Structure and Organization of Nucleic Acids Flashcards
categories of noncoding DNA sequences
spacer sequences
introns
genes encoding nonprotein -coding RNAs
repetition DNA sequecnes
introns
noncoding sequences within genes
what is the most aundant class of noncoding sequences
repeitious DNA
satellite DNA
indentical repeasts of short sequences
how are satellite DNA repeats arranged
long, tandom arrays
organization of satellite DNA is important in what
gives DNA sequence a defined moleculate weight
where is most satellite DNA found
centromere and telomere
what is the most abundant class of repetitious DNA
interspersed repeats
exons
sequences that are translated into proteins
characteristics of genes in eukaryotes
discontinuous and consist of exons and introns
gene families arise form waht
gene duplication events
what are the similiaries between genes within a gene family
simliar nucleotide sequences and encode similiar proteins
pseudogene
when you have a duplicate gene that gets mutated adn inactivated
what is unique about a duplicate copy of a gene
it’s expendable and axxumulates mutations over time
chromatine
nuclear DNA that’s extensively associated with proteins
nucleosome
histone with DNA wrapped around them
homologous chromones
materal and paternal versions of same chromsome are similiar but not identifcal
how is mitochondrial genome different from nuclear genome
it’s circular
it’s poresent in mulitiple copies per organelle
high gene density
not extensively associated with proteins
what is the principal feature that sets eukaryotes apart from prokaryotes
nucleus
heterochromatin
intensely stain, compelxed with proteins, highly condensed and transcriptionally inactive
where is heterochromatin found
periphery of nucleus
euchromatin
translucent, contains transciriptionally active, decondensed DNA
nucleolus
large, intesnly stained area that contains genes encoding ribosomal RNA
what are chromosomes attached to
nuclear matrix
what are chromomsomal territories serprated by
interchromosomal domains
nuclear lamina
meshwork of filaments that astabilize the nuclear envelope on the inner surface
nuclear pore function
regulate traffic between nucleus and cytoplasm
what are teh 3 main types of large molcules that much be actively and selectively transported between nucleus and cytoplasm
mRNA
proteins
ribosomal subinits
what import protein helps with import of molecules into the nucleus
importin
what small GTP bindign protein mediates nucleu export
Ran
the majority of mRNA molecules are exported from the nucleus via what
ran-independent mechanism
what protein associated with the cytoplasmic face of nuclear pore complex and helps provide energy input needed for transport
Dbp5
what type of replication is DNA
semi-convservative
how are replication origins activated
in clusters
replication is _______ from each orgiin
bidirectional
how are nucleosomes replicated
existing histones are recycled whilst an equal numver of new histones are syntheized
what do you call enzymes that syntheisze DNA
DNA polyermases
all DNA polymerases are what
template directed
what is requried for DNA replication
primer
wha ter primers made from
RNA
how are RNA primers degrated
exonuclease
polymerases synthesize DNA in what direction
5’ -> 3’
the newly synthesized DNA straing is _____ to the template strand
antiparallel
what are the nucletide donors for DNA synthesis
dATP, dGTP, dCTp, dTTP
what is released as each nucletoide is incoroprated
pyrophosphate
hydrolysis of pyrophossphate does waht
drices reaction to the right
how are origins of replication marked
oriin recognition compelx
waht DNA sequence is at telomeres
TTAGGG
