Unit Three- DNA Structure Flashcards
How many Rings do pyrimidines have
1, 6 member ring
what are the pyrimidines in DNA
thymine and cytosine
what are the purines
1, 6 member ring fused to a 5 member ring
what are the purines
adenine and guanine
What is a nucleotide made of
-pentose sugar
-phosphate
-1 base
where does the nitrogenous base connect to the sugar
carbon 1
where does the phosphate group bind to the bind to the sugar
carbon 5
what does a nucleoside consist of
-a sugar
-a base
*no phosphate
how are nucleotides linked together
phosphodiester linkages
where do nucleotides link together
C3 of the sugar and the phosphate of the next nucleotide
what direction do nucleotides connect in
5’ to 3’
how are nucleotides joined together in a double helix
hydrogen bonding
what does hydrogen bonding occur between
one pyrimidine and one purine
how often does the double helix turn
10.5 nucleotides
what is the backbone of the DNA made of
alternating sugar and phosphate
what end is the phosphate always attached to
the 5’ end
what is a basic unit of a chromatin
a nucleosome
-compacted DNA
what is DNA associated with in eukaryotes
proteins
what is DNA associated with in prokaryotes
DNA is naked
what is a nucleosome composed of
a segment of DNA wound around a protein core that is composed of histone proteins
what is DNAs charge
negative
what is the charge of the histone proteins
positive
what do nucleosomes coil to form
solenoids
what do solenoids coil to form
chromsomes
what is a gene
a unit of genetic information
what determines the genetic code
order of nucleotides
what is cell differentiation
all cells contain the same genetic information but they do not all express the same genes
–> cells differentiate by genes that are activated
what is an intron area
a non coding area
what is an exon area
an area that codes for proteins
