Chapter 9 Flashcards by Mark Benning

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

The nuclear lamina is built of proteins called

a. lamins.
b. laminins.
c. nucleins.
d. nucleoplasmins.

a. lamins.

p. 347

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

Nuclear pores are organized with _______ symmetry.

a. sixfold
b. eightfold
c. ninefold
d. tenfold

b. eightfold

352

How well did you know this?

Not at all

Perfectly

Small molecules (molecules

a. passive diffusion through nuclear pore complexes.

p. 350

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

True or False

The nuclear envelope is composed of a nuclear membrane and an underlying nuclear
lamina.

False

How well did you know this?

Not at all

Perfectly

True/False

All molecules that are in the nucleus are transported therein via a process that requires
ATP.

Study These Flashcards

False

p. 354

True/False

Small nuclear RNAs are synthesized in the nucleus and function there without ever leaving the nucleus

Study These Flashcards

False

p.359

True/False

The nuclear pore complexes provide the only known routes through which molecules
can travel between the nucleus and the cytoplasm of interphase cells

Study These Flashcards

True

p.350

True/False

Messenger RNAs are transported through the nuclear pores as ribonucleoprotein
particles

Study These Flashcards

False

p.358

(RNAs are transported through the nuclear pore complex as ribonucleoprotein complexes.)

26. The nuclear envelope consists of what three major components?

Nuclear membrane, Nuclear Lamina and Nuclear pore complex

33. Highly condensed, transcriptionally inactive chromatin is called a. euchromatin. b. heterochromatin. c. a chromatin domain. d. histone-containing chromatin.

b. heterochromatin. | p. 359

34. Facultative heterochromatin is heterochromatin that contains a. sequences inactive in one cell type but active in others. b. DNA sequences that are not transcribed in any cell type. c. a mixture of heterochromatin and euchromatin. d. heterochromatin that functions in ways other than for transcription.

a. sequences inactive in one cell type but active in others.

35. Ciliated protozoa have a transcriptionally a. active nucleus that participates in sexual reproduction. b. inactive nucleus that participates in sexual reproduction. c. inactive nucleus that participates in sexual reproduction and a transcriptionally active nucleus that does not participate in sexual reproduction. d. active nucleus that participates in sexual reproduction and a transcriptionally inactive nucleus that does not participate in sexual reproduction.

c. inactive nucleus that participates in sexual reproduction and a transcriptionally active nucleus that does not participate in sexual reproduction.

36. Chromatin that contains sequences that are not transcribed in any cell type is called a. constitutive heterochromatin. b. facultative heterochromatin. c. constitutive euchromatin. d. facultative euchromatin.

a. constitutive heterochromatin. CHECK!!!!!!!!

37. Chromosomes are attached to the nuclear envelope by a. centromeres. b. telomeres. c. origins of replication. d. nuclear lamin genes. e. Both a and b

e. Both a and b | p. 360

38. Chromatin domains are loops of about _______ base pairs of DNA. a. 1000 b. 10,000 c. 100,000 d. 1,000,000

c. 100,000 | p. 361

39. Functional domain loops can be seen by viewing _______ chromosomes with light microscopy. a. normal interphase b. lampbrush c. metaphase d. anaphase

a. normal interphase | p. 361

40. Sites of newly replicated DNA can be detected with antibodies if the DNA is labeled with a. tritiated thymidine. b. tritiated uridine. c. bromodeoxyuridine. d. bromodeoxythymidine.

c. bromodeoxyuridine. | p. 363

41. Newly replicated DNA is located in a few hundred spots in the nucleus because there are a. a few hundred origins of replication per nucleus. b. a few thousand origins of replication but only a few hundred are active at any one time. c. a few thousand origins of replication active at any one time, but they are located in a few hundred discrete clusters. d. None of the above

c. a few thousand origins of replication active at any one time, but they are located in a few hundred discrete clusters. p. 362

42. Cajal bodies are sites of a. RNA transcription. b. RNA processing. c. ribosome assembly. d. DNA replication.

b. RNA processing. | p. 352

True/False 43. Inactive, condensed chromatin is called heterochromatin.

True p.359

True/False 44. Chromatin domains are small units of chromosomes with one promoter, one enhancer, and one coding region.

False p. 361

True/False 45. Individual chromosomes occupy discrete territories within the nucleus.

False p.362

46. The nucleolus is the site where _______ is/are assembled. a. nuclear pores b. ribosomal subunits c. chromatin d. the nuclear matrix

b. ribosomal subunits | p. 365

47. The eukaryotic 45S pre-rRNA transcript codes for the a. 28S rRNA. b. 28S and 18S rRNAs. c. 28S, 18S, and 5.8S rRNAs. d. 28S, 18S, 5.8S, and 5S rRNAs.

c. 28S, 18S, and 5.8S rRNAs. | p. 365

48. The region of chromosomes that codes for most of the rRNAs is called the a. nucleolus. b. nucleolar organizing region. c. ribosomal assembly region. d. ribosomal organizer region.

b. nucleolar organizing region. | p. 787

49. When spread out and viewed with electron microscopy, an active rRNA gene looks like a a. Star of David. b. Christmas tree. c. reindeer. d. Santa Claus.

b. Christmas tree. | p. 367

50. Ribosomes leave the nucleus as a. intact 80S ribosomes. b. intact 70S ribosomes. c. 40S and 60S ribosomal subunits. d. 18S and 28S rRNAs.

c. 40S and 60S ribosomal subunits. | p. 369

51. Splicing of pre-rRNA produces a. the 28S rRNA. b. the 18S rRNA. c. both 28S and 18S rRNAs. d. None of the above

c. both 28S and 18S rRNAs. | p. 367

52. Most snoRNAs function in a. cleaving the 45S rRNA. b. splicing cleaved rRNAs. c. splicing cleaved mRNAs. d. guiding regions of rRNAs to modifying enzymes.

d. guiding regions of rRNAs to modifying enzymes. | p. 368

True/False 53. The nucleolus is the site of rRNA synthesis and processing, and of ribosomal subunit assembly.

True p.365

True/False 54. Ribosomal proteins are synthesized in the nucleolus and then assembled onto rRNAs.

False

True/False 55. Ribosomal RNAs are synthesized as three transcripts, with sizes of 28S, 18S, and 5.8S.

Fasle p.365

True/False 56. The eukaryotic large ribosomal many different proteins.

True p.365

True/False 57. Most proteins destined to become nuclear proteins are synthesized on the membrane-attached polysomes on the outer nuclear membrane.

False p.368

True/False 58. The snoRNP particles contain RNA sequences complementary to rRNA sequences.

False p.368

Chapter 9 Flashcards

(51 cards)