Lecture 1 Flashcards
Describe the structure of DNA
has 2 long polynucleotide chains on the exterior, with nucleotide subunits on the interior
What makes up one nucleotide?
one 5 carbon sugar, deoxyribose, linked to a nitrogenous base via a glycosidic bond
What are the pyrimidines?
Cytosine and Thymine
What are the purines?
Adenine and Guanine
How many base pairs are in 1 “turn” of DNA?
10
Describe the structure of DNA double helix strands
antiparallel and complementary
What is true of all forms of DNA packaging?
they exist in a dynamic state, so that they can still be accessed for gene expression
Define Nucleosome
most basic unit of DNA packaging
“beads on a string”
Define Linker DNA
the “string” that holds nucleosomes together
Define Histone Octamer
2 molecules each of H2A, H2B, H3, and H4 subunites
how many hydrogen bonds are formed between the histone core and the DNA on ONE nucleosome?
142 hydrogen bonds
Define salt linkages in terms of DNA organization
Positively charged lysine and arginine form salt linkages with the negatively charged backbone of DNA
Define Chromatin
what results from the folding of nucleosomes
formed via “zig zag” organization of nucleosomes
What are Chromatin Remodeling Complexes?
structures that consume ATP in order to “loosen” DNA from it’s histones
this ensures a dynamic state of DNA
Chromatin structures are maintained by what force besides salt linkages?
hydrophobic interactions
