GCSE Biology: DNA Structure and Protein Synthesis

In the new AQA GCSE Biology, DNA structure is much more detailed and protein synthesis is now included. In recent years protein synthesis has moved from A2, to AS and is now in the GCSE course. It’s a tricky but exciting topic to teach. Here’s how I did it:

We’d had an introductory lesson learning the basics of DNA and using the Biorad “Genes in a Bottle” kit to make DNA necklaces – the students knew that DNA acted as a code for “how to build everything in a living thing” and that it existed on strands called chromosomes.

In the second lesson we build a giant polynucleotide using a template that I found online (huge apologies – I can’t remember the source but it’s perfect and thanks so much. I edited the document I found a little bit to make it more economical to photocopy).

2 DNA StructureDNA Paper Models Activity for reprographics

2 DNA Structure

I’d tried to save time by making sure each student had 10 sugars and 10 phosphates in a stapled pack. I had four pots with the bases ready for collection once they’d made their backbones. The first students to finish were responsible for assembling the short 5 base pair sections into a long chain.


In the next lesson we started the slightly harder content: how the DNA strand codes for protein. I asked students to imagine our classroom was a pancreas cell (which was a good opportunity to revise basic animal cell structure). We talked about protein from a steak being digested elsewhere in the school. I opened the classroom door to represent a protein channel allowing amino acids into the cell and asked them to imagine the amino acids floating around in the cytoplasm of the cell. I talked about there being 20 different amino acids that are the building blocks of all of the proteins in the body; students could name many uses of proteins in the body.

I told students I’d explain how the proteins were built using an analogy and that we’d then use the correct words. Our analogy was reading a recipe from an old, special recipe book


Jack quickly got the idea that we’d want to take a photocopy of the right recipe and take the photocopy to the kitchen. I asked him who would take control of the recipe, expecting an answer of a chef, but I got the reply “Mrs Stewart!” (one of our Food and Nutrition teachers – well, it works!). I acted out Mrs Stewart reading the recipe calling for one ingredient at a time.

Then we moved to the back of the room where our DNA model was hanging from the ceiling. Prior to the lesson I’d scattered yellow, orange, green and blue hole-punched cards with AA (amino acid) written on around the room. I then told the class we needed to translate the analogy to real biological terms. They quickly got the idea that Mrs Stewart was the ribosomes (Jack was assigned the role of ribosome). I showed them how the DNA was “photocopied” into mRNA by having some pre-made nucleotides ready at the back and a glue stick. I’d crossed out the ‘deoxy’ from the ‘deoxyribose’ label and crossed out thymine and changed it to uracil. I told them not to worry about these changes, but that RNA was really similar in structure to DNA, but I’d made these changes to I could use the materials with the sixth form. We built up the mRNA strand which gave them the chance to practice shouting out the complementary base to the DNA strand. I then showed the mRNA floating out the nucleus and attaching to the ribosome (I draped it over Jack’s head). In the previous lesson we’d talked about the triplet code so they knew Jack would read 3 bases at a time. Four students were assigned the role of tRNA and wore card labels. I did the ‘reading’ for Jack to start with, e.g. “GGC – that codes for a green amino acid”, at which point my green-seeking tRNA student would go and hunt down a green amino acids in the lab and bring it to Jack. Then I would say “AGA – that codes for a red amino acid” and so on. Jack’s job was to use treasury tags to bond together the amino acids and form a long chain.


Once we’d made the long chain we discussed folding of proteins (e.g. the orange ones like to form other bonds – and we looped the treasury tags back). It was also a good chance to start talking about mutations and their effects.

During the lesson, more able students asked about why all proteins aren’t made all of the time which led to an interesting one-on-one chat about transcriptional factors!

Question sheet for DNA structure (based on AQA A-level questions)

DNA Structure Exam Questions MS

DNA Structure Exam Questions

Protein synthesis questions:

Protein Synthesis Exam Qs MS

Protein Synthesis Exam Qs


Practical Science: Free Choice or Fixed Method?

