study biotechnology? Think about animals
- What benefits would biotechnology have on genetics? How have we previously used biotechnology, and what do we use now?
- What are some implications that biotechnology would have on biodiversity? Do you think it would increase or decrease? Would it stay the same?
The New Zealand Science Learning Hub has a great resource on some examples of biotechnology:
Inquiry question: Does artificial manipulation of DNA have the potential to change populations forever?
The previous topic may focus on general uses of biotechnology, but we are now shifting our focus to genetic technologies.
Genetic technology, especially in agriculture, has reduced the gene pool of some animals and plants despite having clear benefits to efficiency of food production. What does this mean for the gene pool to get reduced?
You’ll be asked to do three comparisons:
- artificial insemination and artificial pollination
- whole organism cloning and gene cloning
- Benefits and disadvantages to agricultural, medical and industry applications
What influence does social, economic, cultural contexts have on the range of biotechnologies? How are our current needs satisfied by genetic technologies?
How to Get a Band 6 in HSC Biology Module 6: Genetic Change
Tip #1: Do Outside Research
The more research you do, and examples you discover, the more you’ll be able to understand genetics. Genetics isn’t just about processes like meiosis and mitosis, and it’s not just about what happens cellularly.
If you can understand what real-world implications genetics and genetic technologies have had, the better off you’ll be.
If you can keep one or two really good examples in mind, you can explain yourself better.
Let’s use Sickle Cell Anaemia again as an example:
At the genetic level, we know that this anaemia is recessive, and is caused by a single point mutation in the gene coding for haemoglobin beta, the protein carrying oxygen in red blood cells.
At the cell level, we know that a single point mutation causes translation of a mutated version of haemoglobin beta. An amino acid that isn’t usually incorporated at this position is added. An amino acid change can cause structural changes such as the disappearance of the characteristic biconcave disk shape of red blood cells into ‘sickle’ shaped cells. Blood can stick to each other due to this sickle shape, and can often cause blockages.
At the population level, we know that sickle cell anaemia is one of the most commonly inherited mutations, and has severe consequences such as stroke and blood clots.
In terms of genetic technology, we know that gene editing system CRISPR/Cas9 has been used in 2017 and saw exciting results. The patient’s symptoms were reversed long-term, which is something that drugs couldn’t achieve to this extent and cost.
There’s not a lot of information about the particulars of genetic processes in that example… it’s about the understanding of how genetic processes have a real world impact and effect.
And if you have a couple of really well-developed examples to show your incredible understanding of genetic change, the better off you’ll be in assessments and exams!
Tip #2: Take Note of the Learning Objectives for Assessments
Let’s take a look at the Sample Assessment Schedule for Year 12 Biology:
According to the Principles of Assessment for Stage 6, assessments should:
- Help you learn the content better
- Have clear goals
- Encourage peer-assessment, self-assessment and feedback formally/informally
A great way to get a good mark is to keep the learning objectives in mind and ask for feedback from teachers and peers.
You should also consider what the assessment is looking for: is it testing your understanding? Or is it testing your Working Scientifically skills?
You should equally demonstrate your understanding and your skills as a scientist. How can you best do this in a depth study? Consider a secondary investigation e.g. poster on the developmental gene Gap. How could you best represent the history of its discovery and the significance of these genes?
Choosing the format of your depth study is the first step in tackling your assessment. Pick an appropriate format (in this case, you wouldn’t typically choose a primary investigation) and present your information in the best way (graphs? images?).
For more information on what the HSC Biology Depth Study is all about and how to ace it, check out this article!
Your understanding of genetic change is best explained with an example.
If you are talking about mutagens, include an example like ultraviolet light and pyrimidine dimerisation. If you are talking about biotechnology, consider mentioning gene therapy and its social implications.
Furthermore, taking a multifaceted approach to learning is going to help you in the long run. If you get stuck on a topic, look at a couple YouTube videos or a diagram, get a friend to explain it, or read an example of it.
Genetics can be a big topic to punch out, but if you chip at concepts bit-by-bit, you can achieve a greater understanding of genetic change, and get that Band 6!
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