chapter 14
The DNA structure proposed by WAtson and Crick involves
- a helical structure -a sugar phosphate backbone -two grooves ( major and minor)
DNA primase
-makes a primer of RNA complementary of the DNA - makes a primer about 10-20 nucleotides in length
Required for DNA replication
-nucleotides -polymerase -template
The DNA backbone is composed of
-phosphate groups -sugars
components of a nucleotide
-sugar -nitrogenous base -phosphate group
short fragments of DNA created on the lagging strand DNA during replication are called
Okazaki fragments
Bacterial DNA is typically replicated as
a single replicon
polymerase
attaches a nucleotide to the 3' end of the DNA strand
Helicase
causes DNA strand separation at the origin of replication
The enzyme DNA ___________ is the topoisomerase involved in DNA replication
gyrase
The enzyme ___________ uses ATP to unwind the DNA template
helicase
The enzyme __________ can repair UV damage by binding to a thymine dimer and cleaving it therefore restoring two thymines
photolyase
The enzyme DNA _____________ synthesizes the RNA promers required by DNA polymerases during replication
primase
All DNA polymerases require a short strand of DNA or RNA called a ________ to begin their synthesis
primer
what is the name of the regions at the ends of eukaryotic chromosomes
telomeres
which of the following are short repeats of DNA on the ends of eukaryotic chromosomes
telomeres
Which enzyme covalently links nucleotides together
DNA polymerase
primase
makes a 10-12 bp complementary primer to the DNA
Radiation, UV lights, x-rays, and chemicals int the enviroment can cause mutations in DNA and are therefore referred to as __________
mutagens
the nucleotides in the backbone of the DNA strand are held together by covalent bonds known as ___________ bonds
phosphodiester bonds
In the hershey chase experiment the isotope 35S was used to label _____ and the isotope 32 P was used to label DNA
proteins
topoisomerase
relieves coiling in DNA strands ahead of the replicaiton fork
The DNA controlled by an origin is called a
replicon
DNA replication that leads to the production of double helices with one parental strand and one newly synthesized strand is consistent with
semiconservative replication