Structure and Organization of Nucleic Acids Flashcards Preview

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Flashcards in Structure and Organization of Nucleic Acids Deck (48)
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1
Q

categories of noncoding DNA sequences

A

spacer sequences
introns
genes encoding nonprotein -coding RNAs
repetition DNA sequecnes

2
Q

introns

A

noncoding sequences within genes

3
Q

what is the most aundant class of noncoding sequences

A

repeitious DNA

4
Q

satellite DNA

A

indentical repeasts of short sequences

5
Q

how are satellite DNA repeats arranged

A

long, tandom arrays

6
Q

organization of satellite DNA is important in what

A

gives DNA sequence a defined moleculate weight

7
Q

where is most satellite DNA found

A

centromere and telomere

8
Q

what is the most abundant class of repetitious DNA

A

interspersed repeats

9
Q

exons

A

sequences that are translated into proteins

10
Q

characteristics of genes in eukaryotes

A

discontinuous and consist of exons and introns

11
Q

gene families arise form waht

A

gene duplication events

12
Q

what are the similiaries between genes within a gene family

A

simliar nucleotide sequences and encode similiar proteins

13
Q

pseudogene

A

when you have a duplicate gene that gets mutated adn inactivated

14
Q

what is unique about a duplicate copy of a gene

A

it’s expendable and axxumulates mutations over time

15
Q

chromatine

A

nuclear DNA that’s extensively associated with proteins

16
Q

nucleosome

A

histone with DNA wrapped around them

17
Q

homologous chromones

A

materal and paternal versions of same chromsome are similiar but not identifcal

18
Q

how is mitochondrial genome different from nuclear genome

A

it’s circular
it’s poresent in mulitiple copies per organelle
high gene density
not extensively associated with proteins

19
Q

what is the principal feature that sets eukaryotes apart from prokaryotes

A

nucleus

20
Q

heterochromatin

A

intensely stain, compelxed with proteins, highly condensed and transcriptionally inactive

21
Q

where is heterochromatin found

A

periphery of nucleus

22
Q

euchromatin

A

translucent, contains transciriptionally active, decondensed DNA

23
Q

nucleolus

A

large, intesnly stained area that contains genes encoding ribosomal RNA

24
Q

what are chromosomes attached to

A

nuclear matrix

25
Q

what are chromomsomal territories serprated by

A

interchromosomal domains

26
Q

nuclear lamina

A

meshwork of filaments that astabilize the nuclear envelope on the inner surface

27
Q

nuclear pore function

A

regulate traffic between nucleus and cytoplasm

28
Q

what are teh 3 main types of large molcules that much be actively and selectively transported between nucleus and cytoplasm

A

mRNA
proteins
ribosomal subinits

29
Q

what import protein helps with import of molecules into the nucleus

A

importin

30
Q

what small GTP bindign protein mediates nucleu export

A

Ran

31
Q

the majority of mRNA molecules are exported from the nucleus via what

A

ran-independent mechanism

32
Q

what protein associated with the cytoplasmic face of nuclear pore complex and helps provide energy input needed for transport

A

Dbp5

33
Q

what type of replication is DNA

A

semi-convservative

34
Q

how are replication origins activated

A

in clusters

35
Q

replication is _______ from each orgiin

A

bidirectional

36
Q

how are nucleosomes replicated

A

existing histones are recycled whilst an equal numver of new histones are syntheized

37
Q

what do you call enzymes that syntheisze DNA

A

DNA polyermases

38
Q

all DNA polymerases are what

A

template directed

39
Q

what is requried for DNA replication

A

primer

40
Q

wha ter primers made from

A

RNA

41
Q

how are RNA primers degrated

A

exonuclease

42
Q

polymerases synthesize DNA in what direction

A

5’ -> 3’

43
Q

the newly synthesized DNA straing is _____ to the template strand

A

antiparallel

44
Q

what are the nucletide donors for DNA synthesis

A

dATP, dGTP, dCTp, dTTP

45
Q

what is released as each nucletoide is incoroprated

A

pyrophosphate

46
Q

hydrolysis of pyrophossphate does waht

A

drices reaction to the right

47
Q

how are origins of replication marked

A

oriin recognition compelx

48
Q

waht DNA sequence is at telomeres

A

TTAGGG