The Nucleus

Question 1

What are the three primary functions of the nucleus?

Answer 1

• Storage, replication, and repair of genetic material
• Expression of genetic material
• Ribosome biosynthesis

Question 2

What are the three things considered to be the nuclear content?

Answer 2

• Chromatin
• Nucleoplasm
• Nucleolus

Question 3

Which structure is responsible for separating the nuclear content from the cytoplasm?

Answer 3

The nuclear envelope

Question 4

What kind of barrier is the nuclear envelope?

Answer 4

Selective barrier

Question 5

Which layer of the nuclear envelope binds ribosomes and is continuous with the rough ER?

Answer 5

The outer nuclear membrane

Question 6

Which layer of the nuclear envelope has integral proteins and connects to nuclear lamina?

Answer 6

The inner nuclear membrane

Question 7

What is the primary role of the nuclear lamina?

Answer 7

To support the nuclear envelope

Question 8

What is the structure of the nuclear lamina?

Answer 8

It’s a thin meshwork of filamentous proteins

Question 9

What is the nuclear lamina composed of in animal cells?

Answer 9

Lamins (intermediate filaments)

Question 10

Do plants have a nuclear lamina?

Answer 10

Yes

Question 11

Is the nuclear lamina of plants also composed of lamins?

Answer 11

No

Question 12

How is the nuclear lamina bound to the nuclear envelope?

Answer 12

By integral membrane proteins

Question 13

What is formed where the inner and outer nuclear membrane fuse?

Answer 13

Nuclear pores

Question 14

What is the nuclear pore complex largely composed of?

Answer 14

Nucleoporins

Question 15

What are nucleoporins?

Answer 15

A large group of proteins that make up the nuclear pore complex

Question 16

What are the three types of nucleoporins?

Answer 16

• Structural nucleoporins
• Membrane nucleoporins
• F-G nucleoporins

Question 17

What forms the nuclear basket?

Answer 17

Eight filaments that extend into the nucleoplasm with their distal ends joined by a terminal ring

Question 18

Which type of nucleoporin forms the scaffold of the nuclear pore?

Answer 18

Structural nucleoporins

Question 19

Which type of nucleoporin create an opening for movement of molecules into and out of the nucleus?

Answer 19

Structural nucleoporins

Question 20

Which type of nucleoporin is embedded in the region where the inner and outer membranes of the nuclear envelope connect at the NPC?

Answer 20

Membrane nucleoporins

Question 21

Which type of nucleoporin resides on the inner surface of the nuclear pore complex?

Answer 21

FG-nucleoporins

Question 22

Which type of nucleoporin is associated with the nuclear basket and cytoplasmic filaments?

Answer 22

FG-nucleoporins

Question 23

What is the largest structure inside the nucleus of eukaryotic cells?

Answer 23

The nucleolus

Question 24

What is the primary function of the nucleolus?

Answer 24

Ribosome biosynthesis

Question 25

What is the process of ribosome biosynthesis?

Answer 25

• Synthesis of rRNA
• Assembly of subunits
• Export of subunits to be assembled in cytoplasm

Question 26

What is the role of small ribosomal subunits?

Answer 26

Read RNA

Question 27

What is the role of large ribosomal subunits?

Answer 27

Join amino acids to form polypeptide chains

Question 29

What is the nuclear localization signal?

Answer 29

Several positively charged amino acids within the protein sequence

Question 30

What is the most important protein form nuclear import?

Answer 30

Importin

Question 31

What is the protein that interacts with importin causing it to release the cargo it is carrying?

Answer 31

Ran-GTP

Question 32

After the cargo has been dissociated from importin, what happens to the Ran-GTP/importin complex?

Answer 32

It exists the nucleus through the nuclear pore complex