GENETICS AND EVOLUTION
MOLECULAR BASIS OF INHERITANCE
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
A vesicle containing positively charged histones within nucleolus
|
|
|
They are similar to endosomes
|
|
|
A structure formed by wrapping of negatively charged DNA around positively charged histone octamer.
|
|
|
They are the transforming principles discovered by Griffith
|
Detailed explanation-1: -Nucleosome is the structural unit of a eukaryotic chromosome, and thought to be present only during interphase of cell cycle. It consists of DNA wrapped around histone octamer. (i) A typical nucleosome contains 400 bp of DNA helix.
Detailed explanation-2: -The beads are called nucleosomes. Each nucleosome is made of DNA wrapped around eight histone proteins that function like a spool and are called a histone octamer. Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3, and H4.
Detailed explanation-3: -DNA is negatively charged and histone proteins are positively charged. The DNA is wrapped around histone octamer. DNA wraps in such a way that it appears as beads on string. These small units or beads are nucleosomes consisting of DNA and histone octamer.
Detailed explanation-4: -A nucleosome is composed of histone protein and DNA. DNA carries the negative charge due to the phosphodiester linkage and histone is basic in nature and carries a positive charge because histones are made up of basic amino acids.
Detailed explanation-5: -Nucleosomes consist of a nucleosome core, entailing 145 to 147 bp of DNA in complex with a histone octamer of H2A, H2B, H3 and H4 proteins, in addition to a variable length of linker DNA that can be associated with linker histones.