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Histology 3 > The Nucleus > Flashcards

The Nucleus Flashcards

1
Q

Which of the following is not included in the functions of Nucleus?
A. Site of DNA replication and transcription
B. Storage for DNA
C. Ribosomal formation
D. Site for translation
E. control of all cell activities

A

D

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2
Q

Which of the following is false?
A. nucleoplasm is nuclear content other than the chromatin and nucleolus.
B. Chromatin, is nuclear material i.e. DNA associated with nuclear proteins
C. Chromatin, is nuclear material containing DNA associated with nuclear proteins
D. nucleolus is a small area within the nucleus that contains DNA in the form of transcriptionally active ribosomal RNA genes, RNA, and proteins.
E. None

A

E

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3
Q 
Which of the following are not acidic?
A. DNA
B. RNA in ribosome
C. RNA in the rough endoplasmic reticulum
D. All except B
E. All Except C
F. None
A

F

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4
Q

True/False
DNA must be highly folded and tightly packed in the cell nucleus because The length of the DNA molecule is 100,000 times longer than the nuclear diameter.

A

True

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5
Q

The high folding and tight packaging of DNA in the cell nucleus is accomplished by the formation of a unique nucleoprotein complex called ……………

A

Chromatin

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6
Q

Further folding of chromatin, such as that which occurs during mitosis, produces structures called ………

A

chromosomes.

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7
Q

What is the difference between hetrochromatin and euchromatin?

A

Heterochromatin is highly condensed chromatin which is densely stained
Euchromatin is a lightly stained material where most transcribed genes are located

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8
Q 
In which of the following cell does Heterochromatin cell predominant?
A. Neuron cell
B. Lymphocytes
C. Sperm Cell
D. liver cell
E. Plasma cell
A

Euchromatin- metabolically active cell -liver and neuron
Heterochromatin -metabolically inactive cell -lymphocytes and sperm
-cell that produce one major product- plasma cell

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9
Q

The smallest units of chromatin structure are macromolecular complexes of DNA and histones called ………..

A

nucleosomes.

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10
Q 
Which of the following is not included in octamers (the eight histone molecules?
A. H1
B. H2A
C. H2B
D. H3
E. H4
A

A

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11
Q

True/False

Three loops of DNA (approximately 146 nucleotide pairs) are wrapped around the core octomer.

A

False

2 loops of DNA

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12
Q

What is barr body?

A

small, dense mass of heterochromatin present in females but not males.

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13
Q

Which of the following is true?
A. Each chromosome is formed by two chromatids that are joined together at a point called the centromere.
B. human cells contain 46 chromosomes organized as 23 homologous pairs.
C. Twenty-two pairs have identical chromosomes and are called autosomes
D. In a karyotype, chromosome pairs are sorted according to their size, shape
E. All

A

E

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14
Q

………….is a nonmembranous region of the nucleus that surrounds transcriptionally active rRNA genes.

A

The nucleolus

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15
Q

Which of the following is not true about the nucleolus?
A. It is the primary site of ribosomal production and assembly.
B. It is well developed in cells active in protein synthesis.
C. The nucleolus stains intensely with hematoxylin and basic dyes and metachromatically with thionine dyes.
D. All cells contain one nucleolus
E. None

A

D

Some cells contain more than one nucleolus.

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16
Q

The nucleolus has three morphologically distinct regions:

what are they?

A
  1. Fibrillar Center
  2. Fibrillar Material (Fibrosa)
  3. Granular Material (granulosa)
17
Q

Which of the following is correctly matched with its function.
A. Fibrillar centers (FC)- contain DNA loops of five different chromosomes that contain rRNA genes, RNA polymerase I, and transcription factors.
B. Granular material- represents the site of initial ribosomal assembly and contains densely packed preribosomal particles.
C. Fibrillar material- contains ribosomal genes that are actively undergoing transcription and large amounts of rRNA.
D. All

A

D

18
Q

The network formed by the granular and the fibrillar materials is called the…….

A

nucleolonema

19
Q

………….is a thin, electron-dense intermediate filament networklike layer, resides underneath the nuclear membrane.

A

Nuclear Lamina

20
Q

Which of the following is not the function of nuclear lamina?
A. Stabilize the nuclear envelope
B. essential in many nuclear activities such as DNA replication, transcription, and gene regulation.
C. has a nucleoskeletal function
D. prevent the import of material into nucleus
E. None

A

D

21
Q

………..forms a selectively permeable barrier between the nuclear and cytoplasmic compartments.

A

The nuclear envelope

22
Q

The space between the inner and outer nuclear membrane is called……..

A

perinuclear space

23
Q

Which of the following is false about the nuclear pore complex?
A. are formed from the merging of the inner and outer membranes of the nuclear envelope.
B. is a cylinder-like structure with eight multidomain protein subunits arranged in an octagonal central framework at the periphery of each pore
C. is composed of about 50 different nuclear pore complex proteins collectively referred to as nucleoporins (Nup proteins)
D. regulates the passage of proteins between the nucleus and the cytoplasm.
E. None

A

E

24
Q

Large molecules (such as large proteins and macromolecular complexes) depend on the presence of an attached signal sequence called ……………… for passage through the pores.

A

the nuclear localization signal (NLS)

25
Q

True/False

The NPC transports proteins, all forms of RNA, as well as ribosomal subunits in their fully folded configurations.

A

True

26
Q

True/False
Ions and smaller water-soluble molecules (less than 9 daltons) may cross the water-filled channels of the NPC by facilitated diffusion.

A

False

they use simple diffusion

27
Q

Which of the not following is true?
A. In late prophase of cell division, enzymes (kinases) are activated that cause phosphorylation of the nuclear lamins and other lamina-associated proteins of the nuclear envelope.
B. Reassembly of the nuclear envelope begins in late metaphase when phosphatases are activated to remove the phosphate residues from the nuclear lamins.
C. During telophase, the nuclear lamins begin to repolymerize and form the nuclear lamina material around each set of daughter chromosomes.
D. None

A

B

Reassembly of the nuclear envelope begins in late anaphase

Histology 3 (4 decks)

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