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