Last week my second year class (NC Year 8) were given the task of modelling huddling behaviour in penguins as part of our ‘Adaptations’ topic. We watched a 3 minutes BBC Attenborough clip of penguins huddling and I explained the term ‘model’ to them in the science-sense of the word. I then gave them the task of modelling this behaviour using glass ware instead of penguins. The aim of doing this practical, which I shared with them, was for them to practise identifying variables (IV, DV and CVs) and to practise table design. I also wanted them to practise independent experimental design – I had this group last year and we’d made great progress using our “Brain, Book, Buddy, Boards” system before they were allowed to ask me for help. The results of the experiment were not at all important to me.


Arguments for allowing students to design their own experiment:

  • I love seeing students really using their brains rather than following a method in a zombie-like fashion. I want them to think about the problem and to engineer a solution. I love them hearing them discuss with their practical partner how to keep their test fair – in my view this is REAL science.
  • Sometimes, such as in this case, the results don’t matter. Some groups only got one result but they had designed a great experiment and we’d had interesting discussions about their set-up.
  • This way develops independent learning skills – there is no chance to passively partake in a lesson and students have to think for themselves.
  • By allowing students to make mistakes with table design, e.g. variables the wrong way around, mixed units, incomplete headings etc you have a range of great resources to share and discuss with the class. Having just marked their plans I now know ‘O’ is struggling with table design and ‘M’ and ‘J’ need some help with repeatable and reproducible definitions.
  • Key Stage 3 is largely free from needing to know fixed methods and gives students and teachers much more freedom to allow experimental design to develop.

Arguments for asking students to follow a fixed method:

  • Sometimes the results really matter, and if students design a method that just won’t get the results you want there is a danger of them taking home the wrong message from the practical.
  • There are some procedures which are commonly used and asked about in examinations at GCSE and A-level – being familiar with these methods buts exam candidates at an advantage. Examples include bubbling pond weed (very common in KS3 SATS papers and GCSE Biology papers), transpiration experiments, mass change in potato chips etc.
  • This puts less of a burden on the technician – I know our technician despairs of me sometimes when I invade the prep room several times in a lesson because students have asked for weird and wacky pieces of equipment to conduct an experiment. Leaving the lab to go to the prep room might not be practical in some schools. I’m lucky that my lab is connected to the prep room so I can wedge the door open and pop in an out to get whatever students ask for. I’ve avoid this in the past by asking students to design their own method in one lesson and submit an equipment order to do the practical next lesson.
  • Following instructions carefully is a skill in itself – it’s one of AQA’s competencies which my sixth form students are working on.
  • In real world science, replicating a fixed procedure is done to check for the reliability of results.
  • From a selfish point of view it’s much easier to manage a class of students doing a fixed producre and it’s much easier to mark.

Although it looks like there are more arguments for using a fixed method, I most of these arguments are not student centred and I think every decision made in the classroom should be for the benefit of the students. I’m all for maximising opportunities pre-GCSE for students to design their own practicals.

Theory then Practical? Or Practical then Theory? 

“Telling kids the outcome of an experiment before they’ve done it is like telling them the end of a film before they’ve seen it” @LTMLblog
I’ve tried a few practicals recently where I’ve done an investigation at the start of the topic as a genuine enquiry, rather than after the theory. Both were with Year 10. The first was

The classic osmosis experiment; cylinders of potato in different concentration of salt water. At this point we’d studied diffusion and they knew about concentration gradients. When I asked them what they thought might happen they said that in the high salt concentrations, salt particles would move into the potato cells by diffusion due to the concentration gradient and so the cylinders would gain mass.

