chapter 14: the genetic material (learnsmart)

A chromosome is composed of

DNA and proteins

3'

OH group

chargaffs rules indicates that the amount of A in a sample is equal to the amount of ____________________ and the amount of C in a sample is equal to the amount of ______________

T,G

What is primase part in dna replication?

makes a 10-2 bp complimentary primer to the DNA

1'

nitrogenous base

components of a nucleotide

nitrogenous base, phosphate, sugar

5'

phosphate group

Repeating sugar and phosphate units in a single DNA strand make up the

phosphodiester backbone

Adjacent nucleotides in the same DNA strand are held together by covalent bonds known as

phosphodiester bonds

The enzyme ____________ can repair uv damage by binding to a thymine dimer and cleaving it, therefore restoring two thymines

photolyase

Telomerase function

prevents chromosome shortening by attaching a repeat sequence to the ends of chromosomes

In the 1950"s, the british researcher maurice wilkins contribute to the discovery of DNA's double helix structure by?

producing uniformly oriented DNA fibers

What is gyrase part in dna replication?

relieves coiling in DNA strands ahead of the replication fork

nonspecific repair mechanism

repair multiple kinds of of lesions in DNA using a single mechanism

DNA replication that leads to the production of double helices with one parental strand and one newly synthesized strand is consistent with ?

semiconservative replication

Telemores

short protective repeats of DNA on the ends of eukaryotic chromosomes

How is the lagging strand synthesized?

synthesized in small fragments that are later connected

specific repair mechanism

target a single kind of lesion in DNA and repair that damage

Griffith's experiments were important because they showed?

that the genetic material could be passed from one cell to another

Replication fork

the partial opening of a dna helix to form two single strands

Franklin determined that the structure of DNA was helical based on?

x-ray diffraction analysis

Different models from dna replication

- semiconservative replication -conservative replication -dispersive replication

The dna structure proposed by watson and crick involve?

-A sugar phosphate background -two grooves (major and minor) - a helical structure

Differences in prokaryotic and eukaryotic replication

-number of origins of replications -complexity of enzymology -structure of chromosome (linear vs circular)

What three items are required for dna replication?

-template -nucleotides -polymerase

three phases of DNA replication

1. Initiation 2. Elongation 3. Termination

excision repair steps

1. Recognition of damage 2.Removal of the damaged region 3. Resynthesis using the information on the undamaged strand as a template

Lagging strand synthesis steps

1.synthesize primers using primers 2.synthesize DNA 3.Replace RNA primers with DNA 4.seals nicks in the DNA

What is a phage?

A type of virus that infects bacterial cells

What is polymerase part in dna replication?

attaches a nucleotide to the 3' end of the dna strand

How is the leading strand synthesized?

continuously

Telomerase

enzyme that generates telomeres

Helicase

enzyme that uses ATP to unwind the DNA template

The enzyme DNA _____________ is the topoisomerase involved in DNA replication

gyrase

DNA replication in eukaryotic cells is complicated by the fact that eukaryotic cells have?

linear chromosomes