Histology - Nucleus

Question 0

Nucleolus

Answer 0

The center of ribosomal (rRNA) synthesis

Question 1

Peptidyl transferase

Answer 1

In a rRNA-based enzyme of the large subunit

Question 2

Chromatin

Answer 2

The genetic material of the cell

Question 3

Nucleoplasm

Answer 3

Containing macromolecules and nuclear particles involved in the maintainance of the cell

Question 4

Nuclear envelope

Answer 4

• Inner and outer nuclear membranes
• Perinuclear cisterna
• Nuclear pores

Question 5

Inner nuclear membrane

Answer 5

• In contact with the nuclear lamina
  
  • > Composed of lamins A, B, and C
  • > Located at the periphery of nucleoplasm
  • > Support the lipid bilayer membrane and the perinuclear chromatin
• Integral proteins on the inner nuclear membrane

Question 6

Outer nuclear membrane

Answer 6

• Continuous woth RER
• Surrounded with vimentin
  
  • > Vimentin is a loose network of intermediate filament
• Usually possess ribosomes that actively synthesize transmembrane proteins that are destined for the outer or inner membrane

Question 7

Nuclear pore complex

Answer 7

Glycoproteins (nonmembranous structures) + nuclear pore = nuclear pore complex

Question 8

Nonmembranous structures

Answer 8

Glycoproteins

Question 9

Nuclear pore function

Answer 9

• Simple diffusion of ions and small molecules
• “Receptor-mediated transport” for macromolecules and particles larger than 11nm
• Importins -> NLSs
• Exportins -> NESs
  Both exportins and imprtins are RAN-regulated
• Nucleoplasmic shuttling (NS)
  -> Proteins that carry this signal interact with mRNA

Question 10

Nuclear lamina

Answer 10

• IS IN THE INNER NUCLEAR MEMBRANE
• Interwoven meshwork of intermediate filaments
• Composed of: Lamins A, B, and C
• Location: The periphery of the cytoplasm

Question 11

nonmembranous structures

Answer 11

E.g glycoproteins

Question 12

Cytoplasmic ring is composed of…..

Answer 12

• 8 subunits –> located on the rim of the cytoplasmic aspect of the nuclear pore

Question 13

Importins

Answer 13

Nuclear localization signals (NLSs)

Question 14

Exportins

Answer 14

Nuclear export signals (NESs)

Question 15

What regulates the exportin and importin transport?

Answer 15

they are regulated by a family of GTP-binding proteins known as Ran

Question 16

Nucleocytoplasmic shuttling (NS) signals

Answer 16

• Transport mechanism that shuttle in both directions.

- Proteins that carry this signal interact with mRNA

Question 17

4 types of histones

Answer 17

• H2A
• H2B
• H3
• H4

Question 18

Sex chormatin (Barr body)

Answer 18

Inactive X chormosome (in females)

Question 19

Karyotyping

Answer 19

An analysis of chormosome number

Question 20

G bands

Answer 20

Is unoque for each chromosome pair and is characteristic for each species

Question 21

Purines

Answer 21

• Adenine

- Guanine

Question 22

Pyrimidines

Answer 22

• Cytosine

- Thymine

Question 23

mRNA is catalyzed by….

Answer 23

RNA polymerase II

Question 24

tRNA is catalyzed by….

Answer 24

RNA polymerase III

Question 25

rRNA is catalyzed by….

Answer 25

RNA polymerase I

Question 26

Where is rRNA synthesized?

Answer 26

It is synthesized n the fibrillar (pars fibrosa)

Question 27

snRNPs

Answer 27

• Participate in spicing, cleaving and transporting hnRNPs

- Located in the nucleus

Question 28

When is the nucleolus observed?

Answer 28

Only in the interphase

Question 29

Ocogenes

Answer 29

= mutated proto-ocogenes

• Cancer
• Uncontrolable divisions

Question 30

Cell cycle is divided into:

Answer 30

• Interphase

- Mitosis

Question 31

G0

Answer 31

The cell left the cycle + stable phase/oustide phase

Question 32

Kinase

Answer 32

• Activate a series of intranuclear transcription factors

Question 33

Astral ray + spindle fibers+

Answer 33

Mitotic spindle appartus