As they re weighed the chips there were lots of annoyed “this hasn’t worked”‘noises from the kids just because it didn’t match what they thought. In fact, they were probably the best set of osmosis results I’d ever had (genuine results, that is, not ones fudged by students who want that perfect straight line when they know what should happen!)
We then plotted the data on a graph and they could see a pattern emerging from them nonsensical results – a beautiful straight line! We then annotated the graph to explain what was actually going on.
This week I did the same at the start of our Proteins and Enzymes topic. We looked into digesting milk protein with trypsin. They all told me that the hotter the enzyme, the faster the digestion, because of the particle theory they’d done in chemistry. Again, there were frustrated noises when their 60 degree reaction didn’t work at all due to the enzyme denaturing.

Why do we do practical biology? If it is genuinely to investigate then surely it’s best to do practical work before the theory.
But, as one of my former sixth formers, Ellie, pointed out; “(sometimes) you need the theory to understand why/how you do things in the practical. Plus if you don’t understand the theory then sometimes the practical makes it click.” 


Things to do with your form

Probably my favorite part of my job is my role as a first year form tutor. I’ve always specialised in Key Stage 3 tutoring, but now I’m a Y7 specialist.

Form time is precious! The 30 minutes I spend with my form each day adds up to over 80 hours per year with them! Obvious a great deal of this is spent signing planners, in assemblies and meeting, giving out notices and completing the register but it’s always good to have something up my sleeve for the down-time, especially when assemblies are cancelled during the exam period.

Having a bank of resources is useful to re-use each year and avoid masses of planning time. Here are some random bits and bobs I’ve done with my form. Some last for one registration, some are more of a mini project which might last a few weeks.

Thought for the Day

Stuck for time? If you only have two minutes spare I love “365 Days of Wonder: Mr Browne’s Precepts” which is basically a thought for the day, based on the novel “Wonder”

Getting to Know Each Other

Friendship Bingo is a good start of Y7 activity which can last about 10-30 minutes. Students wander around and chat to people, trying to find people who match various categories. Editable word doc: Friendship Bingo

Learning a Language

Learning to say ‘Hello’ or count from 1-10 in a range of languages is a fun thing. You can get them to answer the register in a different language each week. It’s fun to learn, but you can also link in some discussion about how to learn or revise. counting in japanese

I have used the BBC’s ‘Big Welsh Challenge‘ as we are close to the Welsh border and many students will visit Wales on holiday.

Get your Brain Working!


I have cheap puzzle book and photocopy a page from it now and again. Students pair up to try and complete the puzzle. You can always change the rules, make it into a competition or allow dictionaries or the internet. It’s a pretty good way of teaching internet searches.


If time allows, getting students to crack a code or write their own cyphers and get someone else to decode them is fun. You can set it up as a treasure hunt and hide a bar of chocolate somewhere in the form room – the first one to crack the code finds the chocolate!

Quizzes are always a fun option and there are plenty around on the net. A colleague has set up a leader-board using the weekly 12 question topical news quiz published by The Day. The answers are always available and you can whiz through it in 10 minutes.

Here are a few short quizzes to do:

Rebus Puzzles

Famous Landmarks Photo Quiz

Famous People Quiz

have I got news for you quiz 2

microscopic objects – what am i

name that creature picture quiz

Thought Provoking

I absolutely love this series of photos of food eaten by typical families around the world. I have always found the class gets really involved, making observations about the types and quantities of food, what makes a typical family. It’s amazing to ‘hear’ a hush cross the room when some of the images of the poorest families are shown. Food around the world

Another easy thing to do is watch the News for 10 minutes to catch the headlines. Things like strikes or elections make for interesting discussion. Also, the ‘On this day in history‘ page of the BBC site is good

This website is an interesting thought-provoking thing to ponder: http://www.snopes.com/science/dhmo.asp

Learn about people who are different to you! There are a multitude of videos about people with different disabilities etc.  I really like this video about Steven, an autistic savant, shows off his amazing memory/drawing skills in Rome. (5 mins 17)

Random Acts of Kindness

I have a copy of Danny’s Wallace’s book “Random Acts of Kindness“. Some of the inclusions are not really appropriate for 11 year olds but it’s a good read (there are lots of similar books out there). You can spend time discussing things that make us happier more fulfilled people, read out from the book and challenge the form to spend a few weeks completing random acts of kindness. It’s nice to share ideas of things they have done.



