Interphase Nucleus- Week 1

Question 1

Proteins less than _______ kD can diffuse through nuclear pores

Answer 1

40 kD

Question 2

What is a Nuclear Localization Sequence (NLS)?

Answer 2

the zipcode attached to Nuclear cargo proteins that tag them for escort into the nuclear pore by NLS-Receptor proteins

Question 3

What kind of amino acids to NLS have?

Answer 3

Basic amino acids (K+, R+)

Question 4

What kind of things are exported out of cell pores?

Answer 4

tRNAs, mRNAs, rRNAs, proteins

Question 5

What molecule has Nuclear Export Sequences (NES)?

Answer 5

Exportins

Question 6

Nuclear Export Sequences are rich in what kind of amino acids?

Answer 6

They are leucine rich

Question 7

Where does energy for nuclear import/export come from?

Answer 7

Ran-GTP

Question 8

Ran-GTP is high in the cytosol or the nucleus?

Answer 8

Nucleus

Question 9

Which 3 proteins make up the nuclear lamina?

Answer 9

lamins A,B,C

Question 10

Lamin B attaches where?

Answer 10

Lamin B Receptor (LBR)– it remains attached during the entire cell cycle and helps initiate reformation of nuclear envelope at telophase. Rare diseases also arise from LBR mutations

Question 11

What do lamins A and C attach to?

Answer 11

marginal heterochromatin

Question 12

Why is lamins A and C hyper-phosphorylated during mitosis?

Answer 12

make lamina soluble

Question 13

Which gene codes for the lamin B protein?

Answer 13

LMNB

Question 14

Which gene codes for lamin A protein?

Answer 14

LMNA

Question 15

Which gene codes for lamin C protein?

Answer 15

LMNA

Question 16

What is the purpose of the nucleolus?

Answer 16

to manufacture ribosomes

Question 17

Y/N Do nucleoli have membranes?

Answer 17

No

Question 18

What is the purpose of the internal nuclear matrix?

Answer 18

transcription and replication of DNA