Chapter 9 Flashcards
- The principal difference between eukaryotic and prokaryotic cells is that eukaryotic
cells have
a. larger ribosomes than prokaryotic cells.
b. cell walls, while prokaryotic cells do not.
c. DNA replication and transcription in the same compartment, while prokaryotic cells do
not.
d. a nucleus, while prokaryotic cells do not.
d. a nucleus, while prokaryotic cells do not.
p. 345
- By restricting the traffic of proteins and RNA across the nuclear envelope, eukaryotic cells can regulate
a. translation.
b. transcription.
c. endocytosis.
d. nuclear pH.
b. transcription
- The major pathway for molecules to pass into and out of the nucleus is through
a. gap junctions between the nuclear envelope membranes.
b. porin channels in the nuclear envelope membranes.
c. nuclear pore complexes.
d. diffusion through the membrane bilayers of the nuclear envelope.
c. nuclear pore complexes.
p. 346
- The nuclear envelope is continuous with the
a. mitochondrial outer membrane.
b. rough endoplasmic reticulum.
c. Golgi apparatus.
d. plasma membrane.
b. rough endoplasmic reticulum.
p. 346
- The nuclear lamina is built of proteins called
a. lamins.
b. laminins.
c. nucleins.
d. nucleoplasmins.
a. lamins.
p. 347
- The filaments of the nuclear lamina are composed of a type of
a. microfilament.
b. microtubule.
c. intermediate filament.
d. thick filament.
c. intermediate filament.
p. 347
- The nuclear lamina binds to
a. both the inner nuclear envelope membrane and the chromatin.
b. the inner nuclear envelope only.
c. the chromatin only.
d. neither the inner nuclear envelope nor the chromatin.
a. both the inner nuclear envelope membrane and the chromatin.
p. 350
- The associations of lamins with the inner nuclear envelope membrane is via
a. lamin binding to proteins in the nuclear envelope membrane.
b. GPI anchors on lamins.
c. lipid tails on lamins.
d. Both a and c
d. Both a and c
p. 328 & 349
- Which of the following is a nuclear lamina disease?
a. Emery–Dreifuss muscular dystrophy
b. Charcot–Marie–Tooth disorder type 2B1
c. Hutchinson-Gilford progeria syndrome
d. All of the above
d. All of the above
p. 348
- Nuclear pores are organized with _______ symmetry.
a. sixfold
b. eightfold
c. ninefold
d. tenfold
b. eightfold
352
- Small molecules (molecules
a. passive diffusion through nuclear pore complexes.
p. 350
- Export of RNAs from the nucleus occurs primarily by
a. passive diffusion through nuclear pore complexes.
b. cotranscriptional insertion through nuclear envelope membrane protein pores.
c. selective transport through nuclear pore complexes in association with proteins.
d. release from the nucleus when it breaks down at mitosis.
c. selective transport through nuclear pore complexes in association with proteins.
p. 350
- The nuclear localization signal is recognized by and binds to which protein in the
process of nuclear protein import?
a. Ran
b. Importin
c. Exportin
d. The outer fibril protein
b. Importin
p. 354
- Nuclear localization signals were first identified by Alan Smith and his colleagues in
the protein
a. nucleoplasmin.
b. histone H1.
c. lamin B.
d. SV40 T antigen.
d. SV40 T antigen
p. 353
- The nuclear localization signal is typically a(n) _______, rich in the amino acids
_______.
a. α-helix; Pro, Lys, and Arg
b. α-helix; Leu, Phe, and Gly
c. short chain; Lys and Arg
d. short chain; Phy and Gly
c. short chain; Lys and Arg
Not sure p.352-354
- What localization occurs for proteins that are normally nuclear when their nuclear localization signal is deleted and the protein is injected into the cytoplasm of cultured
cells?
a. Nucleus
b. Cytoplasm
c. In a ring around the outside of the nuclear envelope
d. Extracellular
c. In a ring around the outside of the nuclear envelope
p. 352
- Transport of RNAs out of the nucleus involves all but which of the following?
a. Ran
b. Expenditure of chemical energy
c. Protein translocation signals
d. Small RNAs crossing by passive diffusion
d. Small RNAs crossing by passive diffusion
- snRNAs are synthesized in the
a. nucleus and function in the cytoplasm.
b. cytoplasm and function in the nucleus.
c. nucleus and function in the nucleus without passing into the cytoplasm.
d. nucleus, move to the cytoplasm to pick up proteins to become functional, and then return to the nucleus.
d. nucleus, move to the cytoplasm to pick up proteins to become functional, and then return to the nucleus.
p. 359
- The directionality of nuclear transport is determined by _______ in the nucleus and
_______ in the cytosol.
a. high Ran; low Ran
b. low Ran; high Ran
c. high Ran/GTP; high Ran/GDP
d. high Ran/GDP; high Ran/GTP
c. high Ran/GTP; high Ran/GDP
p. 355
True or False
- The nuclear envelope is composed of a nuclear membrane and an underlying nuclear
lamina.
False