Miscellaneous Bits and Bobs for One-Off Sessions:

Form Assemblies

Getting the students to put on their own assemblies about somehting that interests them is always a winner.

Christmas Activities

Autistic Spectrum (Disorders)?

On Friday we had an INSET day with various workshops to sign up to. I chose to stick to an SEN theme as it’s something I’ve always been really interested in but haven’t had any refreshers on for a while. The aim of the INSET (and this post) was not to teach us about what ASD is, but to remind us of some of the specific difficulties they face and pose questions about how this knowledge should impact upon classroom practice. I thought I’d pop my notes online, mainly (as always) to give myself a little reflection time and think about what I can do differently in my classroom to help my students with ASD. Now I’ve re-read my post back to myself I can see it’s not going to be hugely useful to anyone else, but as I said, the aim was to make me think!

What is ASD?

One in 100 people in the UK have ASD (Autistic Spectrum Disorder). Either way that’s one or two children in each year group at my school.

According to the NHS website, ASD has a range of indicators, which can be grouped into two large categories:

  • Problems with social interaction and communication – including problems understanding and being aware of other people’s emotions and feelings; it can also include delayed language development and an inability to start conversations or take part in them properly.
  • Restricted and repetitive patterns of thought, interests and physical behaviours – including making repetitive physical movements, such as hand tapping or twisting, and becoming upset if these set routines are disrupted.

Although I’m familiar with the more obvious signs and symptoms of ASD I’d never fully appreciated the idea that people with ASD are hypersensitive to sounds etc. I know I get easily bothered in the classroom by tapping of pens, flicking of switches and the bubbling of the fish tank, so I can only begin to imagine how over stimulating a classroom could be for someone with ASD.

Another thing I’ve seen in children in my forms (year 7) over the years is the tendency for the child with ASD to put themselves in a parental role with their peers; telling them off for breaking the rules and correcting them when they make mistakes. This, obviously, isn’t conducive to building friendships and life can be lonely at that age for someone with ASD. I’ve seen glimpses of the excellent social-skills workshop materials used by our SENCO which help children with ASD to work out the right or wrong thing to say in social situations. I’m going to try and sit-in on some of these workshops and see exactly how they work. I need to learn how to sensitively discourage them from doing this. I do feel for children with (often undiagnosed) ASD in the first year as they struggle to make friends. By the time they’re older, their peers have become used to their quirks but as such a young age, life must be hard.

Disorder, or just different?

The first session of the day was on Autistic Spectrum Disorders, or ‘Conditions’ as our SENCo prefers to call them. The label ‘disorder’ obvious implies there is something detrimental about these conditions, and of course there are many negatives to having an ASD way of thinking. However, there have been many cases of companies specifically seeking out people with ASD such as Vodafone and SAP due to their developed analytical skills, patterns spotting and attention to detail.


What can I do to try and make life a little easier for my students with ASD?

  • Reduce the noise in the classroom when they really need to focus – the noise of the clock ticking during an exam was mentioned as being really off-putting for someone with ASD.
  • Plan ahead for things that break-routine. I’m taking a student with ASD on a big week-long trip next year which will be way outside their comfort zone. I’m going to see if they’d like to sit down and look at some photos from last year’s trip to mentally plan for what might happen, what the routine will be like, what the food and rooms are like etc.
  • Writing instructions on the board is important rather than just verbalising them, as students with ASD often have short term or working memory problems
  • One thing I’ve not fully decided in my own mind is about group work. At the INSET we talked about how a lot of children with ASD dislike team sports. I’m not sure whether it’s better to make them comfortable and excuse them from such activities or to push them to take part. I suspect a happy medium between the to is the best approach as group situations are part of adult life which children with aSD are going to need to be able to cope with.

If you’re reading this, either as a teacher, student, someone with ASD or a parent and have more tips please do let me know!

