COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
griffith experiment
showed that heat-killed infectious bacteria can transform harmless live bacteria into
pathogens, used Strep pneumoniae in two forms (pathogenic and harmless)
pathogenic strep
lethal when injected into mice, enchased in polysaccharide capsule
harmless strep
lacks polysaccharide coat
avery, macleod, mccarty experiment
demonstrated DNA is genetic material, used S strain of pneumococci to show
transforming principle changed harmless R-strain to pathogenic, first evidence
hershey and chase experiment
showed genes are made of DNA, put DNA in a batch of viruses with radioactive
phosphorus, put proteins in a batch with radioactive sulfur, phage experiment
structure of dna
two complementary chains of nucleotides, provides mechanism for heredity, double
helix,
double helix
2 sugar-phosphate backbones, 2 hydrogen bonds in A/T, 3 hydrogen bonds in G/C,
major and minor grooves lined by potential hydrogen bond donors and acceptors that
interact with proteins
,mobile DNA elements
45% of human DNA derived from this, contributed to the evolution of contemporary
genomes
eukaryotic DNA
packaged into multiple chromosomes, chromosomes become visible preparing for
division, majority non-coding
FISH
spectral karyotyping, used to paint chromosomes, export unique sequences
reciprocal chromosomal translocation
segment of one chromosome has been swapped with a segment from the other, has
occurred many times during the course of evolution, associated with infertility and
cancer
eukaryotic chromosomes
organize and carry genetic information, segments that encode amino acid sequence are
very small, excess noncoding, can't be seen if not condensed
interphase
where DNA replication occurs, cell expresses many of its genes
M phase
compact chromosomes attached to mitotic spindle at centromere, cell divides to
produce 2 daughter cells
interphase chromosomes
not randomly distributed within nucleus, non-overlapping territories, nucleolus is most
prominent
, nucleolus
contains more than 400 copies of genes for ribosomal RNA
metaphase chromosomes
highly compact, tightly joined together
chromosome packing
occurs on multiple levels, DNA and histone proteins packaged into compact complexes
nucleosomes
basic units of eukaryotic chromosome structure, DNA wrapped around protein core of 8
histone molecules, changes allow access to DNA, ATP hydrolysis loosens these
chromatin-remodeling complexes
contain 15 subunits, one hydrolyzes ATP, 4 recognize modified histones from
nucleosomes
euchromatin
more extended form, light-staining, includes more transcribed regions
heterochromatin
highly condensed, dark-staining, includes centromeres and telomeres, specific histone
modifications needed to form
N-terminal tail modifications
differ in heterochromatin and euchromatin, more extensively acetylated in euchromatin
base pairing
enables DNA replication, G/C and A/T, both strands of double helix can serve as
template
DNA replication characteristics