Epithelium: Cell Nucleus Flashcards Preview

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Flashcards in Epithelium: Cell Nucleus Deck (53):
1

Cell Nucleus is composed of..

nucleolus chromatin nuclear envelope

2

The Nuclear Envelope has

Inner membrane Outer membrane

3

The inner membrane of the Nuclear Envelope is associated with

Nuclear lamina chromatin ribonucleoproteins

4

The outer membrane of the nuclear envelope is associated with

continuous with membrane of ER ribosomes

5

Nuclear Pore Complex has what type of structure?

Tripartate Structure (octogonal rings)

6

The Nuclear Pore Complex is embedded in ..

the Nuclear envelope

7

The Nuclear Pore complex has what type of proteins

Phe-gly nucleoporins (they control the channels)

8

How do Phe-gly nucleoporins control the channels?

they are the docking sites for nuclear transport factor cargo proteins

9

NLS

Nuclear localization signal pro-lys-lys-lys-arg-lys-val

10

X chromosome inactivation

random can be maternal or paternal in every FEMALE SOMATIC CELL (both x chromosomes in oocytes remain active)

11

X Chromosome inactivation can be seen in ...

Barr Bodies Drumsticks of Neutrophil

12

How many times is DNA wrapped around histone octomer in chromatin?

1.65 times

13

What is the linker histone?

H1

14

what is the basic structural unit of chromatin

nucleosome

15

What is the histone octomer composed of ?

H2A, H2B, H3,H4

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During what phase is chromatin uncondensed?

Interphase (g1,s,g2( Euchromatin

17

what is transcriptionally active chromatin?

Euchromatin

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Euchromatin

transcriptionally active 10%total chromatin site of synthesis of nonribosomal RNA (mRNA & tRNA) precursors

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Heterochromatin

condensed transcriptionally inactive 90% of total chromatin

20

Nucleoplasmic Transport What changes Ran-GTP to Ran-GDP? where?

Ran-GAP in cytoplasm

21

What changes Ran-GDP to Ran-GTP

RCC1 In nucleus

22

What does Ran-GBP do?

Ran-gtp binding protein disassociates (NES protein) from Ran-GTP in cytoplasm

23

what do importins bind to?

alpha importin binds to (NLS Protein) beta importin binds to Ran-GDP

24

What is a nuclear exportin?

Crm1

25

Identify from left to right

Q image thumb

dense fibrillar component

Granular component

fibrillar center

 

26

Nucleostemin

Fibrillarin

Nucleolin

are found in...

Nucleolus

27

Nuclelous is the site of..

sytnethesis of rRNA

site of assembly of ribosomal subunits

28

Nucleolus is the product of

chromosome and the nucleolar organizing region (NOR)

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The nucleolus has three main compartments

Fibrillar Center

Dense fibrillar Components

Granular Component

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Fibrillar Center

RNA Pol I

signal regonition particle

chromatin with repeats of rRNA

31

Dense Fibrillar Center

Fibrillarin

Nucleolin

ribonucleic prtoeins for rna modification

where nascent rRNA is present and undergoing processing (pre-RNA processing)

surrounds fibrillar centers

 

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Granular Component

Nucleostemin

site of assembly of pre ribosomal subjunits (18S (small) 28S (large))

75% of nuclear mass

 

33

Nucleolus

diassociates during mitotis (mitotic prophase)

reappears at beginning of G1

more than one per nucleus sometimes

34

Nucleolin

forms a coples with RPA which is required for intiation of DNA Synthesis

35

Fibrillarin & Nucleolin

required for pre-RNA processing (dense fibrillar component)

36

Nucleolin & Nucleostemin

AKA shuttling proteins (relocalize from nucleolus to nucleoplasm)

in resp to cell stree tnry into S phase (DNA synthesis) can be blocked by shuttling proteins

shuttling proteins bidning and inactivate p53 ( protector of DNA damage)

37

Nucleostemin 

unrelated to ribosomal biogensis

granular componenet

 

38

rRNA synthesis occurs in what direction

5' to 3'

39

rRNA genes are seen

as repeating units on chromatin separated by nontranscribed spacers

the entire rRNA gene is covered by 100 RNA Pol I molecules 

40

RNA pol I makes

fibrils that represent rRNA Precursor (45S)

41

45S

rRNA precursor

orientated perpendicular to the chromatin axis

detached from chromatin axis and cleaves into 

28S  18S  5.8S  rRNAS

 

42

What is the large ribosomal subunit?

What precursors create the large ribosomal subunit?

 

60S

28S+5.8S+ 5S( from OUTSIDE of nucleolus)+ 45 proteins

 

43

What is the small ribosomal subunit?

what creates the small ribosomal subunit?

40S

18S+30 proteins

44

The mRNA precursor is transcribed by 

RNA Pol II

45

the tRNA precursor is transcribed by

RNA pol III

46

Feulgen Reaction

Specific for DNA

hydrolysis with HCL forms aldehyde groups on deoxyribose (DNA sugar) but no ribose (RNA sugar)

add Schiff reagents 

stains DNA with chromatin purple

 

47

Effect of Felgen reaction on nucleus and nucleolus

nucleus _stained purple (DNA)

nucleolus _unaffected (RNA)

48

Autoradiography

H^3 Thymine -DNA

H^3Uridine -RNA

 

works on living cells 

49

PAS RXN

glycogen in cytoplasm stains pruple 

nucleus remains unstained

50

Basophillia 

Toludine Blue (basic dye)

binds to negative phospahge group on DNA & RNA

 

All stain blue

DNA-chromatin

RNA-nucleolus

ribosomes (ER)

 

if pretreat with RNAase only identify DNA containing sites

if pretreat with DNAase only identify RNA containing sites

51

Acidophillia

Eosin (dye)

stains basic proteins

 

52

Are basic proteins acidophillic or basophillic

Acidophilic (affinity for acid dyes)

53