Quiz in CMB (November 20, 2023)

From which organ of what animal did Maurice Wilkins obtain the highly pure, high molecular weight DNA Fibers that served as the subject photographed using the x-ray crystallography technique?

(a)  

Who speculated the semi-conservative replication mechanism 26 years before Watson and Crick’s publication in 1953?

(a)  

What scientific principle helped Watson and Crick figure out which nitrogenous bases should be paired with one another?

(a)  

Rosalind Franklin created Photo 51 by using X-ray diffraction on pure DNA fibers. What did the pattern of dark spots on the X-ray film indicate?

• The type of nucleotides in the DNA

• The arrangement of atoms in the DNA

• The number of DNA strands in the fiber

• The sequence of genes in the DNA

In the context of the double helix structure of DNA, why is it crucial that the two DNA strands are antiparallel?

• Antiparallel strands allow for the formation of phosphodiester bonds between the nucleotides, which are essential for the structure of DNA.

• Antiparallel strands ensure the greatest hydrogen bonding between the complementary bases, contributing to the stability of its structure.

• Antiparallel strands facilitate the process of DNA replication by allowing the enzymes to move along the strands in opposite directions.

• Antiparallel strands enable the DNA to coil into a double helix, which is necessary for the DNA to fit inside the cell nucleus.

Which of the following is NOT a function of chromatin?

• Packaging DNA

• Regulating gene expression

• Protecting the genome from damage

• Transporting DNA

The name of the second level of chromatin extraction also known as a “rope-like”

structure.

• Nucleosomal structure

• 30 nm fiber

• Chromatin loops

• Histone

What is the main purpose of chromatin acid extraction?

• To isolate DNA from chromatin

• To isolate histones from chromatin

• To isolate RNA from chromatin

• To isolate proteins from chromatin

What is the advantage of using a gentle method, such as salt extraction or

enzymatic digestion, to isolate histones from chromatin?

• It preserves histone structure.

• It preserves labile post-translational modifications.

• It is purity-specific.

• It is speed-specific.

Core histones are the histones that has two copies of each that are joined to

create an octamer core particle. Give at least one (1) core histone.

(a)