Towards the end of the INSET session, our SENCO read a poem written by one of our students with ASD. She’s currently in the Lower 6th, and though I’ve never taught her, she’s a well-known personality in school and I love spending time with her. I’ve been fortunate enough to go on a few trips with her and get to know her on a more social level and I have a feeling she’ll be one of those students I keep in touch with for years. I asked her if I could publish her poem and she agreed, although I have taken the school name out to try and anonymise her a little.

My School – An Autistic Account


For life on a misunderstood planet

Being an alien isn’t easy

No spaceship here to leave yet

As for the future, we’ll have to wait and see.


The ringing of the bell

The ticking of the clock

Which hurts more it’s hard to tell

The noise in my ears is like heavy rock.


Structure and routine is a definite

Without it I am lost

Social times are difficult

They seem to come at a cost.


Now for a quick bit on advice:

Just treat us all exactly the same

And please not unnecessarily nice

We do not seek that moment of fame.


Emotions are challenging to understand

Expressions just aren’t clear enough

Sometimes we could use that extra hand

With these things that we find really tough.


Sarcasm is an issue

I’m not purposefully being a pain

Sometimes I will need a tissue

When I think that I’m going insane.


My organisation is lacking

I need to learn to time-keep

Oh and one more thing

Easy things to you can sometimes seem like a leap…


One day that spaceship will arrive

And will take me to a different place

Somewhere where I will learn to thrive

Because although it has many hold backs, being on the autistic spectrum is undoubtedly pretty ace.


So teachers of <my school>

The main message can you see:

Please don’t ever change

But continue to encourage and support more people like me.

Useful reading:

Been there, done that: An Aspie’s Guide to the Universe – This was recommended at our INSET although I haven’t read it yet. It’s next on the list.

Freaks, Geeks and Aspergers – I bought this a couple of years ago when a boy in my new form seemed to be showing signs of ASD. It’s a great read and written by a 13 year old boy, Luke, with ASD so offers a great insight into the mind of a young person with ASD

Curious Incident of the Dog in the Night-Time and The Rosie Project are two great novels both centered around characters with ASD. I’ve been reading The Rosie Project over half term and I can’t put it down. Although both are novels I really think they’ve helped me to understand the mind of someone with ASD.

My door’s open, come on in.

I’ve just had my final ‘official’ observation of the year and one thing I noticed was how little the children’s behaviour changed. I was being watched by my HoD teaching my own form for Science, doing a revision lesson.

I remember when I first had OfSted in, listening to discussions in the staffroom about how the children would either be on their best behaviour to try and help you out if they liked you, or go all out to try and get you in trouble if they didn’t like you!

But in this observation, my form were my form. Which was great! There was nothing artificial about the observation at all and I think it reflected a day-to-day lesson. This got to me to thinking about why this was, and I think the answer was pretty obvious; this class are very much used to my HoD being in the classroom. Barely a lesson goes by where he doesn’t pop by to chat to them as they’re lining up waiting to come in or stop by to ask me something while they’re beavering away. Sometimes he stays for longer and has a wander around and talks to them about the practical they’re doing or joins in a game of splat. Occasionally he shows them a quick 5 minute magic trick or plays a joke on them! These antics might seem, to an outsider, like a waste of 5 minutes, but it all contributes to the immense sense of fun and community spirit we have in our department. My form love coming down to the department; science is one of their favourite lessons and many have joined Biology Club and Science Club. On a practical note, sometimes it’s great having an extra pair of hands or an extra adult brain in the word to help them with a piece of equipment or to critique their experimental design. It also gives the students a real sense of pride to show another teacher their work and get praise.

I love popping into classrooms to see my form at work. I love seeing what they’re making in Art and what they’re cooking up in Food and Nutrition. Those teachers don’t seem to mind and the children love showing me what they’re up to. Of course, there’s a time and a place, and I wouldn’t walk in while a teacher was in mid-flow. I also know which teachers would feel very uncomfortable with me doing this.

