Chapter Six: DNA Structure, Replication, and Recombination Flashcards
studied white blood cells in pus from wound bandages
Meischer
Meischer isolated ___
nuclein
studied streptococcus pneumoniae
Griffith
s. pneumoniae has two forms ___ and ___
rough and smooth
when mice are injected with smooth, ___. when they are injected with smooth that has mutated to rough ___. when smooth is heated up and injected, ___. when smooth is heated up and injected with rough, ___.
they died
they live
they live
they died
___ could be recovered from tissue of mice that died from heated up smooth bacteria
living smooth
the ability of a substance to change the genetic characteristic of an organism
transformation
studied and discovered the transforming principle
Avery
Avery found the transforming principle to be ___
nucleic acids (DNA)
studied and discovered base ratios
Chargaff
sugar and a base
nucleoside
sugar, base, phosphate group
nucleotide
studied bacteriophages and performed the blender experiment
Hershey and Chase
three other facts that point to DNA as the transforming principle
- the amount of DNA is constant within organisms but different between species
- haploid cells have half the DNA as diploid cells
- DNA is metabolically stable
performed X-ray diffraction to show a helix structure of DNA
Franklin and Wilkins
took base rations and picture to deduce DNA helices structure
Watson and Crick
bases are connected by ___
hydrogen bonds
A-T with ___ hydrogen bonds, G-C with ___ hydrogen bonds
two
three
there are ___ angstroms between every nucleotide
3.4
there are ___ angstroms and ___ nucleotides in one complete turn
34
10
DNA is ___ angstroms wide
20
when two pyrimidines pair instead of pairing with a purine
DNA bulge
can break hydrogen bonds with ___, takes more heat to break them between ___
heat
G-C
strands of DNA are held together with ___
covalent bonds
in a human genome:
___ base pairs
___ strands of DNA
___ feet long
typical cell is about ___nm
3.2 billion
46
6
10
sequences over and over
tandem repeats
multigene families, low copy number
dispersed repeats
___ are an example of dispersed repeats
short interspersed nuclear elements (SINES)
heritable change in a sequence of bases
mutation
genomic analysis on patients to determine effects of a drug
personalized medicine
most genetic information is read from ___, some is accessible within ___
unwound DNA
double-stranded DNA
___ can access DNA when it is double-stranded
DNA-binding proteins that regulate gene expression
RNAs 3 major differences from DNA
- single stranded (most of the time)
- ribose instead of deoxyribose
- uracil instead of thymine
strands of DNA separate and each strand is copied
semiconservative replication
F1 of semiconservative ___
F2 of semiconservative ___
one old strand with each new strand
two hybrid strands, two strands completely new
prokaryotes are ___ and ___ than eukaryotes
simpler and more prone to error
gene where DNA replication starts
oriC
gene/protein that breaks hydrogen bonds between bases to separate strands of DNA
dnaB/helicase
gene/protein that seals Okazaki fragments
lig/ligase
gene where replication ends
ter (terminator)
dNTP stands for ___
deoxyribonucleotide triphosphates
why are triphosphates required for DNA replication
taking off two phosphates gives every needed to bind the sugar and phosphate together
enzyme that cuts one or both strands of DNA to relax the superhelix
topoisomerase
when DNA is coiled tight into a superhelix
topological isomer
lays down most of DNA in bacteria
DNA polymerase III
three requirements for DNA polymerase action
- four dNTPs
- single stranded template
- primer with exposed 3’ hydroxyl
three ways to ensure fidelity of DNA information
- redundancy
- precision of cellular replication machinery
- DNA repair enzymes
redundancy means that ___
either strand of double helix can specify the sequence of the other strand
___ and ___ have proofreading ability
DNA polymerase I and DNA polymerase III
___ and ___ can cut out mistakes in DNA
exonucleases and endonucleases
DNA synthesis goes in a ___ direction
5’ to 3’
template and newly synthesized strands are ___ to each other
antiparallel
DNA polymerase adds nucleotides to the ___ of the new strand
3’ OH
how can DNA replication be more efficient
DNA is flexible, can loop around the lagging strand so that everything goes in one direction
two events that give rise to new combinations of alleles
independent assortment and crossing over
independent assortment creates new allele combinations for ___; crossing over creates new allele combinations for ___
unlinked genes
linked genes
region of DNA between breakpoints in recombination
heteroduplex
areas where recombination occurs frequently
recombination hotspots
