1002 3rd Pdf

Question 1

Nucleus is present in

Answer 1

All eukaryotic cells except:
1- mammalian erythrocytes
2- blood platelets
3- core fibers of the lens

Question 2

Cells without nucleus ( anucleate cells )

Answer 2

Can not undergo cell division

Question 3

Nucleus staining

Answer 3

Hematoxylin - purple
Kernechtrot-red

Question 4

Functions of nucleus

Answer 4

DNA replication
Transcription
RNA processing

Question 5

Translation occurs in

Answer 5

Cytoplasm

Question 6

Gene expression steps

Answer 6

1- transcription: nucleus’s gene sequence copied into mRNA molecular
2- translation: mRNA to sequence of amino acids

Question 7

Presence of nucleus:

Answer 7

1 gene expression is regulated:
I during transcription - by controlled transport ofproteins
Il post transcription - mechanisms
2 DNA surrounded by envelope - protected from mechanisms force

Question 8

Nucleus:

Answer 8

Nuclear envelope
Chromatin
Nucleolus
Nucleoplasm

Question 9

Nuclear envelope

Answer 9

Two parallel membranes:
Inner and outer separated by peri nuclear space

Question 10

Nuclear pores provide

Answer 10

Communication between nucleus and cytoplasm

Question 11

Lining the inner membrane is protein meshwork called

Answer 11

Nuclear Latina

Question 12

Nuclear envelope acts as

Answer 12

Selective permeability barrier and prevents free passage

Question 13

Nuclear Latina is associated with the

Answer 13

inner membrane

Question 14

Nuclear Latina is composed of 3 polypeptides

Answer 14

Lamin A
Lamin B
Lamin C

Question 15

Nuclear Latina function

Answer 15

1- structural support
2- linkers : between nuclear envelope and chromatin fibers

Question 16

Lamins also bind

Answer 16

Chromatin

Question 17

Inner membrane contains several integral proteins

Answer 17

Emerin
LBR

Question 18

Mutation of lamin A

Answer 18

Breakdown of nuclear envelope → muscular dystrophy

Question 19

CMT
Ed Md → emerin mutations
H gp s

Answer 19

Diseases of nuclear Lamina

Question 20

Nuclear pores

Answer 20

Around the nuclear envelope

Question 21

Nuclear pores provides communication

Answer 21

Between nucleoplasm and cytoplasm

Question 22

Nuclear proteins are synthesized on

Answer 22

Free ribosomes and released into the cytoplasm

Question 23

Protiens entering the nucleus contain signals

Answer 23

NLS

Question 24

NLS

Answer 24

One or two short amino acid sequences
Rich in lysine and arginin

Question 25

NLS are recognized by

Answer 25

Importin

Question 26

Nucleoporins contain amino acid richin

Answer 26

Phenylalanine and glycine (fg repeats)

Question 27

Fg repeats serve as

Answer 27

Binding sites for import receptor

Question 28

GAP

Answer 28

Converts ran GTP → ran GDP

Question 29

GEF

Answer 29

GDP → GTP

Question 30

Nf-kb

Answer 30

Activates transcription of immunoglobulin -kic in B lymphocytes

Question 31

IKB

Answer 31

Mask nuclear localization signal

Question 32

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