At my last school, the biology prep room was accessed through my lab and on some occasions it was like teaching in a corridor with teachers, technicians and trolleys trundling past throughout the lesson. I developed as a teacher with this being the norm, and am so glad this was the case. It’s made me see visitors as welcome, rather than intruders. I know some people hate being disturbed mid-lesson and it’s the same people who get themselves worked to a frazzle before observations.

On an aside, I do remember in my NQT year, my then-Headteacher walking into my classroom *just* as I said the word “vagina” (in the context of the Reproduction topic of course). He made a hasty retreat 🙂

Aside from the benefit to students of a more open-door ethos in schools, there is obviously a huge benefit for teachers. I’ve learnt so much from watching other teachers both formally and informally. An informal observation, or just by wandering around someone else’s classrooms allows you to see (and poach) ideas and resources.

As I type, I have page 94 of  “100 Ideas for Secondary Teachers” by Ross Morrison McGill open on my desk (GREAT book if you haven’t read it). He says: “The benefits of the open classroom are many. They include promoting reflection and evaluation of your teaching, increasing collaboration and trust among teachers and across the curriculum….”


Schools involvement officer Heather Leatt summed up a post published on @TeacherToolkit ‘s blog:

“Schools where dropping in and out of each other’s lessons is the norm tend to thrive on a culture of co-operation and creativity.  Solutions are sought to problems, rather than blame being handed out and colleagues act as critical friends, supporting one another, bringing out the best in everyone… Such schools are usually happy places to work in.”

Want to read more about classrooms without doors? Read these:

Ross Morrison McGill’s (@teachertoolkit) sign for your classroom door and Heather Leatt’s blog post


Pound Land Pedagogy and Bits and Bobs….

One thing I LOVE about Twitter is some amazing ideas that get freely shared around.

As study leave has started, I’ve found myself with a little more time and one of my first jobs this week was sorting out the piles of ‘stuff’ that have accumulated in my cupboards in the lab. I don’t know about you, but sometimes I have so many resources I’ve found over the years I forget I have them, and I need a better way of categorising them.

Any how…. My sort out revealed all kinds of household objects and random props that I use to demonstrate scientific concepts. Some of which I’ve used since I was an NQT and some of which are only a month old. I thought I’d ask around on Twitter and see what other ideas I can poach and share some with you too. Many of these objects are free / very cheap and just as good as expensive resources. Some of these will be very much a case of teaching Grandma to suck eggs, but they might be useful for PGCE students or NQTs. I’d like to keep adding to this when I hear about more – please tweet me your ideas @mrsjmasters

Here’s the stuff I found in my drawers…..!

Coke Bottles:

A great prop or basis for an experiment. You can link it in with nervous system and the effect of caffeine on reflex speed. More importantly it generates great discussion about ‘How Science Works’,  variables, fair testing, control group, placebo effect, errors, table and graph drawing…..



Good for looking at the nervous system. Can use for looking at action potentials. Good for discussions about ‘models’ in science and the limitation of the slinky as a model for impulses. Twitter friend @missaudsley uses them to model waves in physics.



I used 1p and 5p coins to represent Na+ and K+ when looking at action potential and resting potential with my Upper Sixth. Good for animations.



Catapult – useful for demo of elastic potential energy and energy transformations


Sports drink bottle:

I forget which brand this is but it has a value in the tip which is a good model for values in veins and the heart.


Fly Squatters:

Found on Amazon – good for playing SPLAT as a key word / definition plenary


Pipe cleaners:

Useful for chromosomes when looking at meiosis and mitosis

pipe cleaners

Other fellow Tweechers have suggested the following:

@missaudsley – I use a slinky, dice and wheely chairs more than anything else! The chairs for Newton’s 3rd (interaction pairs of forces), dice for radioactive decay and student revision games.

@GMacademic suggests marbles are a go-to item. They can be used to model particle theory, energy transfer, atomic structure, radioactive decay and even keeping scores in quizzes.

@Barbiepanther12 – Straws and balloons

Please keep the suggestions coming….