Course content Course content
Nucleic acids and chromatin
Nucleic acids and chromatin

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

Nucleic acids and chromatin

Summary of Section 3

  1. Watson–Crick base pairing arises due to hydrogen bonding between A and T and G and C and spatial limitations within the hydrophobic core of the helix.

  2. DNA commonly folds into the B-form helix; other forms such as Z-DNA form in vitro. A-form helices are formed primarily by duplex RNA.

  3. The twisting of DNA around its helical axis results in torsional stresses that promote the formation of high-energy alternative conformations such as supercoils.

  4. DNA chains accommodate changes in DNA twist through alterations in their supercoiling.

  5. Naturally occurring B-DNA is negatively twisted, a state that facilitates strand separating activities of DNA metabolism.

  6. Enzymes called DNA topoisomerases are responsible for managing torsional stress in DNA.

  7. Unusual DNA structures can form due to Hoogsteen bond formation between bases and are believed to occur in quadruplex and triplex DNAs.

S377_1
Print Print

Take your learning further371

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 courses372.

If you are new to university level study, we offer two introductory routes to our qualifications. Find out Where to take your learning next?373 You could either choose to start with an Access courses374or an open box module, which allows you to count your previous learning towards an Open University qualification.

Not ready for University study then browse over 1000 free courses on OpenLearn375 and sign up to our newsletter376 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