DNA Structure and X-ray Diffraction

The video tutorial explains the significance of Rosalind Franklin's Photograph 51 in understanding the structure of DNA. It details the X-ray diffraction method used to capture the image and the mathematical relationships that reveal the helical nature of DNA. Key measurements such as the rise per base pair and the pitch of the helix are discussed, along with the arrangement of DNA strands and the presence of major and minor grooves. The tutorial concludes with the calculation of the helix radius and references Franklin's classic paper.

What was the primary method used by Rosalind Franklin to study DNA structure?

• Ultraviolet spectroscopy

• Nuclear magnetic resonance

• X-ray diffraction

• Electron microscopy

What characteristic pattern indicates the helical nature of DNA?

• Zigzag pattern

• Circular pattern

• Linear pattern

• X pattern

What is the rise per base pair in the DNA helix as determined from Photograph 51?

• 3.4 angstroms

• 6.8 angstroms

• 2.0 angstroms

• 5.0 angstroms

How many base pairs are there per turn in the DNA helix?

• 14 base pairs

• 12 base pairs

• 10 base pairs

• 8 base pairs

What does the pitch of the DNA helix refer to?

• The angle of the helix

• The distance the helix repeats itself vertically

• The width of the helix

• The number of strands in the helix

What does the missing fourth layer line in the X-ray diffraction pattern suggest about DNA?

• DNA has more than one strand wound around each other

• DNA has no grooves

• DNA strands are symmetrically placed

• DNA is a single strand

What is the significance of the major and minor grooves in DNA?

• They prevent DNA from unwinding

• They make DNA more stable

• They provide sites for protein binding

• They allow DNA to be more flexible

What is the calculated radius of the DNA helix?

• 20 angstroms

• 5 angstroms

• 10 angstroms

• 15 angstroms

Which paper published alongside Watson and Crick's work is considered a classic in understanding DNA structure?

• Franklin and Gosling's paper

• Darwin's paper on evolution

• Crick's paper on protein synthesis

• Mendel's paper on genetics

What does the spacing between the spots in the X-ray diffraction pattern indicate?

• The radius of the DNA helix

• The length of the DNA strand

• The number of base pairs

• The type of DNA