Lecture 5: Nucleic Acids and DNA Structure

What determines the 3D shape of bio-macromolecules?

Function often depends on proper shape, which is predicted through methods like X-ray crystallography.

What is X-ray crystallography?

A technique where X-rays are shone through a crystal to create a diffraction pattern, which is analyzed to predict the original 3D shape.

Who were the key figures in discovering the structure of DNA?

Francis Crick, James Watson, and Rosalind Franklin.

What is the significance of 'Photo 51'?

It is an X-ray diffraction pattern of DNA taken by Rosalind Franklin in 1951 that contributed to the understanding of DNA's structure.

What are nucleotides?

The monomers of DNA and RNA, consisting of nucleosides plus one phosphate group.

What is the structure of DNA?

DNA is a polymer of A, T, G, C nucleotides arranged in a helical structure with approximately 10.5 base pairs per complete turn.

What type of bond connects nucleotides in DNA?

Phosphodiester bonds connect nucleotides.

What are the major and minor grooves in DNA?

Asymmetrical grooves formed by the helical structure of DNA, with the major groove being wider than the minor groove.

What is the orientation of human genomic DNA?

Human genomic DNA is right-handed, referred to as B-DNA.

What are the alternate conformations of DNA?

A-DNA, B-DNA, and Z-DNA, with B-DNA being the most common form.

How do complementary base pairs interact in DNA?

They interact via hydrogen bonds.

What is the role of A-DNA and Z-DNA?

They are found in short stretches and may be involved in controlling access to genetic information.

What is the significance of the angles of phosphodiester bonds in DNA?

They contribute to the helical structure of DNA.

What is the difference between nucleosides and nucleotides?

Nucleotides include nucleosides plus one or more phosphate groups.

What is the function of nucleotides with two or more phosphate groups?

They have varied functions in other cellular processes.

What is the typical distance between base pairs in DNA?

Approximately 10.5 base pairs per complete turn of the helix.

What is the role of hydrogen bonds in DNA?

They stabilize the pairing between complementary bases.