Terms in this set (56)
what does DNA stand for?
what is dnas primary function?
to make copies of itself/replication
what are the subunits of DNA called?
its a polomer with subunits of a nucleotide
name the 3 parts of a dna nucleotide
sugar phosphate and base
name the 4 nitrogen bases
adinine thymine guinine and cytosine
what is the difference between a purine and a pyrimidine
purine is double ring bases
pyrimidine is single ring bases
name 2 purines
A and G
name 2 pyrimidines
C and T
who is responsible for determiningthe structure of the DNA molecule and in what year was this done?
1953 watson and crick
the model of DNA is known as a ____ because it is composed of ______
two spiral chains wrapped around eachother
what makes up the side of a dna molecule
the backbone- sugar and phosphate
what makes up the steps of a dna molecule
how did rosalind franklin contribute to determining the structure of dna
she provided a photo of a double helix
what type of bonds holds the dna bases together? are they strong or weak bonds?
strong hydrogen bonds
on dna a ____ base will always pair with a ____- base
how many base pairs are in a full turn or twist of a dna molecule
10 bases per spiral
name the complementary base pairs on dna
what does primase do
how does the nucleotide sequence in one chain of dna compare with the other chain of dna
the two sides are anti parallel
what is semi conservative replication?
one half of the chromatid has half original and half brand new
why must dna be able to make copies of itself
define dna replication
makes exact copy of itself
what is the frist step that must occur in dna replication
dna will untwist and make a bubble, separates and copies bases on the inside of the bubble
what acts as the template in dna replication
2 original dna strands (new ones copy original)
what is a replication bubble
when helicase untwists the dna and two sides drift apart
what enzymes help separate the 2 strands of nucleotides on DNA? what bonds do they break
Helicase and SSBP break hydrogen bonds
what is the function of dna polymerases?
adding new nucleotides; replaces primer with a dna nucleotide
_____ are joined to replicating strands of dna by ____ bonds
nucleotide phosphates (free nucleotide)
why does dna replication take place at many places on the molecule simultaneously?
it speds up the process
when replication is complete, how do the 2 new dna molecules compare to each other and the original dna molecule?
they are identical to each other.
a polymer made up of many nycleotides covalently bonded together
the enzyme that links dna nucleotides to a growing daughter strand (add nucleotides only to the 3' end of the strand)
enzyme that links ogazaki fragments together into a single dna strand
what does the enzyme helicase do during dna replication
it unwinds the dna
what does the enzyme polymerase do during dna replication
builds dna strand
what does SSPB do during dna replication?
keeps the dna unwinded
what does primase do during dna replication
it builds primer
when and where does dna replication occur in a cell
in the S phase of interphase and in the nucleus
cytosine, guanine, theymine and adenine are referred to as
replication is performed prior to
complementary base pairing matches up complementary
the letter that make up the dna molecule code for
____ hold nitrogen bases together, forming the rings of the dna ladder
hydrogen bonds (they are covalent)
steps that dna replication occurs
1- helicase begins to break the hydrogen bonds between nitrogen bases
2- free floating nucleotides pair up with exposed nitrogen bases
3- dna polymerase attach the free-floating nucleotides to the exposed nitrogen bases
4- two new molecules of dna are created
5- cell starts into the mitosis phase of a cell cycle
the sequence of __ arries the genetic information of an organism
the basic chemical unit of a nucleic acid
the two kinds of nucleic acids
dna and rna
the tree parts to every nucleotide
base, phosphate and sugar
a pair of these forms a "rung" in the dna ladder
two alternating parts that form the nucleic acid "backbone"
phosphate and sugar
ribose in rna and deoxyribose in dna
watson and crick deduced the structure of this molecule
eukaryotic chromosomes consist of this and dna
links adjacent nucleotides in a polynucleotide chain
links a complementary pair of bases together
a polymer of nucleotides