Chapter 5 Flashcards
building block of DNA
dNTP
nucleoside
ribose with a purine or pyrimdine linked to the 1’ carbon
nucleotides
phosphate esters of nucleosides
deoxynucleoside triphosphate (dNTP)
when nucleotides contain three phosphate residues
backbone of DNA
ribose and phosphate portion of the nucleotide
Oligonucleotide
a polymer of several nucleotides linked together
Polynucleotide
A polymer of many nucleotides linked together
Watson and Crick model
Cellular DNA is a right-handed double helix held together by hydrogen bonds between bases.
The helix pattern resets itself once every 34 angstroms, which is every 10 base pairs. Width is always 20 angstroms.
H-bonded pair always consists of a
Purine plus a pyrimidine
Annealing/Hybridization
The binding of two complementary stands of DNA into a double-stranded structure
Melting/Denaturation
Speration of strands
Tm
Temperature at which a solution of DNA molecules is 50% melted
Tm is (higher/Lower) in pairs of AT
lower, it takes less kinetic energy to disrupt 2 hydrogen bonds than 3
Genome
sum total of an organisms genetic information
Chromosome
each piece of ds-DNA
Is there a correlation between genome size and evolutionary sophistication?
No
Organisms with the largest genome
amphibians
DNA gyrase
uses energy of ATP to twist the gigantic circular molecule and then breaks the DNA and twists the sides of the circle around each other
Supercoils
Created by DNA gyrase; coils of a structure that’s already coiled
Histones
because eukaryotic DNA needs denser packing, DNA is wrapped around these gobular proteins
Nucleosomes
composed of DNA wrapped around an octamer of Histones
Chromatin
Fully packed DNA
Histones are composed of
Basic amino acids; Arginine & Lysine
Histones need to be basic since they must be attracted to acidic DNA
How does DNA affect cells
it contains sequences of nucleotides known as genes that serve as templates for the production of another nucleic acid known as RNA