Basic science: understanding experiments
Basic science: understanding experiments

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Basic science: understanding experiments

Week 4: DNA


Download this video clip.Video player: ou_futurelearn_experiments_vid_1004.mp4
Skip transcript


Hello, and welcome to the final week of the science experiments course. We hope you've enjoyed it so far. The experiments you did last week taught us about the important biological process of respiration. This process is happening in cells only about 100th of a millimetre long, and that's something far too small for us to observe directly without a powerful microscope. But you could get an idea of the strength of the process by measuring the bubbles, which indicate the carbon dioxide being given off by the reaction.
Now, we don't always have to look at very small things using indirect methods. We can be more direct. So this week, you're going to do an experiment which will enable you to look directly at the contents of the nucleus of a cell. You're going to extract and observe DNA-- the material which carries the genetic instructions for the growth and development of life.
All living things contain DNA. And you've probably heard that each person has a DNA code which is unique to them, except for identical twins, who have the same DNA. This uniqueness has led to incredible advances across many areas of science, from our understanding of the evolution of life on earth through to the development of new medical interventions. DNA can even be used to solve crimes.
Your experiment will extract and directly observe the DNA contained inside the cells of a kiwi fruit. Now, you could look at the DNA for many living things, even yourself. But kiwi fruits are simple and straightforward to work with. And on the way, you will learn about how the instructions for life are encoded and passed on. We look forward to discussing your experiment, the science, and even the ethical implications in the forums.
End transcript
Interactive feature not available in single page view (see it in standard view).

Welcome to Week 4. This week, you are going to use some fairly common household chemicals to isolate and observe the DNA (deoxyribonucleic acid) from the nucleus of a kiwi fruit.

DNA was first isolated as far back as 1869, but it wasn’t until 1928 that scientists realised that it carried genetic information. In 1953, the structure of the molecule was discovered by Francis Crick and James D. Watson and other colleagues, while working at Cambridge University.

DNA is a molecule containing sequences of chemicals in very specific arrangements. The shape of the molecule is like a twisted ladder, known as a ‘double helix’, which contains stretches of chemicals, known as genes, which code for certain biological traits and functions. In other words, DNA contains the instructions by which organisms build and maintain their existence.

Skip Your course resources

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371