the dna in a cell's nucleus contains
DESCRIPTION
Nucleus Nuclear Envelope Nuclear Chromatin Nucleolus Function: directs proteins synthesis via rRNA,mRNA, tRNATRANSCRIPT
The DNA in a cell's nucleus contains
All the genetic information needed to generate any cell in any
organism All the genetic information needed to generate any cell in
its particular organism Only the genetic information needed to
generate another cell in its particular organ system Only the
genetic information needed to generate another cell of its
particular histologic type, e.g. endothelial cell, squamous cell,
glandular cell, etc Only the genetic information necessary to
regenerate an exact copy of itself Nucleus Nuclear Envelope Nuclear
Chromatin Nucleolus Function:
directs proteins synthesis via rRNA,mRNA, tRNA Nuclei are
basophilic staining.
In H&E, the nuclei appear blue to black, depending upon the
amount of chromatin condensation. Nuclei contain nucleic acids
(DNA, RNA) and stain with basic dyes (such as hematoxylin). Nucleus
Functions: Contains DNA Site of synthesis Messenger RNA
(mRNA)
Transfer RNA (tRNA) Ribosomal RNA (rRNA) Nuclear envelope and
nuclear pore complex Nuclear Lamina Functions: Maintenance of
nuclear shape
Composed of lamins (a group of intermediate filaments) Functions:
Maintenance of nuclear shape Spatial organisation of nuclear pores
within nuclear membrane Regulation of transcription Anchoring of
interphase heterochromatin DNA replication. Nuclear envelope and
nuclear pore complex
Nuclear pores: Site where inner and outer layers fuse to form
circular gaps with a diameter of 70 nm,bridged by a thin protein
diaphragm. Nuclear pores allow some materials andinformation to
pass through the nuclear membrane, such as mRNA and subunits of
ribosomes. Nuclear envelope and nuclear pore complex- Freeze
Etching.
Nuclear pores Transport across nuclear pore complex
Transport across nuclear pore complex dependent on size: Small
molecules pass freely in either direction. Larger molecules pass by
an active process, dependent on protein recognition. The nuclear
membrane is
A single unit membrane Formed from the rough endoplasmic reticulum
after cell division Visible on light microscopy Continuous with the
outer cell membrane Without interruptions along the nuclear surface
The nuclear lamina Extends throughout the cell's nucleus
Is primarily formed from microtubules Supports the chromatin,
nuclear membranes and nuclear pores Is identifiable on light
microscopy Appears only in the region surrounding the nucleolus
Microvesicular transport
Ribosomal proteins and histones synthesized in the cytoplasm have
been demonstrated to be incorporated into ribosomes in the
nucleolus, or utilized within the nucleus, but without nuclear
protein synthesis. Transport of large molecular size materials,
such as these proteins through the nuclear pore complex occurs by
what process Simple diffusion Selective transport Active transport
Passive diffusion Microvesicular transport A mother brings her
7-year-old son to your office because of limited growth, baldness,
and thick wrinkled skin. He has a history of prenatal growth
retardation and the failure to thrive. On physical examination, you
find short stature and low weight for height child with
characteristic plucked-bird" appearance with small face and jaw,
pinched nose, and diffuse signs of accelerated aging, including
hypodontia, hearing loss, hypertension, cardiomyopathy,
lipodistrophy, and atherosclerotic changes on the fundus oculi. His
intelligence is normal.Stem:You conclude the patient has a rare
disease caused by the disturbance in what? DNA repair Nuclear
lamins Lysosomal storage Mitochondrial function DNA damage Disease-
progeria, Sam berns
https://www.youtube.com/watch?v=36m1o-tM05g Disease- progeria, Sam
berns Nucleolus Synthesis of rRNA and its assembly into
ribosome
precursors; cell-cycle regulator proteins The Nucleolus (LM)
Basophilic staining
LM: usually seen near the center of the nucleus Rich in rRNA Rich
in protein More prominent in some cell types(active) than in other
cell types(inactive) The purpose of the nucleolus is to
Synthesize ribosomal subunits Synthesize protein Synthesize DNA
Synthesize messenger RNA Replicate viral DNA Large nucleoli within
a cell's nucleus indicate That the cell is engaged in active
protein synthesis That the cell is malignant That there is an
approximately 50% chance that the cell is malignant That the cell
is engaged in active DNA synthesis The term chromatin refers
to
Nuclear DNA only Nuclear DNA and histone proteins All nuclear
material All nuclear material that stains with basic dyes Complexes
of DNA, histone proteins, and some non-histone proteins Chromatin
Structural manifestation of chromosomes during interphase.
Basophilic, due to high DNA content. Composed of coiled strands of
DNA and 2 types of basic proteins:histones and nonhistones.
Chromatin Nucleosome, the basic structural unit of
chromatin,consists of 4 types of histones (H2A, H2B, H3 and H4) and
166 DNA base pairs that wrap the histones. The DNA segment between
adjacent nucleosomes contains 48 base pairs, and is bound to
histones (H1 or H5). Chromatin Further coiling of chromatin fibres
is responsible for different levels and types of packaging. This
supercoiling is dependent on the non-histone chromosome proteins.
(NHCP) Among the large variety of NHCP are two enzymes which
control the supercoiling are topoisomerase II and topoisimerase I.
Increased euchromatin indicates increased metabolic activity of
cell
Exists in two forms during interphase: Euchromatin: extended
chromatin. lightly basophilic. Genes readily available for
transcription Heterochromatin: Condensed chromatin. Highly
basophilic. 2 types: Constitutive: always condensed Facultative:
sometimes condensed Typically cells have a mixture of both types of
chromatin. Increased euchromatin indicates increased metabolic
activity of cell Chromatin Basophilic. Contains genes and is
responsible
for the synthesis of RNA. Two Types: Heterochromatin: appears as
course granules. Densely stained and inactive. Euchromatin: lightly
stained, visible as an organized structure only under EM. Active.
Chromatin Heterochromatin and euchromatin A Barr body is A
crystalloid lysosomal inclusion
An acidophilic, degenerated hepatocyte An indicator of a patient's
genetic make-up The hallmark of an always-lethal genetic
abnormality Found only in the extracellular space Chromatins are
condensed into chromosomes during mitosis and meiosis. Chromatin A
sex chromatin mass is frequently observed in female cells
due to the inactivation of the second X chromosome, which is
usually inactive and present in clumps.- Barr bodies. A nucleosome
is A DNA packaging unit found only in chromosomes during mitosis A
DNA packaging unit found only in heterochromatin A DNA packaging
unit found only in euchromatin The smallest unit of chromatin A
complex of DNA and transcribed RNA DNA DNA Genetics DNA RNA
Proteins Transcription Translation The cell in the attached
photomicrographic image displayed between the two arrows is best
described as being in what stage of cell division? Interphase
Prophase Metaphase Anaphase Telophase The earliest readily
appreciable event in cell division is
Dissolution of the nuclear membrane Condensation of the chromosomes
Formation of the mitotic spindle Division of the mitochondria
Replication of the centrioles Prophase is characterized by which
event?
Alignment of the chromosomes along the middle of the cell DNA
replication Separation of the chromatids The chromosomes become
visible Re-establishment of the nuclear membrane